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Diffstat (limited to 'include/linux/ftrace.h')
| -rw-r--r-- | include/linux/ftrace.h | 1173 |
1 files changed, 1173 insertions, 0 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h new file mode 100644 index 000000000..e8921871e --- /dev/null +++ b/include/linux/ftrace.h @@ -0,0 +1,1173 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Ftrace header. For implementation details beyond the random comments + * scattered below, see: Documentation/trace/ftrace-design.rst + */ + +#ifndef _LINUX_FTRACE_H +#define _LINUX_FTRACE_H + +#include <linux/trace_recursion.h> +#include <linux/trace_clock.h> +#include <linux/jump_label.h> +#include <linux/kallsyms.h> +#include <linux/linkage.h> +#include <linux/bitops.h> +#include <linux/ptrace.h> +#include <linux/ktime.h> +#include <linux/sched.h> +#include <linux/types.h> +#include <linux/init.h> +#include <linux/fs.h> + +#include <asm/ftrace.h> + +/* + * If the arch supports passing the variable contents of + * function_trace_op as the third parameter back from the + * mcount call, then the arch should define this as 1. + */ +#ifndef ARCH_SUPPORTS_FTRACE_OPS +#define ARCH_SUPPORTS_FTRACE_OPS 0 +#endif + +#ifdef CONFIG_TRACING +extern void ftrace_boot_snapshot(void); +#else +static inline void ftrace_boot_snapshot(void) { } +#endif + +struct ftrace_ops; +struct ftrace_regs; +struct dyn_ftrace; + +char *arch_ftrace_match_adjust(char *str, const char *search); + +#ifdef CONFIG_HAVE_FUNCTION_GRAPH_RETVAL +struct fgraph_ret_regs; +unsigned long ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs); +#else +unsigned long ftrace_return_to_handler(unsigned long frame_pointer); +#endif + +#ifdef CONFIG_FUNCTION_TRACER +/* + * If the arch's mcount caller does not support all of ftrace's + * features, then it must call an indirect function that + * does. Or at least does enough to prevent any unwelcome side effects. + * + * Also define the function prototype that these architectures use + * to call the ftrace_ops_list_func(). + */ +#if !ARCH_SUPPORTS_FTRACE_OPS +# define FTRACE_FORCE_LIST_FUNC 1 +void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip); +#else +# define FTRACE_FORCE_LIST_FUNC 0 +void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs); +#endif +extern const struct ftrace_ops ftrace_nop_ops; +extern const struct ftrace_ops ftrace_list_ops; +struct ftrace_ops *ftrace_find_unique_ops(struct dyn_ftrace *rec); +#endif /* CONFIG_FUNCTION_TRACER */ + +/* Main tracing buffer and events set up */ +#ifdef CONFIG_TRACING +void trace_init(void); +void early_trace_init(void); +#else +static inline void trace_init(void) { } +static inline void early_trace_init(void) { } +#endif + +struct module; +struct ftrace_hash; +struct ftrace_direct_func; + +#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \ + defined(CONFIG_DYNAMIC_FTRACE) +const char * +ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, + unsigned long *off, char **modname, char *sym); +#else +static inline const char * +ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, + unsigned long *off, char **modname, char *sym) +{ + return NULL; +} +#endif + +#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE) +int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, + char *type, char *name, + char *module_name, int *exported); +#else +static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, + char *type, char *name, + char *module_name, int *exported) +{ + return -1; +} +#endif + +#ifdef CONFIG_FUNCTION_TRACER + +extern int ftrace_enabled; + +#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS + +struct ftrace_regs { + struct pt_regs regs; +}; +#define arch_ftrace_get_regs(fregs) (&(fregs)->regs) + +/* + * ftrace_regs_set_instruction_pointer() is to be defined by the architecture + * if to allow setting of the instruction pointer from the ftrace_regs when + * HAVE_DYNAMIC_FTRACE_WITH_ARGS is set and it supports live kernel patching. + */ +#define ftrace_regs_set_instruction_pointer(fregs, ip) do { } while (0) +#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */ + +static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs) +{ + if (!fregs) + return NULL; + + return arch_ftrace_get_regs(fregs); +} + +/* + * When true, the ftrace_regs_{get,set}_*() functions may be used on fregs. + * Note: this can be true even when ftrace_get_regs() cannot