diff options
Diffstat (limited to 'kernel/trace/trace_uprobe.c')
| -rw-r--r-- | kernel/trace/trace_uprobe.c | 1669 |
1 files changed, 1669 insertions, 0 deletions
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c new file mode 100644 index 000000000..127c78aec --- /dev/null +++ b/kernel/trace/trace_uprobe.c @@ -0,0 +1,1669 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * uprobes-based tracing events + * + * Copyright (C) IBM Corporation, 2010-2012 + * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com> + */ +#define pr_fmt(fmt) "trace_uprobe: " fmt + +#include <linux/bpf-cgroup.h> +#include <linux/security.h> +#include <linux/ctype.h> +#include <linux/module.h> +#include <linux/uaccess.h> +#include <linux/uprobes.h> +#include <linux/namei.h> +#include <linux/string.h> +#include <linux/rculist.h> +#include <linux/filter.h> + +#include "trace_dynevent.h" +#include "trace_probe.h" +#include "trace_probe_tmpl.h" + +#define UPROBE_EVENT_SYSTEM "uprobes" + +struct uprobe_trace_entry_head { + struct trace_entry ent; + unsigned long vaddr[]; +}; + +#define SIZEOF_TRACE_ENTRY(is_return) \ + (sizeof(struct uprobe_trace_entry_head) + \ + sizeof(unsigned long) * (is_return ? 2 : 1)) + +#define DATAOF_TRACE_ENTRY(entry, is_return) \ + ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return)) + +static int trace_uprobe_create(const char *raw_command); +static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev); +static int trace_uprobe_release(struct dyn_event *ev); +static bool trace_uprobe_is_busy(struct dyn_event *ev); +static bool trace_uprobe_match(const char *system, const char *event, + int argc, const char **argv, struct dyn_event *ev); + +static struct dyn_event_operations trace_uprobe_ops = { + .create = trace_uprobe_create, + .show = trace_uprobe_show, + .is_busy = trace_uprobe_is_busy, + .free = trace_uprobe_release, + .match = trace_uprobe_match, +}; + +/* + * uprobe event core functions + */ +struct trace_uprobe { + struct dyn_event devent; + struct uprobe_consumer consumer; + struct path path; + struct inode *inode; + char *filename; + unsigned long offset; + unsigned long ref_ctr_offset; + unsigned long nhit; + struct trace_probe tp; +}; + +static bool is_trace_uprobe(struct dyn_event *ev) +{ + return ev->ops == &trace_uprobe_ops; +} + +static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev) +{ + return container_of(ev, struct trace_uprobe, devent); +} + +/** + * for_each_trace_uprobe - iterate over the trace_uprobe list + * @pos: the struct trace_uprobe * for each entry + * @dpos: the struct dyn_event * to use as a loop cursor + */ +#define for_each_trace_uprobe(pos, dpos) \ + for_each_dyn_event(dpos) \ + if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos))) + +static int register_uprobe_event(struct trace_uprobe *tu); +static int unregister_uprobe_event(struct trace_uprobe *tu); + +struct uprobe_dispatch_data { + struct trace_uprobe *tu; + unsigned long bp_addr; +}; + +static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); +static int uretprobe_dispatcher(struct uprobe_consumer *con, + unsigned long func, struct pt_regs *regs); + +#ifdef CONFIG_STACK_GROWSUP +static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) +{ + return addr - (n * sizeof(long)); +} +#else +static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) +{ + return addr + (n * sizeof(long)); +} +#endif + +static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) +{ + unsigned long ret; + unsigned long addr = user_stack_pointer(regs); + + addr = adjust_stack_addr(addr, n); + + if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret))) + return 0; + + return ret; +} + +/* + * Uprobes-specific fetch functions + */ +static nokprobe_inline int +probe_mem_read(void *dest, void *src, size_t size) +{ + void __user *vaddr = (void __force __user *)src; + + return copy_from_user(dest, vaddr, size) ? -EFAULT : 0; +} + +static nokprobe_inline int +probe_mem_read_user(void *dest, void *src, size_t size) +{ + return probe_mem_read(dest, src, size); +} + +/* + * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max + * length and relative data location. + */ +static nokprobe_inline int +fetch_store_string(unsigned long addr, void *dest, void *base) +{ + long ret; + u32 loc = *(u32 *)dest; + int maxlen = get_loc_len(loc); + u8 *dst = get_loc_data(dest, base); + void __user *src = (void __force __user *) addr; + + if (unlikely(!maxlen)) + return -ENOMEM; + + if (addr == FETCH_TOKEN_COMM) + ret = strlcpy(dst, current->comm, maxlen); + else + ret = strncpy_from_user(dst, src, maxlen); + if (ret >= 0) { + if (ret == maxlen) + dst[ret - 1] = '\0'; + else + /* + * Include the terminating null byte. In this case it + * was copied by strncpy_from_user but not accounted + * for in ret. + */ + ret++; + *(u32 *)dest = make_data_loc(ret, (void *)dst - base); + } else + *(u32 *)dest = make_data_loc(0, (void *)dst - base); + + return ret; +} + +static nokprobe_inline int +fetch_store_string_user(unsigned long addr, void *dest, void *base) +{ + return fetch_store_string(addr, dest, base); +} + +/* Return the length of string -- including null terminal byte */ +static nokprobe_inline int +fetch_store_strlen(unsigned long addr) +{ + int len; + void __user *vaddr = (void __force __user *) addr; + + if (addr == FETCH_TOKEN_COMM) + len = strlen(current->comm) + 1; + else + len = strnlen_user(vaddr, MAX_STRING_SIZE); + + return (len > MAX_STRING_SIZE) ? 