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Diffstat (limited to 'kernel/trace/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 10645 |
1 files changed, 10645 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c new file mode 100644 index 0000000000..fc00356a5a --- /dev/null +++ b/kernel/trace/trace.c @@ -0,0 +1,10645 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * ring buffer based function tracer + * + * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com> + * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com> + * + * Originally taken from the RT patch by: + * Arnaldo Carvalho de Melo <acme@redhat.com> + * + * Based on code from the latency_tracer, that is: + * Copyright (C) 2004-2006 Ingo Molnar + * Copyright (C) 2004 Nadia Yvette Chambers + */ +#include <linux/ring_buffer.h> +#include <generated/utsrelease.h> +#include <linux/stacktrace.h> +#include <linux/writeback.h> +#include <linux/kallsyms.h> +#include <linux/security.h> +#include <linux/seq_file.h> +#include <linux/irqflags.h> +#include <linux/debugfs.h> +#include <linux/tracefs.h> +#include <linux/pagemap.h> +#include <linux/hardirq.h> +#include <linux/linkage.h> +#include <linux/uaccess.h> +#include <linux/vmalloc.h> +#include <linux/ftrace.h> +#include <linux/module.h> +#include <linux/percpu.h> +#include <linux/splice.h> +#include <linux/kdebug.h> +#include <linux/string.h> +#include <linux/mount.h> +#include <linux/rwsem.h> +#include <linux/slab.h> +#include <linux/ctype.h> +#include <linux/init.h> +#include <linux/panic_notifier.h> +#include <linux/poll.h> +#include <linux/nmi.h> +#include <linux/fs.h> +#include <linux/trace.h> +#include <linux/sched/clock.h> +#include <linux/sched/rt.h> +#include <linux/fsnotify.h> +#include <linux/irq_work.h> +#include <linux/workqueue.h> + +#include <asm/setup.h> /* COMMAND_LINE_SIZE */ + +#include "trace.h" +#include "trace_output.h" + +/* + * On boot up, the ring buffer is set to the minimum size, so that + * we do not waste memory on systems that are not using tracing. + */ +bool ring_buffer_expanded; + +#ifdef CONFIG_FTRACE_STARTUP_TEST +/* + * We need to change this state when a selftest is running. + * A selftest will lurk into the ring-buffer to count the + * entries inserted during the selftest although some concurrent + * insertions into the ring-buffer such as trace_printk could occurred + * at the same time, giving false positive or negative results. + */ +static bool __read_mostly tracing_selftest_running; + +/* + * If boot-time tracing including tracers/events via kernel cmdline + * is running, we do not want to run SELFTEST. + */ +bool __read_mostly tracing_selftest_disabled; + +void __init disable_tracing_selftest(const char *reason) +{ + if (!tracing_selftest_disabled) { + tracing_selftest_disabled = true; + pr_info("Ftrace startup test is disabled due to %s\n", reason); + } +} +#else +#define tracing_selftest_running 0 +#define tracing_selftest_disabled 0 +#endif + +/* Pipe tracepoints to printk */ +static struct trace_iterator *tracepoint_print_iter; +int tracepoint_printk; +static bool tracepoint_printk_stop_on_boot __initdata; +static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key); + +/* For tracers that don't implement custom flags */ +static struct tracer_opt dummy_tracer_opt[] = { + { } +}; + +static int +dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) +{ + return 0; +} + +/* + * To prevent the comm cache from being overwritten when no + * tracing is active, only save the comm when a trace event + * occurred. + */ +static DEFINE_PER_CPU(bool, trace_taskinfo_save); + +/* + * Kill all tracing for good (never come back). + * It is initialized to 1 but will turn to zero if the initialization + * of the tracer is successful. But that is the only place that sets + * this back to zero. + */ +static int tracing_disabled = 1; + +cpumask_var_t __read_mostly tracing_buffer_mask; + +/* + * ftrace_dump_on_oops - variable to dump ftrace buffer on oops + * + * If there is an oops (or kernel panic) and the ftrace_dump_on_oops + * is set, then ftrace_dump is called. This will output the contents + * of the ftrace buffers to the console. This is very useful for + * capturing traces that lead to crashes and outputing it to a + * serial console. + * + * It is default off, but you can enable it with either specifying + * "ftrace_dump_on_oops" in the kernel command line, or setting + * /proc/sys/kernel/ftrace_dump_on_oops + * Set 1 if you want to dump buffers of all CPUs + * Set 2 if you want to dump the buffer of the CPU that triggered oops + */ + +enum ftrace_dump_mode ftrace_dump_on_oops; + +/* When set, tracing will stop when a WARN*() is hit */ +int __disable_trace_on_warning; + +#ifdef CONFIG_TRACE_EVAL_MAP_FILE +/* Map of enums to their values, for "eval_map" file */ +struct trace_eval_map_head { + struct module *mod; + unsigned long length; +}; + +union trace_eval_map_item; + +struct trace_eval_map_tail { + /* + * "end" is first and points to NULL as it must be different + * than "mod" or "eval_string" + */ + union trace_eval_map_item *next; + const char *end; /* points to NULL */ +}; + +static DEFINE_MUTEX(trace_eval_mutex); + +/* + * The trace_eval_maps are saved in an array with two extra elements, + * one at the beginning, and one at the end. The beginning item contains + * the count of the saved maps (head.length), and the module they + * belong to if not built in (head.mod). The ending item contains a + * pointer to the next array of saved eval_map items. + */ +union trace_eval_map_item { + struct trace_eval_map map; + struct trace_eval_map_head head; + struct trace_eval_map_tail tail; +}; + +static union trace_eval_map_item *trace_eval_maps; +#endif /* CONFIG_TRACE_EVAL_MAP_FILE */ + +int tracing_set_tracer(struct trace_array *tr, const char *buf); +static void ftrace_trace_userstack(struct trace_array *tr, + struct trace_buffer *buffer, + unsigned int trace_ctx); + +#define MAX_TRACER_SIZE 100 +static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata; +static char *default_bootup_tracer; + +static bool allocate_snapshot; +static bool snapshot_at_boot; + +static char boot_instance_info[COMMAND_LINE_SIZE] __initdata; +static int boot_instance_index; + +static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata; +static int boot_snapshot_index; + +static int __init set_cmdline_ftrace(char *str) +{ + strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE); + default_bootup_tracer = bootup_tracer_buf; + /* We are using ftrace early, expand it */ + ring_buffer_expanded = true; + return 1; +} +__setup("ftrace=", set_cmdline_ftrace); + +static int __init set_ftrace_dump_on_oops(char *str) +{ + if (*str++ != '=' || !*str || !strcmp("1", str)) { + ftrace_dump_on_oops = DUMP_ALL; + return 1; + } + + if (!strcmp("orig_cpu", str) || !strcmp("2", str)) { + ftrace_dump_on_oops = DUMP_ORIG; + return 1; + } + + return 0; +} +__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops); + +static int __init stop_trace_on_warning(char *str) +{ + if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0)) + __disable_trace_on_warning = 1; + return 1; +} +__setup("traceoff_on_warning", stop_trace_on_warning); + +static int __init boot_alloc_snapshot(char *str) +{ + char *slot = boot_snapshot_info + boot_snapshot_index; + int left = sizeof(boot_snapshot_info) - boot_snapshot_index; + int ret; + + if (str[0] == '=') { + str++; + if (strlen(str) >= left) + return -1; + + ret = snprintf(slot, left, "%s\t", str); + boot_snapshot_index += ret; + } else { + allocate_snapshot = true; + /* We also need the main ring buffer expanded */ + ring_buffer_expanded = true; + } + return 1; +} +__setup("alloc_snapshot", boot_alloc_snapshot); + + +static int __init boot_snapshot(char *str) +{ + snapshot_at_boot = true; + boot_alloc_snapshot(str); + return 1; +} +__setup("ftrace_boot_snapshot", boot_snapshot); + + +static int __init boot_instance(char *str) +{ + char *slot = boot_instance_info + boot_instance_index; + int left = sizeof(boot_instance_info) - boot_instance_index; + int ret; + + if (strlen(str) >= left) + return -1; + + ret = snprintf(slot, left, "%s\t", str); + boot_instance_index += ret; + + return 1; +} +__setup("trace_instance=", boot_instance); + + +static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata; + +static int __init set_trace_boot_options(char *str) +{ + strscpy(trace_boot_options_buf, str, MAX_TRACER_SIZE); + return 1; +} +__setup("trace_options=", set_trace_boot_options); + +static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata; +static char *trace_boot_clock __initdata; + +static int __init set_trace_boot_clock(char *str) +{ + strscpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE); + trace_boot_clock = trace_boot_clock_buf; + return 1; +} +__setup("trace_clock=", set_trace_boot_clock); + +static int __init set_tracepoint_printk(char *str) +{ + /* Ignore the "tp_printk_stop_on_boot" param */ + if (*str == '_') + return 0; + + if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0)) + tracepoint_printk = 1; + return 1; +} +__setup("tp_printk", set_tracepoint_printk); + +static int __init set_tracepoint_printk_stop(char *str) +{ + tracepoint_printk_stop_on_boot = true; + return 1; +} +__setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop); + +unsigned long long ns2usecs(u64 nsec) +{ + nsec += 500; + do_div(nsec, 1000); + return nsec; +} + +static void +trace_process_export(struct trace_export *export, + struct ring_buffer_event *event, int flag) +{ + struct trace_entry *entry; + unsigned int size = 0; + + if (export->flags & flag) { + entry = ring_buffer_event_data(event); + size = ring_buffer_event_length(event); + export->write(export, entry, size); + } +} + +static DEFINE_MUTEX(ftrace_export_lock); + +static struct trace_export __rcu *ftrace_exports_list __read_mostly; + +static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled); +static DEFINE_STATIC_KEY_FALSE(trace_event_exports_enabled); +static DEFINE_STATIC_KEY_FALSE(trace_marker_exports_enabled); + +static inline void ftrace_exports_enable(struct trace_export *export) +{ + if (export->flags & TRACE_EXPORT_FUNCTION) + static_branch_inc(&trace_function_exports_enabled); + + if (export->flags & TRACE_EXPORT_EVENT) + static_branch_inc(&trace_event_exports_enabled); + + if (export->flags & TRACE_EXPORT_MARKER) + static_branch_inc(&trace_marker_exports_enabled); +} + +static inline void ftrace_exports_disable(struct trace_export *export) +{ + if (export->flags & TRACE_EXPORT_FUNCTION) + static_branch_dec(&trace_function_exports_enabled); + + if (export->flags & TRACE_EXPORT_EVENT) + static_branch_dec(&trace_event_exports_enabled); + + if (export->flags & TRACE_EXPORT_MARKER) + static_branch_dec(&trace_marker_exports_enabled); +} + +static void ftrace_exports(struct ring_buffer_event *event, int flag) +{ + struct trace_export *export; + + preempt_disable_notrace(); + + export = rcu_dereference_raw_check(ftrace_exports_list); + while (export) { + trace_process_export(export, event, flag); + export = rcu_dereference_raw_check(export->next); + } + + preempt_enable_notrace(); +} + +static inline void +add_trace_export(struct trace_export **list, struct trace_export *export) +{ + rcu_assign_pointer(export->next, *list); + /* + * We are entering export into the list but another + * CPU might be walking that list. We need to make sure + * the export->next pointer is valid before another CPU sees + * the export pointer included into the list. + */ + rcu_assign_pointer(*list, export); +} + +static inline int +rm_trace_export(struct trace_export **list, struct trace_export *export) +{ + struct trace_export **p; + + for (p = list; *p != NULL; p = &(*p)->next) + if (*p == export) + break; + + if (*p != export) + return -1; + + rcu_assign_pointer(*p, (*p)->next); + + return 0; +} + +static inline void +add_ftrace_export(struct trace_export **list, struct trace_export *export) +{ + ftrace_exports_enable(export); + + add_trace_export(list, export); +} + +static inline int +rm_ftrace_export(struct trace_export **list, struct trace_export *export) +{ + int ret; + + ret = rm_trace_export(list, export); + ftrace_exports_disable(export); + + return ret; +} + +int register_ftrace_export(struct trace_export *export) +{ + if (WARN_ON_ONCE(!export->write)) + return -1; + + mutex_lock(&ftrace_export_lock); + + add_ftrace_export(&ftrace_exports_list, export); + + mutex_unlock(&ftrace_export_lock); + + return 0; +} +EXPORT_SYMBOL_GPL(register_ftrace_export); + +int unregister_ftrace_export(struct trace_export *export) +{ + int ret; + + mutex_lock(&ftrace_export_lock); + + ret = rm_ftrace_export(&ftrace_exports_list, export); + + mutex_unlock(&ftrace_export_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(unregister_ftrace_export); + +/* trace_flags holds trace_options default values */ +#define TRACE_DEFAULT_FLAGS \ + (FUNCTION_DEFAULT_FLAGS | \ + TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \ + TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \ + TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \ + TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | \ + TRACE_ITER_HASH_PTR) + +/* trace_options that are only supported by global_trace */ +#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \ + TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD) + +/* trace_flags that are default zero for instances */ +#define ZEROED_TRACE_FLAGS \ + (TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK) + +/* + * The global_trace is the descriptor that holds the top-level tracing + * buffers for the live tracing. + */ +static struct trace_array global_trace = { + .trace_flags = TRACE_DEFAULT_FLAGS, +}; + +LIST_HEAD(ftrace_trace_arrays); + +int trace_array_get(struct trace_array *this_tr) +{ + struct trace_array *tr; + int ret = -ENODEV; + + mutex_lock(&trace_types_lock); + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (tr == this_tr) { + tr->ref++; + ret = 0; + break; + } + } + mutex_unlock(&trace_types_lock); + + return ret; +} + +static void __trace_array_put(struct trace_array *this_tr) +{ + WARN_ON(!this_tr->ref); + this_tr->ref--; +} + +/** + * trace_array_put - Decrement the reference counter for this trace array. + * @this_tr : pointer to the trace array + * + * NOTE: Use this when we no longer need the trace array returned by + * trace_array_get_by_name(). This ensures the trace array can be later + * destroyed. + * + */ +void trace_array_put(struct trace_array *this_tr) +{ + if (!this_tr) + return; + + mutex_lock(&trace_types_lock); + __trace_array_put(this_tr); + mutex_unlock(&trace_types_lock); +} +EXPORT_SYMBOL_GPL(trace_array_put); + +int tracing_check_open_get_tr(struct trace_array *tr) +{ + int ret; + + ret = security_locked_down(LOCKDOWN_TRACEFS); + if (ret) + return ret; + + if (tracing_disabled) + return -ENODEV; + + if (tr && trace_array_get(tr) < 0) + return -ENODEV; + + return 0; +} + +int call_filter_check_discard(struct trace_event_call *call, void *rec, + struct trace_buffer *buffer, + struct ring_buffer_event *event) +{ + if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) && + !filter_match_preds(call->filter, rec)) { + __trace_event_discard_commit(buffer, event); + return 1; + } + + return 0; +} + +/** + * trace_find_filtered_pid - check if a pid exists in a filtered_pid list + * @filtered_pids: The list of pids to check + * @search_pid: The PID to find in @filtered_pids + * + * Returns true if @search_pid is found in @filtered_pids, and false otherwise. + */ +bool +trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid) +{ + return trace_pid_list_is_set(filtered_pids, search_pid); +} + +/** + * trace_ignore_this_task - should a task be ignored for tracing + * @filtered_pids: The list of pids to check + * @filtered_no_pids: The list of pids not to be traced + * @task: The task that should be ignored if not filtered + * + * Checks if @task should be traced or not from @filtered_pids. + * Returns true if @task should *NOT* be traced. + * Returns false if @task should be traced. + */ +bool +trace_ignore_this_task(struct trace_pid_list *filtered_pids, + struct trace_pid_list *filtered_no_pids, + struct task_struct *task) +{ + /* + * If filtered_no_pids is not empty, and the task's pid is listed + * in filtered_no_pids, then return true. + * Otherwise, if filtered_pids is empty, that means we can + * trace all tasks. If it has content, then only trace pids + * within filtered_pids. + */ + + return (filtered_pids && + !trace_find_filtered_pid(filtered_pids, task->pid)) || + (filtered_no_pids && + trace_find_filtered_pid(filtered_no_pids, task->pid)); +} + +/** + * trace_filter_add_remove_task - Add or remove a task from a pid_list + * @pid_list: The list to modify + * @self: The current task for fork or NULL for exit + * @task: The task to add or remove + * + * If adding a task, if @self is defined, the task is only added if @self + * is also included in @pid_list. This happens on fork and tasks should + * only be added when the parent is listed. If @self is NULL, then the + * @task pid will be removed from the list, which would happen on exit + * of a task. + */ +void trace_filter_add_remove_task(struct trace_pid_list *pid_list, + struct task_struct *self, + struct task_struct *task) +{ + if (!pid_list) + return; + + /* For forks, we only add if the forking task is listed */ + if (self) { + if (!trace_find_filtered_pid(pid_list, self->pid)) + return; + } + + /* "self" is set for forks, and NULL for exits */ + if (self) + trace_pid_list_set(pid_list, task->pid); + else + trace_pid_list_clear(pid_list, task->pid); +} + +/** + * trace_pid_next - Used for seq_file to get to the next pid of a pid_list + * @pid_list: The pid list to show + * @v: The last pid that was shown (+1 the actual pid to let zero be displayed) + * @pos: The position of the file + * + * This is used by the seq_file "next" operation to iterate the pids + * listed in a trace_pid_list structure. + * + * Returns the pid+1 as we want to display pid of zero, but NULL would + * stop the iteration. + */ +void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos) +{ + long pid = (unsigned long)v; + unsigned int next; + + (*pos)++; + + /* pid already is +1 of the actual previous bit */ + if (trace_pid_list_next(pid_list, pid, &next) < 0) + return NULL; + + pid = next; + + /* Return pid + 1 to allow zero to be represented */ + return (void *)(pid + 1); +} + +/** + * trace_pid_start - Used for seq_file to start reading pid lists + * @pid_list: The pid list to show + * @pos: The position of the file + * + * This is used by seq_file "start" operation to start the iteration + * of listing pids. + * + * Returns the pid+1 as we want to display pid of zero, but NULL would + * stop the iteration. + */ +void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos) +{ + unsigned long pid; + unsigned int first; + loff_t l = 0; + + if (trace_pid_list_first(pid_list, &first) < 0) + return NULL; + + pid = first; + + /* Return pid + 1 so that zero can be the exit value */ + for (pid++; pid && l < *pos; + pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l)) + ; + return (void *)pid; +} + +/** + * trace_pid_show - show the current pid in seq_file processing + * @m: The seq_file structure to write into + * @v: A void pointer of the pid (+1) value to display + * + * Can be directly used by seq_file operations to display the current + * pid value. + */ +int trace_pid_show(struct seq_file *m, void *v) +{ + unsigned long pid = (unsigned long)v - 1; + + seq_printf(m, "%lu\n", pid); + return 0; +} + +/* 128 should be much more than enough */ +#define PID_BUF_SIZE 127 + +int trace_pid_write(struct trace_pid_list *filtered_pids, + struct trace_pid_list **new_pid_list, + const char __user *ubuf, size_t cnt) +{ + struct trace_pid_list *pid_list; + struct trace_parser parser; + unsigned long val; + int nr_pids = 0; + ssize_t read = 0; + ssize_t ret; + loff_t pos; + pid_t pid; + + if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1)) + return -ENOMEM; + + /* + * Always recreate a new array. The write is an all or nothing + * operation. Always create a new array when adding new pids by + * the user. If the operation fails, then the current list is + * not modified. + */ + pid_list = trace_pid_list_alloc(); + if (!pid_list) { + trace_parser_put(&parser); + return -ENOMEM; + } + + if (filtered_pids) { + /* copy the current bits to the new max */ + ret = trace_pid_list_first(filtered_pids, &pid); + while (!ret) { + trace_pid_list_set(pid_list, pid); + ret = trace_pid_list_next(filtered_pids, pid + 1, &pid); + nr_pids++; + } + } + + ret = 0; + while (cnt > 0) { + + pos = 0; + + ret = trace_get_user(&parser, ubuf, cnt, &pos); + if (ret < 0) + break; + + read += ret; + ubuf += ret; + cnt -= ret; + + if (!trace_parser_loaded(&parser)) + break; + + ret = -EINVAL; + if (kstrtoul(parser.buffer, 0, &val)) + break; + + pid = (pid_t)val; + + if (trace_pid_list_set(pid_list, pid) < 0) { + ret = -1; + break; + } + nr_pids++; + + trace_parser_clear(&parser); + ret = 0; + } + trace_parser_put(&parser); + + if (ret < 0) { + trace_pid_list_free(pid_list); + return ret; + } + + if (!nr_pids) { + /* Cleared the list of pids */ + trace_pid_list_free(pid_list); + pid_list = NULL; + } + + *new_pid_list = pid_list; + + return read; +} + +static u64 buffer_ftrace_now(struct array_buffer *buf, int cpu) +{ + u64 ts; + + /* Early boot up does not have a buffer yet */ + if (!buf->buffer) + return trace_clock_local(); + + ts = ring_buffer_time_stamp(buf->buffer); + ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts); + + return ts; +} + +u64 ftrace_now(int cpu) +{ + return buffer_ftrace_now(&global_trace.array_buffer, cpu); +} + +/** + * tracing_is_enabled - Show if global_trace has been enabled + * + * Shows if the global trace has been enabled or not. It uses the + * mirror flag "buffer_disabled" to be used in fast paths such as for + * the irqsoff tracer. But it may be inaccurate due to races. If you + * need to know the accurate state, use tracing_is_on() which is a little + * slower, but accurate. + */ +int tracing_is_enabled(void) +{ + /* + * For quick access (irqsoff uses this in fast path), just + * return the mirror variable of the state of the ring buffer. + * It's a little racy, but we don't really care. + */ + smp_rmb(); + return !global_trace.buffer_disabled; +} + +/* + * trace_buf_size is the size in bytes that is allocated + * for a buffer. Note, the number of bytes is always rounded + * to page size. + * + * This number is purposely set to a low number of 16384. + * If the dump on oops happens, it will be much appreciated + * to not have to wait for all that output. Anyway this can be + * boot time and run time configurable. + */ +#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */ + +static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT; + +/* trace_types holds a link list of available tracers. */ +static struct tracer *trace_types __read_mostly; + +/* + * trace_types_lock is used to protect the trace_types list. + */ +DEFINE_MUTEX(trace_types_lock); + +/* + * serialize the access of the ring buffer + * + * ring buffer serializes readers, but it is low level protection. + * The validity of the events (which returns by ring_buffer_peek() ..etc) + * are not protected by ring buffer. + * + * The content of events may become garbage if we allow other process consumes + * these events concurrently: + * A) the page of the consumed events may become a normal page + * (not reader page) in ring buffer, and this page will be rewritten + * by events producer. + * B) The page of the consumed events may become a page for splice_read, + * and this page will be returned to system. + * + * These primitives allow multi process access to different cpu ring buffer + * concurrently. + * + * These primitives don't distinguish read-only and read-consume access. + * Multi read-only access are also serialized. + */ + +#ifdef CONFIG_SMP +static DECLARE_RWSEM(all_cpu_access_lock); +static DEFINE_PER_CPU(struct mutex, cpu_access_lock); + +static inline void trace_access_lock(int cpu) +{ + if (cpu == RING_BUFFER_ALL_CPUS) { + /* gain it for accessing the whole ring buffer. */ + down_write(&all_cpu_access_lock); + } else { + /* gain it for accessing a cpu ring buffer. */ + + /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */ + down_read(&all_cpu_access_lock); + + /* Secondly block other access to this @cpu ring buffer. */ + mutex_lock(&per_cpu(cpu_access_lock, cpu)); + } +} + +static inline void trace_access_unlock(int cpu) +{ + if (cpu == RING_BUFFER_ALL_CPUS) { + up_write(&all_cpu_access_lock); + } else { + mutex_unlock(&per_cpu(cpu_access_lock, cpu)); + up_read(&all_cpu_access_lock); + } +} + +static inline void trace_access_lock_init(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + mutex_init(&per_cpu(cpu_access_lock, cpu)); +} + +#else + +static DEFINE_MUTEX(access_lock); + +static inline void trace_access_lock(int cpu) +{ + (void)cpu; + mutex_lock(&access_lock); +} + +static inline void trace_access_unlock(int cpu) +{ + (void)cpu; + mutex_unlock(&access_lock); +} + +static inline void trace_access_lock_init(void) +{ +} + +#endif + +#ifdef CONFIG_STACKTRACE +static void __ftrace_trace_stack(struct trace_buffer *buffer, + unsigned int trace_ctx, + int skip, struct pt_regs *regs); +static inline void ftrace_trace_stack(struct trace_array *tr, + struct trace_buffer *buffer, + unsigned int trace_ctx, + int skip, struct pt_regs *regs); + +#else +static inline void __ftrace_trace_stack(struct trace_buffer *buffer, + unsigned int trace_ctx, + int skip, struct pt_regs *regs) +{ +} +static inline void ftrace_trace_stack(struct trace_array *tr, + struct trace_buffer *buffer, + unsigned long trace_ctx, + int skip, struct pt_regs *regs) +{ +} + +#endif + +static __always_inline void +trace_event_setup(struct ring_buffer_event *event, + int type, unsigned int trace_ctx) +{ + struct trace_entry *ent = ring_buffer_event_data(event); + + tracing_generic_entry_update(ent, type, trace_ctx); +} + +static __always_inline struct ring_buffer_event * +__trace_buffer_lock_reserve(struct trace_buffer *buffer, + int type, + unsigned long len, + unsigned int trace_ctx) +{ + struct ring_buffer_event *event; + + event = ring_buffer_lock_reserve(buffer, len); + if (event != NULL) + trace_event_setup(event, type, trace_ctx); + + return event; +} + +void tracer_tracing_on(struct trace_array *tr) +{ + if (tr->array_buffer.buffer) + ring_buffer_record_on(tr->array_buffer.buffer); + /* + * This flag is looked at when buffers haven't been allocated + * yet, or by some tracers (like irqsoff), that just want to + * know if the ring buffer has been disabled, but it can handle + * races of where it gets disabled but we still do a record. + * As the check is in the fast path of the tracers, it is more + * important to be fast than accurate. + */ + tr->buffer_disabled = 0; + /* Make the flag seen by readers */ + smp_wmb(); +} + +/** + * tracing_on - enable tracing buffers + * + * This function enables tracing buffers that may have been + * disabled with tracing_off. + */ +void tracing_on(void) +{ + tracer_tracing_on(&global_trace); +} +EXPORT_SYMBOL_GPL(tracing_on); + + +static __always_inline void +__buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *event) +{ + __this_cpu_write(trace_taskinfo_save, true); + + /* If this is the temp buffer, we need to commit fully */ + if (this_cpu_read(trace_buffered_event) == event) { + /* Length is in event->array[0] */ + ring_buffer_write(buffer, event->array[0], &event->array[1]); + /* Release the temp buffer */ + this_cpu_dec(trace_buffered_event_cnt); + /* ring_buffer_unlock_commit() enables preemption */ + preempt_enable_notrace(); + } else + ring_buffer_unlock_commit(buffer); +} + +int __trace_array_puts(struct trace_array *tr, unsigned long ip, + const char *str, int size) +{ + struct ring_buffer_event *event; + struct trace_buffer *buffer; + struct print_entry *entry; + unsigned int trace_ctx; + int alloc; + + if (!(tr->trace_flags & TRACE_ITER_PRINTK)) + return 0; + + if (unlikely(tracing_selftest_running && tr == &global_trace)) + return 0; + + if (unlikely(tracing_disabled)) + return 0; + + alloc = sizeof(*entry) + size + 2; /* possible \n added */ + + trace_ctx = tracing_gen_ctx(); + buffer = tr->array_buffer.buffer; + ring_buffer_nest_start(buffer); + event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, + trace_ctx); + if (!event) { + size = 0; + goto out; + } + + entry = ring_buffer_event_data(event); + entry->ip = ip; + + memcpy(&entry->buf, str, size); + + /* Add a newline if necessary */ + if (entry->buf[size - 1] != '\n') { + entry->buf[size] = '\n'; + entry->buf[size + 1] = '\0'; + } else + entry->buf[size] = '\0'; + + __buffer_unlock_commit(buffer, event); + ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL); + out: + ring_buffer_nest_end(buffer); + return size; +} +EXPORT_SYMBOL_GPL(__trace_array_puts); + +/** + * __trace_puts - write a constant string into the trace buffer. + * @ip: The address of the caller + * @str: The constant string to write + * @size: The size of the string. + */ +int __trace_puts(unsigned long ip, const char *str, int size) +{ + return __trace_array_puts(&global_trace, ip, str, size); +} +EXPORT_SYMBOL_GPL(__trace_puts); + +/** + * __trace_bputs - write the pointer to a constant string into trace buffer + * @ip: The address of the caller + * @str: The constant string to write to the buffer to + */ +int __trace_bputs(unsigned long ip, const char *str) +{ + struct ring_buffer_event *event; + struct trace_buffer *buffer; + struct bputs_entry *entry; + unsigned int trace_ctx; + int size = sizeof(struct bputs_entry); + int ret = 0; + + if (!