provide a pt_regs. + */ +static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs) +{ + if (IS_ENABLED(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS)) + return true; + + return ftrace_get_regs(fregs) != NULL; +} + +#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS +#define ftrace_regs_get_instruction_pointer(fregs) \ + instruction_pointer(ftrace_get_regs(fregs)) +#define ftrace_regs_get_argument(fregs, n) \ + regs_get_kernel_argument(ftrace_get_regs(fregs), n) +#define ftrace_regs_get_stack_pointer(fregs) \ + kernel_stack_pointer(ftrace_get_regs(fregs)) +#define ftrace_regs_return_value(fregs) \ + regs_return_value(ftrace_get_regs(fregs)) +#define ftrace_regs_set_return_value(fregs, ret) \ + regs_set_return_value(ftrace_get_regs(fregs), ret) +#define ftrace_override_function_with_return(fregs) \ + override_function_with_return(ftrace_get_regs(fregs)) +#define ftrace_regs_query_register_offset(name) \ + regs_query_register_offset(name) +#endif + +typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs); + +ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops); + +/* + * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are + * set in the flags member. + * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and + * IPMODIFY are a kind of attribute flags which can be set only before + * registering the ftrace_ops, and can not be modified while registered. + * Changing those attribute flags after registering ftrace_ops will + * cause unexpected results. + * + * ENABLED - set/unset when ftrace_ops is registered/unregistered + * DYNAMIC - set when ftrace_ops is registered to denote dynamically + * allocated ftrace_ops which need special care + * SAVE_REGS - The ftrace_ops wants regs saved at each function called + * and passed to the callback. If this flag is set, but the + * architecture does not support passing regs + * (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the + * ftrace_ops will fail to register, unless the next flag + * is set. + * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the + * handler can handle an arch that does not save regs + * (the handler tests if regs == NULL), then it can set + * this flag instead. It will not fail registering the ftrace_ops + * but, the regs field will be NULL if the arch does not support + * passing regs to the handler. + * Note, if this flag is set, the SAVE_REGS flag will automatically + * get set upon registering the ftrace_ops, if the arch supports it. + * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure + * that the call back needs recursion protection. If it does + * not set this, then the ftrace infrastructure will assume + * that the callback can handle recursion on its own. + * STUB - The ftrace_ops is just a place holder. + * INITIALIZED - The ftrace_ops has already been initialized (first use time + * register_ftrace_function() is called, it will initialized the ops) + * DELETED - The ops are being deleted, do not let them be registered again. + * ADDING - The ops is in the process of being added. + * REMOVING - The ops is in the process of being removed. + * MODIFYING - The ops is in the process of changing its filter functions. + * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code. + * The arch specific code sets this flag when it allocated a + * trampoline. This lets the arch know that it can update the + * trampoline in case the callback function changes. + * The ftrace_ops trampoline can be set by the ftrace users, and + * in such cases the arch must not modify it. Only the arch ftrace + * core code should set this flag. + * IPMODIFY - The ops can modify the IP register. This can only be set with + * SAVE_REGS. If another ops with this flag set is already registered + * for any of the functions that this ops will be registered for, then + * this ops will fail to register or set_filter_ip. + * PID - Is affected by set_ftrace_pid (allows filtering on those pids) + * RCU - Set when the ops can only be called when RCU is watching. + * TRACE_ARRAY - The ops->private points to a trace_array descriptor. + * PERMANENT - Set when the ops is permanent and should not be affected by + * ftrace_enabled. + * DIRECT - Used by the direct ftrace_ops helper for direct functions + * (internal ftrace only, should not be used by others) + */ +enum { + FTRACE_OPS_FL_ENABLED = BIT(0), + FTRACE_OPS_FL_DYNAMIC = BIT(1), + FTRACE_OPS_FL_SAVE_REGS = BIT(2), + FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = BIT(3), + FTRACE_OPS_FL_RECURSION = BIT(4), + FTRACE_OPS_FL_STUB = BIT(5), + FTRACE_OPS_FL_INITIALIZED = BIT(6), + FTRACE_OPS_FL_DELETED = BIT(7), + FTRACE_OPS_FL_ADDING = BIT(8), + FTRACE_OPS_FL_REMOVING = BIT(9), + FTRACE_OPS_FL_MODIFYING = BIT(10), + FTRACE_OPS_FL_ALLOC_TRAMP = BIT(11), + FTRACE_OPS_FL_IPMODIFY = BIT(12), + FTRACE_OPS_FL_PID = BIT(13), + FTRACE_OPS_FL_RCU = BIT(14), + FTRACE_OPS_FL_TRACE_ARRAY = BIT(15), + FTRACE_OPS_FL_PERMANENT = BIT(16), + FTRACE_OPS_FL_DIRECT = BIT(17), +}; + +#ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS +#define FTRACE_OPS_FL_SAVE_ARGS FTRACE_OPS_FL_SAVE_REGS +#else +#define FTRACE_OPS_FL_SAVE_ARGS 0 +#endif + +/* + * FTRACE_OPS_CMD_* commands allow the ftrace core logic to request changes + * to a ftrace_ops. Note, the requests may fail. + * + * ENABLE_SHARE_IPMODIFY_SELF - enable a DIRECT ops to work on the same + * function as an ops with IPMODIFY. Called + * when the DIRECT ops is being registered. + * This is called with both direct_mutex and + * ftrace_lock are locked. + * + * ENABLE_SHARE_IPMODIFY_PEER - enable a DIRECT ops to work on the same + * function as an ops with IPMODIFY. Called + * when the other ops (the one with IPMODIFY) + * is being registered. + * This is called with direct_mutex locked. + * + * DISABLE_SHARE_IPMODIFY_PEER - disable a DIRECT ops to work on the same + * function as an ops with IPMODIFY. Called + * when the other ops (the one with IPMODIFY) + * is being unregistered. + * This is called with direct_mutex locked. + */ +enum ftrace_ops_cmd { + FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF, + FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER, + FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER, +}; + +/* + * For most ftrace_ops_cmd, + * Returns: + * 0 - Success. + * Negative on failure. The return value is dependent on the + * callback. + */ +typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, enum ftrace_ops_cmd cmd); + +#ifdef CONFIG_DYNAMIC_FTRACE +/* The hash used to know what functions callbacks trace */ +struct ftrace_ops_hash { + struct ftrace_hash __rcu *notrace_hash; + struct ftrace_hash __rcu *filter_hash; + struct mutex regex_lock; +}; + +void ftrace_free_init_mem(void); +void ftrace_free_mem(struct module *mod, void *start, void *end); +#else +static inline void ftrace_free_init_mem(void) +{ + ftrace_boot_snapshot(); +} +static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { } +#endif + +/* + * Note, ftrace_ops can be referenced outside of RCU protection, unless + * the RCU flag is set. If ftrace_ops is allocated and not part of kernel + * core data, the unregistering of it will perform a scheduling on all CPUs + * to make sure that there are no more users. Depending on the load of the + * system that may take a bit of time. + * + * Any private data added must also take care not to be freed and if private + * data is added to a ftrace_ops that is in core code, the user of the + * ftrace_ops must perform a schedule_on_each_cpu() before freeing it. + */ +struct ftrace_ops { + ftrace_func_t func; + struct ftrace_ops __rcu *next; + unsigned long flags; + void *private; + ftrace_func_t saved_func; +#ifdef CONFIG_DYNAMIC_FTRACE + struct ftrace_ops_hash local_hash; + struct ftrace_ops_hash *func_hash; + struct ftrace_ops_hash old_hash; + unsigned long trampoline; + unsigned long trampoline_size; + struct list_head list; + ftrace_ops_func_t ops_func; +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + unsigned long direct_call; +#endif +#endif +}; + +extern struct ftrace_ops __rcu *ftrace_ops_list; +extern struct ftrace_ops ftrace_list_end; + +/* + * Traverse the ftrace_ops_list, invoking all entries. The reason that we + * can use rcu_dereference_raw_check() is that elements removed from this list + * are simply leaked, so there is no need to interact with a grace-period + * mechanism. The rcu_dereference_raw_check() calls are needed to handle + * concurrent insertions into the ftrace_ops_list. + * + * Silly Alpha and silly pointer-speculation compiler optimizations! + */ +#define do_for_each_ftrace_op(op, list) \ + op = rcu_dereference_raw_check(list); \ + do + +/* + * Optimized for just a single item in the list (as that is the normal case). + */ +#define while_for_each_ftrace_op(op) \ + while (likely(op = rcu_dereference_raw_check((op)->next)) && \ + unlikely((op) != &ftrace_list_end)) + +/* + * Type of the current tracing. + */ +enum ftrace_tracing_type_t { + FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */ + FTRACE_TYPE_RETURN, /* Hook the return of the function */ +}; + +/* Current tracing type, default is FTRACE_TYPE_ENTER */ +extern enum ftrace_tracing_type_t ftrace_tracing_type; + +/* + * The ftrace_ops must be a static and should also + * be read_mostly. These functions do modify read_mostly variables + * so use them sparely. Never free an ftrace_op or modify the + * next pointer after it has been registered. Even after unregistering + * it, the next pointer may still be used internally. + */ +int register_ftrace_function(struct ftrace_ops *ops); +int unregister_ftrace_function(struct ftrace_ops *ops); + +extern void ftrace_stub(unsigned long a0, unsigned long a1, + struct ftrace_ops *op, struct ftrace_regs *fregs); + + +int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs); +#else /* !CONFIG_FUNCTION_TRACER */ +/* + * (un)register_ftrace_function must be a macro since the ops parameter + * must not be evaluated. + */ +#define register_ftrace_function(ops) ({ 0; }) +#define unregister_ftrace_function(ops) ({ 0; }) +static inline void ftrace_kill(void) { } +static inline void ftrace_free_init_mem(void) { } +static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { } +static inline int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs) +{ + return -EOPNOTSUPP; +} +#endif /* CONFIG_FUNCTION_TRACER */ + +struct ftrace_func_entry { + struct hlist_node hlist; + unsigned long ip; + unsigned long direct; /* for direct lookup only */ +}; + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +extern int ftrace_direct_func_count; +unsigned long ftrace_find_rec_direct(unsigned long ip); +int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); +int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr, + bool free_filters); +int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); +int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr); + +void ftrace_stub_direct_tramp(void); + +#else +struct ftrace_ops; +# define ftrace_direct_func_count 0 +static inline unsigned long ftrace_find_rec_direct(unsigned long ip) +{ + return 0; +} +static inline int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) +{ + return -ENODEV; +} +static inline int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr, + bool free_filters) +{ + return -ENODEV; +} +static inline int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) +{ + return -ENODEV; +} +static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr) +{ + return -ENODEV; +} + +/* + * This must be implemented by the architecture. + * It is the way the ftrace direct_ops helper, when called + * via ftrace (because there's other callbacks besides the + * direct call), can inform the architecture's trampoline that this + * routine has a direct caller, and what the caller is. + * + * For example, in x86, it returns the direct caller + * callback function via the regs->orig_ax parameter. + * Then in the ftrace trampoline, if this is set, it makes + * the return from the trampoline jump to the direct caller + * instead of going back to the function it just traced. + */ +static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, + unsigned long addr) { } +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ + +#ifdef CONFIG_STACK_TRACER + +extern int stack_tracer_enabled; + +int stack_trace_sysctl(struct ctl_table *table, int write, void *buffer, + size_t *lenp, loff_t *ppos); + +/* DO NOT MODIFY THIS VARIABLE DIRECTLY! */ +DECLARE_PER_CPU(int, disable_stack_tracer); + +/** + * stack_tracer_disable - temporarily disable the stack tracer + * + * There's a few locations (namely in RCU) where stack tracing + * cannot be executed. This function is used to disable stack + * tracing during those critical sections. + * + * This function must be called with preemption or interrupts + * disabled and stack_tracer_enable() must be called shortly after + * while preemption or interrupts are still disabled. + */ +static inline void stack_tracer_disable(void) +{ + /* Preemption or interrupts must be disabled */ + if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) + WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); + this_cpu_inc(disable_stack_tracer); +} + +/** + * stack_tracer_enable - re-enable the stack tracer + * + * After stack_tracer_disable() is called, stack_tracer_enable() + * must be called shortly afterward. + */ +static inline void stack_tracer_enable(void) +{ + if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) + WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); + this_cpu_dec(disable_stack_tracer); +} +#else +static inline void stack_tracer_disable(void) { } +static inline void stack_tracer_enable(void) { } +#endif + +#ifdef CONFIG_DYNAMIC_FTRACE + +void ftrace_arch_code_modify_prepare(void); +void ftrace_arch_code_modify_post_process(void); + +enum ftrace_bug_type { + FTRACE_BUG_UNKNOWN, + FTRACE_BUG_INIT, + FTRACE_BUG_NOP, + FTRACE_BUG_CALL, + FTRACE_BUG_UPDATE, +}; +extern enum ftrace_bug_type ftrace_bug_type; + +/* + * Archs can set this to point to a variable that holds the value that was + * expected at the call site before calling ftrace_bug(). + */ +extern const void *ftrace_expected; + +void ftrace_bug(int err, struct dyn_ftrace *rec); + +struct seq_file; + +extern int ftrace_text_reserved(const void *start, const void *end); + +struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr); + +bool is_ftrace_trampoline(unsigned long addr); + +/* + * The dyn_ftrace record's flags field is split into two parts. + * the first part which is '0-FTRACE_REF_MAX' is a counter of + * the number of callbacks that have registered the function that + * the dyn_ftrace descriptor represents. + * + * The second part is a mask: + * ENABLED - the function is being traced + * REGS - the record wants the function to save regs + * REGS_EN - the function is set up to save regs. + * IPMODIFY - the record allows for the IP address to be changed. + * DISABLED - the record is not ready to be touched yet + * DIRECT - there is a direct function to call + * CALL_OPS - the record can use callsite-specific ops + * CALL_OPS_EN - the function is set up to use callsite-specific ops + * TOUCHED - A callback was added since boot up + * MODIFIED - The function had IPMODIFY or DIRECT attached to it + * + * When a new ftrace_ops is registered and wants a function to save + * pt_regs, the rec->flags REGS is set. When the function has been + * set up to save regs, the REG_EN flag is set. Once a function + * starts saving regs it will do so until all ftrace_ops are removed + * from tracing that function. + */ +enum { + FTRACE_FL_ENABLED = (1UL << 31), + FTRACE_FL_REGS = (1UL << 30), + FTRACE_FL_REGS_EN = (1UL << 29), + FTRACE_FL_TRAMP = (1UL << 28), + FTRACE_FL_TRAMP_EN = (1UL << 27), + FTRACE_FL_IPMODIFY = (1UL << 26), + FTRACE_FL_DISABLED = (1UL << 25), + FTRACE_FL_DIRECT = (1UL << 24), + FTRACE_FL_DIRECT_EN = (1UL << 23), + FTRACE_FL_CALL_OPS = (1UL << 22), + FTRACE_FL_CALL_OPS_EN = (1UL << 21), + FTRACE_FL_TOUCHED = (1UL << 20), + FTRACE_FL_MODIFIED = (1UL << 19), +}; + +#define FTRACE_REF_MAX_SHIFT 19 +#define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) + +#define ftrace_rec_count(rec) ((rec)->flags & FTRACE_REF_MAX) + +struct dyn_ftrace { + unsigned long ip; /* address of mcount call-site */ + unsigned long flags; + struct dyn_arch_ftrace arch; +}; + +int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, + int remove, int reset); +int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips, + unsigned int cnt, int remove, int reset); +int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, + int len, int reset); +int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, + int len, int reset); +void ftrace_set_global_filter(unsigned char *buf, int len, int reset); +void ftrace_set_global_notrace(unsigned char *buf, int len, int reset); +void ftrace_free_filter(struct ftrace_ops *ops); +void ftrace_ops_set_global_filter(struct ftrace_ops *ops); + +enum { + FTRACE_UPDATE_CALLS = (1 << 0), + FTRACE_DISABLE_CALLS = (1 << 1), + FTRACE_UPDATE_TRACE_FUNC = (1 << 2), + FTRACE_START_FUNC_RET = (1 << 3), + FTRACE_STOP_FUNC_RET = (1 << 4), + FTRACE_MAY_SLEEP = (1 << 5), +}; + +/* + * The FTRACE_UPDATE_* enum is used to pass information back + * from the ftrace_update_record() and ftrace_test_record() + * functions. These are called by the code update routines + * to find out what is to be done for a given function. + * + * IGNORE - The function is already what we want it to be + * MAKE_CALL - Start tracing the function + * MODIFY_CALL - Stop saving regs for the function + * MAKE_NOP - Stop tracing the function + */ +enum { + FTRACE_UPDATE_IGNORE, + FTRACE_UPDATE_MAKE_CALL, + FTRACE_UPDATE_MODIFY_CALL, + FTRACE_UPDATE_MAKE_NOP, +}; + +enum { + FTRACE_ITER_FILTER = (1 << 0), + FTRACE_ITER_NOTRACE = (1 << 1), + FTRACE_ITER_PRINTALL = (1 << 2), + FTRACE_ITER_DO_PROBES = (1 << 3), + FTRACE_ITER_PROBE = (1 << 4), + FTRACE_ITER_MOD = (1 << 5), + FTRACE_ITER_ENABLED = (1 << 6), + FTRACE_ITER_TOUCHED = (1 << 7), + FTRACE_ITER_ADDRS = (1 << 8), +}; + +void arch_ftrace_update_code(int command); +void arch_ftrace_update_trampoline(struct ftrace_ops *ops); +void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec); +void arch_ftrace_trampoline_free(struct ftrace_ops *ops); + +struct ftrace_rec_iter; + +struct ftrace_rec_iter *ftrace_rec_iter_start(void); +struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter); +struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter); + +#define for_ftrace_rec_iter(iter) \ + for (iter = ftrace_rec_iter_start(); \ + iter; \ + iter = ftrace_rec_iter_next(iter)) + + +int ftrace_update_record(struct dyn_ftrace *rec, bool enable); +int ftrace_test_record(struct dyn_ftrace *rec, bool enable); +void ftrace_run_stop_machine(int command); +unsigned long ftrace_location(unsigned long ip); +unsigned long ftrace_location_range(unsigned long start, unsigned long end); +unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec); +unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec); + +extern ftrace_func_t ftrace_trace_function; + +int ftrace_regex_open(struct ftrace_ops *ops, int flag, + struct inode *inode, struct file *file); +ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, + size_t cnt, loff_t *ppos); +ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, + size_t cnt, loff_t *ppos); +int ftrace_regex_release(struct inode *inode, struct file *file); + +void __init +ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable); + +/* defined in arch */ +extern int ftrace_dyn_arch_init(void); +extern void ftrace_replace_code(int enable); +extern int ftrace_update_ftrace_func(ftrace_func_t func); +extern void ftrace_caller(void); +extern void ftrace_regs_caller(void); +extern void ftrace_call(void); +extern void ftrace_regs_call(void); +extern void mcount_call(void); + +void ftrace_modify_all_code(int command); + +#ifndef FTRACE_ADDR +#define FTRACE_ADDR ((unsigned long)ftrace_caller) +#endif + +#ifndef FTRACE_GRAPH_ADDR +#define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller) +#endif + +#ifndef FTRACE_REGS_ADDR +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +# define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller) +#else +# define FTRACE_REGS_ADDR FTRACE_ADDR +#endif +#endif + +/* + * If an arch would like functions that are only traced + * by the function graph tracer to jump directly to its own + * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR + * to be that address to jump to. + */ +#ifndef FTRACE_GRAPH_TRAMP_ADDR +#define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0) +#endif + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +extern void ftrace_graph_caller(void); +extern int ftrace_enable_ftrace_graph_caller(void); +extern int ftrace_disable_ftrace_graph_caller(void); +#else +static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; } +static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; } +#endif + +/** + * ftrace_make_nop - convert code into nop + * @mod: module structure if called by module load initialization + * @rec: the call site record (e.g. mcount/fentry) + * @addr: the address that the call site should be calling + * + * This is a very sensitive operation and great care needs + * to be taken by the arch. The operation should carefully + * read the location, check to see if what is read is indeed + * what we expect it to be, and then on success of the compare, + * it should write to the location. + * + * The code segment at @rec->ip should be a caller to @addr + * + * Return must be: + * 0 on success + * -EFAULT on error reading the location + * -EINVAL on a failed compare of the contents + * -EPERM on error writing to the location + * Any other value will be considered a failure. + */ +extern int ftrace_make_nop(struct module *mod, + struct dyn_ftrace *rec, unsigned long addr); + +/** + * ftrace_need_init_nop - return