0 : len; +} + +static nokprobe_inline int +fetch_store_strlen_user(unsigned long addr) +{ + return fetch_store_strlen(addr); +} + +static unsigned long translate_user_vaddr(unsigned long file_offset) +{ + unsigned long base_addr; + struct uprobe_dispatch_data *udd; + + udd = (void *) current->utask->vaddr; + + base_addr = udd->bp_addr - udd->tu->offset; + return base_addr + file_offset; +} + +/* Note that we don't verify it, since the code does not come from user space */ +static int +process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, + void *base) +{ + struct pt_regs *regs = rec; + unsigned long val; + + /* 1st stage: get value from context */ + switch (code->op) { + case FETCH_OP_REG: + val = regs_get_register(regs, code->param); + break; + case FETCH_OP_STACK: + val = get_user_stack_nth(regs, code->param); + break; + case FETCH_OP_STACKP: + val = user_stack_pointer(regs); + break; + case FETCH_OP_RETVAL: + val = regs_return_value(regs); + break; + case FETCH_OP_IMM: + val = code->immediate; + break; + case FETCH_OP_COMM: + val = FETCH_TOKEN_COMM; + break; + case FETCH_OP_DATA: + val = (unsigned long)code->data; + break; + case FETCH_OP_FOFFS: + val = translate_user_vaddr(code->immediate); + break; + default: + return -EILSEQ; + } + code++; + + return process_fetch_insn_bottom(code, val, dest, base); +} +NOKPROBE_SYMBOL(process_fetch_insn) + +static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) +{ + rwlock_init(&filter->rwlock); + filter->nr_systemwide = 0; + INIT_LIST_HEAD(&filter->perf_events); +} + +static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) +{ + return !filter->nr_systemwide && list_empty(&filter->perf_events); +} + +static inline bool is_ret_probe(struct trace_uprobe *tu) +{ + return tu->consumer.ret_handler != NULL; +} + +static bool trace_uprobe_is_busy(struct dyn_event *ev) +{ + struct trace_uprobe *tu = to_trace_uprobe(ev); + + return trace_probe_is_enabled(&tu->tp); +} + +static bool trace_uprobe_match_command_head(struct trace_uprobe *tu, + int argc, const char **argv) +{ + char buf[MAX_ARGSTR_LEN + 1]; + int len; + + if (!argc) + return true; + + len = strlen(tu->filename); + if (strncmp(tu->filename, argv[0], len) || argv[0][len] != ':') + return false; + + if (tu->ref_ctr_offset == 0) + snprintf(buf, sizeof(buf), "0x%0*lx", + (int)(sizeof(void *) * 2), tu->offset); + else + snprintf(buf, sizeof(buf), "0x%0*lx(0x%lx)", + (int)(sizeof(void *) * 2), tu->offset, + tu->ref_ctr_offset); + if (strcmp(buf, &argv[0][len + 1])) + return false; + + argc--; argv++; + + return trace_probe_match_command_args(&tu->tp, argc, argv); +} + +static bool trace_uprobe_match(const char *system, const char *event, + int argc, const char **argv, struct dyn_event *ev) +{ + struct trace_uprobe *tu = to_trace_uprobe(ev); + + return (event[0] == '\0' || + strcmp(trace_probe_name(&tu->tp), event) == 0) && + (!system || strcmp(trace_probe_group_name(&tu->tp), system) == 0) && + trace_uprobe_match_command_head(tu, argc, argv); +} + +static nokprobe_inline struct trace_uprobe * +trace_uprobe_primary_from_call(struct trace_event_call *call) +{ + struct trace_probe *tp; + + tp = trace_probe_primary_from_call(call); + if (WARN_ON_ONCE(!tp)) + return NULL; + + return container_of(tp, struct trace_uprobe, tp); +} + +/* + * Allocate new trace_uprobe and initialize it (including uprobes). + */ +static struct trace_uprobe * +alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) +{ + struct trace_uprobe *tu; + int ret; + + tu = kzalloc(struct_size(tu, tp.args, nargs), GFP_KERNEL); + if (!tu) + return ERR_PTR(-ENOMEM); + + ret = trace_probe_init(&tu->tp, event, group, true); + if (ret < 0) + goto error; + + dyn_event_init(&tu->devent, &trace_uprobe_ops); + tu->consumer.handler = uprobe_dispatcher; + if (is_ret) + tu->consumer.ret_handler = uretprobe_dispatcher; + init_trace_uprobe_filter(tu->tp.event->filter); + return tu; + +error: + kfree(tu); + + return ERR_PTR(ret); +} + +static void free_trace_uprobe(struct trace_uprobe *tu) +{ + if (!tu) + return; + + path_put(&tu->path); + trace_probe_cleanup(&tu->tp); + kfree(tu->filename); + kfree(tu); +} + +static struct trace_uprobe *find_probe_event(const char *event, const char *group) +{ + struct dyn_event *pos; + struct trace_uprobe *tu; + + for_each_trace_uprobe(tu, pos) + if (strcmp(trace_probe_name(&tu->tp), event) == 0 && + strcmp(trace_probe_group_name(&tu->tp), group) == 0) + return tu; + + return NULL; +} + +/* Unregister a trace_uprobe and probe_event */ +static int