(global_trace.trace_flags & TRACE_ITER_PRINTK)) + return 0; + + if (unlikely(tracing_selftest_running || tracing_disabled)) + return 0; + + trace_ctx = tracing_gen_ctx(); + buffer = global_trace.array_buffer.buffer; + + ring_buffer_nest_start(buffer); + event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size, + trace_ctx); + if (!event) + goto out; + + entry = ring_buffer_event_data(event); + entry->ip = ip; + entry->str = str; + + __buffer_unlock_commit(buffer, event); + ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL); + + ret = 1; + out: + ring_buffer_nest_end(buffer); + return ret; +} +EXPORT_SYMBOL_GPL(__trace_bputs); + +#ifdef CONFIG_TRACER_SNAPSHOT +static void tracing_snapshot_instance_cond(struct trace_array *tr, + void *cond_data) +{ + struct tracer *tracer = tr->current_trace; + unsigned long flags; + + if (in_nmi()) { + trace_array_puts(tr, "*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n"); + trace_array_puts(tr, "*** snapshot is being ignored ***\n"); + return; + } + + if (!tr->allocated_snapshot) { + trace_array_puts(tr, "*** SNAPSHOT NOT ALLOCATED ***\n"); + trace_array_puts(tr, "*** stopping trace here! ***\n"); + tracer_tracing_off(tr); + return; + } + + /* Note, snapshot can not be used when the tracer uses it */ + if (tracer->use_max_tr) { + trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n"); + trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n"); + return; + } + + local_irq_save(flags); + update_max_tr(tr, current, smp_processor_id(), cond_data); + local_irq_restore(flags); +} + +void tracing_snapshot_instance(struct trace_array *tr) +{ + tracing_snapshot_instance_cond(tr, NULL); +} + +/** + * tracing_snapshot - take a snapshot of the current buffer. + * + * This causes a swap between the snapshot buffer and the current live + * tracing buffer. You can use this to take snapshots of the live + * trace when some condition is triggered, but continue to trace. + * + * Note, make sure to allocate the snapshot with either + * a tracing_snapshot_alloc(), or by doing it manually + * with: echo 1 > /sys/kernel/tracing/snapshot + * + * If the snapshot buffer is not allocated, it will stop tracing. + * Basically making a permanent snapshot. + */ +void tracing_snapshot(void) +{ + struct trace_array *tr = &global_trace; + + tracing_snapshot_instance(tr); +} +EXPORT_SYMBOL_GPL(tracing_snapshot); + +/** + * tracing_snapshot_cond - conditionally take a snapshot of the current buffer. + * @tr: The tracing instance to snapshot + * @cond_data: The data to be tested conditionally, and possibly saved + * + * This is the same as tracing_snapshot() except that the snapshot is + * conditional - the snapshot will only happen if the + * cond_snapshot.update() implementation receiving the cond_data + * returns true, which means that the trace array's cond_snapshot + * update() operation used the cond_data to determine whether the + * snapshot should be taken, and if it was, presumably saved it along + * with the snapshot. + */ +void tracing_snapshot_cond(struct trace_array *tr, void *cond_data) +{ + tracing_snapshot_instance_cond(tr, cond_data); +} +EXPORT_SYMBOL_GPL(tracing_snapshot_cond); + +/** + * tracing_cond_snapshot_data - get the user data associated with a snapshot + * @tr: The tracing instance + * + * When the user enables a conditional snapshot using + * tracing_snapshot_cond_enable(), the user-defined cond_data is saved + * with the snapshot. This accessor is used to retrieve it. + * + * Should not be called from cond_snapshot.update(), since it takes + * the tr->max_lock lock, which the code calling + * cond_snapshot.update() has already done. + * + * Returns the cond_data associated with the trace array's snapshot. + */ +void *tracing_cond_snapshot_data(struct trace_array *tr) +{ + void *cond_data = NULL; + + local_irq_disable(); + arch_spin_lock(&tr->max_lock); + + if (tr->cond_snapshot) + cond_data = tr->cond_snapshot->cond_data; + + arch_spin_unlock(&tr->max_lock); + local_irq_enable(); + + return cond_data; +} +EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data); + +static int resize_buffer_duplicate_size(struct array_buffer *trace_buf, + struct array_buffer *size_buf, int cpu_id); +static void set_buffer_entries(struct array_buffer *buf, unsigned long val); + +int tracing_alloc_snapshot_instance(struct trace_array *tr) +{ + int ret; + + if (!tr->allocated_snapshot) { + + /* allocate spare buffer */ + ret = resize_buffer_duplicate_size(&tr->max_buffer, + &tr->array_buffer, RING_BUFFER_ALL_CPUS); + if (ret < 0) + return ret; + + tr->allocated_snapshot = true; + } + + return 0; +} + +static void free_snapshot(struct trace_array *tr) +{ + /* + * We don't free the ring buffer. instead, resize it because + * The max_tr ring buffer has some state (e.g. ring->clock) and + * we want preserve it. + */ + ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS); + set_buffer_entries(&tr->max_buffer, 1); + tracing_reset_online_cpus(&tr->max_buffer); + tr->allocated_snapshot = false; +} + +/** + * tracing_alloc_snapshot - allocate snapshot buffer. + * + * This only allocates the snapshot buffer if it isn't already + * allocated - it doesn't also take a snapshot. + * + * This is meant to be used in cases where the snapshot buffer needs + * to be set up for events that can't sleep but need to be able to + * trigger a snapshot. + */ +int tracing_alloc_snapshot(void) +{ + struct trace_array *tr = &global_trace; + int ret; + + ret = tracing_alloc_snapshot_instance(tr); + WARN_ON(ret < 0); + + return ret; +} +EXPORT_SYMBOL_GPL(tracing_alloc_snapshot); + +/** + * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer. + * + * This is similar to tracing_snapshot(), but it will allocate the + * snapshot buffer if it isn't already allocated. Use this only + * where it is safe to sleep, as the allocation may sleep. + * + * This causes a swap between the snapshot buffer and the current live + * tracing buffer. You can use this to take snapshots of the live + * trace when some condition is triggered, but continue to trace. + */ +void tracing_snapshot_alloc(void) +{ + int ret; + + ret = tracing_alloc_snapshot(); + if (ret < 0) + return; + + tracing_snapshot(); +} +EXPORT_SYMBOL_GPL(tracing_snapshot_alloc); + +/** + * tracing_snapshot_cond_enable - enable conditional snapshot for an instance + * @tr: The tracing instance + * @cond_data: User data to associate with the snapshot + * @update: Implementation of the cond_snapshot update function + * + * Check whether the conditional snapshot for the given instance has + * already been enabled, or if the current tracer is already using a + * snapshot; if so, return -EBUSY, else create a cond_snapshot and + * save the cond_data and update function inside. + * + * Returns 0 if successful, error otherwise. + */ +int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, + cond_update_fn_t update) +{ + struct cond_snapshot *cond_snapshot; + int ret = 0; + + cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL); + if (!cond_snapshot) + return -ENOMEM; + + cond_snapshot->cond_data = cond_data; + cond_snapshot->update = update; + + mutex_lock(&trace_types_lock); + + ret = tracing_alloc_snapshot_instance(tr); + if (ret) + goto fail_unlock; + + if (tr->current_trace->use_max_tr) { + ret = -EBUSY; + goto fail_unlock; + } + + /* + * The cond_snapshot can only change to NULL without the + * trace_types_lock. We don't care if we race with it going + * to NULL, but we want to make sure that it's not set to + * something other than NULL when we get here, which we can + * do safely with only holding the trace_types_lock and not + * having to take the max_lock. + */ + if (tr->cond_snapshot) { + ret = -EBUSY; + goto fail_unlock; + } + + local_irq_disable(); + arch_spin_lock(&tr->max_lock); + tr->cond_snapshot = cond_snapshot; + arch_spin_unlock(&tr->max_lock); + local_irq_enable(); + + mutex_unlock(&trace_types_lock); + + return ret; + + fail_unlock: + mutex_unlock(&trace_types_lock); + kfree(cond_snapshot); + return ret; +} +EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable); + +/** + * tracing_snapshot_cond_disable - disable conditional snapshot for an instance + * @tr: The tracing instance + * + * Check whether the conditional snapshot for the given instance is + * enabled; if so, free the cond_snapshot associated with it, + * otherwise return -EINVAL. + * + * Returns 0 if successful, error otherwise. + */ +int tracing_snapshot_cond_disable(struct trace_array *tr) +{ + int ret = 0; + + local_irq_disable(); + arch_spin_lock(&tr->max_lock); + + if (!tr->cond_snapshot) + ret = -EINVAL; + else { + kfree(tr->cond_snapshot); + tr->cond_snapshot = NULL; + } + + arch_spin_unlock(&tr->max_lock); + local_irq_enable(); + + return ret; +} +EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable); +#else +void tracing_snapshot(void) +{ + WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used"); +} +EXPORT_SYMBOL_GPL(tracing_snapshot); +void tracing_snapshot_cond(struct trace_array *tr, void *cond_data) +{ + WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used"); +} +EXPORT_SYMBOL_GPL(tracing_snapshot_cond); +int tracing_alloc_snapshot(void) +{ + WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used"); + return -ENODEV; +} +EXPORT_SYMBOL_GPL(tracing_alloc_snapshot); +void tracing_snapshot_alloc(void) +{ + /* Give warning */ + tracing_snapshot(); +} +EXPORT_SYMBOL_GPL(tracing_snapshot_alloc); +void *tracing_cond_snapshot_data(struct trace_array *tr) +{ + return NULL; +} +EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data); +int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update) +{ + return -ENODEV; +} +EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable); +int tracing_snapshot_cond_disable(struct trace_array *tr) +{ + return false; +} +EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable); +#define free_snapshot(tr) do { } while (0) +#endif /* CONFIG_TRACER_SNAPSHOT */ + +void tracer_tracing_off(struct trace_array *tr) +{ + if (tr->array_buffer.buffer) + ring_buffer_record_off(tr->array_buffer.buffer); + /* + * This flag is looked at when buffers haven't been allocated + * yet, or by some tracers (like irqsoff), that just want to + * know if the ring buffer has been disabled, but it can handle + * races of where it gets disabled but we still do a record. + * As the check is in the fast path of the tracers, it is more + * important to be fast than accurate. + */ + tr->buffer_disabled = 1; + /* Make the flag seen by readers */ + smp_wmb(); +} + +/** + * tracing_off - turn off tracing buffers + * + * This function stops the tracing buffers from recording data. + * It does not disable any overhead the tracers themselves may + * be causing. This function simply causes all recording to + * the ring buffers to fail. + */ +void tracing_off(void) +{ + tracer_tracing_off(&global_trace); +} +EXPORT_SYMBOL_GPL(tracing_off); + +void disable_trace_on_warning(void) +{ + if (__disable_trace_on_warning) { + trace_array_printk_buf(global_trace.array_buffer.buffer, _THIS_IP_, + "Disabling tracing due to warning\n"); + tracing_off(); + } +} + +/** + * tracer_tracing_is_on - show real state of ring buffer enabled + * @tr : the trace array to know if ring buffer is enabled + * + * Shows real state of the ring buffer if it is enabled or not. + */ +bool tracer_tracing_is_on(struct trace_array *tr) +{ + if (tr->array_buffer.buffer) + return ring_buffer_record_is_on(tr->array_buffer.buffer); + return !tr->buffer_disabled; +} + +/** + * tracing_is_on - show state of ring buffers enabled + */ +int tracing_is_on(void) +{ + return tracer_tracing_is_on(&global_trace); +} +EXPORT_SYMBOL_GPL(tracing_is_on); + +static int __init set_buf_size(char *str) +{ + unsigned long buf_size; + + if (!str) + return 0; + buf_size = memparse(str, &str); + /* + * nr_entries can not be zero and the startup + * tests require some buffer space. Therefore + * ensure we have at least 4096 bytes of buffer. + */ + trace_buf_size = max(4096UL, buf_size); + return 1; +} +__setup("trace_buf_size=", set_buf_size); + +static int __init set_tracing_thresh(char *str) +{ + unsigned long threshold; + int ret; + + if (!str) + return 0; + ret = kstrtoul(str, 0, &threshold); + if (ret < 0) + return 0; + tracing_thresh = threshold * 1000; + return 1; +} +__setup("tracing_thresh=", set_tracing_thresh); + +unsigned long nsecs_to_usecs(unsigned long nsecs) +{ + return nsecs / 1000; +} + +/* + * TRACE_FLAGS is defined as a tuple matching bit masks with strings. + * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that + * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list + * of strings in the order that the evals (enum) were defined. + */ +#undef C +#define C(a, b) b + +/* These must match the bit positions in trace_iterator_flags */ +static const char *trace_options[] = { + TRACE_FLAGS + NULL +}; + +static struct { + u64 (*func)(void); + const char *name; + int in_ns; /* is this clock in nanoseconds? */ +} trace_clocks[] = { + { trace_clock_local, "local", 1 }, + { trace_clock_global, "global", 1 }, + { trace_clock_counter, "counter", 0 }, + { trace_clock_jiffies, "uptime", 0 }, + { trace_clock, "perf", 1 }, + { ktime_get_mono_fast_ns, "mono", 1 }, + { ktime_get_raw_fast_ns, "mono_raw", 1 }, + { ktime_get_boot_fast_ns, "boot", 1 }, + { ktime_get_tai_fast_ns, "tai", 1 }, + ARCH_TRACE_CLOCKS +}; + +bool trace_clock_in_ns(struct trace_array *tr) +{ + if (trace_clocks[tr->clock_id].in_ns) + return true; + + return false; +} + +/* + * trace_parser_get_init - gets the buffer for trace parser + */ +int trace_parser_get_init(struct trace_parser *parser, int size) +{ + memset(parser, 0, sizeof(*parser)); + + parser->buffer = kmalloc(size, GFP_KERNEL); + if (!parser->buffer) + return 1; + + parser->size = size; + return 0; +} + +/* + * trace_parser_put - frees the buffer for trace parser + */ +void trace_parser_put(struct trace_parser *parser) +{ + kfree(parser->buffer); + parser->buffer = NULL; +} + +/* + * trace_get_user - reads the user input string separated by space + * (matched by isspace(ch)) + * + * For each string found the 'struct trace_parser' is updated, + * and the function returns. + * + * Returns number of bytes read. + * + * See kernel/trace/trace.h for 'struct trace_parser' details. + */ +int trace_get_user(struct trace_parser *parser, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char ch; + size_t read = 0; + ssize_t ret; + + if (!*ppos) + trace_parser_clear(parser); + + ret = get_user(ch, ubuf++); + if (ret) + goto out; + + read++; + cnt--; + + /* + * The parser is not finished with the last write, + * continue reading the user input without skipping spaces. + */ + if (!parser->cont) { + /* skip white space */ + while (cnt && isspace(ch)) { + ret = get_user(ch, ubuf++); + if (ret) + goto out; + read++; + cnt--; + } + + parser->idx = 0; + + /* only spaces were written */ + if (isspace(ch) || !ch) { + *ppos += read; + ret = read; + goto out; + } + } + + /* read the non-space input */ + while (cnt && !isspace(ch) && ch) { + if (parser->idx < parser->size - 1) + parser->buffer[parser->idx++] = ch; + else { + ret = -EINVAL; + goto out; + } + ret = get_user(ch, ubuf++); + if (ret) + goto out; + read++; + cnt--; + } + + /* We either got finished input or we have to wait for another call. */ + if (isspace(ch) || !ch) { + parser->buffer[parser->idx] = 0; + parser->cont = false; + } else if (parser->idx < parser->size - 1) { + parser->cont = true; + parser->buffer[parser->idx++] = ch; + /* Make sure the parsed string always terminates with '\0'. */ + parser->buffer[parser->idx] = 0; + } else { + ret = -EINVAL; + goto out; + } + + *ppos += read; + ret = read; + +out: + return ret; +} + +/* TODO add a seq_buf_to_buffer() */ +static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt) +{ + int len; + + if (trace_seq_used(s) <= s->seq.readpos) + return -EBUSY; + + len = trace_seq_used(s) - s->seq.readpos; + if (cnt > len) + cnt = len; + memcpy(buf, s->buffer + s->seq.readpos, cnt); + + s->seq.readpos += cnt; + return cnt; +} + +unsigned long __read_mostly tracing_thresh; + +#ifdef CONFIG_TRACER_MAX_TRACE +static const struct file_operations tracing_max_lat_fops; + +#ifdef LATENCY_FS_NOTIFY + +static struct workqueue_struct *fsnotify_wq; + +static void latency_fsnotify_workfn(struct work_struct *work) +{ + struct trace_array *tr = container_of(work, struct trace_array, + fsnotify_work); + fsnotify_inode(tr->d_max_latency->d_inode, FS_MODIFY); +} + +static void latency_fsnotify_workfn_irq(struct irq_work *iwork) +{ + struct trace_array *tr = container_of(iwork, struct trace_array, + fsnotify_irqwork); + queue_work(fsnotify_wq, &tr->fsnotify_work); +} + +static void trace_create_maxlat_file(struct trace_array *tr, + struct dentry *d_tracer) +{ + INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn); + init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq); + tr->d_max_latency = trace_create_file("tracing_max_latency", + TRACE_MODE_WRITE, + d_tracer, tr, + &tracing_max_lat_fops); +} + +__init static int latency_fsnotify_init(void) +{ + fsnotify_wq = alloc_workqueue("tr_max_lat_wq", + WQ_UNBOUND | WQ_HIGHPRI, 0); + if (!fsnotify_wq) { + pr_err("Unable to allocate tr_max_lat_wq\n"); + return -ENOMEM; + } + return 0; +} + +late_initcall_sync(latency_fsnotify_init); + +void latency_fsnotify(struct trace_array *tr) +{ + if (!fsnotify_wq) + return; + /* + * We cannot call queue_work(&tr->fsnotify_work) from here because it's + * possible that we are called from __schedule() or do_idle(), which + * could cause a deadlock. + */ + irq_work_queue(&tr->fsnotify_irqwork); +} + +#else /* !LATENCY_FS_NOTIFY */ + +#define trace_create_maxlat_file(tr, d_tracer) \ + trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \ + d_tracer, tr, &tracing_max_lat_fops) + +#endif + +/* + * Copy the new maximum trace into the separate maximum-trace + * structure. (this way the maximum trace is permanently saved, + * for later retrieval via /sys/kernel/tracing/tracing_max_latency) + */ +static void +__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) +{ + struct array_buffer *trace_buf = &tr->array_buffer; + struct array_buffer *max_buf = &tr->max_buffer; + struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu); + struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu); + + max_buf->cpu = cpu; + max_buf->time_start = data->preempt_timestamp; + + max_data->saved_latency = tr->max_latency; + max_data->critical_start = data->critical_start; + max_data->critical_end = data->critical_end; + + strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN); + max_data->pid = tsk->pid; + /* + * If tsk == current, then use current_uid(), as that does not use + * RCU. The irq tracer can be called out of RCU scope. + */ + if (tsk == current) + max_data->uid = current_uid(); + else + max_data->uid = task_uid(tsk); + + max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO; + max_data->policy = tsk->policy; + max_data->rt_priority = tsk->rt_priority; + + /* record this tasks comm */ + tracing_record_cmdline(tsk); + latency_fsnotify(tr); +} + +/** + * update_max_tr - snapshot all trace buffers from global_trace to max_tr + * @tr: tracer + * @tsk: the task with the latency + * @cpu: The cpu that initiated the trace. + * @cond_data: User data associated with a conditional snapshot + * + * Flip the buffers between the @tr and the max_tr and record information + * about which task was the cause of this latency. + */ +void +update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu, + void *cond_data) +{ + if (tr->stop_count) + return; + + WARN_ON_ONCE(!irqs_disabled()); + + if (!tr->allocated_snapshot) { + /* Only the nop tracer should hit this when disabling */ + WARN_ON_ONCE(tr->current_trace != &nop_trace); + return; + } + + arch_spin_lock(&tr->max_lock); + + /* Inherit the recordable setting from array_buffer */ + if (ring_buffer_record_is_set_on(tr->array_buffer.buffer)) + ring_buffer_record_on(tr->max_buffer.buffer); + else + ring_buffer_record_off(tr->max_buffer.buffer); + +#ifdef CONFIG_TRACER_SNAPSHOT + if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data)) { + arch_spin_unlock(&tr->max_lock); + return; + } +#endif + swap(tr->array_buffer.buffer, tr->max_buffer.buffer); + + __update_max_tr(tr, tsk, cpu); + + arch_spin_unlock(&tr->max_lock); + + /* Any waiters on the old snapshot buffer need to wake up */ + ring_buffer_wake_waiters(tr->array_buffer.buffer, RING_BUFFER_ALL_CPUS); +} + +/** + * update_max_tr_single - only copy one trace over, and reset the rest + * @tr: tracer + * @tsk: task with the latency + * @cpu: the cpu of the buffer to copy. + * + * Flip the trace of a single CPU buffer between the @tr and the max_tr. + */ +void +update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) +{ + int ret; + + if (tr->stop_count) + return; + + WARN_ON_ONCE(!irqs_disabled()); + if (!tr->allocated_snapshot) { + /* Only the nop tracer should hit this when disabling */ + WARN_ON_ONCE(tr->current_trace != &nop_trace); + return; + } + + arch_spin_lock(&tr->max_lock); + + ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu); + + if (ret == -EBUSY) { + /* + * We failed to swap the buffer due to a commit taking + * place on this CPU. We fail to record, but we reset + * the max trace buffer (no one writes directly to it) + * and flag that it failed. + * Another reason is resize is in progress. + */ + trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_, + "Failed to swap buffers due to commit or resize in progress\n"); + } + + WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY); + + __update_max_tr(tr, tsk, cpu); + arch_spin_unlock(&tr->max_lock); +} + +#endif /* CONFIG_TRACER_MAX_TRACE */ + +static int wait_on_pipe(struct trace_iterator *iter, int full) +{ + int ret; + + /* Iterators are static, they should be filled or empty */ + if (trace_buffer_iter(iter, iter->cpu_file)) + return 0; + + ret = ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file, full); + +#ifdef CONFIG_TRACER_MAX_TRACE + /* + * Make sure this is still the snapshot buffer, as if a snapshot were + * to happen, this would now be the main buffer. + */ + if (iter->snapshot) + iter->array_buffer = &iter->tr->max_buffer; +#endif + return ret; +} + +#ifdef CONFIG_FTRACE_STARTUP_TEST +static bool selftests_can_run; + +struct trace_selftests { + struct list_head list; + struct tracer *type; +}; + +static LIST_HEAD(postponed_selftests); + +static int save_selftest(struct tracer *type) +{ + struct trace_selftests *selftest; + + selftest = kmalloc(sizeof(*selftest), GFP_KERNEL); + if (!selftest) + return -ENOMEM; + + selftest->type = type; + list_add(&selftest->list, &postponed_selftests); + return 0; +} + +static int run_tracer_selftest(struct tracer *type) +{ + struct trace_array *tr = &global_trace; + struct tracer *saved_tracer = tr->current_trace; + int ret; + + if (!type->selftest || tracing_selftest_disabled) + return 0; + + /* + * If a tracer registers early in boot up (before scheduling is + * initialized and such), then do not run its selftests yet. + * Instead, run it a little later in the boot process. + */ + if (!selftests_can_run) + return save_selftest(type); + + if (!tracing_is_on()) { + pr_warn("Selftest for tracer %s skipped due to tracing disabled\n", + type->name); + return 0; + } + + /* + * Run a selftest on this tracer. + * Here we reset the trace buffer, and set the current + * tracer to be this tracer. The tracer can then run some + * internal tracing to verify that everything is in order. + * If we fail, we do not register this tracer. + */ + tracing_reset_online_cpus(&tr->array_buffer); + + tr->current_trace = type; + +#ifdef CONFIG_TRACER_MAX_TRACE + if (type->use_max_tr) { + /* If we expanded the buffers, make sure the max is expanded too */ + if (ring_buffer_expanded) + ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size, + RING_BUFFER_ALL_CPUS); + tr->allocated_snapshot = true; + } +#endif + + /* the test is responsible for initializing and enabling */ + pr_info("Testing tracer %s: ", type->name); + ret = type->selftest(type, tr); + /* the test is responsible for resetting too */ + tr->current_trace = saved_tracer; + if (ret) { + printk(KERN_CONT "FAILED!\n"); + /* Add the warning after printing 'FAILED' */ + WARN_ON(1); + return -1; + } + /* Only reset on passing, to avoid touching corrupted buffers */ + tracing_reset_online_cpus(&tr->array_buffer); + +#ifdef CONFIG_TRACER_MAX_TRACE + if (type->use_max_tr) { + tr->allocated_snapshot = false; + + /* Shrink the max buffer again */ + if (ring_buffer_expanded) + ring_buffer_resize(tr->max_buffer.buffer, 1, + RING_BUFFER_ALL_CPUS); + } +#endif + + printk(KERN_CONT "PASSED\n"); + return 0; +} + +static int do_run_tracer_selftest(struct tracer *type) +{ + int ret; + + /* + * Tests can take a long time, especially if they are run one after the + * other, as does happen during bootup when all the tracers are + * registered. This could cause the soft lockup watchdog to trigger. + */ + cond_resched(); + + tracing_selftest_running = true; + ret = run_tracer_selftest(type); + tracing_selftest_running = false; + + return ret; +} + +static __init int init_trace_selftests(void) +{ + struct trace_selftests *p, *n; + struct tracer *t, **last; + int ret; + + selftests_can_run = true; + + mutex_lock(&trace_types_lock); + + if (list_empty(&postponed_selftests)) + goto out; + + pr_info("Running postponed tracer tests:\n"); + + tracing_selftest_running = true; + list_for_each_entry_safe(p, n, &postponed_selftests, list) { + /* This loop can take minutes when sanitizers are enabled, so + * lets make sure we allow RCU processing. + */ + cond_resched(); + ret = run_tracer_selftest(p->type); + /* If the test fails, then warn and remove from available_tracers */ + if (ret < 0) { + WARN(1, "tracer: %s failed selftest, disabling\n", + p->type->name); + last = &trace_types; + for (t = trace_types; t; t = t->next) { + if (t == p->type) { + *last = t->next; + break; + } + last = &t->next; + } + } + list_del(&p->list); + kfree(p); + } + tracing_selftest_running = false; + + out: + mutex_unlock(&trace_types_lock); + + return 0; +} +core_initcall(init_trace_selftests); +#else +static inline int run_tracer_selftest(struct tracer *type) +{ + return 0; +} +static inline int do_run_tracer_selftest(struct tracer *type) +{ + return 0; +} +#endif /* CONFIG_FTRACE_STARTUP_TEST */ + +static void add_tracer_options(struct trace_array *tr, struct tracer *t); + +static void __init apply_trace_boot_options(void); + +/** + * register_tracer - register a tracer with the ftrace system. + * @type: the plugin for the tracer + * + * Register a new plugin tracer. + */ +int __init register_tracer(struct tracer *type) +{ + struct tracer *t; + int ret = 0; + + if (!type->name) { + pr_info("Tracer must have a name\n"); + return -1; + } + + if (strlen(type->name) >= MAX_TRACER_SIZE) { + pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE); + return -1; + } + + if (security_locked_down(LOCKDOWN_TRACEFS)) { + pr_warn("Can not register tracer %s due to lockdown\n", + type->name); + return -EPERM; + } + + mutex_lock(&trace_types_lock); + + for (t = trace_types; t; t = t->next) { + if (strcmp(type->name, t->name) == 0) { + /* already found */ + pr_info("Tracer %s already registered\n", + type->name); + ret = -1; + goto out; + } + } + + if (!type->set_flag) + type->set_flag = &dummy_set_flag; + if (!type->flags) { + /*allocate a dummy tracer_flags*/ + type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL); + if (!type->flags) { + ret = -ENOMEM; + goto out; + } + type->flags->val = 0; + type->flags->opts = dummy_tracer_opt; + } else + if (!type->flags->opts) + type->flags->opts = dummy_tracer_opt; + + /* store the tracer for __set_tracer_option */ + type->flags->trace = type; + + ret = do_run_tracer_selftest(type); + if (ret < 0) + goto out; + + type->next = trace_types; + trace_types = type; + add_tracer_options(&global_trace, type); + + out: + mutex_unlock(&trace_types_lock); + + if (ret || !default_bootup_tracer) + goto out_unlock; + + if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE)) + goto out_unlock; + + printk(KERN_INFO "Starting tracer '%s'\n", type->name); + /* Do we want this tracer to start on bootup? */ + tracing_set_tracer(&global_trace, type->name); + default_bootup_tracer = NULL; + + apply_trace_boot_options(); + + /* disable other selftests, since this will break it. */ + disable_tracing_selftest("running a tracer"); + + out_unlock: + return ret; +} + +static void tracing_reset_cpu(struct array_buffer *buf, int cpu) +{ + struct trace_buffer *buffer = buf->buffer; + + if (!buffer) + return; + + ring_buffer_record_disable(buffer); + + /* Make sure all commits have finished */ + synchronize_rcu(); + ring_buffer_reset_cpu(buffer, cpu); + + ring_buffer_record_enable(buffer); +} + +void tracing_reset_online_cpus(struct array_buffer *buf) +{ + struct trace_buffer *buffer = buf->buffer; + + if (!buffer) + return; + + ring_buffer_record_disable(buffer); + + /* Make sure all commits have finished */ + synchronize_rcu(); + + buf->time_start = buffer_ftrace_now(buf, buf->cpu); + + ring_buffer_reset_online_cpus(buffer); + + ring_buffer_record_enable(buffer); +} + +/* Must have trace_types_lock held */ +void tracing_reset_all_online_cpus_unlocked(void) +{ + struct trace_array *tr; + + lockdep_assert_held(&trace_types_lock); + + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (!tr->clear_trace) + continue; + tr->clear_trace = false; + tracing_reset_online_cpus(&tr->array_buffer); +#ifdef CONFIG_TRACER_MAX_TRACE + tracing_reset_online_cpus(&tr->max_buffer); +#endif + } +} + +void tracing_reset_all_online_cpus(void) +{ + mutex_lock(&trace_types_lock); + tracing_reset_all_online_cpus_unlocked(); + mutex_unlock(&trace_types_lock); +} + +/* + * The tgid_map array maps from pid to tgid; i.e. the value stored at index i + * is the tgid last observed corresponding to pid=i. + */ +static int *tgid_map; + +/* The maximum valid index into tgid_map. */ +static size_t tgid_map_max; + +#define SAVED_CMDLINES_DEFAULT 128 +#define NO_CMDLINE_MAP UINT_MAX +/* + * Preemption must be disabled before acquiring trace_cmdline_lock. + * The various trace_arrays' max_lock must be acquired in a context + * where interrupt is disabled. + */ +static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED; +struct saved_cmdlines_buffer { + unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1]; + unsigned *map_cmdline_to_pid; + unsigned cmdline_num; + int cmdline_idx; + char *saved_cmdlines; +}; +static struct saved_cmdlines_buffer *savedcmd; + +static inline char *get_saved_cmdlines(int idx) +{ + return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN]; +} + +static inline void set_cmdline(int idx, const char *cmdline) +{ + strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN); +} + +static int allocate_cmdlines_buffer(unsigned int val, + struct saved_cmdlines_buffer *s) +{ + s->map_cmdline_to_pid = kmalloc_array(val, + sizeof(*s->map_cmdline_to_pid), + GFP_KERNEL); + if (!s->map_cmdline_to_pid) + return -ENOMEM; + + s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL); + if (!s->saved_cmdlines) { + kfree(s->map_cmdline_to_pid); + return -ENOMEM; + } + + s->cmdline_idx = 0; + s->cmdline_num = val; + memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP, + sizeof(s->map_pid_to_cmdline)); + memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP, + val * sizeof(*s->map_cmdline_to_pid)); + + return 0; +} + +static int trace_create_savedcmd(void) +{ + int ret; + + savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL); + if (!savedcmd) + return -ENOMEM; + + ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd); + if (ret < 0) { + kfree(savedcmd); + savedcmd = NULL; + return -ENOMEM; + } + + return 0; +} + +int is_tracing_stopped(void) +{ + return global_trace.stop_count; +} + +static void tracing_start_tr(struct trace_array *tr) +{ + struct trace_buffer *buffer; + unsigned long flags; + + if (tracing_disabled) + return; + + raw_spin_lock_irqsave(&tr->start_lock, flags); + if (--tr->stop_count) { + if (WARN_ON_ONCE(tr->stop_count < 0)) { + /* Someone screwed up their debugging */ + tr->stop_count = 0; + } + goto out; + } + + /* Prevent the buffers from switching */ + arch_spin_lock(&tr->max_lock); + + buffer = tr->array_buffer.buffer; + if (buffer) + ring_buffer_record_enable(buffer); + +#ifdef CONFIG_TRACER_MAX_TRACE + buffer = tr->max_buffer.buffer; + if (buffer) + ring_buffer_record_enable(buffer); +#endif + + arch_spin_unlock(&tr->max_lock); + + out: + raw_spin_unlock_irqrestore(&tr->start_lock, flags); +} + +/** + * tracing_start - quick start of the tracer + * + * If tracing is enabled but was stopped by tracing_stop, + * this will start the tracer back up. + */ +void tracing_start(void) + +{ + return tracing_start_tr(&global_trace); +} + +static void tracing_stop_tr(struct trace_array *tr) +{ + struct trace_buffer *buffer; + unsigned long flags; + + raw_spin_lock_irqsave(&tr->start_lock, flags); + if (tr->stop_count++) + goto out; + + /* Prevent the buffers from switching */ + arch_spin_lock(&tr->max_lock); + + buffer = tr->array_buffer.buffer; + if (buffer) + ring_buffer_record_disable(buffer); + +#ifdef CONFIG_TRACER_MAX_TRACE + buffer = tr->max_buffer.buffer; + if (buffer) + ring_buffer_record_disable(buffer); +#endif + + arch_spin_unlock(&tr->max_lock); + + out: + raw_spin_unlock_irqrestore(&tr->start_lock, flags); +} + +/** + * tracing_stop - quick stop of the tracer + * + * Light weight way to stop tracing. Use in conjunction with + * tracing_start. + */ +void tracing_stop(void) +{ + return tracing_stop_tr(&global_trace); +} + +static int trace_save_cmdline(struct task_struct *tsk) +{ + unsigned tpid, idx; + + /* treat recording of idle task as a success */ + if (!tsk->pid) + return 1; + + tpid = tsk->pid & (PID_MAX_DEFAULT - 1); + + /* + * It's not the end of the world if we don't get + * the lock, but we also don't want to spin + * nor do we want to disable interrupts, + * so if we miss here, then better luck next time. + * + * This is called within the scheduler and wake up, so interrupts + * had better been disabled and run queue lock been held. + */ + lockdep_assert_preemption_disabled(); + if (!arch_spin_trylock(&trace_cmdline_lock)) + return 0; + + idx = savedcmd->map_pid_to_cmdline[tpid]; + if (idx == NO_CMDLINE_MAP) { + idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num; + + savedcmd->map_pid_to_cmdline[tpid] = idx; + savedcmd->cmdline_idx = idx; + } + + savedcmd->map_cmdline_to_pid[idx] = tsk->pid; + set_cmdline(idx, tsk->comm); + + arch_spin_unlock(&trace_cmdline_lock); + + return 1; +} + +static void __trace_find_cmdline(int pid, char comm[]) +{ + unsigned map; + int tpid; + + if (!pid) { + strcpy(comm, "<idle>"); + return; + } + + if (WARN_ON_ONCE(pid < 0)) { + strcpy(comm, "<XXX>"); + return; + } + + tpid = pid & (PID_MAX_DEFAULT - 1); + map = savedcmd->map_pid_to_cmdline[tpid]; + if (map != NO_CMDLINE_MAP) { + tpid = savedcmd->map_cmdline_to_pid[map]; + if (tpid == pid) { + strscpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN); + return; + } + } + strcpy(comm, "<...>"); +} + +void trace_find_cmdline(int pid, char comm[]) +{ + preempt_disable(); + arch_spin_lock(&trace_cmdline_lock); + + __trace_find_cmdline(pid, comm); + + arch_spin_unlock(&trace_cmdline_lock); + preempt_enable(); +} + +static int *trace_find_tgid_ptr(int pid) +{ + /* + * Pairs with the smp_store_release in set_tracer_flag() to ensure that + * if we observe a non-NULL tgid_map then we also observe the correct + * tgid_map_max. + */ + int *map = smp_load_acquire(&tgid_map); + + if (unlikely(!map || pid > tgid_map_max)) + return NULL; + + return &map[pid]; +} + +int trace_find_tgid(int pid) +{ + int *ptr = trace_find_tgid_ptr(pid); + + return ptr ? *ptr : 0; +} + +static int trace_save_tgid(struct task_struct *tsk) +{ + int *ptr; + + /* treat recording of idle task as a success */ + if (!tsk->pid) + return 1; + + ptr = trace_find_tgid_ptr(tsk->pid); + if (!ptr) + return 0; + + *ptr = tsk->tgid; + return 1; +} + +static bool tracing_record_taskinfo_skip(int flags) +{ + if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID)))) + return true; + if (!__this_cpu_read(trace_taskinfo_save)) + return true; + return false; +} + +/** + * tracing_record_taskinfo - record the task info of a task + * + * @task: task to record + * @flags: TRACE_RECORD_CMDLINE for recording comm + * TRACE_RECORD_TGID for recording tgid + */ +void tracing_record_taskinfo(struct task_struct *task, int flags) +{ + bool done; + + if (tracing_record_taskinfo_skip(flags)) + return; + + /* + * Record as much task information as possible. If some fail, continue + * to try to record the others. + */ + done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task); + done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task); + + /* If recording any information failed, retry again soon. */ + if (!done) + return; + + __this_cpu_write(trace_taskinfo_save, false); +} + +/** + * tracing_record_taskinfo_sched_switch - record task info for sched_switch + * + * @prev: previous task during sched_switch + * @next: next task during sched_switch + * @flags: TRACE_RECORD_CMDLINE for recording comm + * TRACE_RECORD_TGID for recording tgid + */ +void tracing_record_taskinfo_sched_switch(struct task_struct *prev, + struct task_struct *next, int flags) +{ + bool done; + + if (tracing_record_taskinfo_skip(flags)) + return; + + /* + * Record as much task information as possible. If some fail, continue + * to try to record the others. + */ + done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev); + done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next); + done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev); + done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next); + + /* If recording any information failed, retry again soon. */ + if (!done) + return; + + __this_cpu_write(trace_taskinfo_save, false); +} + +/* Helpers to record a specific task information */ +void tracing_record_cmdline(struct task_struct *task) +{ + tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE); +} + +void tracing_record_tgid(struct task_struct *task) +{ + tracing_record_taskinfo(task, TRACE_RECORD_TGID); +} + +/* + * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq + * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function + * simplifies those functions and keeps them in sync. + */ +enum print_line_t trace_handle_return(struct trace_seq *s) +{ + return trace_seq_has_overflowed(s) ? + TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED; +} +EXPORT_SYMBOL_GPL(trace_handle_return); + +static unsigned short migration_disable_value(void) +{ +#if defined(CONFIG_SMP) + return current->migration_disabled; +#else + return 0; +#endif +} + +unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status) +{ + unsigned int trace_flags = irqs_status; + unsigned int pc; + + pc = preempt_count(); + + if (pc & NMI_MASK) + trace_flags |= TRACE_FLAG_NMI; + if (pc & HARDIRQ_MASK) + trace_flags |= TRACE_FLAG_HARDIRQ; + if (in_serving_softirq()) + trace_flags |= TRACE_FLAG_SOFTIRQ; + if (softirq_count() >> (SOFTIRQ_SHIFT + 1)) + trace_flags |= TRACE_FLAG_BH_OFF; + + if (tif_need_resched()) + trace_flags |= TRACE_FLAG_NEED_RESCHED; + if (test_preempt_need_resched()) + trace_flags |= TRACE_FLAG_PREEMPT_RESCHED; + return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) | + (min_t(unsigned int, migration_disable_value(), 0xf)) << 4; +} + +struct ring_buffer_event * +trace_buffer_lock_reserve(struct trace_buffer *buffer, + int type, + unsigned long len, + unsigned int trace_ctx) +{ + return __trace_buffer_lock_reserve(buffer, type, len, trace_ctx); +} + +DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event); +DEFINE_PER_CPU(int, trace_buffered_event_cnt); +static int trace_buffered_event_ref; + +/** + * trace_buffered_event_enable - enable buffering events + * + * When events are being filtered, it is quicker to use a temporary + * buffer to write the event data into if there's a likely chance + * that it will not be committed. The discard of the ring buffer + * is not as fast as committing, and is much slower than copying + * a commit. + * + * When an event is to be filtered, allocate per cpu buffers to + * write the event data into, and if the event is filtered and discarded + * it is simply dropped, otherwise, the entire data is to be committed + * in one shot. + */ +void trace_buffered_event_enable(void) +{ + struct ring_buffer_event *event; + struct page *page; + int cpu; + + WARN_ON_ONCE(!mutex_is_locked(&event_mutex)); + + if (trace_buffered_event_ref++) + return; + + for_each_tracing_cpu(cpu) { + page = alloc_pages_node(cpu_to_node(cpu), + GFP_KERNEL | __GFP_NORETRY, 0); + /* This is just an optimization and can handle failures */ + if (!page) { + pr_err("Failed to allocate event buffer\n"); + break; + } + + event = page_address(page); + memset(event, 0, sizeof(*event)); + + per_cpu(trace_buffered_event, cpu) = event; + + preempt_disable(); + if (cpu == smp_processor_id() && + __this_cpu_read(trace_buffered_event) != + per_cpu(trace_buffered_event, cpu)) + WARN_ON_ONCE(1); + preempt_enable(); + } +} + +static void enable_trace_buffered_event(void *data) +{ + /* Probably not needed, but do it anyway */ + smp_rmb(); + this_cpu_dec(trace_buffered_event_cnt); +} + +static void disable_trace_buffered_event(void *data) +{ + this_cpu_inc(trace_buffered_event_cnt); +} + +/** + * trace_buffered_event_disable - disable buffering events + * + * When a filter is removed, it is faster to not use the buffered + * events, and to commit directly into the ring buffer. Free up + * the temp buffers when there are no more users. This requires + * special synchronization with current events. + */ +void trace_buffered_event_disable(void) +{ + int cpu; + + WARN_ON_ONCE(!mutex_is_locked(&event_mutex)); + + if (WARN_ON_ONCE(!trace_buffered_event_ref)) + return; + + if (--trace_buffered_event_ref) + return; + + /* For each CPU, set the buffer as used. */ + on_each_cpu_mask(tracing_buffer_mask, disable_trace_buffered_event, + NULL, true); + + /* Wait for all current users to finish */ + synchronize_rcu(); + + for_each_tracing_cpu(cpu) { + free_page((unsigned long)per_cpu(trace_buffered_event, cpu)); + per_cpu(trace_buffered_event, cpu) = NULL; + } + + /* + * Wait for all CPUs that potentially started checking if they can use + * their event buffer only after the previous synchronize_rcu() call and + * they still read a valid pointer from trace_buffered_event. It must be + * ensured they don't see cleared trace_buffered_event_cnt else they + * could wrongly decide to use the pointed-to buffer which is now freed. + */ + synchronize_rcu(); + + /* For each CPU, relinquish the buffer */ + on_each_cpu_mask(tracing_buffer_mask, enable_trace_buffered_event, NULL, + true); +} + +static struct trace_buffer *temp_buffer; + +struct ring_buffer_event * +trace_event_buffer_lock_reserve(struct trace_buffer **current_rb, + struct trace_event_file *trace_file, + int type, unsigned long len, + unsigned int trace_ctx) +{ + struct ring_buffer_event *entry; + struct trace_array *tr = trace_file->tr; + int val; + + *current_rb = tr->array_buffer.buffer; + + if (!tr->no_filter_buffering_ref && + (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED))) { + preempt_disable_notrace(); + /* + * Filtering is on, so try to use the per cpu buffer first. + * This buffer will simulate a ring_buffer_event, + * where the type_len is zero and the array[0] will + * hold the full length. + * (see include/linux/ring-buffer.h for details on + * how the ring_buffer_event is structured). + * + * Using a temp buffer during filtering and copying it + * on a matched filter is quicker than writing directly + * into the ring buffer and then discarding it when + * it doesn't match. That is because the discard + * requires several atomic operations to get right. + * Copying on match and doing nothing on a failed match + * is still quicker than no copy on match, but having + * to discard out of the ring buffer on a failed match. + */ + if ((entry = __this_cpu_read(trace_buffered_event))) { + int max_len = PAGE_SIZE - struct_size(entry, array, 1); + + val = this_cpu_inc_return(trace_buffered_event_cnt); + + /* + * Preemption is disabled, but interrupts and NMIs + * can still come in now. If that happens after + * the above increment, then it will have to go + * back to the old method of allocating the event + * on the ring buffer, and if the filter fails, it + * will have to call ring_buffer_discard_commit() + * to remove it. + * + * Need to also check the unlikely case that the + * length is bigger than the temp buffer size. + * If that happens, then the reserve is pretty much + * guaranteed to fail, as the ring buffer currently + * only allows events less than a page. But that may + * change in the future, so let the ring buffer reserve + * handle the failure in that case. + */ + if (val == 1 && likely(len <= max_len)) { + trace_event_setup(entry, type, trace_ctx); + entry->array[0] = len; + /* Return with preemption disabled */ + return entry; + } + this_cpu_dec(trace_buffered_event_cnt); + } + /* __trace_buffer_lock_reserve() disables preemption */ + preempt_enable_notrace(); + } + + entry = __trace_buffer_lock_reserve(*current_rb, type, len, + trace_ctx); + /* + * If tracing is off, but we have triggers enabled + * we still need to look at the event data. Use the temp_buffer + * to store the trace event for the trigger to use. It's recursive + * safe and will not be recorded anywhere. + */ + if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) { + *current_rb = temp_buffer; + entry = __trace_buffer_lock_reserve(*current_rb, type, len, + trace_ctx); + } + return entry; +} +EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve); + +static DEFINE_RAW_SPINLOCK(tracepoint_iter_lock); +static DEFINE_MUTEX(tracepoint_printk_mutex); + +static void output_printk(struct trace_event_buffer *fbuffer) +{ + struct trace_event_call *event_call; + struct trace_event_file *file; + struct trace_event *event; + unsigned long flags; + struct trace_iterator *iter = tracepoint_print_iter; + + /* We should never get here if iter is NULL */ + if (WARN_ON_ONCE(!iter)) + return; + + event_call = fbuffer->trace_file->event_call; + if (!event_call || !event_call->event.funcs || + !event_call->event.funcs->trace) + return; + + file = fbuffer->trace_file; + if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) || + (unlikely(file->flags & EVENT_FILE_FL_FILTERED) && + !filter_match_preds(file->filter, fbuffer->entry))) + return; + + event = &fbuffer->trace_file->event_call->event; + + raw_spin_lock_irqsave(&tracepoint_iter_lock, flags); + trace_seq_init(&iter->seq); + iter->ent = fbuffer->entry; + event_call->event.funcs->trace(iter, 0, event); + trace_seq_putc(&iter->seq, 0); + printk("%s", iter->seq.buffer); + + raw_spin_unlock_irqrestore(&tracepoint_iter_lock, flags); +} + +int tracepoint_printk_sysctl(struct ctl_table *table, int write, + void *buffer, size_t *lenp, + loff_t *ppos) +{ + int save_tracepoint_printk; + int ret; + + mutex_lock(&tracepoint_printk_mutex); + save_tracepoint_printk = tracepoint_printk; + + ret = proc_dointvec(table, write, buffer, lenp, ppos); + + /* + * This will force exiting early, as tracepoint_printk + * is always zero when tracepoint_printk_iter is not allocated + */ + if (!tracepoint_print_iter) + tracepoint_printk = 0; + + if (save_tracepoint_printk == tracepoint_printk) + goto out; + + if (tracepoint_printk) + static_key_enable(&tracepoint_printk_key.key); + else + static_key_disable(&tracepoint_printk_key.key); + + out: + mutex_unlock(&tracepoint_printk_mutex); + + return ret; +} + +void trace_event_buffer_commit(struct trace_event_buffer *fbuffer) +{ + enum event_trigger_type tt = ETT_NONE; + struct trace_event_file *file = fbuffer->trace_file; + + if (__event_trigger_test_discard(file, fbuffer->buffer, fbuffer->event, + fbuffer->entry, &tt)) + goto discard; + + if (static_key_false(&tracepoint_printk_key.key)) + output_printk(fbuffer); + + if (static_branch_unlikely(&trace_event_exports_enabled)) + ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT); + + trace_buffer_unlock_commit_regs(file->tr, fbuffer->buffer, + fbuffer->event, fbuffer->trace_ctx, fbuffer->regs); + +discard: + if (tt) + event_triggers_post_call(file, tt); + +} +EXPORT_SYMBOL_GPL(trace_event_buffer_commit); + +/* + * Skip 3: + * + * trace_buffer_unlock_commit_regs() + * trace_event_buffer_commit() + * trace_event_raw_event_xxx() + */ +# define STACK_SKIP 3 + +void trace_buffer_unlock_commit_regs(struct trace_array *tr, + struct trace_buffer *buffer, + struct ring_buffer_event *event, + unsigned int trace_ctx, + struct pt_regs *regs) +{ + __buffer_unlock_commit(buffer, event); + + /* + * If regs is not set, then skip the necessary functions. + * Note, we can still get here via blktrace, wakeup tracer + * and mmiotrace, but that's ok if they lose a function or + * two. They are not that meaningful. + */ + ftrace_trace_stack(tr, buffer, trace_ctx, regs ? 0 : STACK_SKIP, regs); + ftrace_trace_userstack(tr, buffer, trace_ctx); +} + +/* + * Similar to trace_buffer_unlock_commit_regs() but do not dump stack. + */ +void +trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer, + struct ring_buffer_event *event) +{ + __buffer_unlock_commit(buffer, event); +} + +void +trace_function(struct trace_array *tr, unsigned long ip, unsigned long + parent_ip, unsigned int trace_ctx) +{ + struct trace_event_call *call = &event_function; + struct trace_buffer *buffer = tr->array_buffer.buffer; + struct ring_buffer_event *event; + struct ftrace_entry *entry; + + event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry), + trace_ctx); + if (!event) + return; + entry = ring_buffer_event_data(event); + entry->ip = ip; + entry->parent_ip = parent_ip; + + if (!call_filter_check_discard(call, entry, buffer, event)) { + if (static_branch_unlikely(&trace_function_exports_enabled)) + ftrace_exports(event, TRACE_EXPORT_FUNCTION); + __buffer_unlock_commit(buffer, event); + } +} + +#ifdef CONFIG_STACKTRACE + +/* Allow 4 levels of nesting: normal, softirq, irq, NMI */ +#define FTRACE_KSTACK_NESTING 4 + +#define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING) + +struct ftrace_stack { + unsigned long calls[FTRACE_KSTACK_ENTRIES]; +}; + + +struct ftrace_stacks { + struct ftrace_stack stacks[FTRACE_KSTACK_NESTING]; +}; + +static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks); +static DEFINE_PER_CPU(int, ftrace_stack_reserve); + +static void __ftrace_trace_stack(struct trace_buffer *buffer, + unsigned int trace_ctx, + int skip, struct pt_regs *regs) +{ + struct trace_event_call *call = &event_kernel_stack; + struct ring_buffer_event *event; + unsigned int size, nr_entries; + struct ftrace_stack *fstack; + struct stack_entry *entry; + int stackidx; + + /* + * Add one, for this function and the call to save_stack_trace() + * If regs is set, then these functions will not be in the way. + */ +#ifndef CONFIG_UNWINDER_ORC + if (!regs) + skip++; +#endif + + preempt_disable_notrace(); + + stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1; + + /* This should never happen. If it does, yell once and skip */ + if (WARN_ON_ONCE(stackidx >= FTRACE_KSTACK_NESTING)) + goto out; + + /* + * The above __this_cpu_inc_return() is 'atomic' cpu local. An + * interrupt will either see the value pre increment or post + * increment. If the interrupt happens pre increment it will have + * restored the counter when it returns. We just need a barrier to + * keep gcc from moving things around. + */ + barrier(); + + fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx; + size = ARRAY_SIZE(fstack->calls); + + if (regs) { + nr_entries = stack_trace_save_regs(regs, fstack->calls, + size, skip); + } else { + nr_entries = stack_trace_save(fstack->calls, size, skip); + } + + event = __trace_buffer_lock_reserve(buffer, TRACE_STACK, + struct_size(entry, caller, nr_entries), + trace_ctx); + if (!event) + goto out; + entry = ring_buffer_event_data(event); + + entry->size = nr_entries; + memcpy(&entry->caller, fstack->calls, + flex_array_size(entry, caller, nr_entries)); + + if (!call_filter_check_discard(call, entry, buffer, event)) + __buffer_unlock_commit(buffer, event); + + out: + /* Again, don't let gcc optimize things here */ + barrier(); + __this_cpu_dec(ftrace_stack_reserve); + preempt_enable_notrace(); + +} + +static inline void ftrace_trace_stack(struct trace_array *tr, + struct trace_buffer *buffer, + unsigned int trace_ctx, + int skip, struct pt_regs *regs) +{ + if (!(tr->trace_flags & TRACE_ITER_STACKTRACE)) + return; + + __ftrace_trace_stack(buffer, trace_ctx, skip, regs); +} + +void __trace_stack(struct trace_array *tr, unsigned int trace_ctx, + int skip) +{ + struct trace_buffer *buffer = tr->array_buffer.buffer; + + if (rcu_is_watching()) { + __ftrace_trace_stack(buffer, trace_ctx, skip, NULL); + return; + } + + if (WARN_ON_ONCE(IS_ENABLED(CONFIG_GENERIC_ENTRY))) + return; + + /* + * When an NMI triggers, RCU is enabled via ct_nmi_enter(), + * but if the above rcu_is_watching() failed, then the NMI + * triggered someplace critical, and ct_irq_enter() should + * not be called from NMI. + */ + if (unlikely(in_nmi())) + return; + + ct_irq_enter_irqson(); + __ftrace_trace_stack(buffer, trace_ctx, skip, NULL); + ct_irq_exit_irqson(); +} + +/** + * trace_dump_stack - record a stack back trace in the trace buffer + * @skip: Number of functions to skip (helper handlers) + */ +void trace_dump_stack(int skip) +{ + if (tracing_disabled || tracing_selftest_running) + return; + +#ifndef CONFIG_UNWINDER_ORC + /* Skip 1 to skip this function. */ + skip++; +#endif + __ftrace_trace_stack(global_trace.array_buffer.buffer, + tracing_gen_ctx(), skip, NULL); +} +EXPORT_SYMBOL_GPL(trace_dump_stack); + +#ifdef CONFIG_USER_STACKTRACE_SUPPORT +static DEFINE_PER_CPU(int, user_stack_count); + +static void +ftrace_trace_userstack(struct trace_array *tr, + struct trace_buffer *buffer, unsigned int trace_ctx) +{ + struct trace_event_call *call = &event_user_stack; + struct ring_buffer_event *event; + struct userstack_entry *entry; + + if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE)) + return; + + /* + * NMIs can not handle page faults, even with fix ups. + * The save user stack can (and often does) fault. + */ + if (unlikely(in_nmi())) + return; + + /* + * prevent recursion, since the user stack tracing may + * trigger other kernel events. + */ + preempt_disable(); + if (__this_cpu_read(user_stack_count)) + goto out; + + __this_cpu_inc(user_stack_count); + + event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK, + sizeof(*entry), trace_ctx); + if (!event) + goto out_drop_count; + entry = ring_buffer_event_data(event); + + entry->tgid = current->tgid; + memset(&entry->caller, 0, sizeof(entry->caller)); + + stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES); + if (!call_filter_check_discard(call, entry, buffer, event)) + __buffer_unlock_commit(buffer, event); + + out_drop_count: + __this_cpu_dec(user_stack_count); + out: + preempt_enable(); +} +#else /* CONFIG_USER_STACKTRACE_SUPPORT */ +static void ftrace_trace_userstack(struct trace_array *tr, + struct trace_buffer *buffer, + unsigned int trace_ctx) +{ +} +#endif /* !CONFIG_USER_STACKTRACE_SUPPORT */ + +#endif /* CONFIG_STACKTRACE */ + +static inline void +func_repeats_set_delta_ts(struct func_repeats_entry *entry, + unsigned long long delta) +{ + entry->bottom_delta_ts = delta & U32_MAX; + entry->top_delta_ts = (delta >> 32); +} + +void trace_last_func_repeats(struct trace_array *tr, + struct trace_func_repeats *last_info, + unsigned int trace_ctx) +{ + struct trace_buffer *buffer = tr->array_buffer.buffer; + struct func_repeats_entry *entry; + struct ring_buffer_event *event; + u64 delta; + + event = __trace_buffer_lock_reserve(buffer, TRACE_FUNC_REPEATS, + sizeof(*entry), trace_ctx); + if (!event) + return; + + delta = ring_buffer_event_time_stamp(buffer, event) - + last_info->ts_last_call; + + entry = ring_buffer_event_data(event); + entry->ip = last_info->ip; + entry->parent_ip = last_info->parent_ip; + entry->count = last_info->count; + func_repeats_set_delta_ts(entry, delta); + + __buffer_unlock_commit(buffer, event); +} + +/* created for use with alloc_percpu */ +struct trace_buffer_struct { + int nesting; + char buffer[4][TRACE_BUF_SIZE]; +}; + +static struct trace_buffer_struct __percpu *trace_percpu_buffer; + +/* + * This allows for lockless recording. If we're nested too deeply, then + * this returns NULL. + */ +static char *get_trace_buf(void) +{ + struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer); + + if (!trace_percpu_buffer || buffer->nesting >= 4) + return NULL; + + buffer->nesting++; + + /* Interrupts must see nesting incremented before we use the buffer */ + barrier(); + return &buffer->buffer[buffer->nesting - 1][0]; +} + +static void put_trace_buf(void) +{ + /* Don't let the decrement of nesting leak before this */ + barrier(); + this_cpu_dec(trace_percpu_buffer->nesting); +} + +static int alloc_percpu_trace_buffer(void) +{ + struct trace_buffer_struct __percpu *buffers; + + if (trace_percpu_buffer) + return 0; + + buffers = alloc_percpu(struct trace_buffer_struct); + if (MEM_FAIL(!buffers, "Could not allocate percpu trace_printk buffer")) + return -ENOMEM; + + trace_percpu_buffer = buffers; + return 0; +} + +static int buffers_allocated; + +void trace_printk_init_buffers(void) +{ + if (buffers_allocated) + return; + + if (alloc_percpu_trace_buffer()) + return; + + /* trace_printk() is for debug use only. Don't use it in production. */ + + pr_warn("\n"); + pr_warn("**********************************************************\n"); + pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); + pr_warn("** **\n"); + pr_warn("** trace_printk() being used. Allocating extra memory. **\n"); + pr_warn("** **\n"); + pr_warn("** This means that this is a DEBUG kernel and it is **\n"); + pr_warn("** unsafe for production use. **\n"); + pr_warn("** **\n"); + pr_warn("** If you see this message and you are not debugging **\n"); + pr_warn("** the kernel, report this immediately to your vendor! **\n"); + pr_warn("** **\n"); + pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); + pr_warn("**********************************************************\n"); + + /* Expand the buffers to set size */ + tracing_update_buffers(); + + buffers_allocated = 1; + + /* + * trace_printk_init_buffers() can be called by modules. + * If that happens, then we need to start cmdline recording + * directly here. If the global_trace.buffer is already + * allocated here, then this was called by module code. + */ + if (global_trace.array_buffer.buffer) + tracing_start_cmdline_record(); +} +EXPORT_SYMBOL_GPL(trace_printk_init_buffers); + +void trace_printk_start_comm(void) +{ + /* Start tracing comms if trace printk is set */ + if (!buffers_allocated) + return; + tracing_start_cmdline_record(); +} + +static void trace_printk_start_stop_comm(int enabled) +{ + if (!buffers_allocated) + return; + + if (enabled) + tracing_start_cmdline_record(); + else + tracing_stop_cmdline_record(); +} + +/** + * trace_vbprintk - write binary msg to tracing buffer + * @ip: The address of the caller + * @fmt: The string format to write to the buffer + * @args: Arguments for @fmt + */ +int trace_vbprintk(unsigned long ip, const char *fmt, va_list args) +{ + struct trace_event_call *call = &event_bprint; + struct ring_buffer_event *event; + struct trace_buffer *buffer; + struct trace_array *tr = &global_trace; + struct bprint_entry *entry; + unsigned int trace_ctx; + char *tbuffer; + int len = 0, size; + + if (unlikely(tracing_selftest_running || tracing_disabled)) + return 0; + + /* Don't pollute graph traces with trace_vprintk internals */ + pause_graph_tracing(); + + trace_ctx = tracing_gen_ctx(); + preempt_disable_notrace(); + + tbuffer = get_trace_buf(); + if (!tbuffer) { + len = 0; + goto out_nobuffer; + } + + len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args); + + if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0) + goto out_put; + + size = sizeof(*entry) + sizeof(u32) * len; + buffer = tr->array_buffer.buffer; + ring_buffer_nest_start(buffer); + event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size, + trace_ctx); + if (!event) + goto out; + entry = ring_buffer_event_data(event); + entry->ip = ip; + entry->fmt = fmt; + + memcpy(entry->buf, tbuffer, sizeof(u32) * len); + if (!call_filter_check_discard(call, entry, buffer, event)) { + __buffer_unlock_commit(buffer, event); + ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL); + } + +out: + ring_buffer_nest_end(buffer); +out_put: + put_trace_buf(); + +out_nobuffer: + preempt_enable_notrace(); + unpause_graph_tracing(); + + return len; +} +EXPORT_SYMBOL_GPL(trace_vbprintk); + +__printf(3, 0) +static int +__trace_array_vprintk(struct trace_buffer *buffer, + unsigned long ip, const char *fmt, va_list args) +{ + struct trace_event_call *call = &event_print; + struct ring_buffer_event *event; + int len = 0, size; + struct print_entry *entry; + unsigned int trace_ctx; + char *tbuffer; + + if (tracing_disabled) + return 0; + + /* Don't pollute graph traces with trace_vprintk internals */ + pause_graph_tracing(); + + trace_ctx = tracing_gen_ctx(); + preempt_disable_notrace(); + + + tbuffer = get_trace_buf(); + if (!tbuffer) { + len = 0; + goto out_nobuffer; + } + + len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args); + + size = sizeof(*entry) + len + 1; + ring_buffer_nest_start(buffer); + event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, + trace_ctx); + if (!event) + goto out; + entry = ring_buffer_event_data(event); + entry->ip = ip; + + memcpy(&entry->buf, tbuffer, len + 1); + if (!call_filter_check_discard(call, entry, buffer, event)) { + __buffer_unlock_commit(buffer, event); + ftrace_trace_stack(&global_trace, buffer, trace_ctx, 6, NULL); + } + +out: + ring_buffer_nest_end(buffer); + put_trace_buf(); + +out_nobuffer: + preempt_enable_notrace(); + unpause_graph_tracing(); + + return len; +} + +__printf(3, 0) +int trace_array_vprintk(struct trace_array *tr, + unsigned long ip, const char *fmt, va_list args) +{ + if (tracing_selftest_running && tr == &global_trace) + return 0; + + return __trace_array_vprintk(tr->array_buffer.buffer, ip, fmt, args); +} + +/** + * trace_array_printk - Print a message to a specific instance + * @tr: The instance trace_array descriptor + * @ip: The instruction pointer that this is called from. + * @fmt: The format to print (printf format) + * + * If a subsystem sets up its own instance, they have the right to + * printk strings into their tracing instance buffer using this + * function. Note, this function will not write into the top level + * buffer (use trace_printk() for that), as writing into the top level + * buffer should only have events that can be individually disabled. + * trace_printk() is only used for debugging a kernel, and should not + * be ever incorporated in normal use. + * + * trace_array_printk() can be used, as it will not add noise to the + * top level tracing buffer. + * + * Note, trace_array_init_printk() must be called on @tr before this + * can be used. + */ +__printf(3, 0) +int trace_array_printk(struct trace_array *tr, + unsigned long ip, const char *fmt, ...) +{ + int ret; + va_list ap; + + if (!tr) + return -ENOENT; + + /* This is only allowed for created instances */ + if (tr == &global_trace) + return 0; + + if (!(tr->trace_flags & TRACE_ITER_PRINTK)) + return 0; + + va_start(ap, fmt); + ret = trace_array_vprintk(tr, ip, fmt, ap); + va_end(ap); + return ret; +} +EXPORT_SYMBOL_GPL(trace_array_printk); + +/** + * trace_array_init_printk - Initialize buffers for trace_array_printk() + * @tr: The trace array to initialize the buffers for + * + * As trace_array_printk() only writes into instances, they are OK to + * have in the kernel (unlike trace_printk()). This needs to be called + * before trace_array_printk() can be used on a trace_array. + */ +int trace_array_init_printk(struct trace_array *tr) +{ + if (!tr) + return -ENOENT; + + /* This is only allowed for created instances */ + if (tr == &global_trace) + return -EINVAL; + + return alloc_percpu_trace_buffer(); +} +EXPORT_SYMBOL_GPL(trace_array_init_printk); + +__printf(3, 4) +int trace_array_printk_buf(struct trace_buffer *buffer, + unsigned long ip, const char *fmt, ...) +{ + int ret; + va_list ap; + + if (!(global_trace.trace_flags & TRACE_ITER_PRINTK)) + return 0; + + va_start(ap, fmt); + ret = __trace_array_vprintk(buffer, ip, fmt, ap); + va_end(ap); + return ret; +} + +__printf(2, 0) +int trace_vprintk(unsigned long ip, const char *fmt, va_list args) +{ + return trace_array_vprintk(&global_trace, ip, fmt, args); +} +EXPORT_SYMBOL_GPL(trace_vprintk); + +static void trace_iterator_increment(struct trace_iterator *iter) +{ + struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu); + + iter->idx++; + if (buf_iter) + ring_buffer_iter_advance(buf_iter); +} + +static struct trace_entry * +peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts, + unsigned long *lost_events) +{ + struct ring_buffer_event *event; + struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu); + + if (buf_iter) { + event = ring_buffer_iter_peek(buf_iter, ts); + if (lost_events) + *lost_events = ring_buffer_iter_dropped(buf_iter) ? + (unsigned long)-1 : 0; + } else { + event = ring_buffer_peek(iter->array_buffer->buffer, cpu, ts, + lost_events); + } + + if (event) { + iter->ent_size = ring_buffer_event_length(event); + return ring_buffer_event_data(event); + } + iter->ent_size = 0; + return NULL; +} + +static struct trace_entry * +__find_next_entry(struct trace_iterator *iter, int *ent_cpu, + unsigned long *missing_events, u64 *ent_ts) +{ + struct trace_buffer *buffer = iter->array_buffer->buffer; + struct trace_entry *ent, *next = NULL; + unsigned long lost_events = 0, next_lost = 0; + int cpu_file = iter->cpu_file; + u64 next_ts = 0, ts; + int next_cpu = -1; + int next_size = 0; + int cpu; + + /* + * If we are in a per_cpu trace file, don't bother by iterating over + * all cpu and peek directly. + */ + if (cpu_file > RING_BUFFER_ALL_CPUS) { + if (ring_buffer_empty_cpu(buffer, cpu_file)) + return NULL; + ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events); + if (ent_cpu) + *ent_cpu = cpu_file; + + return ent; + } + + for_each_tracing_cpu(cpu) { + + if (ring_buffer_empty_cpu(buffer, cpu)) + continue; + + ent = peek_next_entry(iter, cpu, &ts, &lost_events); + + /* + * Pick the entry with the smallest timestamp: + */ + if (ent && (!next || ts < next_ts)) { + next = ent; + next_cpu = cpu; + next_ts = ts; + next_lost = lost_events; + next_size = iter->ent_size; + } + } + + iter->ent_size = next_size; + + if (ent_cpu) + *ent_cpu = next_cpu; + + if (ent_ts) + *ent_ts = next_ts; + + if (missing_events) + *missing_events = next_lost; + + return next; +} + +#define STATIC_FMT_BUF_SIZE 128 +static char static_fmt_buf[STATIC_FMT_BUF_SIZE]; + +char *trace_iter_expand_format(struct trace_iterator *iter) +{ + char *tmp; + + /* + * iter->tr is NULL when used with tp_printk, which makes + * this get called where it is not safe to call krealloc(). + */ + if (!iter->tr || iter->fmt == static_fmt_buf) + return NULL; + + tmp = krealloc(iter->fmt, iter->fmt_size + STATIC_FMT_BUF_SIZE, + GFP_KERNEL); + if (tmp) { + iter->fmt_size += STATIC_FMT_BUF_SIZE; + iter->fmt = tmp; + } + + return tmp; +} + +/* Returns true if the string is safe to dereference from an event */ +static bool trace_safe_str(struct trace_iterator *iter, const char *str, + bool star, int len) +{ + unsigned long addr = (unsigned long)str; + struct trace_event *trace_event; + struct trace_event_call *event; + + /* Ignore strings with no length */ + if (star && !len) + return true; + + /* OK if part of the event data */ + if ((addr >= (unsigned long)iter->ent) && + (addr < (unsigned long)iter->ent + iter->ent_size)) + return true; + + /* OK if part of the temp seq buffer */ + if ((addr >= (unsigned long)iter->tmp_seq.buffer) && + (addr < (unsigned long)iter->tmp_seq.buffer + PAGE_SIZE)) + return true; + + /* Core rodata can not be freed */ + if (is_kernel_rodata(addr)) + return true; + + if (trace_is_tracepoint_string(str)) + return true; + + /* + * Now this could be a module event, referencing core module + * data, which is OK. + */ + if (!iter->ent) + return false; + + trace_event = ftrace_find_event(iter->ent->type); + if (!trace_event) + return false; + + event = container_of(trace_event, struct trace_event_call, event); + if ((event->flags & TRACE_EVENT_FL_DYNAMIC) || !event->module) + return false; + + /* Would rather have rodata, but this will suffice */ + if (within_module_core(addr, event->module)) + return true; + + return false; +} + +static const char *show_buffer(struct trace_seq *s) +{ + struct seq_buf *seq = &s->seq; + + seq_buf_terminate(seq); + + return seq->buffer; +} + +static DEFINE_STATIC_KEY_FALSE(trace_no_verify); + +static int test_can_verify_check(const char *fmt, ...) +{ + char buf[16]; + va_list ap; + int ret; + + /* + * The verifier is dependent on vsnprintf() modifies the va_list + * passed to it, where it is sent as a reference. Some architectures + * (like x86_32) passes it by value, which means that vsnprintf() + * does not modify the va_list passed to it, and the verifier + * would then need to be able to understand all the values that + * vsnprintf can use. If it is passed by value, then the verifier + * is disabled. + */ + va_start(ap, fmt); + vsnprintf(buf, 16, "%d", ap); + ret = va_arg(ap, int); + va_end(ap); + + return ret; +} + +static void test_can_verify(void) +{ + if (!test_can_verify_check("%d %d", 0, 1)) { + pr_info("trace event string verifier disabled\n"); + static_branch_inc(&trace_no_verify); + } +} + +/** + * trace_check_vprintf - Check dereferenced strings while writing to the seq buffer + * @iter: The iterator that holds the seq buffer and the event being printed + * @fmt: The format used to print the event + * @ap: The va_list holding the data to print from @fmt. + * + * This writes the data into the @iter->seq buffer using the data from + * @fmt and @ap. If the format has a %s, then the source of the string + * is examined to make sure it is safe to print, otherwise it will + * warn and print "[UNSAFE MEMORY]" in place of the dereferenced string + * pointer. + */ +void trace_check_vprintf(struct trace_iterator *iter, const char *fmt, + va_list ap) +{ + const char *p = fmt; + const char *str; + int i, j; + + if (WARN_ON_ONCE(!fmt)) + return; + + if (static_branch_unlikely(&trace_no_verify)) + goto print; + + /* Don't bother checking when doing a ftrace_dump() */ + if (iter->fmt == static_fmt_buf) + goto print; + + while (*p) { + bool star = false; + int len = 0; + + j = 0; + + /* We only care about %s and variants */ + for (i = 0; p[i]; i++) { + if (i + 1 >= iter->fmt_size) { + /* + * If we can't expand the copy buffer, + * just print it. + */ + if (!trace_iter_expand_format(iter)) + goto print; + } + + if (p[i] == '\\' && p[i+1]) { + i++; + continue; + } + if (p[i] == '%') { + /* Need to test cases like %08.