unregister_trace_uprobe(struct trace_uprobe *tu) +{ + int ret; + + if (trace_probe_has_sibling(&tu->tp)) + goto unreg; + + /* If there's a reference to the dynamic event */ + if (trace_event_dyn_busy(trace_probe_event_call(&tu->tp))) + return -EBUSY; + + ret = unregister_uprobe_event(tu); + if (ret) + return ret; + +unreg: + dyn_event_remove(&tu->devent); + trace_probe_unlink(&tu->tp); + free_trace_uprobe(tu); + return 0; +} + +static bool trace_uprobe_has_same_uprobe(struct trace_uprobe *orig, + struct trace_uprobe *comp) +{ + struct trace_probe_event *tpe = orig->tp.event; + struct inode *comp_inode = d_real_inode(comp->path.dentry); + int i; + + list_for_each_entry(orig, &tpe->probes, tp.list) { + if (comp_inode != d_real_inode(orig->path.dentry) || + comp->offset != orig->offset) + continue; + + /* + * trace_probe_compare_arg_type() ensured that nr_args and + * each argument name and type are same. Let's compare comm. + */ + for (i = 0; i < orig->tp.nr_args; i++) { + if (strcmp(orig->tp.args[i].comm, + comp->tp.args[i].comm)) + break; + } + + if (i == orig->tp.nr_args) + return true; + } + + return false; +} + +static int append_trace_uprobe(struct trace_uprobe *tu, struct trace_uprobe *to) +{ + int ret; + + ret = trace_probe_compare_arg_type(&tu->tp, &to->tp); + if (ret) { + /* Note that argument starts index = 2 */ + trace_probe_log_set_index(ret + 1); + trace_probe_log_err(0, DIFF_ARG_TYPE); + return -EEXIST; + } + if (trace_uprobe_has_same_uprobe(to, tu)) { + trace_probe_log_set_index(0); + trace_probe_log_err(0, SAME_PROBE); + return -EEXIST; + } + + /* Append to existing event */ + ret = trace_probe_append(&tu->tp, &to->tp); + if (!ret) + dyn_event_add(&tu->devent, trace_probe_event_call(&tu->tp)); + + return ret; +} + +/* + * Uprobe with multiple reference counter is not allowed. i.e. + * If inode and offset matches, reference counter offset *must* + * match as well. Though, there is one exception: If user is + * replacing old trace_uprobe with new one(same group/event), + * then we allow same uprobe with new reference counter as far + * as the new one does not conflict with any other existing + * ones. + */ +static int validate_ref_ctr_offset(struct trace_uprobe *new) +{ + struct dyn_event *pos; + struct trace_uprobe *tmp; + struct inode *new_inode = d_real_inode(new->path.dentry); + + for_each_trace_uprobe(tmp, pos) { + if (new_inode == d_real_inode(tmp->path.dentry) && + new->offset == tmp->offset && + new->ref_ctr_offset != tmp->ref_ctr_offset) { + pr_warn("Reference counter offset mismatch."); + return -EINVAL; + } + } + return 0; +} + +/* Register a trace_uprobe and probe_event */ +static int register_trace_uprobe(struct trace_uprobe *tu) +{ + struct trace_uprobe *old_tu; + int ret; + + mutex_lock(&event_mutex); + + ret = validate_ref_ctr_offset(tu); + if (ret) + goto end; + + /* register as an event */ + old_tu = find_probe_event(trace_probe_name(&tu->tp), + trace_probe_group_name(&tu->tp)); + if (old_tu) { + if (is_ret_probe(tu) != is_ret_probe(old_tu)) { + trace_probe_log_set_index(0); + trace_probe_log_err(0, DIFF_PROBE_TYPE); + ret = -EEXIST; + } else { + ret = append_trace_uprobe(tu, old_tu); + } + goto end; + } + + ret = register_uprobe_event(tu); + if (ret) { + if (ret == -EEXIST) { + trace_probe_log_set_index(0); + trace_probe_log_err(0, EVENT_EXIST); + } else + pr_warn("Failed to register probe event(%d)\n", ret); + goto end; + } + + dyn_event_add(&tu->devent, trace_probe_event_call(&tu->tp)); + +end: + mutex_unlock(&event_mutex); + + return ret; +} + +/* + * Argument syntax: + * - Add uprobe: p|r[:[GRP/][EVENT]] PATH:OFFSET[%return][(REF)] [FETCHARGS] + */ +static int __trace_uprobe_create(int argc, const char **argv) +{ + struct trace_uprobe *tu; + const char *event = NULL, *group = UPROBE_EVENT_SYSTEM; + char *arg, *filename, *rctr, *rctr_end, *tmp; + char buf[MAX_EVENT_NAME_LEN]; + char gbuf[MAX_EVENT_NAME_LEN]; + enum probe_print_type ptype; + struct path path; + unsigned long offset, ref_ctr_offset; + bool is_return = false; + int i, ret; + + ref_ctr_offset = 0; + + switch (argv[0][0]) { + case 'r': + is_return = true; + break; + case 'p': + break; + default: + return -ECANCELED; + } + + if (argc < 2) + return -ECANCELED; + + if (argv[0][1] == ':') + event = &argv[0][2]; + + if (!strchr(argv[1], '/')) + return -ECANCELED; + + filename = kstrdup(argv[1], GFP_KERNEL); + if (!filename) + return -ENOMEM; + + /* Find the last occurrence, in case the path contains ':' too. */ + arg = strrchr(filename, ':'); + if (!arg || !isdigit(arg[1])) { + kfree(filename); + return -ECANCELED; + } + + trace_probe_log_init("trace_uprobe", argc, argv); + trace_probe_log_set_index(1); /* filename is the 2nd argument */ + + *arg++ = '\0'; + ret = kern_path(filename, LOOKUP_FOLLOW, &path); + if (ret) { + trace_probe_log_err(0, FILE_NOT_FOUND); + kfree(filename); + trace_probe_log_clear(); + return ret; + } + if (!d_is_reg(path.dentry)) { + trace_probe_log_err(0, NO_REGULAR_FILE); + ret = -EINVAL; + goto