*s */ + for (j = 1; p[i+j]; j++) { + if (isdigit(p[i+j]) || + p[i+j] == '.') + continue; + if (p[i+j] == '*') { + star = true; + continue; + } + break; + } + if (p[i+j] == 's') + break; + star = false; + } + j = 0; + } + /* If no %s found then just print normally */ + if (!p[i]) + break; + + /* Copy up to the %s, and print that */ + strncpy(iter->fmt, p, i); + iter->fmt[i] = '\0'; + trace_seq_vprintf(&iter->seq, iter->fmt, ap); + + /* + * If iter->seq is full, the above call no longer guarantees + * that ap is in sync with fmt processing, and further calls + * to va_arg() can return wrong positional arguments. + * + * Ensure that ap is no longer used in this case. + */ + if (iter->seq.full) { + p = ""; + break; + } + + if (star) + len = va_arg(ap, int); + + /* The ap now points to the string data of the %s */ + str = va_arg(ap, const char *); + + /* + * If you hit this warning, it is likely that the + * trace event in question used %s on a string that + * was saved at the time of the event, but may not be + * around when the trace is read. Use __string(), + * __assign_str() and __get_str() helpers in the TRACE_EVENT() + * instead. See samples/trace_events/trace-events-sample.h + * for reference. + */ + if (WARN_ONCE(!trace_safe_str(iter, str, star, len), + "fmt: '%s' current_buffer: '%s'", + fmt, show_buffer(&iter->seq))) { + int ret; + + /* Try to safely read the string */ + if (star) { + if (len + 1 > iter->fmt_size) + len = iter->fmt_size - 1; + if (len < 0) + len = 0; + ret = copy_from_kernel_nofault(iter->fmt, str, len); + iter->fmt[len] = 0; + star = false; + } else { + ret = strncpy_from_kernel_nofault(iter->fmt, str, + iter->fmt_size); + } + if (ret < 0) + trace_seq_printf(&iter->seq, "(0x%px)", str); + else + trace_seq_printf(&iter->seq, "(0x%px:%s)", + str, iter->fmt); + str = "[UNSAFE-MEMORY]"; + strcpy(iter->fmt, "%s"); + } else { + strncpy(iter->fmt, p + i, j + 1); + iter->fmt[j+1] = '\0'; + } + if (star) + trace_seq_printf(&iter->seq, iter->fmt, len, str); + else + trace_seq_printf(&iter->seq, iter->fmt, str); + + p += i + j + 1; + } + print: + if (*p) + trace_seq_vprintf(&iter->seq, p, ap); +} + +const char *trace_event_format(struct trace_iterator *iter, const char *fmt) +{ + const char *p, *new_fmt; + char *q; + + if (WARN_ON_ONCE(!fmt)) + return fmt; + + if (!iter->tr || iter->tr->trace_flags & TRACE_ITER_HASH_PTR) + return fmt; + + p = fmt; + new_fmt = q = iter->fmt; + while (*p) { + if (unlikely(q - new_fmt + 3 > iter->fmt_size)) { + if (!trace_iter_expand_format(iter)) + return fmt; + + q += iter->fmt - new_fmt; + new_fmt = iter->fmt; + } + + *q++ = *p++; + + /* Replace %p with %px */ + if (p[-1] == '%') { + if (p[0] == '%') { + *q++ = *p++; + } else if (p[0] == 'p' && !isalnum(p[1])) { + *q++ = *p++; + *q++ = 'x'; + } + } + } + *q = '\0'; + + return new_fmt; +} + +#define STATIC_TEMP_BUF_SIZE 128 +static char static_temp_buf[STATIC_TEMP_BUF_SIZE] __aligned(4); + +/* Find the next real entry, without updating the iterator itself */ +struct trace_entry *trace_find_next_entry(struct trace_iterator *iter, + int *ent_cpu, u64 *ent_ts) +{ + /* __find_next_entry will reset ent_size */ + int ent_size = iter->ent_size; + struct trace_entry *entry; + + /* + * If called from ftrace_dump(), then the iter->temp buffer + * will be the static_temp_buf and not created from kmalloc. + * If the entry size is greater than the buffer, we can + * not save it. Just return NULL in that case. This is only + * used to add markers when two consecutive events' time + * stamps have a large delta. See trace_print_lat_context() + */ + if (iter->temp == static_temp_buf && + STATIC_TEMP_BUF_SIZE < ent_size) + return NULL; + + /* + * The __find_next_entry() may call peek_next_entry(), which may + * call ring_buffer_peek() that may make the contents of iter->ent + * undefined. Need to copy iter->ent now. + */ + if (iter->ent && iter->ent != iter->temp) { + if ((!iter->temp || iter->temp_size < iter->ent_size) && + !WARN_ON_ONCE(iter->temp == static_temp_buf)) { + void *temp; + temp = kmalloc(iter->ent_size, GFP_KERNEL); + if (!temp) + return NULL; + kfree(iter->temp); + iter->temp = temp; + iter->temp_size = iter->ent_size; + } + memcpy(iter->temp, iter->ent, iter->ent_size); + iter->ent = iter->temp; + } + entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts); + /* Put back the original ent_size */ + iter->ent_size = ent_size; + + return entry; +} + +/* Find the next real entry, and increment the iterator to the next entry */ +void *trace_find_next_entry_inc(struct trace_iterator *iter) +{ + iter->ent = __find_next_entry(iter, &iter->cpu, + &iter->lost_events, &iter->ts); + + if (iter->ent) + trace_iterator_increment(iter); + + return iter->ent ? iter : NULL; +} + +static void trace_consume(struct trace_iterator *iter) +{ + ring_buffer_consume(iter->array_buffer->buffer, iter->cpu, &iter->ts, + &iter->lost_events); +} + +static void *s_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct trace_iterator *iter = m->private; + int i = (int)*pos; + void *ent; + + WARN_ON_ONCE(iter->leftover); + + (*pos)++; + + /* can't go backwards */ + if (iter->idx > i) + return NULL; + + if (iter->idx < 0) + ent = trace_find_next_entry_inc(iter); + else + ent = iter; + + while (ent && iter->idx < i) + ent = trace_find_next_entry_inc(iter); + + iter->pos = *pos; + + return ent; +} + +void tracing_iter_reset(struct trace_iterator *iter, int cpu) +{ + struct ring_buffer_iter *buf_iter; + unsigned long entries = 0; + u64 ts; + + per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = 0; + + buf_iter = trace_buffer_iter(iter, cpu); + if (!buf_iter) + return; + + ring_buffer_iter_reset(buf_iter); + + /* + * We could have the case with the max latency tracers + * that a reset never took place on a cpu. This is evident + * by the timestamp being before the start of the buffer. + */ + while (ring_buffer_iter_peek(buf_iter, &ts)) { + if (ts >= iter->array_buffer->time_start) + break; + entries++; + ring_buffer_iter_advance(buf_iter); + } + + per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = entries; +} + +/* + * The current tracer is copied to avoid a global locking + * all around. + */ +static void *s_start(struct seq_file *m, loff_t *pos) +{ + struct trace_iterator *iter = m->private; + struct trace_array *tr = iter->tr; + int cpu_file = iter->cpu_file; + void *p = NULL; + loff_t l = 0; + int cpu; + + mutex_lock(&trace_types_lock); + if (unlikely(tr->current_trace != iter->trace)) { + /* Close iter->trace before switching to the new current tracer */ + if (iter->trace->close) + iter->trace->close(iter); + iter->trace = tr->current_trace; + /* Reopen the new current tracer */ + if (iter->trace->open) + iter->trace->open(iter); + } + mutex_unlock(&trace_types_lock); + +#ifdef CONFIG_TRACER_MAX_TRACE + if (iter->snapshot && iter->trace->use_max_tr) + return ERR_PTR(-EBUSY); +#endif + + if (*pos != iter->pos) { + iter->ent = NULL; + iter->cpu = 0; + iter->idx = -1; + + if (cpu_file == RING_BUFFER_ALL_CPUS) { + for_each_tracing_cpu(cpu) + tracing_iter_reset(iter, cpu); + } else + tracing_iter_reset(iter, cpu_file); + + iter->leftover = 0; + for (p = iter; p && l < *pos; p = s_next(m, p, &l)) + ; + + } else { + /* + * If we overflowed the seq_file before, then we want + * to just reuse the trace_seq buffer again. + */ + if (iter->leftover) + p = iter; + else { + l = *pos - 1; + p = s_next(m, p, &l); + } + } + + trace_event_read_lock(); + trace_access_lock(cpu_file); + return p; +} + +static void s_stop(struct seq_file *m, void *p) +{ + struct trace_iterator *iter = m->private; + +#ifdef CONFIG_TRACER_MAX_TRACE + if (iter->snapshot && iter->trace->use_max_tr) + return; +#endif + + trace_access_unlock(iter->cpu_file); + trace_event_read_unlock(); +} + +static void +get_total_entries_cpu(struct array_buffer *buf, unsigned long *total, + unsigned long *entries, int cpu) +{ + unsigned long count; + + count = ring_buffer_entries_cpu(buf->buffer, cpu); + /* + * If this buffer has skipped entries, then we hold all + * entries for the trace and we need to ignore the + * ones before the time stamp. + */ + if (per_cpu_ptr(buf->data, cpu)->skipped_entries) { + count -= per_cpu_ptr(buf->data, cpu)->skipped_entries; + /* total is the same as the entries */ + *total = count; + } else + *total = count + + ring_buffer_overrun_cpu(buf->buffer, cpu); + *entries = count; +} + +static void +get_total_entries(struct array_buffer *buf, + unsigned long *total, unsigned long *entries) +{ + unsigned long t, e; + int cpu; + + *total = 0; + *entries = 0; + + for_each_tracing_cpu(cpu) { + get_total_entries_cpu(buf, &t, &e, cpu); + *total += t; + *entries += e; + } +} + +unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu) +{ + unsigned long total, entries; + + if (!tr) + tr = &global_trace; + + get_total_entries_cpu(&tr->array_buffer, &total, &entries, cpu); + + return entries; +} + +unsigned long trace_total_entries(struct trace_array *tr) +{ + unsigned long total, entries; + + if (!tr) + tr = &global_trace; + + get_total_entries(&tr->array_buffer, &total, &entries); + + return entries; +} + +static void print_lat_help_header(struct seq_file *m) +{ + seq_puts(m, "# _------=> CPU# \n" + "# / _-----=> irqs-off/BH-disabled\n" + "# | / _----=> need-resched \n" + "# || / _---=> hardirq/softirq \n" + "# ||| / _--=> preempt-depth \n" + "# |||| / _-=> migrate-disable \n" + "# ||||| / delay \n" + "# cmd pid |||||| time | caller \n" + "# \\ / |||||| \\ | / \n"); +} + +static void print_event_info(struct array_buffer *buf, struct seq_file *m) +{ + unsigned long total; + unsigned long entries; + + get_total_entries(buf, &total, &entries); + seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n", + entries, total, num_online_cpus()); + seq_puts(m, "#\n"); +} + +static void print_func_help_header(struct array_buffer *buf, struct seq_file *m, + unsigned int flags) +{ + bool tgid = flags & TRACE_ITER_RECORD_TGID; + + print_event_info(buf, m); + + seq_printf(m, "# TASK-PID %s CPU# TIMESTAMP FUNCTION\n", tgid ? " TGID " : ""); + seq_printf(m, "# | | %s | | |\n", tgid ? " | " : ""); +} + +static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file *m, + unsigned int flags) +{ + bool tgid = flags & TRACE_ITER_RECORD_TGID; + static const char space[] = " "; + int prec = tgid ? 12 : 2; + + print_event_info(buf, m); + + seq_printf(m, "# %.*s _-----=> irqs-off/BH-disabled\n", prec, space); + seq_printf(m, "# %.*s / _----=> need-resched\n", prec, space); + seq_printf(m, "# %.*s| / _---=> hardirq/softirq\n", prec, space); + seq_printf(m, "# %.*s|| / _--=> preempt-depth\n", prec, space); + seq_printf(m, "# %.*s||| / _-=> migrate-disable\n", prec, space); + seq_printf(m, "# %.*s|||| / delay\n", prec, space); + seq_printf(m, "# TASK-PID %.*s CPU# ||||| TIMESTAMP FUNCTION\n", prec, " TGID "); + seq_printf(m, "# | | %.*s | ||||| | |\n", prec, " | "); +} + +void +print_trace_header(struct seq_file *m, struct trace_iterator *iter) +{ + unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK); + struct array_buffer *buf = iter->array_buffer; + struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu); + struct tracer *type = iter->trace; + unsigned long entries; + unsigned long total; + const char *name = type->name; + + get_total_entries(buf, &total, &entries); + + seq_printf(m, "# %s latency trace v1.1.5 on %s\n", + name, UTS_RELEASE); + seq_puts(m, "# -----------------------------------" + "---------------------------------\n"); + seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |" + " (M:%s VP:%d, KP:%d, SP:%d HP:%d", + nsecs_to_usecs(data->saved_latency), + entries, + total, + buf->cpu, + preempt_model_none() ? "server" : + preempt_model_voluntary() ? "desktop" : + preempt_model_full() ? "preempt" : + preempt_model_rt() ? "preempt_rt" : + "unknown", + /* These are reserved for later use */ + 0, 0, 0, 0); +#ifdef CONFIG_SMP + seq_printf(m, " #P:%d)\n", num_online_cpus()); +#else + seq_puts(m, ")\n"); +#endif + seq_puts(m, "# -----------------\n"); + seq_printf(m, "# | task: %.16s-%d " + "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n", + data->comm, data->pid, + from_kuid_munged(seq_user_ns(m), data->uid), data->nice, + data->policy, data->rt_priority); + seq_puts(m, "# -----------------\n"); + + if (data->critical_start) { + seq_puts(m, "# => started at: "); + seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags); + trace_print_seq(m, &iter->seq); + seq_puts(m, "\n# => ended at: "); + seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags); + trace_print_seq(m, &iter->seq); + seq_puts(m, "\n#\n"); + } + + seq_puts(m, "#\n"); +} + +static void test_cpu_buff_start(struct trace_iterator *iter) +{ + struct trace_seq *s = &iter->seq; + struct trace_array *tr = iter->tr; + + if (!(tr->trace_flags & TRACE_ITER_ANNOTATE)) + return; + + if (!(iter->iter_flags & TRACE_FILE_ANNOTATE)) + return; + + if (cpumask_available(iter->started) && + cpumask_test_cpu(iter->cpu, iter->started)) + return; + + if (per_cpu_ptr(iter->array_buffer->data, iter->cpu)->skipped_entries) + return; + + if (cpumask_available(iter->started)) + cpumask_set_cpu(iter->cpu, iter->started); + + /* Don't print started cpu buffer for the first entry of the trace */ + if (iter->idx > 1) + trace_seq_printf(s, "##### CPU %u buffer started ####\n", + iter->cpu); +} + +static enum print_line_t print_trace_fmt(struct trace_iterator *iter) +{ + struct trace_array *tr = iter->tr; + struct trace_seq *s = &iter->seq; + unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK); + struct trace_entry *entry; + struct trace_event *event; + + entry = iter->ent; + + test_cpu_buff_start(iter); + + event = ftrace_find_event(entry->type); + + if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) { + if (iter->iter_flags & TRACE_FILE_LAT_FMT) + trace_print_lat_context(iter); + else + trace_print_context(iter); + } + + if (trace_seq_has_overflowed(s)) + return TRACE_TYPE_PARTIAL_LINE; + + if (event) { + if (tr->trace_flags & TRACE_ITER_FIELDS) + return print_event_fields(iter, event); + return event->funcs->trace(iter, sym_flags, event); + } + + trace_seq_printf(s, "Unknown type %d\n", entry->type); + + return trace_handle_return(s); +} + +static enum print_line_t print_raw_fmt(struct trace_iterator *iter) +{ + struct trace_array *tr = iter->tr; + struct trace_seq *s = &iter->seq; + struct trace_entry *entry; + struct trace_event *event; + + entry = iter->ent; + + if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) + trace_seq_printf(s, "%d %d %llu ", + entry->pid, iter->cpu, iter->ts); + + if (trace_seq_has_overflowed(s)) + return TRACE_TYPE_PARTIAL_LINE; + + event = ftrace_find_event(entry->type); + if (event) + return event->funcs->raw(iter, 0, event); + + trace_seq_printf(s, "%d ?\n", entry->type); + + return trace_handle_return(s); +} + +static enum print_line_t print_hex_fmt(struct trace_iterator *iter) +{ + struct trace_array *tr = iter->tr; + struct trace_seq *s = &iter->seq; + unsigned char newline = '\n'; + struct trace_entry *entry; + struct trace_event *event; + + entry = iter->ent; + + if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) { + SEQ_PUT_HEX_FIELD(s, entry->pid); + SEQ_PUT_HEX_FIELD(s, iter->cpu); + SEQ_PUT_HEX_FIELD(s, iter->ts); + if (trace_seq_has_overflowed(s)) + return TRACE_TYPE_PARTIAL_LINE; + } + + event = ftrace_find_event(entry->type); + if (event) { + enum print_line_t ret = event->funcs->hex(iter, 0, event); + if (ret != TRACE_TYPE_HANDLED) + return ret; + } + + SEQ_PUT_FIELD(s, newline); + + return trace_handle_return(s); +} + +static enum print_line_t print_bin_fmt(struct trace_iterator *iter) +{ + struct trace_array *tr = iter->tr; + struct trace_seq *s = &iter->seq; + struct trace_entry *entry; + struct trace_event *event; + + entry = iter->ent; + + if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) { + SEQ_PUT_FIELD(s, entry->pid); + SEQ_PUT_FIELD(s, iter->cpu); + SEQ_PUT_FIELD(s, iter->ts); + if (trace_seq_has_overflowed(s)) + return TRACE_TYPE_PARTIAL_LINE; + } + + event = ftrace_find_event(entry->type); + return event ? event->funcs->binary(iter, 0, event) : + TRACE_TYPE_HANDLED; +} + +int trace_empty(struct trace_iterator *iter) +{ + struct ring_buffer_iter *buf_iter; + int cpu; + + /* If we are looking at one CPU buffer, only check that one */ + if (iter->cpu_file != RING_BUFFER_ALL_CPUS) { + cpu = iter->cpu_file; + buf_iter = trace_buffer_iter(iter, cpu); + if (buf_iter) { + if (!ring_buffer_iter_empty(buf_iter)) + return 0; + } else { + if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu)) + return 0; + } + return 1; + } + + for_each_tracing_cpu(cpu) { + buf_iter = trace_buffer_iter(iter, cpu); + if (buf_iter) { + if (!ring_buffer_iter_empty(buf_iter)) + return 0; + } else { + if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu)) + return 0; + } + } + + return 1; +} + +/* Called with trace_event_read_lock() held. */ +enum print_line_t print_trace_line(struct trace_iterator *iter) +{ + struct trace_array *tr = iter->tr; + unsigned long trace_flags = tr->trace_flags; + enum print_line_t ret; + + if (iter->lost_events) { + if (iter->lost_events == (unsigned long)-1) + trace_seq_printf(&iter->seq, "CPU:%d [LOST EVENTS]\n", + iter->cpu); + else + trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n", + iter->cpu, iter->lost_events); + if (trace_seq_has_overflowed(&iter->seq)) + return TRACE_TYPE_PARTIAL_LINE; + } + + if (iter->trace && iter->trace->print_line) { + ret = iter->trace->print_line(iter); + if (ret != TRACE_TYPE_UNHANDLED) + return ret; + } + + if (iter->ent->type == TRACE_BPUTS && + trace_flags & TRACE_ITER_PRINTK && + trace_flags & TRACE_ITER_PRINTK_MSGONLY) + return trace_print_bputs_msg_only(iter); + + if (iter->ent->type == TRACE_BPRINT && + trace_flags & TRACE_ITER_PRINTK && + trace_flags & TRACE_ITER_PRINTK_MSGONLY) + return trace_print_bprintk_msg_only(iter); + + if (iter->ent->type == TRACE_PRINT && + trace_flags & TRACE_ITER_PRINTK && + trace_flags & TRACE_ITER_PRINTK_MSGONLY) + return trace_print_printk_msg_only(iter); + + if (trace_flags & TRACE_ITER_BIN) + return print_bin_fmt(iter); + + if (trace_flags & TRACE_ITER_HEX) + return print_hex_fmt(iter); + + if (trace_flags & TRACE_ITER_RAW) + return print_raw_fmt(iter); + + return print_trace_fmt(iter); +} + +void trace_latency_header(struct seq_file *m) +{ + struct trace_iterator *iter = m->private; + struct trace_array *tr = iter->tr; + + /* print nothing if the buffers are empty */ + if (trace_empty(iter)) + return; + + if (iter->iter_flags & TRACE_FILE_LAT_FMT) + print_trace_header(m, iter); + + if (!(tr->trace_flags & TRACE_ITER_VERBOSE)) + print_lat_help_header(m); +} + +void trace_default_header(struct seq_file *m) +{ + struct trace_iterator *iter = m->private; + struct trace_array *tr = iter->tr; + unsigned long trace_flags = tr->trace_flags; + + if (!(trace_flags & TRACE_ITER_CONTEXT_INFO)) + return; + + if (iter->iter_flags & TRACE_FILE_LAT_FMT) { + /* print nothing if the buffers are empty */ + if (trace_empty(iter)) + return; + print_trace_header(m, iter); + if (!(trace_flags & TRACE_ITER_VERBOSE)) + print_lat_help_header(m); + } else { + if (!(trace_flags & TRACE_ITER_VERBOSE)) { + if (trace_flags & TRACE_ITER_IRQ_INFO) + print_func_help_header_irq(iter->array_buffer, + m, trace_flags); + else + print_func_help_header(iter->array_buffer, m, + trace_flags); + } + } +} + +static void test_ftrace_alive(struct seq_file *m) +{ + if (!ftrace_is_dead()) + return; + seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n" + "# MAY BE MISSING FUNCTION EVENTS\n"); +} + +#ifdef CONFIG_TRACER_MAX_TRACE +static void show_snapshot_main_help(struct seq_file *m) +{ + seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n" + "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n" + "# Takes a snapshot of the main buffer.\n" + "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n" + "# (Doesn't have to be '2' works with any number that\n" + "# is not a '0' or '1')\n"); +} + +static void show_snapshot_percpu_help(struct seq_file *m) +{ + seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n"); +#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP + seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n" + "# Takes a snapshot of the main buffer for this cpu.\n"); +#else + seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n" + "# Must use main snapshot file to allocate.\n"); +#endif + seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n" + "# (Doesn't have to be '2' works with any number that\n" + "# is not a '0' or '1')\n"); +} + +static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) +{ + if (iter->tr->allocated_snapshot) + seq_puts(m, "#\n# * Snapshot is allocated *\n#\n"); + else + seq_puts(m, "#\n# * Snapshot is freed *\n#\n"); + + seq_puts(m, "# Snapshot commands:\n"); + if (iter->cpu_file == RING_BUFFER_ALL_CPUS) + show_snapshot_main_help(m); + else + show_snapshot_percpu_help(m); +} +#else +/* Should never be called */ +static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { } +#endif + +static int s_show(struct seq_file *m, void *v) +{ + struct trace_iterator *iter = v; + int ret; + + if (iter->ent == NULL) { + if (iter->tr) { + seq_printf(m, "# tracer: %s\n", iter->trace->name); + seq_puts(m, "#\n"); + test_ftrace_alive(m); + } + if (iter->snapshot && trace_empty(iter)) + print_snapshot_help(m, iter); + else if (iter->trace && iter->trace->print_header) + iter->trace->print_header(m); + else + trace_default_header(m); + + } else if (iter->leftover) { + /* + * If we filled the seq_file buffer earlier, we + * want to just show it now. + */ + ret = trace_print_seq(m, &iter->seq); + + /* ret should this time be zero, but you never know */ + iter->leftover = ret; + + } else { + ret = print_trace_line(iter); + if (ret == TRACE_TYPE_PARTIAL_LINE) { + iter->seq.full = 0; + trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n"); + } + ret = trace_print_seq(m, &iter->seq); + /* + * If we overflow the seq_file buffer, then it will + * ask us for this data again at start up. + * Use that instead. + * ret is 0 if seq_file write succeeded. + * -1 otherwise. + */ + iter->leftover = ret; + } + + return 0; +} + +/* + * Should be used after trace_array_get(), trace_types_lock + * ensures that i_cdev was already initialized. + */ +static inline int tracing_get_cpu(struct inode *inode) +{ + if (inode->i_cdev) /* See trace_create_cpu_file() */ + return (long)inode->i_cdev - 1; + return RING_BUFFER_ALL_CPUS; +} + +static const struct seq_operations tracer_seq_ops = { + .start = s_start, + .next = s_next, + .stop = s_stop, + .show = s_show, +}; + +/* + * Note, as iter itself can be allocated and freed in different + * ways, this function is only used to free its content, and not + * the iterator itself. The only requirement to all the allocations + * is that it must zero all fields (kzalloc), as freeing works with + * ethier allocated content or NULL. + */ +static void free_trace_iter_content(struct trace_iterator *iter) +{ + /* The fmt is either NULL, allocated or points to static_fmt_buf */ + if (iter->fmt != static_fmt_buf) + kfree(iter->fmt); + + kfree(iter->temp); + kfree(iter->buffer_iter); + mutex_destroy(&iter->mutex); + free_cpumask_var(iter->started); +} + +static struct trace_iterator * +__tracing_open(struct inode *inode, struct file *file, bool snapshot) +{ + struct trace_array *tr = inode->i_private; + struct trace_iterator *iter; + int cpu; + + if (tracing_disabled) + return ERR_PTR(-ENODEV); + + iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter)); + if (!iter) + return ERR_PTR(-ENOMEM); + + iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter), + GFP_KERNEL); + if (!iter->buffer_iter) + goto release; + + /* + * trace_find_next_entry() may need to save off iter->ent. + * It will place it into the iter->temp buffer. As most + * events are less than 128, allocate a buffer of that size. + * If one is greater, then trace_find_next_entry() will + * allocate a new buffer to adjust for the bigger iter->ent. + * It's not critical if it fails to get allocated here. + */ + iter->temp = kmalloc(128, GFP_KERNEL); + if (iter->temp) + iter->temp_size = 128; + + /* + * trace_event_printf() may need to modify given format + * string to replace %p with %px so that it shows real address + * instead of hash value. However, that is only for the event + * tracing, other tracer may not need. Defer the allocation + * until it is needed. + */ + iter->fmt = NULL; + iter->fmt_size = 0; + + mutex_lock(&trace_types_lock); + iter->trace = tr->current_trace; + + if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL)) + goto fail; + + iter->tr = tr; + +#ifdef CONFIG_TRACER_MAX_TRACE + /* Currently only the top directory has a snapshot */ + if (tr->current_trace->print_max || snapshot) + iter->array_buffer = &tr->max_buffer; + else +#endif + iter->array_buffer = &tr->array_buffer; + iter->snapshot = snapshot; + iter->pos = -1; + iter->cpu_file = tracing_get_cpu(inode); + mutex_init(&iter->mutex); + + /* Notify the tracer early; before we stop tracing. */ + if (iter->trace->open) + iter->trace->open(iter); + + /* Annotate start of buffers if we had overruns */ + if (ring_buffer_overruns(iter->array_buffer->buffer)) + iter->iter_flags |= TRACE_FILE_ANNOTATE; + + /* Output in nanoseconds only if we are using a clock in nanoseconds. */ + if (trace_clocks[tr->clock_id].in_ns) + iter->iter_flags |= TRACE_FILE_TIME_IN_NS; + + /* + * If pause-on-trace is enabled, then stop the trace while + * dumping, unless this is the "snapshot" file + */ + if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE)) + tracing_stop_tr(tr); + + if (iter->cpu_file == RING_BUFFER_ALL_CPUS) { + for_each_tracing_cpu(cpu) { + iter->buffer_iter[cpu] = + ring_buffer_read_prepare(iter->array_buffer->buffer, + cpu, GFP_KERNEL); + } + ring_buffer_read_prepare_sync(); + for_each_tracing_cpu(cpu) { + ring_buffer_read_start(iter->buffer_iter[cpu]); + tracing_iter_reset(iter, cpu); + } + } else { + cpu = iter->cpu_file; + iter->buffer_iter[cpu] = + ring_buffer_read_prepare(iter->array_buffer->buffer, + cpu, GFP_KERNEL); + ring_buffer_read_prepare_sync(); + ring_buffer_read_start(iter->buffer_iter[cpu]); + tracing_iter_reset(iter, cpu); + } + + mutex_unlock(&trace_types_lock); + + return iter; + + fail: + mutex_unlock(&trace_types_lock); + free_trace_iter_content(iter); +release: + seq_release_private(inode, file); + return ERR_PTR(-ENOMEM); +} + +int tracing_open_generic(struct inode *inode, struct file *filp) +{ + int ret; + + ret = tracing_check_open_get_tr(NULL); + if (ret) + return ret; + + filp->private_data = inode->i_private; + return 0; +} + +bool tracing_is_disabled(void) +{ + return (tracing_disabled) ? true: false; +} + +/* + * Open and update trace_array ref count. + * Must have the current trace_array passed to it. + */ +int tracing_open_generic_tr(struct inode *inode, struct file *filp) +{ + struct trace_array *tr = inode->i_private; + int ret; + + ret = tracing_check_open_get_tr(tr); + if (ret) + return ret; + + filp->private_data = inode->i_private; + + return 0; +} + +/* + * The private pointer of the inode is the trace_event_file. + * Update the tr ref count associated to it. + */ +int tracing_open_file_tr(struct inode *inode, struct file *filp) +{ + struct trace_event_file *file = inode->i_private; + int ret; + + ret = tracing_check_open_get_tr(file->tr); + if (ret) + return ret; + + mutex_lock(&event_mutex); + + /* Fail if the file is marked for removal */ + if (file->flags & EVENT_FILE_FL_FREED) { + trace_array_put(file->tr); + ret = -ENODEV; + } else { + event_file_get(file); + } + + mutex_unlock(&event_mutex); + if (ret) + return ret; + + filp->private_data = inode->i_private; + + return 0; +} + +int tracing_release_file_tr(struct inode *inode, struct file *filp) +{ + struct trace_event_file *file = inode->i_private; + + trace_array_put(file->tr); + event_file_put(file); + + return 0; +} + +int tracing_single_release_file_tr(struct inode *inode, struct file *filp) +{ + tracing_release_file_tr(inode, filp); + return single_release(inode, filp); +} + +static int tracing_mark_open(struct inode *inode, struct file *filp) +{ + stream_open(inode, filp); + return tracing_open_generic_tr(inode, filp); +} + +static int tracing_release(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + struct seq_file *m = file->private_data; + struct trace_iterator *iter; + int cpu; + + if (!(file->f_mode & FMODE_READ)) { + trace_array_put(tr); + return 0; + } + + /* Writes do not use seq_file */ + iter = m->private; + mutex_lock(&trace_types_lock); + + for_each_tracing_cpu(cpu) { + if (iter->buffer_iter[cpu]) + ring_buffer_read_finish(iter->buffer_iter[cpu]); + } + + if (iter->trace && iter->trace->close) + iter->trace->close(iter); + + if (!iter->snapshot && tr->stop_count) + /* reenable tracing if it was previously enabled */ + tracing_start_tr(tr); + + __trace_array_put(tr); + + mutex_unlock(&trace_types_lock); + + free_trace_iter_content(iter); + seq_release_private(inode, file); + + return 0; +} + +static int tracing_release_generic_tr(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + + trace_array_put(tr); + return 0; +} + +static int tracing_single_release_tr(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + + trace_array_put(tr); + + return single_release(inode, file); +} + +static int tracing_open(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + struct trace_iterator *iter; + int ret; + + ret = tracing_check_open_get_tr(tr); + if (ret) + return ret; + + /* If this file was open for write, then erase contents */ + if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { + int cpu = tracing_get_cpu(inode); + struct array_buffer *trace_buf = &tr->array_buffer; + +#ifdef CONFIG_TRACER_MAX_TRACE + if (tr->current_trace->print_max) + trace_buf = &tr->max_buffer; +#endif + + if (cpu == RING_BUFFER_ALL_CPUS) + tracing_reset_online_cpus(trace_buf); + else + tracing_reset_cpu(trace_buf, cpu); + } + + if (file->f_mode & FMODE_READ) { + iter = __tracing_open(inode, file, false); + if (IS_ERR(iter)) + ret = PTR_ERR(iter); + else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) + iter->iter_flags |= TRACE_FILE_LAT_FMT; + } + + if (ret < 0) + trace_array_put(tr); + + return ret; +} + +/* + * Some tracers are not suitable for instance buffers. + * A tracer is always available for the global array (toplevel) + * or if it explicitly states that it is. + */ +static bool +trace_ok_for_array(struct tracer *t, struct trace_array *tr) +{ + return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances; +} + +/* Find the next tracer that this trace array may use */ +static struct tracer * +get_tracer_for_array(struct trace_array *tr, struct tracer *t) +{ + while (t && !trace_ok_for_array(t, tr)) + t = t->next; + + return t; +} + +static void * +t_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct trace_array *tr = m->private; + struct tracer *t = v; + + (*pos)++; + + if (t) + t = get_tracer_for_array(tr, t->next); + + return t; +} + +static void *t_start(struct seq_file *m, loff_t *pos) +{ + struct trace_array *tr = m->private; + struct tracer *t; + loff_t l = 0; + + mutex_lock(&trace_types_lock); + + t = get_tracer_for_array(tr, trace_types); + for (; t && l < *pos; t = t_next(m, t, &l)) + ; + + return t; +} + +static void t_stop(struct seq_file *m, void *p) +{ + mutex_unlock(&trace_types_lock); +} + +static int t_show(struct seq_file *m, void *v) +{ + struct tracer *t = v; + + if (!t) + return 0; + + seq_puts(m, t->name); + if (t->next) + seq_putc(m, ' '); + else + seq_putc(m, '\n'); + + return 0; +} + +static const struct seq_operations show_traces_seq_ops = { + .start = t_start, + .next = t_next, + .stop = t_stop, + .show = t_show, +}; + +static int show_traces_open(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + struct seq_file *m; + int ret; + + ret = tracing_check_open_get_tr(tr); + if (ret) + return ret; + + ret = seq_open(file, &show_traces_seq_ops); + if (ret) { + trace_array_put(tr); + return ret; + } + + m = file->private_data; + m->private = tr; + + return 0; +} + +static int show_traces_release(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + + trace_array_put(tr); + return seq_release(inode, file); +} + +static ssize_t +tracing_write_stub(struct file *filp, const char __user *ubuf, + size_t count, loff_t *ppos) +{ + return count; +} + +loff_t tracing_lseek(struct file *file, loff_t offset, int whence) +{ + int ret; + + if (file->f_mode & FMODE_READ) + ret = seq_lseek(file, offset, whence); + else + file->f_pos = ret = 0; + + return ret; +} + +static const struct file_operations tracing_fops = { + .open = tracing_open, + .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = copy_splice_read, + .write = tracing_write_stub, + .llseek = tracing_lseek, + .release = tracing_release, +}; + +static const struct file_operations show_traces_fops = { + .open = show_traces_open, + .read = seq_read, + .llseek = seq_lseek, + .release = show_traces_release, +}; + +static ssize_t +tracing_cpumask_read(struct file *filp, char __user *ubuf, + size_t count, loff_t *ppos) +{ + struct trace_array *tr = file_inode(filp)->i_private; + char *mask_str; + int len; + + len = snprintf(NULL, 0, "%*pb\n", + cpumask_pr_args(tr->tracing_cpumask)) + 1; + mask_str = kmalloc(len, GFP_KERNEL); + if (!mask_str) + return -ENOMEM; + + len = snprintf(mask_str, len, "%*pb\n", + cpumask_pr_args(tr->tracing_cpumask)); + if (len >= count) { + count = -EINVAL; + goto out_err; + } + count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len); + +out_err: + kfree(mask_str); + + return count; +} + +int tracing_set_cpumask(struct trace_array *tr, + cpumask_var_t tracing_cpumask_new) +{ + int cpu; + + if (!tr) + return -EINVAL; + + local_irq_disable(); + arch_spin_lock(&tr->max_lock); + for_each_tracing_cpu(cpu) { + /* + * Increase/decrease the disabled counter if we are + * about to flip a bit in the cpumask: + */ + if (cpumask_test_cpu(cpu, tr->tracing_cpumask) && + !cpumask_test_cpu(cpu, tracing_cpumask_new)) { + atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled); + ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu); +#ifdef CONFIG_TRACER_MAX_TRACE + ring_buffer_record_disable_cpu(tr->max_buffer.buffer, cpu); +#endif + } + if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) && + cpumask_test_cpu(cpu, tracing_cpumask_new)) { + atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled); + ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu); +#ifdef CONFIG_TRACER_MAX_TRACE + ring_buffer_record_enable_cpu(tr->max_buffer.buffer, cpu); +#endif + } + } + arch_spin_unlock(&tr->max_lock); + local_irq_enable(); + + cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new); + + return 0; +} + +static ssize_t +tracing_cpumask_write(struct file *filp, const char __user *ubuf, + size_t count, loff_t *ppos) +{ + struct trace_array *tr = file_inode(filp)->i_private; + cpumask_var_t tracing_cpumask_new; + int err; + + if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL)) + return -ENOMEM; + + err = cpumask_parse_user(ubuf, count, tracing_cpumask_new); + if (err) + goto err_free; + + err = tracing_set_cpumask(tr, tracing_cpumask_new); + if (err) + goto err_free; + + free_cpumask_var(tracing_cpumask_new); + + return count; + +err_free: + free_cpumask_var(tracing_cpumask_new); + + return err; +} + +static const struct file_operations tracing_cpumask_fops = { + .open = tracing_open_generic_tr, + .read = tracing_cpumask_read, + .write = tracing_cpumask_write, + .release = tracing_release_generic_tr, + .llseek = generic_file_llseek, +}; + +static int tracing_trace_options_show(struct seq_file *m, void *v) +{ + struct tracer_opt *trace_opts; + struct trace_array *tr = m->private; + u32 tracer_flags; + int i; + + mutex_lock(&trace_types_lock); + tracer_flags = tr->current_trace->flags->val; + trace_opts = tr->current_trace->flags->opts; + + for (i = 0; trace_options[i]; i++) { + if (tr->trace_flags & (1 << i)) + seq_printf(m, "%s\n", trace_options[i]); + else + seq_printf(m, "no%s\n", trace_options[i]); + } + + for (i = 0; trace_opts[i].name; i++) { + if (tracer_flags & trace_opts[i].bit) + seq_printf(m, "%s\n", trace_opts[i].name); + else + seq_printf(m, "no%s\n", trace_opts[i].name); + } + mutex_unlock(&trace_types_lock); + + return 0; +} + +static int __set_tracer_option(struct trace_array *tr, + struct tracer_flags *tracer_flags, + struct tracer_opt *opts, int neg) +{ + struct tracer *trace = tracer_flags->trace; + int ret; + + ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg); + if (ret) + return ret; + + if (neg) + tracer_flags->val &= ~opts->bit; + else + tracer_flags->val |= opts->bit; + return 0; +} + +/* Try to assign a tracer specific option */ +static int set_tracer_option(struct trace_array *tr, char *cmp, int neg) +{ + struct tracer *trace = tr->current_trace; + struct tracer_flags *tracer_flags = trace->flags; + struct tracer_opt *opts = NULL; + int i; + + for (i = 0; tracer_flags->opts[i].name; i++) { + opts = &tracer_flags->opts[i]; + + if (strcmp(cmp, opts->name) == 0) + return __set_tracer_option(tr, trace->flags, opts, neg); + } + + return -EINVAL; +} + +/* Some tracers require overwrite to stay enabled */ +int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set) +{ + if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set) + return -1; + + return 0; +} + +int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled) +{ + int *map; + + if ((mask == TRACE_ITER_RECORD_TGID) || + (mask == TRACE_ITER_RECORD_CMD)) + lockdep_assert_held(&event_mutex); + + /* do nothing if flag is already set */ + if (!!(tr->trace_flags & mask) == !!enabled) + return 0; + + /* Give the tracer a chance to approve the change */ + if (tr->current_trace->flag_changed) + if (tr->current_trace->flag_changed(tr, mask, !!enabled)) + return -EINVAL; + + if (enabled) + tr->trace_flags |= mask; + else + tr->trace_flags &= ~mask; + + if (mask == TRACE_ITER_RECORD_CMD) + trace_event_enable_cmd_record(enabled); + + if (mask == TRACE_ITER_RECORD_TGID) { + if (!tgid_map) { + tgid_map_max = pid_max; + map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map), + GFP_KERNEL); + + /* + * Pairs with smp_load_acquire() in + * trace_find_tgid_ptr() to ensure that if it observes + * the tgid_map we just allocated then it also observes + * the corresponding tgid_map_max value. + */ + smp_store_release(&tgid_map, map); + } + if (!tgid_map) { + tr->trace_flags &= ~TRACE_ITER_RECORD_TGID; + return -ENOMEM; + } + + trace_event_enable_tgid_record(enabled); + } + + if (mask == TRACE_ITER_EVENT_FORK) + trace_event_follow_fork(tr, enabled); + + if (mask == TRACE_ITER_FUNC_FORK) + ftrace_pid_follow_fork(tr, enabled); + + if (mask == TRACE_ITER_OVERWRITE) { + ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled); +#ifdef CONFIG_TRACER_MAX_TRACE + ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled); +#endif + } + + if (mask == TRACE_ITER_PRINTK) { + trace_printk_start_stop_comm(enabled); + trace_printk_control(enabled); + } + + return 0; +} + +int trace_set_options(struct trace_array *tr, char *option) +{ + char *cmp; + int neg = 0; + int ret; + size_t orig_len = strlen(option); + int len; + + cmp = strstrip(option); + + len = str_has_prefix(cmp, "no"); + if (len) + neg = 1; + + cmp += len; + + mutex_lock(&event_mutex); + mutex_lock(&trace_types_lock); + + ret = match_string(trace_options, -1, cmp); + /* If no option could be set, test the specific tracer options */ + if (ret < 0) + ret = set_tracer_option(tr, cmp, neg); + else + ret = set_tracer_flag(tr, 1 << ret, !neg); + + mutex_unlock(&trace_types_lock); + mutex_unlock(&event_mutex); + + /* + * If the first trailing whitespace is replaced with '\0' by strstrip, + * turn it back into a space. + */ + if (orig_len > strlen(option)) + option[strlen(option)] = ' '; + + return ret; +} + +static void __init apply_trace_boot_options(void) +{ + char *buf = trace_boot_options_buf; + char *option; + + while (true) { + option = strsep(&buf, ","); + + if (!option) + break; + + if (*option) + trace_set_options(&global_trace, option); + + /* Put back the comma to allow this to be called again */ + if (buf) + *(buf - 1) = ','; + } +} + +static ssize_t +tracing_trace_options_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct seq_file *m = filp->private_data; + struct trace_array *tr = m->private; + char buf[64]; + int ret; + + if (cnt >= sizeof(buf)) + return -EINVAL; + + if (copy_from_user(buf, ubuf, cnt)) + return -EFAULT; + + buf[cnt] = 0; + + ret = trace_set_options(tr, buf); + if (ret < 0) + return ret; + + *ppos += cnt; + + return cnt; +} + +static int tracing_trace_options_open(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + int ret; + + ret = tracing_check_open_get_tr(tr); + if (ret) + return ret; + + ret = single_open(file, tracing_trace_options_show, inode->i_private); + if (ret < 0) + trace_array_put(tr); + + return ret; +} + +static const struct file_operations tracing_iter_fops = { + .open = tracing_trace_options_open, + .read = seq_read, + .llseek = seq_lseek, + .release = tracing_single_release_tr, + .write = tracing_trace_options_write, +}; + +static const char readme_msg[] = + "tracing mini-HOWTO:\n\n" + "# echo 0 > tracing_on : quick way to disable tracing\n" + "# echo 1 > tracing_on : quick way to re-enable tracing\n\n" + " Important files:\n" + " trace\t\t\t- The static contents of the buffer\n" + "\t\t\t To clear the buffer write into this file: echo > trace\n" + " trace_pipe\t\t- A consuming read to see the contents of the buffer\n" + " current_tracer\t- function and latency tracers\n" + " available_tracers\t- list of configured tracers for current_tracer\n" + " error_log\t- error log for failed commands (that support it)\n" + " buffer_size_kb\t- view and modify size of per cpu buffer\n" + " buffer_total_size_kb - view total size of all cpu buffers\n\n" + " trace_clock\t\t- change the clock used to order events\n" + " local: Per cpu clock but may not be synced across CPUs\n" + " global: Synced across CPUs but slows tracing down.\n" + " counter: Not a clock, but just an increment\n" + " uptime: Jiffy counter from time of boot\n" + " perf: Same clock that perf events use\n" +#ifdef CONFIG_X86_64 + " x86-tsc: TSC cycle counter\n" +#endif + "\n timestamp_mode\t- view the mode used to timestamp events\n" + " delta: Delta difference against a buffer-wide timestamp\n" + " absolute: Absolute (standalone) timestamp\n" + "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n" + "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n" + " tracing_cpumask\t- Limit which CPUs to trace\n" + " instances\t\t- Make sub-buffers with: mkdir instances/foo\n" + "\t\t\t Remove sub-buffer with rmdir\n" + " trace_options\t\t- Set format or modify how tracing happens\n" + "\t\t\t Disable an option by prefixing 'no' to the\n" + "\t\t\t option name\n" + " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n" +#ifdef CONFIG_DYNAMIC_FTRACE + "\n available_filter_functions - list of functions that can be filtered on\n" + " set_ftrace_filter\t- echo function name in here to only trace these\n" + "\t\t\t functions\n" + "\t accepts: func_full_name or glob-matching-pattern\n" + "\t modules: Can select a group via module\n" + "\t Format: :mod:<module-name>\n" + "\t example: echo :mod:ext3 > set_ftrace_filter\n" + "\t triggers: a command to perform when function is hit\n" + "\t Format: <function>:<trigger>[:count]\n" + "\t trigger: traceon, traceoff\n" + "\t\t enable_event:<system>:<event>\n" + "\t\t disable_event:<system>:<event>\n" +#ifdef CONFIG_STACKTRACE + "\t\t stacktrace\n" +#endif +#ifdef CONFIG_TRACER_SNAPSHOT + "\t\t snapshot\n" +#endif + "\t\t dump\n" + "\t\t cpudump\n" + "\t example: echo do_fault:traceoff > set_ftrace_filter\n" + "\t echo do_trap:traceoff:3 > set_ftrace_filter\n" + "\t The first one will disable tracing every time do_fault is hit\n" + "\t The second will disable tracing at most 3 times when do_trap is hit\n" + "\t The first time do trap is hit and it disables tracing, the\n" + "\t counter will decrement to 2. If tracing is already disabled,\n" + "\t the counter will not decrement. It only decrements when the\n" + "\t trigger did work\n" + "\t To remove trigger without count:\n" + "\t echo '!<function>:<trigger> > set_ftrace_filter\n" + "\t To remove trigger with a count:\n" + "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n" + " set_ftrace_notrace\t- echo function name in here to never trace.\n" + "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n" + "\t modules: Can select a group via module command :mod:\n" + "\t Does not accept triggers\n" +#endif /* CONFIG_DYNAMIC_FTRACE */ +#ifdef CONFIG_FUNCTION_TRACER + " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n" + "\t\t (function)\n" + " set_ftrace_notrace_pid\t- Write pid(s) to not function trace those pids\n" + "\t\t (function)\n" +#endif +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + " set_graph_function\t- Trace the nested calls of a function (function_graph)\n" + " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n" + " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n" +#endif +#ifdef CONFIG_TRACER_SNAPSHOT + "\n snapshot\t\t- Like 'trace' but shows the content of the static\n" + "\t\t\t snapshot buffer. Read the contents for more\n" + "\t\t\t information\n" +#endif +#ifdef CONFIG_STACK_TRACER + " stack_trace\t\t- Shows the max stack trace when active\n" + " stack_max_size\t- Shows current max stack size that was traced\n" + "\t\t\t Write into this file to reset the max size (trigger a\n" + "\t\t\t new trace)\n" +#ifdef CONFIG_DYNAMIC_FTRACE + " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n" + "\t\t\t traces\n" +#endif +#endif /* CONFIG_STACK_TRACER */ +#ifdef CONFIG_DYNAMIC_EVENTS + " dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n" + "\t\t\t Write into this file to define/undefine new trace events.\n" +#endif +#ifdef CONFIG_KPROBE_EVENTS + " kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n" + "\t\t\t Write into this file to define/undefine new trace events.\n" +#endif +#ifdef CONFIG_UPROBE_EVENTS + " uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n" + "\t\t\t Write into this file to define/undefine new trace events.\n" +#endif +#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) || \ + defined(CONFIG_FPROBE_EVENTS) + "\t accepts: event-definitions (one definition per line)\n" +#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) + "\t Format: p[:[<group>/][<event>]] <place> [<args>]\n" + "\t r[maxactive][:[<group>/][<event>]] <place> [<args>]\n" +#endif +#ifdef CONFIG_FPROBE_EVENTS + "\t f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n" + "\t t[:[<group>/][<event>]] <tracepoint> [<args>]\n" +#endif +#ifdef CONFIG_HIST_TRIGGERS + "\t s:[synthetic/]<event> <field> [<field>]\n" +#endif + "\t e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>] [if <filter>]\n" + "\t -:[<group>/][<event>]\n" +#ifdef CONFIG_KPROBE_EVENTS + "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n" + "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n" +#endif +#ifdef CONFIG_UPROBE_EVENTS + " place (uprobe): <path>:<offset>[%return][(ref_ctr_offset)]\n" +#endif + "\t args: <name>=fetcharg[:type]\n" + "\t fetcharg: (%<register>|$<efield>), @<address>, @<symbol>[+|-<offset>],\n" +#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API +#ifdef CONFIG_PROBE_EVENTS_BTF_ARGS + "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n" + "\t <argname>[->field[->field|.field...]],\n" +#else + "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n" +#endif +#else + "\t $stack<index>, $stack, $retval, $comm,\n" +#endif + "\t +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n" + "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, char, string, symbol,\n" + "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n" + "\t symstr, <type>\\[<array-size>\\]\n" +#ifdef CONFIG_HIST_TRIGGERS + "\t field: <stype> <name>;\n" + "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n" + "\t [unsigned] char/int/long\n" +#endif + "\t efield: For event probes ('e' types), the field is on of the fields\n" + "\t of the <attached-group>/<attached-event>.\n" +#endif + " events/\t\t- Directory containing all trace event subsystems:\n" + " enable\t\t- Write 0/1 to enable/disable tracing of all events\n" + " events/<system>/\t- Directory containing all trace events for <system>:\n" + " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n" + "\t\t\t events\n" + " filter\t\t- If set, only events passing filter are traced\n" + " events/<system>/<event>/\t- Directory containing control files for\n" + "\t\t\t <event>:\n" + " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n" + " filter\t\t- If set, only events passing filter are traced\n" + " trigger\t\t- If set, a command to perform when event is hit\n" + "\t Format: <trigger>[:count][if <filter>]\n" + "\t trigger: traceon, traceoff\n" + "\t enable_event:<system>:<event>\n" + "\t disable_event:<system>:<event>\n" +#ifdef CONFIG_HIST_TRIGGERS + "\t enable_hist:<system>:<event>\n" + "\t disable_hist:<system>:<event>\n" +#endif +#ifdef CONFIG_STACKTRACE + "\t\t stacktrace\n" +#endif +#ifdef CONFIG_TRACER_SNAPSHOT + "\t\t snapshot\n" +#endif +#ifdef CONFIG_HIST_TRIGGERS + "\t\t hist (see below)\n" +#endif + "\t example: echo traceoff > events/block/block_unplug/trigger\n" + "\t echo traceoff:3 > events/block/block_unplug/trigger\n" + "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n" + "\t events/block/block_unplug/trigger\n" + "\t The first disables tracing every time block_unplug is hit.\n" + "\t The second disables tracing the first 3 times block_unplug is hit.\n" + "\t The third enables the kmalloc event the first 3 times block_unplug\n" + "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n" + "\t Like function triggers, the counter is only decremented if it\n" + "\t enabled or disabled tracing.\n" + "\t To remove a trigger without a count:\n" + "\t echo '!<trigger> > <system>/<event>/trigger\n" + "\t To remove a trigger with a count:\n" + "\t echo '!<trigger>:0 > <system>/<event>/trigger\n" + "\t Filters can be ignored when removing a trigger.\n" +#ifdef CONFIG_HIST_TRIGGERS + " hist trigger\t- If set, event hits are aggregated into a hash table\n" + "\t Format: hist:keys=<field1[,field2,...]>\n" + "\t [:<var1>=<field|var_ref|numeric_literal>[,<var2>=...]]\n" + "\t [:values=<field1[,field2,...]>]\n" + "\t [:sort=<field1[,field2,...]>]\n" + "\t [:size=#entries]\n" + "\t [:pause][:continue][:clear]\n" + "\t [:name=histname1]\n" + "\t [:nohitcount]\n" + "\t [:<handler>.<action>]\n" + "\t [if <filter>]\n\n" + "\t Note, special fields can be used as well:\n" + "\t common_timestamp - to record current timestamp\n" + "\t common_cpu - to record the CPU the event happened on\n" + "\n" + "\t A hist trigger variable can be:\n" + "\t - a reference to a field e.g. x=current_timestamp,\n" + "\t - a reference to another variable e.g. y=$x,\n" + "\t - a numeric literal: e.g. ms_per_sec=1000,\n" + "\t - an arithmetic expression: e.g. time_secs=current_timestamp/1000\n" + "\n" + "\t hist trigger arithmetic expressions support addition(+), subtraction(-),\n" + "\t multiplication(*) and division(/) operators. An operand can be either a\n" + "\t variable reference, field or numeric literal.\n" + "\n" + "\t When a matching event is hit, an entry is added to a hash\n" + "\t table using the key(s) and value(s) named, and the value of a\n" + "\t sum called 'hitcount' is incremented. Keys and values\n" + "\t correspond to fields in the event's format description. Keys\n" + "\t can be any field, or the special string 'common_stacktrace'.\n" + "\t Compound keys consisting of up to two fields can be specified\n" + "\t by the 'keys' keyword. Values must correspond to numeric\n" + "\t fields. Sort keys consisting of up to two fields can be\n" + "\t specified using the 'sort' keyword. The sort direction can\n" + "\t be modified by appending '.descending' or '.ascending' to a\n" + "\t sort field. The 'size' parameter can be used to specify more\n" + "\t or fewer than the default 2048 entries for the hashtable size.\n" + "\t If a hist trigger is given a name using the 'name' parameter,\n" + "\t its histogram data will be shared with other triggers of the\n" + "\t same name, and trigger hits will update this common data.\n\n" + "\t Reading the 'hist' file for the event will dump the hash\n" + "\t table in its entirety to stdout. If there are multiple hist\n" + "\t triggers attached to an event, there will be a table for each\n" + "\t trigger in the output. The table displayed for a named\n" + "\t trigger will be the same as any other instance having the\n" + "\t same name. The default format used to display a given field\n" + "\t can be modified by appending any of the following modifiers\n" + "\t to the field name, as applicable:\n\n" + "\t .hex display a number as a hex value\n" + "\t .sym display an address as a symbol\n" + "\t .sym-offset display an address as a symbol and offset\n" + "\t .execname display a common_pid as a program name\n" + "\t .syscall display a syscall id as a syscall name\n" + "\t .log2 display log2 value rather than raw number\n" + "\t .buckets=size display values in groups of size rather than raw number\n" + "\t .usecs display a common_timestamp in microseconds\n" + "\t .percent display a number of percentage value\n" + "\t .graph display a bar-graph of a value\n\n" + "\t The 'pause' parameter can be used to pause an existing hist\n" + "\t trigger or to start a hist trigger but not log any events\n" + "\t until told to do so. 'continue' can be used to start or\n" + "\t restart a paused hist trigger.\n\n" + "\t The 'clear' parameter will clear the contents of a running\n" + "\t hist trigger and leave its current paused/active state\n" + "\t unchanged.\n\n" + "\t The 'nohitcount' (or NOHC) parameter will suppress display of\n" + "\t raw hitcount in the histogram.\n\n" + "\t The enable_hist and disable_hist triggers can be used to\n" + "\t have one event conditionally start and stop another event's\n" + "\t already-attached hist trigger. The syntax is analogous to\n" + "\t the enable_event and disable_event triggers.\n\n" + "\t Hist trigger handlers and actions are executed whenever a\n" + "\t a histogram entry is added or updated. They take the form:\n\n" + "\t <handler>.<action>\n\n" + "\t The available handlers are:\n\n" + "\t onmatch(matching.event) - invoke on addition or update\n" + "\t onmax(var) - invoke if var exceeds current max\n" + "\t onchange(var) - invoke action if var changes\n\n" + "\t The available actions are:\n\n" + "\t trace(<synthetic_event>,param list) - generate synthetic event\n" + "\t save(field,...) - save current event fields\n" +#ifdef CONFIG_TRACER_SNAPSHOT + "\t snapshot() - snapshot the trace buffer\n\n" +#endif +#ifdef CONFIG_SYNTH_EVENTS + " events/synthetic_events\t- Create/append/remove/show synthetic events\n" + "\t Write into this file to define/undefine new synthetic events.\n" + "\t example: echo 'myevent u64 lat; char name[]; long[] stack' >> synthetic_events\n" +#endif +#endif +; + +static ssize_t +tracing_readme_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + return simple_read_from_buffer(ubuf, cnt, ppos, + readme_msg, strlen(readme_msg)); +} + +static const struct file_operations tracing_readme_fops = { + .open = tracing_open_generic, + .read = tracing_readme_read, + .llseek = generic_file_llseek, +}; + +static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos) +{ + int pid = ++(*pos); + + return trace_find_tgid_ptr(pid); +} + +static void *saved_tgids_start(struct seq_file *m, loff_t *pos) +{ + int pid = *pos; + + return trace_find_tgid_ptr(pid); +} + +static void saved_tgids_stop(struct seq_file *m, void *v) +{ +} + +static int saved_tgids_show(struct seq_file *m, void *v) +{ + int *entry = (int *)v; + int pid = entry - tgid_map; + int tgid = *entry; + + if (tgid == 0) + return SEQ_SKIP; + + seq_printf(m, "%d %d\n", pid, tgid); + return 0; +} + +static const struct seq_operations tracing_saved_tgids_seq_ops = { + .start = saved_tgids_start, + .stop = saved_tgids_stop, + .next = saved_tgids_next, + .show = saved_tgids_show, +}; + +static int tracing_saved_tgids_open(struct inode *inode, struct file *filp) +{ + int ret; + + ret = tracing_check_open_get_tr(NULL); + if (ret) + return ret; + + return seq_open(filp, &tracing_saved_tgids_seq_ops); +} + + +static const struct file_operations tracing_saved_tgids_fops = { + .open = tracing_saved_tgids_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos) +{ + unsigned int *ptr = v; + + if (*pos || m->count) + ptr++; + + (*pos)++; + + for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num]; + ptr++) { + if (*ptr == -1 || *ptr == NO_CMDLINE_MAP) + continue; + + return ptr; + } + + return NULL; +} + +static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos) +{ + void *v; + loff_t l = 0; + + preempt_disable(); + arch_spin_lock(&trace_cmdline_lock); + + v = &savedcmd->map_cmdline_to_pid[0]; + while (l <= *pos) { + v = saved_cmdlines_next(m, v, &l); + if (!v) + return NULL; + } + + return v; +} + +static void saved_cmdlines_stop(struct seq_file *m, void *v) +{ + arch_spin_unlock(&trace_cmdline_lock); + preempt_enable(); +} + +static int saved_cmdlines_show(struct seq_file *m, void *v) +{ + char buf[TASK_COMM_LEN]; + unsigned int *pid = v; + + __trace_find_cmdline(*pid, buf); + seq_printf(m, "%d %s\n", *pid, buf); + return 0; +} + +static const struct seq_operations tracing_saved_cmdlines_seq_ops = { + .start = saved_cmdlines_start, + .next = saved_cmdlines_next, + .stop = saved_cmdlines_stop, + .show = saved_cmdlines_show, +}; + +static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp) +{ + int ret; + + ret = tracing_check_open_get_tr(NULL); + if (ret) + return ret; + + return seq_open(filp, &tracing_saved_cmdlines_seq_ops); +} + +static const struct file_operations tracing_saved_cmdlines_fops = { + .open = tracing_saved_cmdlines_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static ssize_t +tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[64]; + int r; + + preempt_disable(); + arch_spin_lock(&trace_cmdline_lock); + r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num); + arch_spin_unlock(&trace_cmdline_lock); + preempt_enable(); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s) +{ + kfree(s->saved_cmdlines); + kfree(s->map_cmdline_to_pid); + kfree(s); +} + +static int tracing_resize_saved_cmdlines(unsigned int val) +{ + struct saved_cmdlines_buffer *s, *savedcmd_temp; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (!s) + return -ENOMEM; + + if (allocate_cmdlines_buffer(val, s) < 0) { + kfree(s); + return -ENOMEM; + } + + preempt_disable(); + arch_spin_lock(&trace_cmdline_lock); + savedcmd_temp = savedcmd; + savedcmd = s; + arch_spin_unlock(&trace_cmdline_lock); + preempt_enable(); + free_saved_cmdlines_buffer(savedcmd_temp); + + return 0; +} + +static ssize_t +tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + unsigned long val; + int ret; + + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; + + /* must have at least 1 entry or less than PID_MAX_DEFAULT */ + if (!val || val > PID_MAX_DEFAULT) + return -EINVAL; + + ret = tracing_resize_saved_cmdlines((unsigned int)val); + if (ret < 0) + return ret; + + *ppos += cnt; + + return cnt; +} + +static const struct file_operations tracing_saved_cmdlines_size_fops = { + .open = tracing_open_generic, + .read = tracing_saved_cmdlines_size_read, + .write = tracing_saved_cmdlines_size_write, +}; + +#ifdef CONFIG_TRACE_EVAL_MAP_FILE +static union trace_eval_map_item * +update_eval_map(union trace_eval_map_item *ptr) +{ + if (!ptr->map.eval_string) { + if (ptr->tail.next) { + ptr = ptr->tail.next; + /* Set ptr to the next real item (skip head) */ + ptr++; + } else + return NULL; + } + return ptr; +} + +static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos) +{ + union trace_eval_map_item *ptr = v; + + /* + * Paranoid! If ptr points to end, we don't want to increment past it. + * This really should never happen. + */ + (*pos)++; + ptr = update_eval_map(ptr); + if (WARN_ON_ONCE(!ptr)) + return NULL; + + ptr++; + ptr = update_eval_map(ptr); + + return ptr; +} + +static void *eval_map_start(struct seq_file *m, loff_t *pos) +{ + union trace_eval_map_item *v; + loff_t l = 0; + + mutex_lock(&trace_eval_mutex); + + v = trace_eval_maps; + if (v) + v++; + + while (v && l < *pos) { + v = eval_map_next(m, v, &l); + } + + return v; +} + +static void eval_map_stop(struct seq_file *m, void *v) +{ + mutex_unlock(&trace_eval_mutex); +} + +static int eval_map_show(struct seq_file *m, void *v) +{ + union trace_eval_map_item *ptr = v; + + seq_printf(m, "%s %ld (%s)\n", + ptr->map.eval_string, ptr->map.eval_value, + ptr->map.system); + + return 0; +} + +static const struct seq_operations tracing_eval_map_seq_ops = { + .start = eval_map_start, + .next = eval_map_next, + .stop = eval_map_stop, + .show = eval_map_show, +}; + +static int tracing_eval_map_open(struct inode *inode, struct file *filp) +{ + int ret; + + ret = tracing_check_open_get_tr(NULL); + if (ret) + return ret; + + return seq_open(filp, &tracing_eval_map_seq_ops); +} + +static const struct file_operations tracing_eval_map_fops = { + .open = tracing_eval_map_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static inline union trace_eval_map_item * +trace_eval_jmp_to_tail(union trace_eval_map_item *ptr) +{ + /* Return tail of array given the head */ + return ptr + ptr->head.length + 1; +} + +static void +trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start, + int len) +{ + struct trace_eval_map **stop; + struct trace_eval_map **map; + union trace_eval_map_item *map_array; + union trace_eval_map_item *ptr; + + stop = start + len; + + /* + * The trace_eval_maps contains the map plus a head and tail item, + * where the head holds the module and length of array, and the + * tail holds a pointer to the next list. + */ + map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL); + if (!map_array) { + pr_warn("Unable to allocate trace eval mapping\n"); + return; + } + + mutex_lock(&trace_eval_mutex); + + if (!trace_eval_maps) + trace_eval_maps = map_array; + else { + ptr = trace_eval_maps; + for (;;) { + ptr = trace_eval_jmp_to_tail(ptr); + if (!ptr->tail.next) + break; + ptr = ptr->tail.next; + + } + ptr->tail.next = map_array; + } + map_array->head.mod = mod; + map_array->head.length = len; + map_array++; + + for (map = start; (unsigned long)map < (unsigned long)stop; map++) { + map_array->map = **map; + map_array++; + } + memset(map_array, 0, sizeof(*map_array)); + + mutex_unlock(&trace_eval_mutex); +} + +static void trace_create_eval_file(struct dentry *d_tracer) +{ + trace_create_file("eval_map", TRACE_MODE_READ, d_tracer, + NULL, &tracing_eval_map_fops); +} + +#else /* CONFIG_TRACE_EVAL_MAP_FILE */ +static inline void trace_create_eval_file(struct dentry *d_tracer) { } +static inline void trace_insert_eval_map_file(struct module *mod, + struct trace_eval_map **start, int len) { } +#endif /* !CONFIG_TRACE_EVAL_MAP_FILE */ + +static void trace_insert_eval_map(struct module *mod, + struct trace_eval_map **start, int len) +{ + struct trace_eval_map **map; + + if (len <= 0) + return; + + map = start; + + trace_event_eval_update(map, len); + + trace_insert_eval_map_file(mod, start, len); +} + +static ssize_t +tracing_set_trace_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + char buf[MAX_TRACER_SIZE+2]; + int r; + + mutex_lock(&trace_types_lock); + r = sprintf(buf, "%s\n", tr->current_trace->name); + mutex_unlock(&trace_types_lock); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +int tracer_init(struct tracer *t, struct trace_array *tr) +{ + tracing_reset_online_cpus(&tr->array_buffer); + return t->init(tr); +} + +static void set_buffer_entries(struct array_buffer *buf, unsigned long val) +{ + int cpu; + + for_each_tracing_cpu(cpu) + per_cpu_ptr(buf->data, cpu)->entries = val; +} + +static void update_buffer_entries(struct array_buffer *buf, int cpu) +{ + if (cpu == RING_BUFFER_ALL_CPUS) { + set_buffer_entries(buf, ring_buffer_size(buf->buffer, 0)); + } else { + per_cpu_ptr(buf->data, cpu)->entries = ring_buffer_size(buf->buffer, cpu); + } +} + +#ifdef CONFIG_TRACER_MAX_TRACE +/* resize @tr's buffer to the size of @size_tr's entries */ +static int resize_buffer_duplicate_size(struct array_buffer *trace_buf, + struct array_buffer *size_buf, int cpu_id) +{ + int cpu, ret = 0; + + if (cpu_id == RING_BUFFER_ALL_CPUS) { + for_each_tracing_cpu(cpu) { + ret = ring_buffer_resize(trace_buf->buffer, + per_cpu_ptr(size_buf->data, cpu)->entries, cpu); + if (ret < 0) + break; + per_cpu_ptr(trace_buf->data, cpu)->entries = + per_cpu_ptr(size_buf->data, cpu)->entries; + } + } else { + ret = ring_buffer_resize(trace_buf->buffer, + per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id); + if (ret == 0) + per_cpu_ptr(trace_buf->data, cpu_id)->entries = + per_cpu_ptr(size_buf->data, cpu_id)->entries; + } + + return ret; +} +#endif /* CONFIG_TRACER_MAX_TRACE */ + +static int __tracing_resize_ring_buffer(struct trace_array *tr, + unsigned long size, int cpu) +{ + int ret; + + /* + * If kernel or user changes the size of the ring buffer + * we use the size that was given, and we can forget about + * expanding it later. + */ + ring_buffer_expanded = true; + + /* May be called before buffers are initialized */ + if (!tr->array_buffer.buffer) + return 0; + + /* Do not allow tracing while resizing ring buffer */ + tracing_stop_tr(tr); + + ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu); + if (ret < 0) + goto out_start; + +#ifdef CONFIG_TRACER_MAX_TRACE + if (!tr->allocated_snapshot) + goto out; + + ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu); + if (ret < 0) { + int r = resize_buffer_duplicate_size(&tr->array_buffer, + &tr->array_buffer, cpu); + if (r < 0) { + /* + * AARGH! We are left with different + * size max buffer!!!! + * The max buffer is our "snapshot" buffer. + * When a tracer needs a snapshot (one of the + * latency tracers), it swaps the max buffer + * with the saved snap shot. We succeeded to + * update the size of the main buffer, but failed to + * update the size of the max buffer. But when we tried + * to reset the main buffer to the original size, we + * failed there too. This is very unlikely to + * happen, but if it does, warn and kill all + * tracing. + */ + WARN_ON(1); + tracing_disabled = 1; + } + goto out_start; + } + + update_buffer_entries(&tr->max_buffer, cpu); + + out: +#endif /* CONFIG_TRACER_MAX_TRACE */ + + update_buffer_entries(&tr->array_buffer, cpu); + out_start: + tracing_start_tr(tr); + return ret; +} + +ssize_t tracing_resize_ring_buffer(struct trace_array *tr, + unsigned long size, int cpu_id) +{ + int ret; + + mutex_lock(&trace_types_lock); + + if (cpu_id != RING_BUFFER_ALL_CPUS) { + /* make sure, this cpu is enabled in the mask */ + if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) { + ret = -EINVAL; + goto out; + } + } + + ret = __tracing_resize_ring_buffer(tr, size, cpu_id); + if (ret < 0) + ret = -ENOMEM; + +out: + mutex_unlock(&trace_types_lock); + + return ret; +} + + +/** + * tracing_update_buffers - used by tracing facility to expand ring buffers + * + * To save on memory when the tracing is never used on a system with it + * configured in. The ring buffers are set to a minimum size. But once + * a user starts to use the tracing facility, then they need to grow + * to their default size. + * + * This function is to be called when a tracer is about to be used. + */ +int tracing_update_buffers(void) +{ + int ret = 0; + + mutex_lock(&trace_types_lock); + if (!ring_buffer_expanded) + ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size, + RING_BUFFER_ALL_CPUS); + mutex_unlock(&trace_types_lock); + + return ret; +} + +struct trace_option_dentry; + +static void +create_trace_option_files(struct trace_array *tr, struct tracer *tracer); + +/* + * Used to clear out the tracer before deletion of an instance. + * Must have trace_types_lock held. + */ +static void tracing_set_nop(struct trace_array *tr) +{ + if (tr->current_trace == &nop_trace) + return; + + tr->current_trace->enabled--; + + if (tr->current_trace->reset) + tr->current_trace->reset(tr); + + tr->current_trace = &nop_trace; +} + +static bool tracer_options_updated; + +static void add_tracer_options(struct trace_array *tr, struct tracer *t) +{ + /* Only enable if the directory has been created already. */ + if (!tr->dir) + return; + + /* Only create trace option files after update_tracer_options finish */ + if (!tracer_options_updated) + return; + + create_trace_option_files(tr, t); +} + +int tracing_set_tracer(struct trace_array *tr, const char *buf) +{ + struct tracer *t; +#ifdef CONFIG_TRACER_MAX_TRACE + bool had_max_tr; +#endif + int ret = 0; + + mutex_lock(&trace_types_lock); + + if (!ring_buffer_expanded) { + ret = __tracing_resize_ring_buffer(tr, trace_buf_size, + RING_BUFFER_ALL_CPUS); + if (ret < 0) + goto out; + ret = 0; + } + + for (t = trace_types; t; t = t->next) { + if (strcmp(t->name, buf) == 0) + break; + } + if (!t) { + ret = -EINVAL; + goto out; + } + if (t == tr->current_trace) + goto out; + +#ifdef CONFIG_TRACER_SNAPSHOT + if (t->use_max_tr) { + local_irq_disable(); + arch_spin_lock(&tr->max_lock); + if (tr->cond_snapshot) + ret = -EBUSY; + arch_spin_unlock(&tr->max_lock); + local_irq_enable(); + if (ret) + goto out; + } +#endif + /* Some tracers won't work on kernel command line */ + if (system_state < SYSTEM_RUNNING && t->noboot) { + pr_warn("Tracer '%s' is not allowed on command line, ignored\n", + t->name); + goto out; + } + + /* Some tracers are only allowed for the top level buffer */ + if (!trace_ok_for_array(t, tr)) { + ret = -EINVAL; + goto out; + } + + /* If trace pipe files are being read, we can't change the tracer */ + if (tr->trace_ref) { + ret = -EBUSY; + goto out; + } + + trace_branch_disable(); + + tr->current_trace->enabled--; + + if (tr->current_trace->reset) + tr->current_trace->reset(tr); + +#ifdef CONFIG_TRACER_MAX_TRACE + had_max_tr = tr->current_trace->use_max_tr; + + /* Current trace needs to be nop_trace before synchronize_rcu */ + tr->current_trace = &nop_trace; + + if (had_max_tr && !t->use_max_tr) { + /* + * We need to make sure that the update_max_tr sees that + * current_trace changed to nop_trace to keep it from + * swapping the buffers after we resize it. + * The update_max_tr is called from interrupts disabled + * so a synchronized_sched() is sufficient. + */ + synchronize_rcu(); + free_snapshot(tr); + } + + if (t->use_max_tr && !tr->allocated_snapshot) { + ret = tracing_alloc_snapshot_instance(tr); + if (ret < 0) + goto out; + } +#else + tr->current_trace = &nop_trace; +#endif + + if (t->init) { + ret = tracer_init(t, tr); + if (ret) + goto out; + } + + tr->current_trace = t; + tr->current_trace->enabled++; + trace_branch_enable(tr); + out: + mutex_unlock(&trace_types_lock); + + return ret; +} + +static ssize_t +tracing_set_trace_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + char buf[MAX_TRACER_SIZE+1]; + char *name; + size_t ret; + int err; + + ret = cnt; + + if (cnt > MAX_TRACER_SIZE) + cnt = MAX_TRACER_SIZE; + + if (copy_from_user(buf, ubuf, cnt)) + return -EFAULT; + + buf[cnt] = 0; + + name = strim(buf); + + err = tracing_set_tracer(tr, name); + if (err) + return err; + + *ppos += ret; + + return ret; +} + +static ssize_t +tracing_nsecs_read(unsigned long *ptr, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[64]; + int r; + + r = snprintf(buf, sizeof(buf), "%ld\n", + *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr)); + if (r > sizeof(buf)) + r = sizeof(buf); + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +static ssize_t +tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + unsigned long val; + int ret; + + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; + + *ptr = val * 1000; + + return cnt; +} + +static ssize_t +tracing_thresh_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos); +} + +static ssize_t +tracing_thresh_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + int ret; + + mutex_lock(&trace_types_lock); + ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos); + if (ret < 0) + goto out; + + if (tr->current_trace->update_thresh) { + ret = tr->current_trace->update_thresh(tr); + if (ret < 0) + goto out; + } + + ret = cnt; +out: + mutex_unlock(&trace_types_lock); + + return ret; +} + +#ifdef CONFIG_TRACER_MAX_TRACE + +static ssize_t +tracing_max_lat_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + + return tracing_nsecs_read(&tr->max_latency, ubuf, cnt, ppos); +} + +static ssize_t +tracing_max_lat_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + + return tracing_nsecs_write(&tr->max_latency, ubuf, cnt, ppos); +} + +#endif + +static int open_pipe_on_cpu(struct trace_array *tr, int cpu) +{ + if (cpu == RING_BUFFER_ALL_CPUS) { + if (cpumask_empty(tr->pipe_cpumask)) { + cpumask_setall(tr->pipe_cpumask); + return 0; + } + } else if (!cpumask_test_cpu(cpu, tr->pipe_cpumask)) { + cpumask_set_cpu(cpu, tr->pipe_cpumask); + return 0; + } + return -EBUSY; +} + +static void close_pipe_on_cpu(struct trace_array *tr, int cpu) +{ + if (cpu == RING_BUFFER_ALL_CPUS) { + WARN_ON(!cpumask_full(tr->pipe_cpumask)); + cpumask_clear(tr->pipe_cpumask); + } else { + WARN_ON(!cpumask_test_cpu(cpu, tr->pipe_cpumask)); + cpumask_clear_cpu(cpu, tr->pipe_cpumask); + } +} + +static int tracing_open_pipe(struct inode *inode, struct file *filp) +{ + struct trace_array *tr = inode->i_private; + struct trace_iterator *iter; + int cpu; + int ret; + + ret = tracing_check_open_get_tr(tr); + if (ret) + return ret; + + mutex_lock(&trace_types_lock); + cpu = tracing_get_cpu(inode); + ret = open_pipe_on_cpu(tr, cpu); + if (ret) + goto fail_pipe_on_cpu; + + /* create a buffer to store the information to pass to userspace */ + iter = kzalloc(sizeof(*iter), GFP_KERNEL); + if (!iter) { + ret = -ENOMEM; + goto fail_alloc_iter; + } + + trace_seq_init(&iter->seq); + iter->trace = tr->current_trace; + + if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) { + ret = -ENOMEM; + goto fail; + } + + /* trace pipe does not show start of buffer */ + cpumask_setall(iter->started); + + if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) + iter->iter_flags |= TRACE_FILE_LAT_FMT; + + /* Output in nanoseconds only if we are using a clock in nanoseconds. */ + if (trace_clocks[tr->clock_id].in_ns) + iter->iter_flags |= TRACE_FILE_TIME_IN_NS; + + iter->tr = tr; + iter->array_buffer = &tr->array_buffer; + iter->cpu_file = cpu; + mutex_init(&iter->mutex); + filp->private_data = iter; + + if (iter->trace->pipe_open) + iter->trace->pipe_open(iter); + + nonseekable_open(inode, filp); + + tr->trace_ref++; + + mutex_unlock(&trace_types_lock); + return ret; + +fail: + kfree(iter); +fail_alloc_iter: + close_pipe_on_cpu(tr, cpu); +fail_pipe_on_cpu: + __trace_array_put(tr); + mutex_unlock(&trace_types_lock); + return ret; +} + +static int tracing_release_pipe(struct inode *inode, struct file *file) +{ + struct trace_iterator *iter = file->private_data; + struct trace_array *tr = inode->i_private; + + mutex_lock(&trace_types_lock); + + tr->trace_ref--; + + if (iter->trace->pipe_close) + iter->trace->pipe_close(iter); + close_pipe_on_cpu(tr, iter->cpu_file); + mutex_unlock(&trace_types_lock); + + free_trace_iter_content(iter); + kfree(iter); + + trace_array_put(tr); + + return 0; +} + +static __poll_t +trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table) +{ + struct trace_array *tr = iter->tr; + + /* Iterators are static, they should be filled or empty */ + if (trace_buffer_iter(iter, iter->cpu_file)) + return EPOLLIN | EPOLLRDNORM; + + if (tr->trace_flags & TRACE_ITER_BLOCK) + /* + * Always select as readable when in blocking mode + */ + return EPOLLIN | EPOLLRDNORM; + else + return ring_buffer_poll_wait(iter->array_buffer->buffer, iter->cpu_file, + filp, poll_table, iter->tr->buffer_percent); +} + +static __poll_t +tracing_poll_pipe(struct file *filp, poll_table *poll_table) +{ + struct trace_iterator *iter = filp->private_data; + + return trace_poll(iter, filp, poll_table); +} + +/* Must be called with iter->mutex held. */ +static int tracing_wait_pipe(struct file *filp) +{ + struct trace_iterator *iter = filp->private_data; + int ret; + + while (trace_empty(iter)) { + + if ((filp->f_flags & O_NONBLOCK)) { + return -EAGAIN; + } + + /* + * We block until we read something and tracing is disabled. + * We still block if tracing is disabled, but we have never + * read anything. This allows a user to cat this file, and + * then enable tracing. But after we have read something, + * we give an EOF when tracing is again disabled. + * + * iter->pos will be 0 if we haven't read anything. + */ + if (!tracer_tracing_is_on(iter->tr) && iter->pos) + break; + + mutex_unlock(&iter->mutex); + + ret = wait_on_pipe(iter, 0); + + mutex_lock(&iter->mutex); + + if (ret) + return ret; + } + + return 1; +} + +/* + * Consumer reader. + */ +static ssize_t +tracing_read_pipe(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_iterator *iter = filp->private_data; + ssize_t sret; + + /* + * Avoid more than one consumer on a single file descriptor + * This is just a matter of traces coherency, the ring buffer itself + * is protected. + */ + mutex_lock(&iter->mutex); + + /* return any leftover data */ + sret = trace_seq_to_user(&iter->seq, ubuf, cnt); + if (sret != -EBUSY) + goto out; + + trace_seq_init(&iter->seq); + + if (iter->trace->read) { + sret = iter->trace->read(iter, filp, ubuf, cnt, ppos); + if (sret) + goto out; + } + +waitagain: + sret = tracing_wait_pipe(filp); + if (sret <= 0) + goto out; + + /* stop when tracing is finished */ + if (trace_empty(iter)) { + sret = 0; + goto out; + } + + if (cnt >= PAGE_SIZE) + cnt = PAGE_SIZE - 1; + + /* reset all but tr, trace, and overruns */ + trace_iterator_reset(iter); + cpumask_clear(iter->started); + trace_seq_init(&iter->seq); + + trace_event_read_lock(); + trace_access_lock(iter->cpu_file); + while (trace_find_next_entry_inc(iter) != NULL) { + enum print_line_t ret; + int save_len = iter->seq.seq.len; + + ret = print_trace_line(iter); + if (ret == TRACE_TYPE_PARTIAL_LINE) { + /* + * If one print_trace_line() fills entire trace_seq in one shot, + * trace_seq_to_user() will returns -EBUSY because save_len == 0, + * In this case, we need to consume it, otherwise, loop will peek + * this event next time, resulting in an infinite loop. + */ + if (save_len == 0) { + iter->seq.full = 0; + trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n"); + trace_consume(iter); + break; + } + + /* In other cases, don't print partial lines */ + iter->seq.seq.len = save_len; + break; + } + if (ret != TRACE_TYPE_NO_CONSUME) + trace_consume(iter); + + if (trace_seq_used(&iter->seq) >= cnt) + break; + + /* + * Setting the full flag means we reached the trace_seq buffer + * size and we should leave by partial output condition above. + * One of the trace_seq_* functions is not used properly. + */ + WARN_ONCE(iter->seq.full, "full flag set for trace type %d", + iter->ent->type); + } + trace_access_unlock(iter->cpu_file); + trace_event_read_unlock(); + + /* Now copy what we have to the user */ + sret = trace_seq_to_user(&iter->seq, ubuf, cnt); + if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq)) + trace_seq_init(&iter->seq); + + /* + * If there was nothing to send to user, in spite of consuming trace + * entries, go back to wait for more entries. + */ + if (sret == -EBUSY) + goto waitagain; + +out: + mutex_unlock(&iter->mutex); + + return sret; +} + +static void tracing_spd_release_pipe(struct splice_pipe_desc *spd, + unsigned int idx) +{ + __free_page(spd->pages[idx]); +} + +static size_t +tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter) +{ + size_t count; + int save_len; + int ret; + + /* Seq buffer is page-sized, exactly what we need. */ + for (;;) { + save_len = iter->seq.seq.len; + ret = print_trace_line(iter); + + if (trace_seq_has_overflowed(&iter->seq)) { + iter->seq.seq.len = save_len; + break; + } + + /* + * This should not be hit, because it should only + * be set if the iter->seq overflowed. But check it + * anyway to be safe. + */ + if (ret == TRACE_TYPE_PARTIAL_LINE) { + iter->seq.seq.len = save_len; + break; + } + + count = trace_seq_used(&iter->seq) - save_len; + if (rem < count) { + rem = 0; + iter->seq.seq.len = save_len; + break; + } + + if (ret != TRACE_TYPE_NO_CONSUME) + trace_consume(iter); + rem -= count; + if (!trace_find_next_entry_inc(iter)) { + rem = 0; + iter->ent = NULL; + break; + } + } + + return rem; +} + +static ssize_t tracing_splice_read_pipe(struct file *filp, + loff_t *ppos, + struct pipe_inode_info *pipe, + size_t len, + unsigned int flags) +{ + struct page *pages_def[PIPE_DEF_BUFFERS]; + struct partial_page partial_def[PIPE_DEF_BUFFERS]; + struct trace_iterator *iter = filp->private_data; + struct splice_pipe_desc spd = { + .pages = pages_def, + .partial = partial_def, + .nr_pages = 0, /* This gets updated below. */ + .nr_pages_max = PIPE_DEF_BUFFERS, + .ops = &default_pipe_buf_ops, + .spd_release = tracing_spd_release_pipe, + }; + ssize_t ret; + size_t rem; + unsigned int i; + + if (splice_grow_spd(pipe, &spd)) + return -ENOMEM; + + mutex_lock(&iter->mutex); + + if (iter->trace->splice_read) { + ret = iter->trace->splice_read(iter, filp, + ppos, pipe, len, flags); + if (ret) + goto out_err; + } + + ret = tracing_wait_pipe(filp); + if (ret <= 0) + goto out_err; + + if (!iter->ent && !trace_find_next_entry_inc(iter)) { + ret = -EFAULT; + goto out_err; + } + + trace_event_read_lock(); + trace_access_lock(iter->cpu_file); + + /* Fill as many pages as possible. */ + for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) { + spd.pages[i] = alloc_page(GFP_KERNEL); + if (!spd.pages[i]) + break; + + rem = tracing_fill_pipe_page(rem, iter); + + /* Copy the data into the page, so we can start over. */ + ret = trace_seq_to_buffer(&iter->seq, + page_address(spd.pages[i]), + trace_seq_used(&iter->seq)); + if (ret < 0) { + __free_page(spd.pages[i]); + break; + } + spd.partial[i].offset = 0; + spd.partial[i].len = trace_seq_used(&iter->seq); + + trace_seq_init(&iter->seq); + } + + trace_access_unlock(iter->cpu_file); + trace_event_read_unlock(); + mutex_unlock(&iter->mutex); + + spd.nr_pages = i; + + if (i) + ret = splice_to_pipe(pipe, &spd); + else + ret = 0; +out: + splice_shrink_spd(&spd); + return ret; + +out_err: + mutex_unlock(&iter->mutex); + goto out; +} + +static ssize_t +tracing_entries_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct inode *inode = file_inode(filp); + struct trace_array *tr = inode->i_private; + int cpu = tracing_get_cpu(inode); + char buf[64]; + int r = 0; + ssize_t ret; + + mutex_lock(&trace_types_lock); + + if (cpu == RING_BUFFER_ALL_CPUS) { + int cpu, buf_size_same; + unsigned long size; + + size = 0; + buf_size_same = 1; + /* check if all cpu sizes are same */ + for_each_tracing_cpu(cpu) { + /* fill in the size from first enabled cpu */ + if (size == 0) + size = per_cpu_ptr(tr->array_buffer.data, cpu)->entries; + if (size != per_cpu_ptr(tr->array_buffer.data, cpu)->entries) { + buf_size_same = 0; + break; + } + } + + if (buf_size_same) { + if (!ring_buffer_expanded) + r = sprintf(buf, "%lu (expanded: %lu)\n", + size >> 10, + trace_buf_size >> 10); + else + r = sprintf(buf, "%lu\n", size >> 10); + } else + r = sprintf(buf, "X\n"); + } else + r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10); + + mutex_unlock(&trace_types_lock); + + ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r); + return ret; +} + +static ssize_t +tracing_entries_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct inode *inode = file_inode(filp); + struct trace_array *tr = inode->i_private; + unsigned long val; + int ret; + + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; + + /* must have at least 1 entry */ + if (!val) + return -EINVAL; + + /* value is in KB */ + val <<= 10; + ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode)); + if (ret < 0) + return ret; + + *ppos += cnt; + + return cnt; +} + +static ssize_t +tracing_total_entries_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + char buf[64]; + int r, cpu; + unsigned long size = 0, expanded_size = 0; + + mutex_lock(&trace_types_lock); + for_each_tracing_cpu(cpu) { + size += per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10; + if (!ring_buffer_expanded) + expanded_size += trace_buf_size >> 10; + } + if (ring_buffer_expanded) + r = sprintf(buf, "%lu\n", size); + else + r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size); + mutex_unlock(&trace_types_lock); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +static ssize_t +tracing_free_buffer_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + /* + * There is no need to read what the user has written, this function + * is just to make sure that there is no error when "echo" is used + */ + + *ppos += cnt; + + return cnt; +} + +static int +tracing_free_buffer_release(struct inode *inode, struct file *filp) +{ + struct trace_array *tr = inode->i_private; + + /* disable tracing ? */ + if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE) + tracer_tracing_off(tr); + /* resize the ring buffer to 0 */ + tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS); + + trace_array_put(tr); + + return 0; +} + +static ssize_t +tracing_mark_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *fpos) +{ + struct trace_array *tr = filp->private_data; + struct ring_buffer_event *event; + enum event_trigger_type tt = ETT_NONE; + struct trace_buffer *buffer; + struct print_entry *entry; + ssize_t written; + int size; + int len; + +/* Used in tracing_mark_raw_write() as well */ +#define FAULTED_STR "<faulted>" +#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */ + + if (tracing_disabled) + return -EINVAL; + + if (!(tr->trace_flags & TRACE_ITER_MARKERS)) + return -EINVAL; + + if (cnt > TRACE_BUF_SIZE) + cnt = TRACE_BUF_SIZE; + + BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE); + + size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */ + + /* If less than "<faulted>", then make sure we can still add that */ + if (cnt < FAULTED_SIZE) + size += FAULTED_SIZE - cnt; + + buffer = tr->array_buffer.buffer; + event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, + tracing_gen_ctx()); + if (unlikely(!event)) + /* Ring buffer disabled, return as if not open for write */ + return -EBADF; + + entry = ring_buffer_event_data(event); + entry->ip = _THIS_IP_; + + len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt); + if (len) { + memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE); + cnt = FAULTED_SIZE; + written = -EFAULT; + } else + written = cnt; + + if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) { + /* do not add \n before testing triggers, but add \0 */ + entry->buf[cnt] = '\0'; + tt = event_triggers_call(tr->trace_marker_file, buffer, entry, event); + } + + if (entry->buf[cnt - 1] != '\n') { + entry->buf[cnt] = '\n'; + entry->buf[cnt + 1] = '\0'; + } else + entry->buf[cnt] = '\0'; + + if (static_branch_unlikely(&trace_marker_exports_enabled)) + ftrace_exports(event, TRACE_EXPORT_MARKER); + __buffer_unlock_commit(buffer, event); + + if (tt) + event_triggers_post_call(tr->trace_marker_file, tt); + + return written; +} + +/* Limit it for now to 3K (including tag) */ +#define RAW_DATA_MAX_SIZE (1024*3) + +static ssize_t +tracing_mark_raw_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *fpos) +{ + struct trace_array *tr = filp->private_data; + struct ring_buffer_event *event; + struct trace_buffer *buffer; + struct raw_data_entry *entry; + ssize_t written; + int size; + int len; + +#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int)) + + if (tracing_disabled) + return -EINVAL; + + if (!(tr->trace_flags & TRACE_ITER_MARKERS)) + return -EINVAL; + + /* The marker must at least have a tag id */ + if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE) + return -EINVAL; + + if (cnt > TRACE_BUF_SIZE) + cnt = TRACE_BUF_SIZE; + + BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE); + + size = sizeof(*entry) + cnt; + if (cnt < FAULT_SIZE_ID) + size += FAULT_SIZE_ID - cnt; + + buffer = tr->array_buffer.buffer; + event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size, + tracing_gen_ctx()); + if (!event) + /* Ring buffer disabled, return as if not open for write */ + return -EBADF; + + entry = ring_buffer_event_data(event); + + len = __copy_from_user_inatomic(&entry->id, ubuf, cnt); + if (len) { + entry->id = -1; + memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE); + written = -EFAULT; + } else + written = cnt; + + __buffer_unlock_commit(buffer, event); + + return written; +} + +static int tracing_clock_show(struct seq_file *m, void *v) +{ + struct trace_array *tr = m->private; + int i; + + for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) + seq_printf(m, + "%s%s%s%s", i ? " " : "", + i == tr->clock_id ? "[" : "", trace_clocks[i].name, + i == tr->clock_id ? "]" : ""); + seq_putc(m, '\n'); + + return 0; +} + +int tracing_set_clock(struct trace_array *tr, const char *clockstr) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) { + if (strcmp(trace_clocks[i].name, clockstr) == 0) + break; + } + if (i == ARRAY_SIZE(trace_clocks)) + return -EINVAL; + + mutex_lock(&trace_types_lock); + + tr->clock_id = i; + + ring_buffer_set_clock(tr->array_buffer.buffer, trace_clocks[i].func); + + /* + * New clock may not be consistent with the previous clock. + * Reset the buffer so that it doesn't have incomparable timestamps. + */ + tracing_reset_online_cpus(&tr->array_buffer); + +#ifdef CONFIG_TRACER_MAX_TRACE + if (tr->max_buffer.buffer) + ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func); + tracing_reset_online_cpus(&tr->max_buffer); +#endif + + mutex_unlock(&trace_types_lock); + + return 0; +} + +static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *fpos) +{ + struct seq_file *m = filp->private_data; + struct trace_array *tr = m->private; + char buf[64]; + const char *clockstr; + int ret; + + if (cnt >= sizeof(buf)) + return -EINVAL; + + if (copy_from_user(buf, ubuf, cnt)) + return -EFAULT; + + buf[cnt] = 0; + + clockstr = strstrip(buf); + + ret = tracing_set_clock(tr, clockstr); + if (ret) + return ret; + + *fpos += cnt; + + return cnt; +} + +static int tracing_clock_open(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + int ret; + + ret = tracing_check_open_get_tr(tr); + if (ret) + return ret; + + ret = single_open(file, tracing_clock_show, inode->i_private); + if (ret < 0) + trace_array_put(tr); + + return ret; +} + +static int tracing_time_stamp_mode_show(struct seq_file *m, void *v) +{ + struct trace_array *tr = m->private; + + mutex_lock(&trace_types_lock); + + if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer)) + seq_puts(m, "delta [absolute]\n"); + else + seq_puts(m, "[delta] absolute\n"); + + mutex_unlock(&trace_types_lock); + + return 0; +} + +static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + int ret; + + ret = tracing_check_open_get_tr(tr); + if (ret) + return ret; + + ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private); + if (ret < 0) + trace_array_put(tr); + + return ret; +} + +u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe) +{ + if (rbe == this_cpu_read(trace_buffered_event)) + return ring_buffer_time_stamp(buffer); + + return ring_buffer_event_time_stamp(buffer, rbe); +} + +/* + * Set or disable using the per CPU trace_buffer_event when possible. + */ +int tracing_set_filter_buffering(struct trace_array *tr, bool set) +{ + int ret = 0; + + mutex_lock(&trace_types_lock); + + if (set && tr->no_filter_buffering_ref++) + goto out; + + if (!set) { + if (WARN_ON_ONCE(!tr->no_filter_buffering_ref)) { + ret = -EINVAL; + goto out; + } + + --tr->no_filter_buffering_ref; + } + out: + mutex_unlock(&trace_types_lock); + + return ret; +} + +struct ftrace_buffer_info { + struct trace_iterator iter; + void *spare; + unsigned int spare_cpu; + unsigned int read; +}; + +#ifdef CONFIG_TRACER_SNAPSHOT +static int tracing_snapshot_open(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + struct trace_iterator *iter; + struct seq_file *m; + int ret; + + ret = tracing_check_open_get_tr(tr); + if (ret) + return ret; + + if (file->f_mode & FMODE_READ) { + iter = __tracing_open(inode, file, true); + if (IS_ERR(iter)) + ret = PTR_ERR(iter); + } else { + /* Writes still need the seq_file to hold the private data */ + ret = -ENOMEM; + m = kzalloc(sizeof(*m), GFP_KERNEL); + if (!m) + goto out; + iter = kzalloc(sizeof(*iter), GFP_KERNEL); + if (!iter) { + kfree(m); + goto out; + } + ret = 0; + + iter->tr = tr; + iter->array_buffer = &tr->max_buffer; + iter->cpu_file = tracing_get_cpu(inode); + m->private = iter; + file->private_data = m; + } +out: + if (ret < 0) + trace_array_put(tr); + + return ret; +} + +static void tracing_swap_cpu_buffer(void *tr) +{ + update_max_tr_single((struct trace_array *)tr, current, smp_processor_id()); +} + +static ssize_t +tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, + loff_t *ppos) +{ + struct seq_file *m = filp->private_data; + struct trace_iterator *iter = m->private; + struct trace_array *tr = iter->tr; + unsigned long val; + int ret; + + ret = tracing_update_buffers(); + if (ret < 0) + return ret; + + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; + + mutex_lock(&trace_types_lock); + + if (tr->current_trace->use_max_tr) { + ret = -EBUSY; + goto out; + } + + local_irq_disable(); + arch_spin_lock(&tr->max_lock); + if (tr->cond_snapshot) + ret = -EBUSY; + arch_spin_unlock(&tr->max_lock); + local_irq_enable(); + if (ret) + goto out; + + switch (val) { + case 0: + if (iter->cpu_file != RING_BUFFER_ALL_CPUS) { + ret = -EINVAL; + break; + } + if (tr->allocated_snapshot) + free_snapshot(tr); + break; + case 1: +/* Only allow per-cpu swap if the ring buffer supports it */ +#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP + if (iter->cpu_file != RING_BUFFER_ALL_CPUS) { + ret = -EINVAL; + break; + } +#endif + if (tr->allocated_snapshot) + ret = resize_buffer_duplicate_size(&tr->max_buffer, + &tr->array_buffer, iter->cpu_file); + else + ret = tracing_alloc_snapshot_instance(tr); + if (ret < 0) + break; + /* Now, we're going to swap */ + if (iter->cpu_file == RING_BUFFER_ALL_CPUS) { + local_irq_disable(); + update_max_tr(tr, current, smp_processor_id(), NULL); + local_irq_enable(); + } else { + smp_call_function_single(iter->cpu_file, tracing_swap_cpu_buffer, + (void *)tr, 1); + } + break; + default: + if (tr->allocated_snapshot) { + if (iter->cpu_file == RING_BUFFER_ALL_CPUS) + tracing_reset_online_cpus(&tr->max_buffer); + else + tracing_reset_cpu(&tr->max_buffer, iter->cpu_file); + } + break; + } + + if (ret >= 0) { + *ppos += cnt; + ret = cnt; + } +out: + mutex_unlock(&trace_types_lock); + return ret; +} + +static int tracing_snapshot_release(struct inode *inode, struct file *file) +{ + struct seq_file *m = file->private_data; + int ret; + + ret = tracing_release(inode, file); + + if (file->f_mode & FMODE_READ) + return ret; + + /* If write only, the seq_file is just a stub */ + if (m) + kfree(m->private); + kfree(m); + + return 0; +} + +static int tracing_buffers_open(struct inode *inode, struct file *filp); +static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf, + size_t count, loff_t *ppos); +static int tracing_buffers_release(struct inode *inode, struct file *file); +static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos, + struct pipe_inode_info *pipe, size_t len, unsigned int flags); + +static int snapshot_raw_open(struct inode *inode, struct file *filp) +{ + struct ftrace_buffer_info *info; + int ret; + + /* The following checks for tracefs lockdown */ + ret = tracing_buffers_open(inode, filp); + if (ret < 0) + return ret; + + info = filp->private_data; + + if (info->iter.trace->use_max_tr) { + tracing_buffers_release(inode, filp); + return -EBUSY; + } + + info->iter.snapshot = true; + info->iter.array_buffer = &info->iter.tr->max_buffer; + + return ret; +} + +#endif /* CONFIG_TRACER_SNAPSHOT */ + + +static const struct file_operations tracing_thresh_fops = { + .open = tracing_open_generic, + .read = tracing_thresh_read, + .write = tracing_thresh_write, + .llseek = generic_file_llseek, +}; + +#ifdef CONFIG_TRACER_MAX_TRACE +static const struct file_operations tracing_max_lat_fops = { + .open = tracing_open_generic_tr, + .read = tracing_max_lat_read, + .write = tracing_max_lat_write, + .llseek = generic_file_llseek, + .release = tracing_release_generic_tr, +}; +#endif + +static const struct file_operations set_tracer_fops = { + .open = tracing_open_generic_tr, + .read = tracing_set_trace_read, + .write = tracing_set_trace_write, + .llseek = generic_file_llseek, + .release = tracing_release_generic_tr, +}; + +static const struct file_operations tracing_pipe_fops = { + .open = tracing_open_pipe, + .poll = tracing_poll_pipe, + .read = tracing_read_pipe, + .splice_read = tracing_splice_read_pipe, + .release = tracing_release_pipe, + .llseek = no_llseek, +}; + +static const struct file_operations tracing_entries_fops = { + .open = tracing_open_generic_tr, + .read = tracing_entries_read, + .write = tracing_entries_write, + .llseek = generic_file_llseek, + .release = tracing_release_generic_tr, +}; + +static const struct file_operations tracing_total_entries_fops = { + .open = tracing_open_generic_tr, + .read = tracing_total_entries_read, + .llseek = generic_file_llseek, + .release = tracing_release_generic_tr, +}; + +static const struct file_operations tracing_free_buffer_fops = { + .open = tracing_open_generic_tr, + .write = tracing_free_buffer_write, + .release = tracing_free_buffer_release, +}; + +static const struct file_operations tracing_mark_fops = { + .open = tracing_mark_open, + .write = tracing_mark_write, + .release = tracing_release_generic_tr, +}; + +static const struct file_operations tracing_mark_raw_fops = { + .open = tracing_mark_open, + .write = tracing_mark_raw_write, + .release = tracing_release_generic_tr, +}; + +static const struct file_operations trace_clock_fops = { + .open = tracing_clock_open, + .read = seq_read, + .llseek = seq_lseek, + .release = tracing_single_release_tr, + .write = tracing_clock_write, +}; + +static const struct file_operations trace_time_stamp_mode_fops = { + .open = tracing_time_stamp_mode_open, + .read = seq_read, + .llseek = seq_lseek, + .release = tracing_single_release_tr, +}; + +#ifdef CONFIG_TRACER_SNAPSHOT +static const struct file_operations snapshot_fops = { + .open = tracing_snapshot_open, + .read = seq_read, + .write = tracing_snapshot_write, + .llseek = tracing_lseek, + .release = tracing_snapshot_release, +}; + +static const struct file_operations snapshot_raw_fops = { + .open = snapshot_raw_open, + .read = tracing_buffers_read, + .release = tracing_buffers_release, + .splice_read = tracing_buffers_splice_read, + .llseek = no_llseek, +}; + +#endif /* CONFIG_TRACER_SNAPSHOT */ + +/* + * trace_min_max_write - Write a u64 value to a trace_min_max_param struct + * @filp: The active open file structure + * @ubuf: The userspace provided buffer to read value into + * @cnt: The maximum number of bytes to read + * @ppos: The current "file" position + * + * This function implements the write interface for a struct trace_min_max_param. + * The filp->private_data must point to a trace_min_max_param structure that + * defines where to write the value, the min and the max acceptable values, + * and a lock to protect the write. + */ +static ssize_t +trace_min_max_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) +{ + struct trace_min_max_param *param = filp->private_data; + u64 val; + int err; + + if (!param) + return -EFAULT; + + err = kstrtoull_from_user(ubuf, cnt, 10, &val); + if (err) + return err; + + if (param->lock) + mutex_lock(param->lock); + + if (param->min && val < *param->min) + err = -EINVAL; + + if (param->max && val > *param->max) + err = -EINVAL; + + if (!err) + *param->val = val; + + if (param->lock) + mutex_unlock(param->lock); + + if (err) + return err; + + return cnt; +} + +/* + * trace_min_max_read - Read a u64 value from a trace_min_max_param struct + * @filp: The active open file structure + * @ubuf: The userspace provided buffer to read value into + * @cnt: The maximum number of bytes to read + * @ppos: The current "file" position + * + * This function implements the read interface for a struct trace_min_max_param. + * The filp->private_data must point to a trace_min_max_param struct with valid + * data. + */ +static ssize_t +trace_min_max_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) +{ + struct trace_min_max_param *param = filp->private_data; + char buf[U64_STR_SIZE]; + int len; + u64 val; + + if (!param) + return -EFAULT; + + val = *param->val; + + if (cnt > sizeof(buf)) + cnt = sizeof(buf); + + len = snprintf(buf, sizeof(buf), "%llu\n", val); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, len); +} + +const struct file_operations trace_min_max_fops = { + .open = tracing_open_generic, + .read = trace_min_max_read, + .write = trace_min_max_write, +}; + +#define TRACING_LOG_ERRS_MAX 8 +#define TRACING_LOG_LOC_MAX 128 + +#define CMD_PREFIX " Command: " + +struct err_info { + const char **errs; /* ptr to loc-specific array of err strings */ + u8 type; /* index into errs -> specific err string */ + u16 pos; /* caret position */ + u64 ts; +}; + +struct tracing_log_err { + struct list_head list; + struct err_info info; + char loc[TRACING_LOG_LOC_MAX]; /* err location */ + char *cmd; /* what caused err */ +}; + +static DEFINE_MUTEX(tracing_err_log_lock); + +static struct tracing_log_err *alloc_tracing_log_err(int len) +{ + struct tracing_log_err *err; + + err = kzalloc(sizeof(*err), GFP_KERNEL); + if (!err) + return ERR_PTR(-ENOMEM); + + err->cmd = kzalloc(len, GFP_KERNEL); + if (!err->cmd) { + kfree(err); + return ERR_PTR(-ENOMEM); + } + + return err; +} + +static void free_tracing_log_err(struct tracing_log_err *err) +{ + kfree(err->cmd); + kfree(err); +} + +static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr, + int len) +{ + struct tracing_log_err *err; + char *cmd; + + if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) { + err = alloc_tracing_log_err(len); + if (PTR_ERR(err) != -ENOMEM) + tr->n_err_log_entries++; + + return err; + } + cmd = kzalloc(len, GFP_KERNEL); + if (!cmd) + return ERR_PTR(-ENOMEM); + err = list_first_entry(&tr->err_log, struct tracing_log_err, list); + kfree(err->cmd); + err->cmd = cmd; + list_del(&err->list); + + return err; +} + +/** + * err_pos - find the position of a string within a command for error careting + * @cmd: The tracing command that caused the error + * @str: The string to position the caret at within @cmd + * + * Finds the position of the first occurrence of @str within @cmd. The + * return value can be passed to tracing_log_err() for caret placement + * within @cmd. + * + * Returns the index within @cmd of the first occurrence of @str or 0 + * if @str was not found. + */ +unsigned int err_pos(char *cmd, const char *str) +{ + char *found; + + if (WARN_ON(!strlen(cmd))) + return 0; + + found = strstr(cmd, str); + if (found) + return found - cmd; + + return 0; +} + +/** + * tracing_log_err - write an error to the tracing error log + * @tr: The associated trace array for the error (NULL for top level array) + * @loc: A string describing where the error occurred + * @cmd: The tracing command that caused the error + * @errs: The array of loc-specific static error strings + * @type: The index into errs[], which produces the specific static err string + * @pos: The position the caret should be placed in the cmd + * + * Writes an error into tracing/error_log of the form: + * + * <loc>: error: <text> + * Command: <cmd> + * ^ + * + * tracing/error_log is a small log file containing the last + * TRACING_LOG_ERRS_MAX errors (8). Memory for errors isn't allocated + * unless there has been a tracing error, and the error log can be + * cleared and have its memory freed by writing the empty string in + * truncation mode to it i.e. echo > tracing/error_log. + * + * NOTE: the @errs array along with the @type param are used to + * produce a static error string - this string is not copied and saved + * when the error is logged - only a pointer to it is saved. See + * existing callers for examples of how static strings are typically + * defined for use with tracing_log_err(). + */ +void tracing_log_err(struct trace_array *tr, + const char *loc, const char *cmd, + const char **errs, u8 type, u16 pos) +{ + struct tracing_log_err *err; + int len = 0; + + if (!tr) + tr = &global_trace; + + len += sizeof(CMD_PREFIX) + 2 * sizeof("\n") + strlen(cmd) + 1; + + mutex_lock(&tracing_err_log_lock); + err = get_tracing_log_err(tr, len); + if (PTR_ERR(err) == -ENOMEM) { + mutex_unlock(&tracing_err_log_lock); + return; + } + + snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc); + snprintf(err->cmd, len, "\n" CMD_PREFIX "%s\n", cmd); + + err->info.errs = errs; + err->info.type = type; + err->info.pos = pos; + err->info.ts = local_clock(); + + list_add_tail(&err->list, &tr->err_log); + mutex_unlock(&tracing_err_log_lock); +} + +static void clear_tracing_err_log(struct trace_array *tr) +{ + struct tracing_log_err *err, *next; + + mutex_lock(&tracing_err_log_lock); + list_for_each_entry_safe(err, next, &tr->err_log, list) { + list_del(&err->list); + free_tracing_log_err(err); + } + + tr->n_err_log_entries = 0; + mutex_unlock(&tracing_err_log_lock); +} + +static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos) +{ + struct trace_array *tr = m->private; + + mutex_lock(&tracing_err_log_lock); + + return seq_list_start(&tr->err_log, *pos); +} + +static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct trace_array *tr = m->private; + + return seq_list_next(v, &tr->err_log, pos); +} + +static void tracing_err_log_seq_stop(struct seq_file *m, void *v) +{ + mutex_unlock(&tracing_err_log_lock); +} + +static void tracing_err_log_show_pos(struct seq_file *m, u16 pos) +{ + u16 i; + + for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++) + seq_putc(m, ' '); + for (i = 0; i < pos; i++) + seq_putc(m, ' '); + seq_puts(m, "^\n"); +} + +static int tracing_err_log_seq_show(struct seq_file *m, void *v) +{ + struct tracing_log_err *err = v; + + if (err) { + const char *err_text = err->info.errs[err->info.type]; + u64 sec = err->info.ts; + u32 nsec; + + nsec = do_div(sec, NSEC_PER_SEC); + seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000, + err->loc, err_text); + seq_printf(m, "%s", err->cmd); + tracing_err_log_show_pos(m, err->info.pos); + } + + return 0; +} + +static const struct seq_operations tracing_err_log_seq_ops = { + .start = tracing_err_log_seq_start, + .next = tracing_err_log_seq_next, + .stop = tracing_err_log_seq_stop, + .show = tracing_err_log_seq_show +}; + +static int tracing_err_log_open(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + int ret = 0; + + ret = tracing_check_open_get_tr(tr); + if (ret) + return ret; + + /* If this file was opened for write, then erase contents */ + if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) + clear_tracing_err_log(tr); + + if (file->f_mode & FMODE_READ) { + ret = seq_open(file, &tracing_err_log_seq_ops); + if (!ret) { + struct seq_file *m = file->private_data; + m->private = tr; + } else { + trace_array_put(tr); + } + } + return ret; +} + +static ssize_t tracing_err_log_write(struct file *file, + const char __user *buffer, + size_t count, loff_t *ppos) +{ + return count; +} + +static int tracing_err_log_release(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + + trace_array_put(tr); + + if (file->f_mode & FMODE_READ) + seq_release(inode, file); + + return 0; +} + +static const struct file_operations tracing_err_log_fops = { + .open = tracing_err_log_open, + .write = tracing_err_log_write, + .read = seq_read, + .llseek = tracing_lseek, + .release = tracing_err_log_release, +}; + +static int tracing_buffers_open(struct inode *inode, struct file *filp) +{ + struct trace_array *tr = inode->i_private; + struct ftrace_buffer_info *info; + int ret; + + ret = tracing_check_open_get_tr(tr); + if (ret) + return ret; + + info = kvzalloc(sizeof(*info), GFP_KERNEL); + if (!info) { + trace_array_put(tr); + return -ENOMEM; + } + + mutex_lock(&trace_types_lock); + + info->iter.tr = tr; + info->iter.cpu_file = tracing_get_cpu(inode); + info->iter.trace = tr->current_trace; + info->iter.array_buffer = &tr->array_buffer; + info->spare = NULL; + /* Force reading ring buffer for first read */ + info->read = (unsigned int)-1; + + filp->private_data = info; + + tr->trace_ref++; + + mutex_unlock(&trace_types_lock); + + ret = nonseekable_open(inode, filp); + if (ret < 0) + trace_array_put(tr); + + return ret; +} + +static __poll_t +tracing_buffers_poll(struct file *filp, poll_table *poll_table) +{ + struct ftrace_buffer_info *info = filp->private_data; + struct trace_iterator *iter = &info->iter; + + return trace_poll(iter, filp, poll_table); +} + +static ssize_t +tracing_buffers_read(struct file *filp, char __user *ubuf, + size_t count, loff_t *ppos) +{ + struct ftrace_buffer_info *info = filp->private_data; + struct trace_iterator *iter = &info->iter; + ssize_t ret = 0; + ssize_t size; + + if (!count) + return 0; + +#ifdef CONFIG_TRACER_MAX_TRACE + if (iter->snapshot && iter->tr->current_trace->use_max_tr) + return -EBUSY; +#endif + + if (!info->spare) { + info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer, + iter->cpu_file); + if (IS_ERR(info->spare)) { + ret = PTR_ERR(info->spare); + info->spare = NULL; + } else { + info->spare_cpu = iter->cpu_file; + } + } + if (!info->spare) + return ret; + + /* Do we have previous read data to read? */ + if (info->read < PAGE_SIZE) + goto read; + + again: + trace_access_lock(iter->cpu_file); + ret = ring_buffer_read_page(iter->array_buffer->buffer, + &info->spare, + count, + iter->cpu_file, 0); + trace_access_unlock(iter->cpu_file); + + if (ret < 0) { + if (trace_empty(iter)) { + if ((filp->f_flags & O_NONBLOCK)) + return -EAGAIN; + + ret = wait_on_pipe(iter, 0); + if (ret) + return ret; + + goto again; + } + return 0; + } + + info->read = 0; + read: + size = PAGE_SIZE - info->read; + if (size > count) + size = count; + + ret = copy_to_user(ubuf, info->spare + info->read, size); + if (ret == size) + return -EFAULT; + + size -= ret; + + *ppos += size; + info->read += size; + + return size; +} + +static int tracing_buffers_release(struct inode *inode, struct file *file) +{ + struct ftrace_buffer_info *info = file->private_data; + struct trace_iterator *iter = &info->iter; + + mutex_lock(&trace_types_lock); + + iter->tr->trace_ref--; + + __trace_array_put(iter->tr); + + iter->wait_index++; + /* Make sure the waiters see the new wait_index */ + smp_wmb(); + + ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file); + + if (info->spare) + ring_buffer_free_read_page(iter->array_buffer->buffer, + info->spare_cpu, info->spare); + kvfree(info); + + mutex_unlock(&trace_types_lock); + + return 0; +} + +struct buffer_ref { + struct trace_buffer *buffer; + void *page; + int cpu; + refcount_t refcount; +}; + +static void buffer_ref_release(struct buffer_ref *ref) +{ + if (!refcount_dec_and_test(&ref->refcount)) + return; + ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page); + kfree(ref); +} + +static void buffer_pipe_buf_release(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + struct buffer_ref *ref = (struct buffer_ref *)buf->private; + + buffer_ref_release(ref); + buf->private = 0; +} + +static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + struct buffer_ref *ref = (struct buffer_ref *)buf->private; + + if (refcount_read(&ref->refcount) > INT_MAX/2) + return false; + + refcount_inc(&ref->refcount); + return true; +} + +/* Pipe buffer operations for a buffer. */ +static const struct pipe_buf_operations buffer_pipe_buf_ops = { + .release = buffer_pipe_buf_release, + .get = buffer_pipe_buf_get, +}; + +/* + * Callback from splice_to_pipe(), if we need to release some pages + * at the end of the spd in case we error'ed out in filling the pipe. + */ +static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i) +{ + struct buffer_ref *ref = + (struct buffer_ref *)spd->partial[i].private; + + buffer_ref_release(ref); + spd->partial[i].private = 0; +} + +static ssize_t +tracing_buffers_splice_read(struct file *file, loff_t *ppos, + struct pipe_inode_info *pipe, size_t len, + unsigned int flags) +{ + struct ftrace_buffer_info *info = file->private_data; + struct trace_iterator *iter = &info->iter; + struct partial_page partial_def[PIPE_DEF_BUFFERS]; + struct page *pages_def[PIPE_DEF_BUFFERS]; + struct splice_pipe_desc spd = { + .pages = pages_def, + .partial = partial_def, + .nr_pages_max = PIPE_DEF_BUFFERS, + .ops = &buffer_pipe_buf_ops, + .spd_release = buffer_spd_release, + }; + struct buffer_ref *ref; + int entries, i; + ssize_t ret = 0; + +#ifdef CONFIG_TRACER_MAX_TRACE + if (iter->snapshot && iter->tr->current_trace->use_max_tr) + return -EBUSY; +#endif + + if (*ppos & (PAGE_SIZE - 1)) + return -EINVAL; + + if (len & (PAGE_SIZE - 1)) { + if (len < PAGE_SIZE) + return -EINVAL; + len &= PAGE_MASK; + } + + if (splice_grow_spd(pipe, &spd)) + return -ENOMEM; + + again: + trace_access_lock(iter->cpu_file); + entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file); + + for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) { + struct page *page; + int r; + + ref = kzalloc(sizeof(*ref), GFP_KERNEL); + if (!ref) { + ret = -ENOMEM; + break; + } + + refcount_set(&ref->refcount, 1); + ref->buffer = iter->array_buffer->buffer; + ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file); + if (IS_ERR(ref->page)) { + ret = PTR_ERR(ref->page); + ref->page = NULL; + kfree(ref); + break; + } + ref->cpu = iter->cpu_file; + + r = ring_buffer_read_page(ref->buffer, &ref->page, + len, iter->cpu_file, 1); + if (r < 0) { + ring_buffer_free_read_page(ref->buffer, ref->cpu, + ref->page); + kfree(ref); + break; + } + + page = virt_to_page(ref->page); + + spd.pages[i] = page; + spd.partial[i].len = PAGE_SIZE; + spd.partial[i].offset = 0; + spd.partial[i].private = (unsigned long)ref; + spd.nr_pages++; + *ppos += PAGE_SIZE; + + entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file); + } + + trace_access_unlock(iter->cpu_file); + spd.nr_pages = i; + + /* did we read anything? */ + if (!spd.nr_pages) { + long wait_index; + + if (ret) + goto out; + + ret = -EAGAIN; + if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) + goto out; + + wait_index = READ_ONCE(iter->wait_index); + + ret = wait_on_pipe(iter, iter->snapshot ? 0 : iter->tr->buffer_percent); + if (ret) + goto out; + + /* No need to wait after waking up when tracing is off */ + if (!tracer_tracing_is_on(iter->tr)) + goto out; + + /* Make sure we see the new wait_index */ + smp_rmb(); + if (wait_index != iter->wait_index) + goto out; + + goto again; + } + + ret = splice_to_pipe(pipe, &spd); +out: + splice_shrink_spd(&spd); + + return ret; +} + +/* An ioctl call with cmd 0 to the ring buffer file will wake up all waiters */ +static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct ftrace_buffer_info *info = file->private_data; + struct trace_iterator *iter = &info->iter; + + if (cmd) + return -ENOIOCTLCMD; + + mutex_lock(&trace_types_lock); + + iter->wait_index++; + /* Make sure the waiters see the new wait_index */ + smp_wmb(); + + ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file); + + mutex_unlock(&trace_types_lock); + return 0; +} + +static const struct file_operations tracing_buffers_fops = { + .open = tracing_buffers_open, + .read = tracing_buffers_read, + .poll = tracing_buffers_poll, + .release = tracing_buffers_release, + .splice_read = tracing_buffers_splice_read, + .unlocked_ioctl = tracing_buffers_ioctl, + .llseek = no_llseek, +}; + +static ssize_t +tracing_stats_read(struct file *filp, char __user *ubuf, + size_t count, loff_t *ppos) +{ + struct inode *inode = file_inode(filp); + struct trace_array *tr = inode->i_private; + struct array_buffer *trace_buf = &tr->array_buffer; + int cpu = tracing_get_cpu(inode); + struct trace_seq *s; + unsigned long cnt; + unsigned long long t; + unsigned long usec_rem; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (!s) + return -ENOMEM; + + trace_seq_init(s); + + cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu); + trace_seq_printf(s, "entries: %ld\n", cnt); + + cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu); + trace_seq_printf(s, "overrun: %ld\n", cnt); + + cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu); + trace_seq_printf(s, "commit overrun: %ld\n", cnt); + + cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu); + trace_seq_printf(s, "bytes: %ld\n", cnt); + + if (trace_clocks[tr->clock_id].in_ns) { + /* local or global for trace_clock */ + t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu)); + usec_rem = do_div(t, USEC_PER_SEC); + trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n", + t, usec_rem); + + t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer)); + usec_rem = do_div(t, USEC_PER_SEC); + trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem); + } else { + /* counter or tsc mode for trace_clock */ + trace_seq_printf(s, "oldest event ts: %llu\n", + ring_buffer_oldest_event_ts(trace_buf->buffer, cpu)); + + trace_seq_printf(s, "now ts: %llu\n", + ring_buffer_time_stamp(trace_buf->buffer)); + } + + cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu); + trace_seq_printf(s, "dropped events: %ld\n", cnt); + + cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu); + trace_seq_printf(s, "read events: %ld\n", cnt); + + count = simple_read_from_buffer(ubuf, count, ppos, + s->buffer, trace_seq_used(s)); + + kfree(s); + + return count; +} + +static const struct file_operations tracing_stats_fops = { + .open = tracing_open_generic_tr, + .read = tracing_stats_read, + .llseek = generic_file_llseek, + .release = tracing_release_generic_tr, +}; + +#ifdef CONFIG_DYNAMIC_FTRACE + +static ssize_t +tracing_read_dyn_info(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + ssize_t ret; + char *buf; + int r; + + /* 256 should be plenty to hold the amount needed */ + buf = kmalloc(256, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + r = scnprintf(buf, 256, "%ld pages:%ld groups: %ld\n", + ftrace_update_tot_cnt, + ftrace_number_of_pages, + ftrace_number_of_groups); + + ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r); + kfree(buf); + return ret; +} + +static const struct file_operations tracing_dyn_info_fops = { + .open = tracing_open_generic, + .read = tracing_read_dyn_info, + .llseek = generic_file_llseek, +}; +#endif /* CONFIG_DYNAMIC_FTRACE */ + +#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) +static void +ftrace_snapshot(unsigned long ip, unsigned long parent_ip, + struct trace_array *tr, struct ftrace_probe_ops *ops, + void *data) +{ + tracing_snapshot_instance(tr); +} + +static void +ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip, + struct trace_array *tr, struct ftrace_probe_ops *ops, + void *data) +{ + struct ftrace_func_mapper *mapper = data; + long *count = NULL; + + if (mapper) + count = (long *)ftrace_func_mapper_find_ip(mapper, ip); + + if (count) { + + if (*count <= 0) + return; + + (*count)--; + } + + tracing_snapshot_instance(tr); +} + +static int +ftrace_snapshot_print(struct seq_file *m, unsigned long ip, + struct ftrace_probe_ops *ops, void *data) +{ + struct ftrace_func_mapper *mapper = data; + long *count = NULL; + + seq_printf(m, "%ps:", (void *)ip); + + seq_puts(m, "snapshot"); + + if (mapper) + count = (long *)ftrace_func_mapper_find_ip(mapper, ip); + + if (count) + seq_printf(m, ":count=%ld\n", *count); + else + seq_puts(m, ":unlimited\n"); + + return 0; +} + +static int +ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr, + unsigned long ip, void *init_data, void **data) +{ + struct ftrace_func_mapper *mapper = *data; + + if (!mapper) { + mapper = allocate_ftrace_func_mapper(); + if (!mapper) + return -ENOMEM; + *data = mapper; + } + + return ftrace_func_mapper_add_ip(mapper, ip, init_data); +} + +static void +ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr, + unsigned long ip, void *data) +{ + struct ftrace_func_mapper *mapper = data; + + if (!ip) { + if (!mapper) + return; + free_ftrace_func_mapper(mapper, NULL); + return; + } + + ftrace_func_mapper_remove_ip(mapper, ip); +} + +static struct ftrace_probe_ops snapshot_probe_ops = { + .func = ftrace_snapshot, + .print = ftrace_snapshot_print, +}; + +static struct ftrace_probe_ops snapshot_count_probe_ops = { + .func = ftrace_count_snapshot, + .print = ftrace_snapshot_print, + .init = ftrace_snapshot_init, + .free = ftrace_snapshot_free, +}; + +static int +ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash, + char *glob, char *cmd, char *param, int enable) +{ + struct ftrace_probe_ops *ops; + void *count = (void *)-1; + char *number; + int ret; + + if (!tr) + return -ENODEV; + + /* hash funcs only work with set_ftrace_filter */ + if (!enable) + return -EINVAL; + + ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops; + + if (glob[0] == '!') + return unregister_ftrace_function_probe_func(glob+1, tr, ops); + + if (!param) + goto out_reg; + + number = strsep(¶m, ":"); + + if (!strlen(number)) + goto out_reg; + + /* + * We use the callback data field (which is a pointer) + * as our counter. + */ + ret = kstrtoul(number, 0, (unsigned long *)&count); + if (ret) + return ret; + + out_reg: + ret = tracing_alloc_snapshot_instance(tr); + if (ret < 0) + goto out; + + ret = register_ftrace_function_probe(glob, tr, ops, count); + + out: + return ret < 0 ? ret : 0; +} + +static struct ftrace_func_command ftrace_snapshot_cmd = { + .name = "snapshot", + .func = ftrace_trace_snapshot_callback, +}; + +static __init int register_snapshot_cmd(void) +{ + return register_ftrace_command(&ftrace_snapshot_cmd); +} +#else +static inline __init int register_snapshot_cmd(void) { return 0; } +#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */ + +static struct dentry *tracing_get_dentry(struct trace_array *tr) +{ + if (WARN_ON(!tr->dir)) + return ERR_PTR(-ENODEV); + + /* Top directory uses NULL as the parent */ + if (tr->flags & TRACE_ARRAY_FL_GLOBAL) + return NULL; + + /* All sub buffers have a descriptor */ + return tr->dir; +} + +static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu) +{ + struct dentry *d_tracer; + + if (tr->percpu_dir) + return tr->percpu_dir; + + d_tracer = tracing_get_dentry(tr); + if (IS_ERR(d_tracer)) + return NULL; + + tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer); + + MEM_FAIL(!tr->percpu_dir, + "Could not create tracefs directory 'per_cpu/%d'\n", cpu); + + return tr->percpu_dir; +} + +static struct dentry * +trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent, + void *data, long cpu, const struct file_operations *fops) +{ + struct dentry *ret = trace_create_file(name, mode, parent, data, fops); + + if (ret) /* See tracing_get_cpu() */ + d_inode(ret)->i_cdev = (void *)(cpu + 1); + return ret; +} + +static void +tracing_init_tracefs_percpu(struct trace_array *tr, long cpu) +{ + struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu); + struct dentry *d_cpu; + char cpu_dir[30]; /* 30 characters should be more than enough */ + + if (!d_percpu) + return; + + snprintf(cpu_dir, 30, "cpu%ld", cpu); + d_cpu = tracefs_create_dir(cpu_dir, d_percpu); + if (!d_cpu) { + pr_warn("Could not create tracefs '%s' entry\n", cpu_dir); + return; + } + + /* per cpu trace_pipe */ + trace_create_cpu_file("trace_pipe", TRACE_MODE_READ, d_cpu, + tr, cpu, &tracing_pipe_fops); + + /* per cpu trace */ + trace_create_cpu_file("trace", TRACE_MODE_WRITE, d_cpu, + tr, cpu, &tracing_fops); + + trace_create_cpu_file("trace_pipe_raw", TRACE_MODE_READ, d_cpu, + tr, cpu, &tracing_buffers_fops); + + trace_create_cpu_file("stats", TRACE_MODE_READ, d_cpu, + tr, cpu, &tracing_stats_fops); + + trace_create_cpu_file("buffer_size_kb", TRACE_MODE_READ, d_cpu, + tr, cpu, &tracing_entries_fops); + +#ifdef CONFIG_TRACER_SNAPSHOT + trace_create_cpu_file("snapshot", TRACE_MODE_WRITE, d_cpu, + tr, cpu, &snapshot_fops); + + trace_create_cpu_file("snapshot_raw", TRACE_MODE_READ, d_cpu, + tr, cpu, &snapshot_raw_fops); +#endif +} + +#ifdef CONFIG_FTRACE_SELFTEST +/* Let selftest have access to static functions in this file */ +#include "trace_selftest.c" +#endif + +static ssize_t +trace_options_read(struct file *filp, char __user *ubuf, size_t cnt, + loff_t *ppos) +{ + struct trace_option_dentry *topt = filp->private_data; + char *buf; + + if (topt->flags->val & topt->opt->bit) + buf = "1\n"; + else + buf = "0\n"; + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2); +} + +static ssize_t +trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt, + loff_t *ppos) +{ + struct trace_option_dentry *topt = filp->private_data; + unsigned long val; + int ret; + + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; + + if (val != 0 && val != 1) + return -EINVAL; + + if (!!(topt->flags->val & topt->opt->bit) != val) { + mutex_lock(&trace_types_lock); + ret = __set_tracer_option(topt->tr, topt->flags, + topt->opt, !val); + mutex_unlock(&trace_types_lock); + if (ret) + return ret; + } + + *ppos += cnt; + + return cnt; +} + +static int tracing_open_options(struct inode *inode, struct file *filp) +{ + struct trace_option_dentry *topt = inode->i_private; + int ret; + + ret = tracing_check_open_get_tr(topt->tr); + if (ret) + return ret; + + filp->private_data = inode->i_private; + return 0; +} + +static int tracing_release_options(struct inode *inode, struct file *file) +{ + struct trace_option_dentry *topt = file->private_data; + + trace_array_put(topt->tr); + return 0; +} + +static const struct file_operations trace_options_fops = { + .open = tracing_open_options, + .read = trace_options_read, + .write = trace_options_write, + .llseek = generic_file_llseek, + .release = tracing_release_options, +}; + +/* + * In order to pass in both the trace_array descriptor as well as the index + * to the flag that the trace option file represents, the trace_array + * has a character array of trace_flags_index[], which holds the index + * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc. + * The address of this character array is passed to the flag option file + * read/write callbacks. + * + * In order to extract both the index and the trace_array descriptor, + * get_tr_index() uses the following algorithm. + * + * idx = *ptr; + * + * As the pointer itself contains the address of the index (remember + * index[1] == 1). + * + * Then to get the trace_array descriptor, by subtracting that index + * from the ptr, we get to the start of the index itself. + * + * ptr - idx == &index[0] + * + * Then a simple container_of() from that pointer gets us to the + * trace_array descriptor. + */ +static void get_tr_index(void *data, struct trace_array **ptr, + unsigned int *pindex) +{ + *pindex = *(unsigned char *)data; + + *ptr = container_of(data - *pindex, struct trace_array, + trace_flags_index); +} + +static ssize_t +trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt, + loff_t *ppos) +{ + void *tr_index = filp->private_data; + struct trace_array *tr; + unsigned int index; + char *buf; + + get_tr_index(tr_index, &tr, &index); + + if (tr->trace_flags & (1 << index)) + buf = "1\n"; + else + buf = "0\n"; + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2); +} + +static ssize_t +trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt, + loff_t *ppos) +{ + void *tr_index = filp->private_data; + struct trace_array *tr; + unsigned int index; + unsigned long val; + int ret; + + get_tr_index(tr_index, &tr, &index); + + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; + + if (val != 0 && val != 1) + return -EINVAL; + + mutex_lock(&event_mutex); + mutex_lock(&trace_types_lock); + ret = set_tracer_flag(tr, 1 << index, val); + mutex_unlock(&trace_types_lock); + mutex_unlock(&event_mutex); + + if (ret < 0) + return ret; + + *ppos += cnt; + + return cnt; +} + +static const struct file_operations trace_options_core_fops = { + .open = tracing_open_generic, + .read = trace_options_core_read, + .write = trace_options_core_write, + .llseek = generic_file_llseek, +}; + +struct dentry *trace_create_file(const char *name, + umode_t mode, + struct dentry *parent, + void *data, + const struct file_operations *fops) +{ + struct dentry *ret; + + ret = tracefs_create_file(name, mode, parent, data, fops); + if (!ret) + pr_warn("Could not create tracefs '%s' entry\n", name); + + return ret; +} + + +static struct dentry *trace_options_init_dentry(struct trace_array *tr) +{ + struct dentry *d_tracer; + + if (tr->options) + return tr->options; + + d_tracer = tracing_get_dentry(tr); + if (IS_ERR(d_tracer)) + return NULL; + + tr->options = tracefs_create_dir("options", d_tracer); + if (!tr->options) { + pr_warn("Could not create tracefs directory 'options'\n"); + return NULL; + } + + return tr->options; +} + +static void +create_trace_option_file(struct trace_array *tr, + struct trace_option_dentry *topt, + struct tracer_flags *flags, + struct tracer_opt *opt) +{ + struct dentry *t_options; + + t_options = trace_options_init_dentry(tr); + if (!t_options) + return; + + topt->flags = flags; + topt->opt = opt; + topt->tr = tr; + + topt->entry = trace_create_file(opt->name, TRACE_MODE_WRITE, + t_options, topt, &trace_options_fops); + +} + +static void +create_trace_option_files(struct trace_array *tr, struct tracer *tracer) +{ + struct trace_option_dentry *topts; + struct trace_options *tr_topts; + struct tracer_flags *flags; + struct tracer_opt *opts; + int cnt; + int i; + + if (!tracer) + return; + + flags = tracer->flags; + + if (!flags || !flags->opts) + return; + + /* + * If this is an instance, only create flags for tracers + * the instance may have. + */ + if (!trace_ok_for_array(tracer, tr)) + return; + + for (i = 0; i < tr->nr_topts; i++) { + /* Make sure there's no duplicate flags. */ + if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags)) + return; + } + + opts = flags->opts; + + for (cnt = 0; opts[cnt].name; cnt++) + ; + + topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL); + if (!topts) + return; + + tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1), + GFP_KERNEL); + if (!tr_topts) { + kfree(topts); + return; + } + + tr->topts = tr_topts; + tr->topts[tr->nr_topts].tracer = tracer; + tr->topts[tr->nr_topts].topts = topts; + tr->nr_topts++; + + for (cnt = 0; opts[cnt].name; cnt++) { + create_trace_option_file(tr, &topts[cnt], flags, + &opts[cnt]); + MEM_FAIL(topts[cnt].entry == NULL, + "Failed to create trace option: %s", + opts[cnt].name); + } +} + +static struct dentry * +create_trace_option_core_file(struct trace_array *tr, + const char *option, long index) +{ + struct dentry *t_options; + + t_options = trace_options_init_dentry(tr); + if (!t_options) + return NULL; + + return trace_create_file(option, TRACE_MODE_WRITE, t_options, + (void *)&tr->trace_flags_index[index], + &trace_options_core_fops); +} + +static void create_trace_options_dir(struct trace_array *tr) +{ + struct dentry *t_options; + bool top_level = tr == &global_trace; + int i; + + t_options = trace_options_init_dentry(tr); + if (!t_options) + return; + + for (i = 0; trace_options[i]; i++) { + if (top_level || + !