fail_address_parse; + } + + /* Parse reference counter offset if specified. */ + rctr = strchr(arg, '('); + if (rctr) { + rctr_end = strchr(rctr, ')'); + if (!rctr_end) { + ret = -EINVAL; + rctr_end = rctr + strlen(rctr); + trace_probe_log_err(rctr_end - filename, + REFCNT_OPEN_BRACE); + goto fail_address_parse; + } else if (rctr_end[1] != '\0') { + ret = -EINVAL; + trace_probe_log_err(rctr_end + 1 - filename, + BAD_REFCNT_SUFFIX); + goto fail_address_parse; + } + + *rctr++ = '\0'; + *rctr_end = '\0'; + ret = kstrtoul(rctr, 0, &ref_ctr_offset); + if (ret) { + trace_probe_log_err(rctr - filename, BAD_REFCNT); + goto fail_address_parse; + } + } + + /* Check if there is %return suffix */ + tmp = strchr(arg, '%'); + if (tmp) { + if (!strcmp(tmp, "%return")) { + *tmp = '\0'; + is_return = true; + } else { + trace_probe_log_err(tmp - filename, BAD_ADDR_SUFFIX); + ret = -EINVAL; + goto fail_address_parse; + } + } + + /* Parse uprobe offset. */ + ret = kstrtoul(arg, 0, &offset); + if (ret) { + trace_probe_log_err(arg - filename, BAD_UPROBE_OFFS); + goto fail_address_parse; + } + + /* setup a probe */ + trace_probe_log_set_index(0); + if (event) { + ret = traceprobe_parse_event_name(&event, &group, gbuf, + event - argv[0]); + if (ret) + goto fail_address_parse; + } + + if (!event) { + char *tail; + char *ptr; + + tail = kstrdup(kbasename(filename), GFP_KERNEL); + if (!tail) { + ret = -ENOMEM; + goto fail_address_parse; + } + + ptr = strpbrk(tail, ".-_"); + if (ptr) + *ptr = '\0'; + + snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); + event = buf; + kfree(tail); + } + + argc -= 2; + argv += 2; + + tu = alloc_trace_uprobe(group, event, argc, is_return); + if (IS_ERR(tu)) { + ret = PTR_ERR(tu); + /* This must return -ENOMEM otherwise there is a bug */ + WARN_ON_ONCE(ret != -ENOMEM); + goto fail_address_parse; + } + tu->offset = offset; + tu->ref_ctr_offset = ref_ctr_offset; + tu->path = path; + tu->filename = filename; + + /* parse arguments */ + for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { + trace_probe_log_set_index(i + 2); + ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i], + is_return ? TPARG_FL_RETURN : 0); + if (ret) + goto error; + } + + ptype = is_ret_probe(tu) ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL; + ret = traceprobe_set_print_fmt(&tu->tp, ptype); + if (ret < 0) + goto error; + + ret = register_trace_uprobe(tu); + if (!ret) + goto out; + +error: + free_trace_uprobe(tu); +out: + trace_probe_log_clear(); + return ret; + +fail_address_parse: + trace_probe_log_clear(); + path_put(&path); + kfree(filename); + + return ret; +} + +int trace_uprobe_create(const char *raw_command) +{ + return trace_probe_create(raw_command, __trace_uprobe_create); +} + +static int create_or_delete_trace_uprobe(const char *raw_command) +{ + int ret; + + if (raw_command[0] == '-') + return dyn_event_release(raw_command, &trace_uprobe_ops); + + ret = trace_uprobe_create(raw_command); + return ret == -ECANCELED ? -EINVAL : ret; +} + +static int trace_uprobe_release(struct dyn_event *ev) +{ + struct trace_uprobe *tu = to_trace_uprobe(ev); + + return unregister_trace_uprobe(tu); +} + +/* Probes listing interfaces */ +static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev) +{ + struct trace_uprobe *tu = to_trace_uprobe(ev); + char c = is_ret_probe(tu) ? 'r' : 'p'; + int i; + + seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, trace_probe_group_name(&tu->tp), + trace_probe_name(&tu->tp), tu->filename, + (int)(sizeof(void *) * 2), tu->offset); + + if (tu->ref_ctr_offset) + seq_printf(m, "(0x%lx)", tu->ref_ctr_offset); + + for (i = 0; i < tu->tp.nr_args; i++) + seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); + + seq_putc(m, '\n'); + return 0; +} + +static int probes_seq_show(struct seq_file *m, void *v) +{ + struct dyn_event *ev = v; + + if (!is_trace_uprobe(ev)) + return 0; + + return trace_uprobe_show(m, ev); +} + +static const struct seq_operations probes_seq_op = { + .start = dyn_event_seq_start, + .next = dyn_event_seq_next, + .stop = dyn_event_seq_stop, + .show = probes_seq_show +}; + +static int probes_open(struct inode *inode, struct file *file) +{ + int ret; + + ret = security_locked_down(LOCKDOWN_TRACEFS); + if (ret) + return ret; + + if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { + ret = dyn_events_release_all(&trace_uprobe_ops); + if (ret) + return ret; + } + + return seq_open(file, &probes_seq_op); +} + +static ssize_t probes_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + return trace_parse_run_command(file, buffer, count, ppos, + create_or_delete_trace_uprobe); +} + +static const struct file_operations uprobe_events_ops = { + .owner = THIS_MODULE, + .open = probes_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, + .write = probes_write, +}; + +/* Probes profiling interfaces */ +static int probes_profile_seq_show(struct seq_file *m, void *v) +{ + struct dyn_event *ev = v; + struct trace_uprobe *tu; + + if (!is_trace_uprobe(ev)) + return 0; + + tu = to_trace_uprobe(ev); + seq_printf(m, " %s %-44s %15lu\n", tu->filename, + trace_probe_name(&tu->tp), tu->nhit); + return 0; +} + +static const struct seq_operations profile_seq_op = { + .start = dyn_event_seq_start, + .next = dyn_event_seq_next, + .stop = dyn_event_seq_stop, + .show = probes_profile_seq_show +}; + +static int profile_open(struct inode *inode, struct file *file) +{ + int ret; + + ret = security_locked_down(LOCKDOWN_TRACEFS); + if (ret) + return ret; + + return seq_open(file, &profile_seq_op); +} + +static const struct file_operations uprobe_profile_ops = { + .owner = THIS_MODULE, + .open = profile_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +struct uprobe_cpu_buffer { + struct mutex mutex; + void *buf; +}; +static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; +static int uprobe_buffer_refcnt; + +static int uprobe_buffer_init(void) +{ + int cpu, err_cpu; + + uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); + if (uprobe_cpu_buffer == NULL) + return -ENOMEM; + + for_each_possible_cpu(cpu) { + struct page *p = alloc_pages_node(cpu_to_node(cpu), + GFP_KERNEL, 0); + if (p == NULL) { + err_cpu = cpu; + goto err; + } + per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); + mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); + } + + return 0; + +err: + for_each_possible_cpu(cpu) { + if (cpu == err_cpu) + break; + free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); + } + + free_percpu(uprobe_cpu_buffer); + return -ENOMEM; +} + +static int uprobe_buffer_enable(void) +{ + int ret = 0; + + BUG_ON(!mutex_is_locked(&event_mutex)); + + if (uprobe_buffer_refcnt++ == 0) { + ret = uprobe_buffer_init(); + if (ret < 0) + uprobe_buffer_refcnt--; + } + + return ret; +} + +static void uprobe_buffer_disable(void) +{ + int cpu; + + BUG_ON(!mutex_is_locked(&event_mutex)); + + if (--uprobe_buffer_refcnt == 0) { + for_each_possible_cpu(cpu) + free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, + cpu)->buf); + + free_percpu(uprobe_cpu_buffer); + uprobe_cpu_buffer = NULL; + } +} + +static struct uprobe_cpu_buffer *uprobe_buffer_get(void) +{ + struct uprobe_cpu_buffer *ucb; + int cpu; + + cpu = raw_smp_processor_id(); + ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); + + /* + * Use per-cpu buffers for fastest access, but we might migrate + * so the mutex makes sure we have sole access to it. + */ + mutex_lock(&ucb->mutex); + + return ucb; +} + +static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) +{ + mutex_unlock(&ucb->mutex); +} + +static void __uprobe_trace_func(struct trace_uprobe *tu, + unsigned long func, struct pt_regs *regs, + struct uprobe_cpu_buffer *ucb, int dsize, + struct trace_event_file *trace_file) +{ + struct uprobe_trace_entry_head *entry; + struct trace_event_buffer fbuffer; + void *data; + int size, esize; + struct trace_event_call *call = trace_probe_event_call(&tu->tp); + + WARN_ON(call != trace_file->event_call); + + if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) + return; + + if (trace_trigger_soft_disabled(trace_file)) + return; + + esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); + size = esize + tu->tp.size + dsize; + entry = trace_event_buffer_reserve(&fbuffer, trace_file, size); + if (!entry) + return; + + if (is_ret_probe(tu)) { + entry->vaddr[0] = func; + entry->vaddr[1] = instruction_pointer(regs); + data = DATAOF_TRACE_ENTRY(entry, true); + } else { + entry->vaddr[0] = instruction_pointer(regs); + data = DATAOF_TRACE_ENTRY(entry, false); + } + + memcpy(data, ucb->buf, tu->tp.size + dsize); + + trace_event_buffer_commit(&fbuffer); +} + +/* uprobe handler */ +static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, + struct uprobe_cpu_buffer *ucb, int dsize) +{ + struct event_file_link *link; + + if (is_ret_probe(tu)) + return 0; + + rcu_read_lock(); + trace_probe_for_each_link_rcu(link, &tu->tp) + __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); + rcu_read_unlock(); + + return 0; +} + +static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, + struct pt_regs *regs, + struct uprobe_cpu_buffer *ucb, int dsize) +{ + struct event_file_link *link; + + rcu_read_lock(); + trace_probe_for_each_link_rcu(link, &tu->tp) + __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); + rcu_read_unlock(); +} + +/* Event entry printers */ +static enum print_line_t +print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) +{ + struct uprobe_trace_entry_head *entry; + struct trace_seq *s = &iter->seq; + struct trace_uprobe *tu; + u8 *data; + + entry = (struct uprobe_trace_entry_head *)iter->ent; + tu = trace_uprobe_primary_from_call( + container_of(event, struct trace_event_call, event)); + if (unlikely(!tu)) + goto out; + + if (is_ret_probe(tu)) { + trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", + trace_probe_name(&tu->tp), + entry->vaddr[1], entry->vaddr[0]); + data = DATAOF_TRACE_ENTRY(entry, true); + } else { + trace_seq_printf(s, "%s: (0x%lx)", + trace_probe_name(&tu->tp), + entry->vaddr[0]); + data = DATAOF_TRACE_ENTRY(entry, false); + } + + if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0) + goto out; + + trace_seq_putc(s, '\n'); + + out: + return trace_handle_return(s); +} + +typedef bool (*filter_func_t)(struct uprobe_consumer *self, + enum uprobe_filter_ctx ctx, + struct mm_struct *mm); + +static int trace_uprobe_enable(struct trace_uprobe *tu, filter_func_t filter) +{ + int ret; + + tu->consumer.filter = filter; + tu->inode = d_real_inode(tu->path.dentry); + + if (tu->ref_ctr_offset) + ret = uprobe_register_refctr(tu->inode, tu->offset, + tu->ref_ctr_offset, &tu->consumer); + else + ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); + + if (ret) + tu->inode = NULL; + + return ret; +} + +static void __probe_event_disable(struct trace_probe *tp) +{ + struct trace_uprobe *tu; + + tu = container_of(tp, struct trace_uprobe, tp); + WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter)); + + list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) { + if (!tu->inode) + continue; + + uprobe_unregister(tu->inode, tu->offset, &tu->consumer); + tu->inode = NULL; + } +} + +static int probe_event_enable(struct trace_event_call *call, + struct trace_event_file *file, filter_func_t filter) +{ + struct trace_probe *tp; + struct trace_uprobe *tu; + bool enabled; + int ret; + + tp = trace_probe_primary_from_call(call); + if (WARN_ON_ONCE(!tp)) + return -ENODEV; + enabled = trace_probe_is_enabled(tp); + + /* This may also change "enabled" state */ + if (file) { + if (trace_probe_test_flag(tp, TP_FLAG_PROFILE)) + return -EINTR; + + ret = trace_probe_add_file(tp, file); + if (ret < 0) + return ret; + } else { + if (trace_probe_test_flag(tp, TP_FLAG_TRACE)) + return -EINTR; + + trace_probe_set_flag(tp, TP_FLAG_PROFILE); + } + + tu = container_of(tp, struct trace_uprobe, tp); + WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter)); + + if (enabled) + return 0; + + ret = uprobe_buffer_enable(); + if (ret) + goto err_flags; + + list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) { + ret = trace_uprobe_enable(tu, filter); + if (ret) { + __probe_event_disable(tp); + goto err_buffer; + } + } + + return 0; + + err_buffer: + uprobe_buffer_disable(); + + err_flags: + if (file) + trace_probe_remove_file(tp, file); + else + trace_probe_clear_flag(tp, TP_FLAG_PROFILE); + + return ret; +} + +static void probe_event_disable(struct trace_event_call *call, + struct trace_event_file *file) +{ + struct trace_probe *tp; + + tp = trace_probe_primary_from_call(call); + if (WARN_ON_ONCE(!tp)) + return; + + if (!trace_probe_is_enabled(tp)) + return; + + if (file) { + if (trace_probe_remove_file(tp, file) < 0) + return; + + if (trace_probe_is_enabled(tp)) + return; + } else + trace_probe_clear_flag(tp, TP_FLAG_PROFILE); + + __probe_event_disable(tp); + uprobe_buffer_disable(); +} + +static int uprobe_event_define_fields(struct trace_event_call *event_call) +{ + int ret, size; + struct uprobe_trace_entry_head field; + struct trace_uprobe *tu; + + tu = trace_uprobe_primary_from_call(event_call); + if (unlikely(!tu)) + return -ENODEV; + + if (is_ret_probe(tu)) { + DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); + DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); + size = SIZEOF_TRACE_ENTRY(true); + } else { + DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); + size = SIZEOF_TRACE_ENTRY(false); + } + + return traceprobe_define_arg_fields(event_call, size, &tu->tp); +} + +#ifdef CONFIG_PERF_EVENTS +static bool +__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) +{ + struct perf_event *event; + + if (filter->nr_systemwide) + return true; + + list_for_each_entry(event, &filter->perf_events, hw.tp_list) { + if (event->hw.target->mm == mm) + return true; + } + + return false; +} + +static inline bool +trace_uprobe_filter_event(struct trace_uprobe_filter *filter, + struct perf_event *event) +{ + return __uprobe_perf_filter(filter, event->hw.target->mm); +} + +static bool trace_uprobe_filter_remove(struct trace_uprobe_filter *filter, + struct perf_event *event) +{ + bool done; + + write_lock(&filter->rwlock); + if (event->hw.target) { + list_del(&event->hw.tp_list); + done = filter->nr_systemwide || + (event->hw.target->flags & PF_EXITING) || + trace_uprobe_filter_event(filter, event); + } else { + filter->nr_systemwide--; + done = filter->nr_systemwide; + } + write_unlock(&filter->rwlock); + + return done; +} + +/* This returns true if the filter always covers target mm */ +static bool trace_uprobe_filter_add(struct trace_uprobe_filter *filter, + struct perf_event *event) +{ + bool done; + + write_lock(&filter->rwlock); + if (event->hw.target) { + /* + * event->parent != NULL means copy_process(), we can avoid + * uprobe_apply(). current->mm must be probed and we can rely + * on dup_mmap() which preserves the already installed bp's. + * + * attr.enable_on_exec means that exec/mmap will install the + * breakpoints we need. + */ + done = filter->nr_systemwide || + event->parent || event->attr.enable_on_exec || + trace_uprobe_filter_event(filter, event); + list_add(&event->hw.tp_list, &filter->perf_events); + } else { + done = filter->nr_systemwide; + filter->nr_systemwide++; + } + write_unlock(&filter->rwlock); + + return done; +} + +static int uprobe_perf_close(struct trace_event_call *call, + struct perf_event *event) +{ + struct trace_probe *tp; + struct trace_uprobe *tu; + int ret = 0; + + tp = trace_probe_primary_from_call(call); + if (WARN_ON_ONCE(!tp)) + return -ENODEV; + + tu = container_of(tp, struct trace_uprobe, tp); + if (trace_uprobe_filter_remove(tu->tp.event->filter, event)) + return 0; + + list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) { + ret = uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); + if (ret) + break; + } + + return ret; +} + +static int uprobe_perf_open(struct trace_event_call *call, + struct perf_event *event) +{ + struct trace_probe *tp; + struct trace_uprobe *tu; + int err = 0; + + tp = trace_probe_primary_from_call(call); + if (WARN_ON_ONCE(!tp)) + return -ENODEV; + + tu = container_of(tp, struct trace_uprobe, tp); + if (trace_uprobe_filter_add(tu->tp.event->filter, event)) + return 0; + + list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) { + err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); + if (err) { + uprobe_perf_close(call, event); + break; + } + } + + return err; +} + +static bool uprobe_perf_filter(struct uprobe_consumer *uc, + enum uprobe_filter_ctx ctx, struct mm_struct *mm) +{ + struct trace_uprobe_filter *filter; + struct trace_uprobe *tu; + int ret; + + tu = container_of(uc, struct trace_uprobe, consumer); + filter = tu->tp.event->filter; + + read_lock(&filter->rwlock); + ret = __uprobe_perf_filter(filter, mm); + read_unlock(&filter->rwlock); + + return ret; +} + +static void __uprobe_perf_func(struct trace_uprobe *tu, + unsigned long func, struct pt_regs *regs, + struct uprobe_cpu_buffer *ucb, int dsize) +{ + struct trace_event_call *call = trace_probe_event_call(&tu->tp); + struct uprobe_trace_entry_head *entry; + struct hlist_head *head; + void *data; + int size, esize; + int rctx; + +#ifdef CONFIG_BPF_EVENTS + if (bpf_prog_array_valid(call)) { + u32 ret; + + ret = bpf_prog_run_array_sleepable(call->prog_array, regs, bpf_prog_run); + if (!ret) + return; + } +#endif /* CONFIG_BPF_EVENTS */ + + esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); + + size = esize + tu->tp.size + dsize; + size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); + if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) + return; + + preempt_disable(); + head = this_cpu_ptr(call->perf_events); + if (hlist_empty(head)) + goto out; + + entry = perf_trace_buf_alloc(size, NULL, &rctx); + if (!entry) + goto out; + + if (is_ret_probe(tu)) { + entry->vaddr[0] = func; + entry->vaddr[1] = instruction_pointer(regs); + data = DATAOF_TRACE_ENTRY(entry, true); + } else { + entry->vaddr[0] = instruction_pointer(regs); + data = DATAOF_TRACE_ENTRY(entry, false); + } + + memcpy(data, ucb->buf, tu->tp.size + dsize); + + if (size - esize > tu->tp.size + dsize) { + int len = tu->tp.size + dsize; + + memset(data + len, 0, size - esize - len); + } + + perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, + head, NULL); + out: + preempt_enable(); +} + +/* uprobe profile handler */ +static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, + struct uprobe_cpu_buffer *ucb, int dsize) +{ + if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) + return UPROBE_HANDLER_REMOVE; + + if (!is_ret_probe(tu)) + __uprobe_perf_func(tu, 0, regs, ucb, dsize); + return 0; +} + +static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, + struct pt_regs *regs, + struct uprobe_cpu_buffer *ucb, int dsize) +{ + __uprobe_perf_func(tu, func, regs, ucb, dsize); +} + +int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type, + const char **filename, u64 *probe_offset, + u64 *probe_addr, bool perf_type_tracepoint) +{ + const char *pevent = trace_event_name(event->tp_event); + const char *group = event->tp_event->class->system; + struct trace_uprobe *tu; + + if (perf_type_tracepoint) + tu = find_probe_event(pevent, group); + else + tu = trace_uprobe_primary_from_call(event->tp_event); + if (!tu) + return -EINVAL; + + *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE + : BPF_FD_TYPE_UPROBE; + *filename = tu->filename; + *probe_offset = tu->offset; + *probe_addr = 0; + return 0; +} +#endif /* CONFIG_PERF_EVENTS */ + +static int +trace_uprobe_register(struct trace_event_call *event, enum trace_reg type, + void *data) +{ + struct trace_event_file *file = data; + + switch (type) { + case TRACE_REG_REGISTER: + return probe_event_enable(event, file, NULL); + + case TRACE_REG_UNREGISTER: + probe_event_disable(event, file); + return 0; + +#ifdef CONFIG_PERF_EVENTS + case TRACE_REG_PERF_REGISTER: + return probe_event_enable(event, NULL, uprobe_perf_filter); + + case TRACE_REG_PERF_UNREGISTER: + probe_event_disable(event, NULL); + return 0; + + case TRACE_REG_PERF_OPEN: + return uprobe_perf_open(event, data); + + case TRACE_REG_PERF_CLOSE: + return uprobe_perf_close(event, data); + +#endif + default: + return 0; + } +} + +static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) +{ + struct trace_uprobe *tu; + struct uprobe_dispatch_data udd; + struct uprobe_cpu_buffer *ucb; + int dsize, esize; + int ret = 0; + + + tu = container_of(con, struct trace_uprobe, consumer); + tu->nhit++; + + udd.tu = tu; + udd.bp_addr = instruction_pointer(regs); + + current->utask->vaddr = (unsigned long) &udd; + + if (WARN_ON_ONCE(!uprobe_cpu_buffer)) + return 0; + + dsize = __get_data_size(&tu->tp, regs); + esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); + + ucb = uprobe_buffer_get(); + store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); + + if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE)) + ret |= uprobe_trace_func(tu, regs, ucb, dsize); + +#ifdef CONFIG_PERF_EVENTS + if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE)) + ret |= uprobe_perf_func(tu, regs, ucb, dsize); +#endif + uprobe_buffer_put(ucb); + return ret; +} + +static int uretprobe_dispatcher(struct uprobe_consumer *con, + unsigned long func, struct pt_regs *regs) +{ + struct trace_uprobe *tu; + struct uprobe_dispatch_data udd; + struct uprobe_cpu_buffer *ucb; + int dsize, esize; + + tu = container_of(con, struct trace_uprobe, consumer); + + udd.tu = tu; + udd.bp_addr = func; + + current->utask->vaddr = (unsigned long) &udd; + + if (WARN_ON_ONCE(!uprobe_cpu_buffer)) + return 0; + + dsize = __get_data_size(&tu->tp, regs); + esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); + + ucb = uprobe_buffer_get(); + store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); + + if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE)) + uretprobe_trace_func(tu, func, regs, ucb, dsize); + +#ifdef CONFIG_PERF_EVENTS + if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE)) + uretprobe_perf_func(tu, func, regs, ucb, dsize); +#endif + uprobe_buffer_put(ucb); + return 0; +} + +static struct trace_event_functions uprobe_funcs = { + .trace = print_uprobe_event +}; + +static struct trace_event_fields uprobe_fields_array[] = { + { .type = TRACE_FUNCTION_TYPE, + .define_fields = uprobe_event_define_fields }, + {} +}; + +static inline void init_trace_event_call(struct trace_uprobe *tu) +{ + struct trace_event_call *call = trace_probe_event_call(&tu->tp); + call->event.funcs = &uprobe_funcs; + call->class->fields_array = uprobe_fields_array; + + call->flags = TRACE_EVENT_FL_UPROBE | TRACE_EVENT_FL_CAP_ANY; + call->class->reg = trace_uprobe_register; +} + +static int register_uprobe_event(struct trace_uprobe *tu) +{ + init_trace_event_call(tu); + + return trace_probe_register_event_call(&tu->tp); +} + +static int unregister_uprobe_event(struct trace_uprobe *tu) +{ + return trace_probe_unregister_event_call(&tu->tp); +} + +#ifdef CONFIG_PERF_EVENTS +struct trace_event_call * +create_local_trace_uprobe(char *name, unsigned long offs, + unsigned long ref_ctr_offset, bool is_return) +{ + enum probe_print_type ptype; + struct trace_uprobe *tu; + struct path path; + int ret; + + ret = kern_path(name, LOOKUP_FOLLOW, &path); + if (ret) + return ERR_PTR(ret); + + if (!d_is_reg(path.dentry)) { + path_put(&path); + return ERR_PTR(-EINVAL); + } + + /* + * local trace_kprobes are not added to dyn_event, so they are never + * searched in find_trace_kprobe(). Therefore, there is no concern of + * duplicated name "DUMMY_EVENT" here. + */ + tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0, + is_return); + + if (IS_ERR(tu)) { + pr_info("Failed to allocate trace_uprobe.(%d)\n", + (int)PTR_ERR(tu)); + path_put(&path); + return ERR_CAST(tu); + } + + tu->offset = offs; + tu->path = path; + tu->ref_ctr_offset = ref_ctr_offset; + tu->filename = kstrdup(name, GFP_KERNEL); + if (!tu->filename) { + ret = -ENOMEM; + goto error; + } + + init_trace_event_call(tu); + + ptype = is_ret_probe(tu) ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL; + if (traceprobe_set_print_fmt(&tu->tp, ptype) < 0) { + ret = -ENOMEM; + goto error; + } + + return trace_probe_event_call(&tu->tp); +error: + free_trace_uprobe(tu); + return ERR_PTR(ret); +} + +void destroy_local_trace_uprobe(struct trace_event_call *event_call) +{ + struct trace_uprobe *tu; + + tu = trace_uprobe_primary_from_call(event_call); + + free_trace_uprobe(tu); +} +#endif /* CONFIG_PERF_EVENTS */ + +/* Make a trace interface for controlling probe points */ +static __init int init_uprobe_trace(void) +{ + int ret; + + ret = dyn_event_register(&trace_uprobe_ops); + if (ret) + return ret; + + ret = tracing_init_dentry(); + if (ret) + return 0; + + trace_create_file("uprobe_events", TRACE_MODE_WRITE, NULL, + NULL, &uprobe_events_ops); + /* Profile interface */ + trace_create_file("uprobe_profile", TRACE_MODE_READ, NULL, + NULL, &uprobe_profile_ops); + return 0; +} + +fs_initcall(init_uprobe_trace); |