((1 << i) & TOP_LEVEL_TRACE_FLAGS)) + create_trace_option_core_file(tr, trace_options[i], i); + } +} + +static ssize_t +rb_simple_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + char buf[64]; + int r; + + r = tracer_tracing_is_on(tr); + r = sprintf(buf, "%d\n", r); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +static ssize_t +rb_simple_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + struct trace_buffer *buffer = tr->array_buffer.buffer; + unsigned long val; + int ret; + + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; + + if (buffer) { + mutex_lock(&trace_types_lock); + if (!!val == tracer_tracing_is_on(tr)) { + val = 0; /* do nothing */ + } else if (val) { + tracer_tracing_on(tr); + if (tr->current_trace->start) + tr->current_trace->start(tr); + } else { + tracer_tracing_off(tr); + if (tr->current_trace->stop) + tr->current_trace->stop(tr); + /* Wake up any waiters */ + ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS); + } + mutex_unlock(&trace_types_lock); + } + + (*ppos)++; + + return cnt; +} + +static const struct file_operations rb_simple_fops = { + .open = tracing_open_generic_tr, + .read = rb_simple_read, + .write = rb_simple_write, + .release = tracing_release_generic_tr, + .llseek = default_llseek, +}; + +static ssize_t +buffer_percent_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + char buf[64]; + int r; + + r = tr->buffer_percent; + r = sprintf(buf, "%d\n", r); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +static ssize_t +buffer_percent_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + unsigned long val; + int ret; + + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; + + if (val > 100) + return -EINVAL; + + tr->buffer_percent = val; + + (*ppos)++; + + return cnt; +} + +static const struct file_operations buffer_percent_fops = { + .open = tracing_open_generic_tr, + .read = buffer_percent_read, + .write = buffer_percent_write, + .release = tracing_release_generic_tr, + .llseek = default_llseek, +}; + +static struct dentry *trace_instance_dir; + +static void +init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer); + +static int +allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size) +{ + enum ring_buffer_flags rb_flags; + + rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0; + + buf->tr = tr; + + buf->buffer = ring_buffer_alloc(size, rb_flags); + if (!buf->buffer) + return -ENOMEM; + + buf->data = alloc_percpu(struct trace_array_cpu); + if (!buf->data) { + ring_buffer_free(buf->buffer); + buf->buffer = NULL; + return -ENOMEM; + } + + /* Allocate the first page for all buffers */ + set_buffer_entries(&tr->array_buffer, + ring_buffer_size(tr->array_buffer.buffer, 0)); + + return 0; +} + +static void free_trace_buffer(struct array_buffer *buf) +{ + if (buf->buffer) { + ring_buffer_free(buf->buffer); + buf->buffer = NULL; + free_percpu(buf->data); + buf->data = NULL; + } +} + +static int allocate_trace_buffers(struct trace_array *tr, int size) +{ + int ret; + + ret = allocate_trace_buffer(tr, &tr->array_buffer, size); + if (ret) + return ret; + +#ifdef CONFIG_TRACER_MAX_TRACE + ret = allocate_trace_buffer(tr, &tr->max_buffer, + allocate_snapshot ? size : 1); + if (MEM_FAIL(ret, "Failed to allocate trace buffer\n")) { + free_trace_buffer(&tr->array_buffer); + return -ENOMEM; + } + tr->allocated_snapshot = allocate_snapshot; + + allocate_snapshot = false; +#endif + + return 0; +} + +static void free_trace_buffers(struct trace_array *tr) +{ + if (!tr) + return; + + free_trace_buffer(&tr->array_buffer); + +#ifdef CONFIG_TRACER_MAX_TRACE + free_trace_buffer(&tr->max_buffer); +#endif +} + +static void init_trace_flags_index(struct trace_array *tr) +{ + int i; + + /* Used by the trace options files */ + for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) + tr->trace_flags_index[i] = i; +} + +static void __update_tracer_options(struct trace_array *tr) +{ + struct tracer *t; + + for (t = trace_types; t; t = t->next) + add_tracer_options(tr, t); +} + +static void update_tracer_options(struct trace_array *tr) +{ + mutex_lock(&trace_types_lock); + tracer_options_updated = true; + __update_tracer_options(tr); + mutex_unlock(&trace_types_lock); +} + +/* Must have trace_types_lock held */ +struct trace_array *trace_array_find(const char *instance) +{ + struct trace_array *tr, *found = NULL; + + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (tr->name && strcmp(tr->name, instance) == 0) { + found = tr; + break; + } + } + + return found; +} + +struct trace_array *trace_array_find_get(const char *instance) +{ + struct trace_array *tr; + + mutex_lock(&trace_types_lock); + tr = trace_array_find(instance); + if (tr) + tr->ref++; + mutex_unlock(&trace_types_lock); + + return tr; +} + +static int trace_array_create_dir(struct trace_array *tr) +{ + int ret; + + tr->dir = tracefs_create_dir(tr->name, trace_instance_dir); + if (!tr->dir) + return -EINVAL; + + ret = event_trace_add_tracer(tr->dir, tr); + if (ret) { + tracefs_remove(tr->dir); + return ret; + } + + init_tracer_tracefs(tr, tr->dir); + __update_tracer_options(tr); + + return ret; +} + +static struct trace_array *trace_array_create(const char *name) +{ + struct trace_array *tr; + int ret; + + ret = -ENOMEM; + tr = kzalloc(sizeof(*tr), GFP_KERNEL); + if (!tr) + return ERR_PTR(ret); + + tr->name = kstrdup(name, GFP_KERNEL); + if (!tr->name) + goto out_free_tr; + + if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL)) + goto out_free_tr; + + if (!zalloc_cpumask_var(&tr->pipe_cpumask, GFP_KERNEL)) + goto out_free_tr; + + tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS; + + cpumask_copy(tr->tracing_cpumask, cpu_all_mask); + + raw_spin_lock_init(&tr->start_lock); + + tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; + + tr->current_trace = &nop_trace; + + INIT_LIST_HEAD(&tr->systems); + INIT_LIST_HEAD(&tr->events); + INIT_LIST_HEAD(&tr->hist_vars); + INIT_LIST_HEAD(&tr->err_log); + + if (allocate_trace_buffers(tr, trace_buf_size) < 0) + goto out_free_tr; + + if (ftrace_allocate_ftrace_ops(tr) < 0) + goto out_free_tr; + + ftrace_init_trace_array(tr); + + init_trace_flags_index(tr); + + if (trace_instance_dir) { + ret = trace_array_create_dir(tr); + if (ret) + goto out_free_tr; + } else + __trace_early_add_events(tr); + + list_add(&tr->list, &ftrace_trace_arrays); + + tr->ref++; + + return tr; + + out_free_tr: + ftrace_free_ftrace_ops(tr); + free_trace_buffers(tr); + free_cpumask_var(tr->pipe_cpumask); + free_cpumask_var(tr->tracing_cpumask); + kfree(tr->name); + kfree(tr); + + return ERR_PTR(ret); +} + +static int instance_mkdir(const char *name) +{ + struct trace_array *tr; + int ret; + + mutex_lock(&event_mutex); + mutex_lock(&trace_types_lock); + + ret = -EEXIST; + if (trace_array_find(name)) + goto out_unlock; + + tr = trace_array_create(name); + + ret = PTR_ERR_OR_ZERO(tr); + +out_unlock: + mutex_unlock(&trace_types_lock); + mutex_unlock(&event_mutex); + return ret; +} + +/** + * trace_array_get_by_name - Create/Lookup a trace array, given its name. + * @name: The name of the trace array to be looked up/created. + * + * Returns pointer to trace array with given name. + * NULL, if it cannot be created. + * + * NOTE: This function increments the reference counter associated with the + * trace array returned. This makes sure it cannot be freed while in use. + * Use trace_array_put() once the trace array is no longer needed. + * If the trace_array is to be freed, trace_array_destroy() needs to + * be called after the trace_array_put(), or simply let user space delete + * it from the tracefs instances directory. But until the + * trace_array_put() is called, user space can not delete it. + * + */ +struct trace_array *trace_array_get_by_name(const char *name) +{ + struct trace_array *tr; + + mutex_lock(&event_mutex); + mutex_lock(&trace_types_lock); + + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (tr->name && strcmp(tr->name, name) == 0) + goto out_unlock; + } + + tr = trace_array_create(name); + + if (IS_ERR(tr)) + tr = NULL; +out_unlock: + if (tr) + tr->ref++; + + mutex_unlock(&trace_types_lock); + mutex_unlock(&event_mutex); + return tr; +} +EXPORT_SYMBOL_GPL(trace_array_get_by_name); + +static int __remove_instance(struct trace_array *tr) +{ + int i; + + /* Reference counter for a newly created trace array = 1. */ + if (tr->ref > 1 || (tr->current_trace && tr->trace_ref)) + return -EBUSY; + + list_del(&tr->list); + + /* Disable all the flags that were enabled coming in */ + for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) { + if ((1 << i) & ZEROED_TRACE_FLAGS) + set_tracer_flag(tr, 1 << i, 0); + } + + tracing_set_nop(tr); + clear_ftrace_function_probes(tr); + event_trace_del_tracer(tr); + ftrace_clear_pids(tr); + ftrace_destroy_function_files(tr); + tracefs_remove(tr->dir); + free_percpu(tr->last_func_repeats); + free_trace_buffers(tr); + clear_tracing_err_log(tr); + + for (i = 0; i < tr->nr_topts; i++) { + kfree(tr->topts[i].topts); + } + kfree(tr->topts); + + free_cpumask_var(tr->pipe_cpumask); + free_cpumask_var(tr->tracing_cpumask); + kfree(tr->name); + kfree(tr); + + return 0; +} + +int trace_array_destroy(struct trace_array *this_tr) +{ + struct trace_array *tr; + int ret; + + if (!this_tr) + return -EINVAL; + + mutex_lock(&event_mutex); + mutex_lock(&trace_types_lock); + + ret = -ENODEV; + + /* Making sure trace array exists before destroying it. */ + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (tr == this_tr) { + ret = __remove_instance(tr); + break; + } + } + + mutex_unlock(&trace_types_lock); + mutex_unlock(&event_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(trace_array_destroy); + +static int instance_rmdir(const char *name) +{ + struct trace_array *tr; + int ret; + + mutex_lock(&event_mutex); + mutex_lock(&trace_types_lock); + + ret = -ENODEV; + tr = trace_array_find(name); + if (tr) + ret = __remove_instance(tr); + + mutex_unlock(&trace_types_lock); + mutex_unlock(&event_mutex); + + return ret; +} + +static __init void create_trace_instances(struct dentry *d_tracer) +{ + struct trace_array *tr; + + trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer, + instance_mkdir, + instance_rmdir); + if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n")) + return; + + mutex_lock(&event_mutex); + mutex_lock(&trace_types_lock); + + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (!tr->name) + continue; + if (MEM_FAIL(trace_array_create_dir(tr) < 0, + "Failed to create instance directory\n")) + break; + } + + mutex_unlock(&trace_types_lock); + mutex_unlock(&event_mutex); +} + +static void +init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer) +{ + struct trace_event_file *file; + int cpu; + + trace_create_file("available_tracers", TRACE_MODE_READ, d_tracer, + tr, &show_traces_fops); + + trace_create_file("current_tracer", TRACE_MODE_WRITE, d_tracer, + tr, &set_tracer_fops); + + trace_create_file("tracing_cpumask", TRACE_MODE_WRITE, d_tracer, + tr, &tracing_cpumask_fops); + + trace_create_file("trace_options", TRACE_MODE_WRITE, d_tracer, + tr, &tracing_iter_fops); + + trace_create_file("trace", TRACE_MODE_WRITE, d_tracer, + tr, &tracing_fops); + + trace_create_file("trace_pipe", TRACE_MODE_READ, d_tracer, + tr, &tracing_pipe_fops); + + trace_create_file("buffer_size_kb", TRACE_MODE_WRITE, d_tracer, + tr, &tracing_entries_fops); + + trace_create_file("buffer_total_size_kb", TRACE_MODE_READ, d_tracer, + tr, &tracing_total_entries_fops); + + trace_create_file("free_buffer", 0200, d_tracer, + tr, &tracing_free_buffer_fops); + + trace_create_file("trace_marker", 0220, d_tracer, + tr, &tracing_mark_fops); + + file = __find_event_file(tr, "ftrace", "print"); + if (file && file->ef) + eventfs_add_file("trigger", TRACE_MODE_WRITE, file->ef, + file, &event_trigger_fops); + tr->trace_marker_file = file; + + trace_create_file("trace_marker_raw", 0220, d_tracer, + tr, &tracing_mark_raw_fops); + + trace_create_file("trace_clock", TRACE_MODE_WRITE, d_tracer, tr, + &trace_clock_fops); + + trace_create_file("tracing_on", TRACE_MODE_WRITE, d_tracer, + tr, &rb_simple_fops); + + trace_create_file("timestamp_mode", TRACE_MODE_READ, d_tracer, tr, + &trace_time_stamp_mode_fops); + + tr->buffer_percent = 50; + + trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer, + tr, &buffer_percent_fops); + + create_trace_options_dir(tr); + +#ifdef CONFIG_TRACER_MAX_TRACE + trace_create_maxlat_file(tr, d_tracer); +#endif + + if (ftrace_create_function_files(tr, d_tracer)) + MEM_FAIL(1, "Could not allocate function filter files"); + +#ifdef CONFIG_TRACER_SNAPSHOT + trace_create_file("snapshot", TRACE_MODE_WRITE, d_tracer, + tr, &snapshot_fops); +#endif + + trace_create_file("error_log", TRACE_MODE_WRITE, d_tracer, + tr, &tracing_err_log_fops); + + for_each_tracing_cpu(cpu) + tracing_init_tracefs_percpu(tr, cpu); + + ftrace_init_tracefs(tr, d_tracer); +} + +static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore) +{ + struct vfsmount *mnt; + struct file_system_type *type; + + /* + * To maintain backward compatibility for tools that mount + * debugfs to get to the tracing facility, tracefs is automatically + * mounted to the debugfs/tracing directory. + */ + type = get_fs_type("tracefs"); + if (!type) + return NULL; + mnt = vfs_submount(mntpt, type, "tracefs", NULL); + put_filesystem(type); + if (IS_ERR(mnt)) + return NULL; + mntget(mnt); + + return mnt; +} + +/** + * tracing_init_dentry - initialize top level trace array + * + * This is called when creating files or directories in the tracing + * directory. It is called via fs_initcall() by any of the boot up code + * and expects to return the dentry of the top level tracing directory. + */ +int tracing_init_dentry(void) +{ + struct trace_array *tr = &global_trace; + + if (security_locked_down(LOCKDOWN_TRACEFS)) { + pr_warn("Tracing disabled due to lockdown\n"); + return -EPERM; + } + + /* The top level trace array uses NULL as parent */ + if (tr->dir) + return 0; + + if (WARN_ON(!tracefs_initialized())) + return -ENODEV; + + /* + * As there may still be users that expect the tracing + * files to exist in debugfs/tracing, we must automount + * the tracefs file system there, so older tools still + * work with the newer kernel. + */ + tr->dir = debugfs_create_automount("tracing", NULL, + trace_automount, NULL); + + return 0; +} + +extern struct trace_eval_map *__start_ftrace_eval_maps[]; +extern struct trace_eval_map *__stop_ftrace_eval_maps[]; + +static struct workqueue_struct *eval_map_wq __initdata; +static struct work_struct eval_map_work __initdata; +static struct work_struct tracerfs_init_work __initdata; + +static void __init eval_map_work_func(struct work_struct *work) +{ + int len; + + len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps; + trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len); +} + +static int __init trace_eval_init(void) +{ + INIT_WORK(&eval_map_work, eval_map_work_func); + + eval_map_wq = alloc_workqueue("eval_map_wq", WQ_UNBOUND, 0); + if (!eval_map_wq) { + pr_err("Unable to allocate eval_map_wq\n"); + /* Do work here */ + eval_map_work_func(&eval_map_work); + return -ENOMEM; + } + + queue_work(eval_map_wq, &eval_map_work); + return 0; +} + +subsys_initcall(trace_eval_init); + +static int __init trace_eval_sync(void) +{ + /* Make sure the eval map updates are finished */ + if (eval_map_wq) + destroy_workqueue(eval_map_wq); + return 0; +} + +late_initcall_sync(trace_eval_sync); + + +#ifdef CONFIG_MODULES +static void trace_module_add_evals(struct module *mod) +{ + if (!mod->num_trace_evals) + return; + + /* + * Modules with bad taint do not have events created, do + * not bother with enums either. + */ + if (trace_module_has_bad_taint(mod)) + return; + + trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals); +} + +#ifdef CONFIG_TRACE_EVAL_MAP_FILE +static void trace_module_remove_evals(struct module *mod) +{ + union trace_eval_map_item *map; + union trace_eval_map_item **last = &trace_eval_maps; + + if (!mod->num_trace_evals) + return; + + mutex_lock(&trace_eval_mutex); + + map = trace_eval_maps; + + while (map) { + if (map->head.mod == mod) + break; + map = trace_eval_jmp_to_tail(map); + last = &map->tail.next; + map = map->tail.next; + } + if (!map) + goto out; + + *last = trace_eval_jmp_to_tail(map)->tail.next; + kfree(map); + out: + mutex_unlock(&trace_eval_mutex); +} +#else +static inline void trace_module_remove_evals(struct module *mod) { } +#endif /* CONFIG_TRACE_EVAL_MAP_FILE */ + +static int trace_module_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct module *mod = data; + + switch (val) { + case MODULE_STATE_COMING: + trace_module_add_evals(mod); + break; + case MODULE_STATE_GOING: + trace_module_remove_evals(mod); + break; + } + + return NOTIFY_OK; +} + +static struct notifier_block trace_module_nb = { + .notifier_call = trace_module_notify, + .priority = 0, +}; +#endif /* CONFIG_MODULES */ + +static __init void tracer_init_tracefs_work_func(struct work_struct *work) +{ + + event_trace_init(); + + init_tracer_tracefs(&global_trace, NULL); + ftrace_init_tracefs_toplevel(&global_trace, NULL); + + trace_create_file("tracing_thresh", TRACE_MODE_WRITE, NULL, + &global_trace, &tracing_thresh_fops); + + trace_create_file("README", TRACE_MODE_READ, NULL, + NULL, &tracing_readme_fops); + + trace_create_file("saved_cmdlines", TRACE_MODE_READ, NULL, + NULL, &tracing_saved_cmdlines_fops); + + trace_create_file("saved_cmdlines_size", TRACE_MODE_WRITE, NULL, + NULL, &tracing_saved_cmdlines_size_fops); + + trace_create_file("saved_tgids", TRACE_MODE_READ, NULL, + NULL, &tracing_saved_tgids_fops); + + trace_create_eval_file(NULL); + +#ifdef CONFIG_MODULES + register_module_notifier(&trace_module_nb); +#endif + +#ifdef CONFIG_DYNAMIC_FTRACE + trace_create_file("dyn_ftrace_total_info", TRACE_MODE_READ, NULL, + NULL, &tracing_dyn_info_fops); +#endif + + create_trace_instances(NULL); + + update_tracer_options(&global_trace); +} + +static __init int tracer_init_tracefs(void) +{ + int ret; + + trace_access_lock_init(); + + ret = tracing_init_dentry(); + if (ret) + return 0; + + if (eval_map_wq) { + INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func); + queue_work(eval_map_wq, &tracerfs_init_work); + } else { + tracer_init_tracefs_work_func(NULL); + } + + rv_init_interface(); + + return 0; +} + +fs_initcall(tracer_init_tracefs); + +static int trace_die_panic_handler(struct notifier_block *self, + unsigned long ev, void *unused); + +static struct notifier_block trace_panic_notifier = { + .notifier_call = trace_die_panic_handler, + .priority = INT_MAX - 1, +}; + +static struct notifier_block trace_die_notifier = { + .notifier_call = trace_die_panic_handler, + .priority = INT_MAX - 1, +}; + +/* + * The idea is to execute the following die/panic callback early, in order + * to avoid showing irrelevant information in the trace (like other panic + * notifier functions); we are the 2nd to run, after hung_task/rcu_stall + * warnings get disabled (to prevent potential log flooding). + */ +static int trace_die_panic_handler(struct notifier_block *self, + unsigned long ev, void *unused) +{ + if (!ftrace_dump_on_oops) + return NOTIFY_DONE; + + /* The die notifier requires DIE_OOPS to trigger */ + if (self == &trace_die_notifier && ev != DIE_OOPS) + return NOTIFY_DONE; + + ftrace_dump(ftrace_dump_on_oops); + + return NOTIFY_DONE; +} + +/* + * printk is set to max of 1024, we really don't need it that big. + * Nothing should be printing 1000 characters anyway. + */ +#define TRACE_MAX_PRINT 1000 + +/* + * Define here KERN_TRACE so that we have one place to modify + * it if we decide to change what log level the ftrace dump + * should be at. + */ +#define KERN_TRACE KERN_EMERG + +void +trace_printk_seq(struct trace_seq *s) +{ + /* Probably should print a warning here. */ + if (s->seq.len >= TRACE_MAX_PRINT) + s->seq.len = TRACE_MAX_PRINT; + + /* + * More paranoid code. Although the buffer size is set to + * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just + * an extra layer of protection. + */ + if (WARN_ON_ONCE(s->seq.len >= s->seq.size)) + s->seq.len = s->seq.size - 1; + + /* should be zero ended, but we are paranoid. */ + s->buffer[s->seq.len] = 0; + + printk(KERN_TRACE "%s", s->buffer); + + trace_seq_init(s); +} + +void trace_init_global_iter(struct trace_iterator *iter) +{ + iter->tr = &global_trace; + iter->trace = iter->tr->current_trace; + iter->cpu_file = RING_BUFFER_ALL_CPUS; + iter->array_buffer = &global_trace.array_buffer; + + if (iter->trace && iter->trace->open) + iter->trace->open(iter); + + /* Annotate start of buffers if we had overruns */ + if (ring_buffer_overruns(iter->array_buffer->buffer)) + iter->iter_flags |= TRACE_FILE_ANNOTATE; + + /* Output in nanoseconds only if we are using a clock in nanoseconds. */ + if (trace_clocks[iter->tr->clock_id].in_ns) + iter->iter_flags |= TRACE_FILE_TIME_IN_NS; + + /* Can not use kmalloc for iter.temp and iter.fmt */ + iter->temp = static_temp_buf; + iter->temp_size = STATIC_TEMP_BUF_SIZE; + iter->fmt = static_fmt_buf; + iter->fmt_size = STATIC_FMT_BUF_SIZE; +} + +void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) +{ + /* use static because iter can be a bit big for the stack */ + static struct trace_iterator iter; + static atomic_t dump_running; + struct trace_array *tr = &global_trace; + unsigned int old_userobj; + unsigned long flags; + int cnt = 0, cpu; + + /* Only allow one dump user at a time. */ + if (atomic_inc_return(&dump_running) != 1) { + atomic_dec(&dump_running); + return; + } + + /* + * Always turn off tracing when we dump. + * We don't need to show trace output of what happens + * between multiple crashes. + * + * If the user does a sysrq-z, then they can re-enable + * tracing with echo 1 > tracing_on. + */ + tracing_off(); + + local_irq_save(flags); + + /* Simulate the iterator */ + trace_init_global_iter(&iter); + + for_each_tracing_cpu(cpu) { + atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled); + } + + old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ; + + /* don't look at user memory in panic mode */ + tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ; + + switch (oops_dump_mode) { + case DUMP_ALL: + iter.cpu_file = RING_BUFFER_ALL_CPUS; + break; + case DUMP_ORIG: + iter.cpu_file = raw_smp_processor_id(); + break; + case DUMP_NONE: + goto out_enable; + default: + printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n"); + iter.cpu_file = RING_BUFFER_ALL_CPUS; + } + + printk(KERN_TRACE "Dumping ftrace buffer:\n"); + + /* Did function tracer already get disabled? */ + if (ftrace_is_dead()) { + printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n"); + printk("# MAY BE MISSING FUNCTION EVENTS\n"); + } + + /* + * We need to stop all tracing on all CPUS to read + * the next buffer. This is a bit expensive, but is + * not done often. We fill all what we can read, + * and then release the locks again. + */ + + while (!trace_empty(&iter)) { + + if (!cnt) + printk(KERN_TRACE "---------------------------------\n"); + + cnt++; + + trace_iterator_reset(&iter); + iter.iter_flags |= TRACE_FILE_LAT_FMT; + + if (trace_find_next_entry_inc(&iter) != NULL) { + int ret; + + ret = print_trace_line(&iter); + if (ret != TRACE_TYPE_NO_CONSUME) + trace_consume(&iter); + } + touch_nmi_watchdog(); + + trace_printk_seq(&iter.seq); + } + + if (!cnt) + printk(KERN_TRACE " (ftrace buffer empty)\n"); + else + printk(KERN_TRACE "---------------------------------\n"); + + out_enable: + tr->trace_flags |= old_userobj; + + for_each_tracing_cpu(cpu) { + atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled); + } + atomic_dec(&dump_running); + local_irq_restore(flags); +} +EXPORT_SYMBOL_GPL(ftrace_dump); + +#define WRITE_BUFSIZE 4096 + +ssize_t trace_parse_run_command(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos, + int (*createfn)(const char *)) +{ + char *kbuf, *buf, *tmp; + int ret = 0; + size_t done = 0; + size_t size; + + kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL); + if (!kbuf) + return -ENOMEM; + + while (done < count) { + size = count - done; + + if (size >= WRITE_BUFSIZE) + size = WRITE_BUFSIZE - 1; + + if (copy_from_user(kbuf, buffer + done, size)) { + ret = -EFAULT; + goto out; + } + kbuf[size] = '\0'; + buf = kbuf; + do { + tmp = strchr(buf, '\n'); + if (tmp) { + *tmp = '\0'; + size = tmp - buf + 1; + } else { + size = strlen(buf); + if (done + size < count) { + if (buf != kbuf) + break; + /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */ + pr_warn("Line length is too long: Should be less than %d\n", + WRITE_BUFSIZE - 2); + ret = -EINVAL; + goto out; + } + } + done += size; + + /* Remove comments */ + tmp = strchr(buf, '#'); + + if (tmp) + *tmp = '\0'; + + ret = createfn(buf); + if (ret) + goto out; + buf += size; + + } while (done < count); + } + ret = done; + +out: + kfree(kbuf); + + return ret; +} + +#ifdef CONFIG_TRACER_MAX_TRACE +__init static bool tr_needs_alloc_snapshot(const char *name) +{ + char *test; + int len = strlen(name); + bool ret; + + if (!boot_snapshot_index) + return false; + + if (strncmp(name, boot_snapshot_info, len) == 0 && + boot_snapshot_info[len] == '\t') + return true; + + test = kmalloc(strlen(name) + 3, GFP_KERNEL); + if (!test) + return false; + + sprintf(test, "\t%s\t", name); + ret = strstr(boot_snapshot_info, test) == NULL; + kfree(test); + return ret; +} + +__init static void do_allocate_snapshot(const char *name) +{ + if (!tr_needs_alloc_snapshot(name)) + return; + + /* + * When allocate_snapshot is set, the next call to + * allocate_trace_buffers() (called by trace_array_get_by_name()) + * will allocate the snapshot buffer. That will alse clear + * this flag. + */ + allocate_snapshot = true; +} +#else +static inline void do_allocate_snapshot(const char *name) { } +#endif + +__init static void enable_instances(void) +{ + struct trace_array *tr; + char *curr_str; + char *str; + char *tok; + + /* A tab is always appended */ + boot_instance_info[boot_instance_index - 1] = '\0'; + str = boot_instance_info; + + while ((curr_str = strsep(&str, "\t"))) { + + tok = strsep(&curr_str, ","); + + if (IS_ENABLED(CONFIG_TRACER_MAX_TRACE)) + do_allocate_snapshot(tok); + + tr = trace_array_get_by_name(tok); + if (!tr) { + pr_warn("Failed to create instance buffer %s\n", curr_str); + continue; + } + /* Allow user space to delete it */ + trace_array_put(tr); + + while ((tok = strsep(&curr_str, ","))) { + early_enable_events(tr, tok, true); + } + } +} + +__init static int tracer_alloc_buffers(void) +{ + int ring_buf_size; + int ret = -ENOMEM; + + + if (security_locked_down(LOCKDOWN_TRACEFS)) { + pr_warn("Tracing disabled due to lockdown\n"); + return -EPERM; + } + + /* + * Make sure we don't accidentally add more trace options + * than we have bits for. + */ + BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE); + + if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL)) + goto out; + + if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL)) + goto out_free_buffer_mask; + + /* Only allocate trace_printk buffers if a trace_printk exists */ + if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt) + /* Must be called before global_trace.buffer is allocated */ + trace_printk_init_buffers(); + + /* To save memory, keep the ring buffer size to its minimum */ + if (ring_buffer_expanded) + ring_buf_size = trace_buf_size; + else + ring_buf_size = 1; + + cpumask_copy(tracing_buffer_mask, cpu_possible_mask); + cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask); + + raw_spin_lock_init(&global_trace.start_lock); + + /* + * The prepare callbacks allocates some memory for the ring buffer. We + * don't free the buffer if the CPU goes down. If we were to free + * the buffer, then the user would lose any trace that was in the + * buffer. The memory will be removed once the "instance" is removed. + */ + ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE, + "trace/RB:prepare", trace_rb_cpu_prepare, + NULL); + if (ret < 0) + goto out_free_cpumask; + /* Used for event triggers */ + ret = -ENOMEM; + temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE); + if (!temp_buffer) + goto out_rm_hp_state; + + if (trace_create_savedcmd() < 0) + goto out_free_temp_buffer; + + if (!zalloc_cpumask_var(&global_trace.pipe_cpumask, GFP_KERNEL)) + goto out_free_savedcmd; + + /* TODO: make the number of buffers hot pluggable with CPUS */ + if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) { + MEM_FAIL(1, "tracer: failed to allocate ring buffer!\n"); + goto out_free_pipe_cpumask; + } + if (global_trace.buffer_disabled) + tracing_off(); + + if (trace_boot_clock) { + ret = tracing_set_clock(&global_trace, trace_boot_clock); + if (ret < 0) + pr_warn("Trace clock %s not defined, going back to default\n", + trace_boot_clock); + } + + /* + * register_tracer() might reference current_trace, so it + * needs to be set before we register anything. This is + * just a bootstrap of current_trace anyway. + */ + global_trace.current_trace = &nop_trace; + + global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; + + ftrace_init_global_array_ops(&global_trace); + + init_trace_flags_index(&global_trace); + + register_tracer(&nop_trace); + + /* Function tracing may start here (via kernel command line) */ + init_function_trace(); + + /* All seems OK, enable tracing */ + tracing_disabled = 0; + + atomic_notifier_chain_register(&panic_notifier_list, + &trace_panic_notifier); + + register_die_notifier(&trace_die_notifier); + + global_trace.flags = TRACE_ARRAY_FL_GLOBAL; + + INIT_LIST_HEAD(&global_trace.systems); + INIT_LIST_HEAD(&global_trace.events); + INIT_LIST_HEAD(&global_trace.hist_vars); + INIT_LIST_HEAD(&global_trace.err_log); + list_add(&global_trace.list, &ftrace_trace_arrays); + + apply_trace_boot_options(); + + register_snapshot_cmd(); + + test_can_verify(); + + return 0; + +out_free_pipe_cpumask: + free_cpumask_var(global_trace.pipe_cpumask); +out_free_savedcmd: + free_saved_cmdlines_buffer(savedcmd); +out_free_temp_buffer: + ring_buffer_free(temp_buffer); +out_rm_hp_state: + cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE); +out_free_cpumask: + free_cpumask_var(global_trace.tracing_cpumask); +out_free_buffer_mask: + free_cpumask_var(tracing_buffer_mask); +out: + return ret; +} + +void __init ftrace_boot_snapshot(void) +{ +#ifdef CONFIG_TRACER_MAX_TRACE + struct trace_array *tr; + + if (!snapshot_at_boot) + return; + + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (!tr->allocated_snapshot) + continue; + + tracing_snapshot_instance(tr); + trace_array_puts(tr, "** Boot snapshot taken **\n"); + } +#endif +} + +void __init early_trace_init(void) +{ + if (tracepoint_printk) { + tracepoint_print_iter = + kzalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL); + if (MEM_FAIL(!tracepoint_print_iter, + "Failed to allocate trace iterator\n")) + tracepoint_printk = 0; + else + static_key_enable(&tracepoint_printk_key.key); + } + tracer_alloc_buffers(); + + init_events(); +} + +void __init trace_init(void) +{ + trace_event_init(); + + if (boot_instance_index) + enable_instances(); +} + +__init static void clear_boot_tracer(void) +{ + /* + * The default tracer at boot buffer is an init section. + * This function is called in lateinit. If we did not + * find the boot tracer, then clear it out, to prevent + * later registration from accessing the buffer that is + * about to be freed. + */ + if (!default_bootup_tracer) + return; + + printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n", + default_bootup_tracer); + default_bootup_tracer = NULL; +} + +#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK +__init static void tracing_set_default_clock(void) +{ + /* sched_clock_stable() is determined in late_initcall */ + if (!trace_boot_clock && !sched_clock_stable()) { + if (security_locked_down(LOCKDOWN_TRACEFS)) { + pr_warn("Can not set tracing clock due to lockdown\n"); + return; + } + + printk(KERN_WARNING + "Unstable clock detected, switching default tracing clock to \"global\"\n" + "If you want to keep using the local clock, then add:\n" + " \"trace_clock=local\"\n" + "on the kernel command line\n"); + tracing_set_clock(&global_trace, "global"); + } +} +#else +static inline void tracing_set_default_clock(void) { } +#endif + +__init static int late_trace_init(void) +{ + if (tracepoint_printk && tracepoint_printk_stop_on_boot) { + static_key_disable(&tracepoint_printk_key.key); + tracepoint_printk = 0; + } + + tracing_set_default_clock(); + clear_boot_tracer(); + return 0; +} + +late_initcall_sync(late_trace_init); |