whether nop call sites should be initialized + * + * Normally the compiler's -mnop-mcount generates suitable nops, so we don't + * need to call ftrace_init_nop() if the code is built with that flag. + * Architectures where this is not always the case may define their own + * condition. + * + * Return must be: + * 0 if ftrace_init_nop() should be called + * Nonzero if ftrace_init_nop() should not be called + */ + +#ifndef ftrace_need_init_nop +#define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT)) +#endif + +/** + * ftrace_init_nop - initialize a nop call site + * @mod: module structure if called by module load initialization + * @rec: the call site record (e.g. mcount/fentry) + * + * This is a very sensitive operation and great care needs + * to be taken by the arch. The operation should carefully + * read the location, check to see if what is read is indeed + * what we expect it to be, and then on success of the compare, + * it should write to the location. + * + * The code segment at @rec->ip should contain the contents created by + * the compiler + * + * Return must be: + * 0 on success + * -EFAULT on error reading the location + * -EINVAL on a failed compare of the contents + * -EPERM on error writing to the location + * Any other value will be considered a failure. + */ +#ifndef ftrace_init_nop +static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) +{ + return ftrace_make_nop(mod, rec, MCOUNT_ADDR); +} +#endif + +/** + * ftrace_make_call - convert a nop call site into a call to addr + * @rec: the call site record (e.g. mcount/fentry) + * @addr: the address that the call site should call + * + * This is a very sensitive operation and great care needs + * to be taken by the arch. The operation should carefully + * read the location, check to see if what is read is indeed + * what we expect it to be, and then on success of the compare, + * it should write to the location. + * + * The code segment at @rec->ip should be a nop + * + * Return must be: + * 0 on success + * -EFAULT on error reading the location + * -EINVAL on a failed compare of the contents + * -EPERM on error writing to the location + * Any other value will be considered a failure. + */ +extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr); + +#if defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) || \ + defined(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) +/** + * ftrace_modify_call - convert from one addr to another (no nop) + * @rec: the call site record (e.g. mcount/fentry) + * @old_addr: the address expected to be currently called to + * @addr: the address to change to + * + * This is a very sensitive operation and great care needs + * to be taken by the arch. The operation should carefully + * read the location, check to see if what is read is indeed + * what we expect it to be, and then on success of the compare, + * it should write to the location. + * + * When using call ops, this is called when the associated ops change, even + * when (addr == old_addr). + * + * The code segment at @rec->ip should be a caller to @old_addr + * + * Return must be: + * 0 on success + * -EFAULT on error reading the location + * -EINVAL on a failed compare of the contents + * -EPERM on error writing to the location + * Any other value will be considered a failure. + */ +extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, + unsigned long addr); +#else +/* Should never be called */ +static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, + unsigned long addr) +{ + return -EINVAL; +} +#endif + +extern int skip_trace(unsigned long ip); +extern void ftrace_module_init(struct module *mod); +extern void ftrace_module_enable(struct module *mod); +extern void ftrace_release_mod(struct module *mod); +#else /* CONFIG_DYNAMIC_FTRACE */ +static inline int skip_trace(unsigned long ip) { return 0; } +static inline void ftrace_module_init(struct module *mod) { } +static inline void ftrace_module_enable(struct module *mod) { } +static inline void ftrace_release_mod(struct module *mod) { } +static inline int ftrace_text_reserved(const void *start, const void *end) +{ + return 0; +} +static inline unsigned long ftrace_location(unsigned long ip) +{ + return 0; +} + +/* + * Again users of functions that have ftrace_ops may not + * have them defined when ftrace is not enabled, but these + * functions may still be called. Use a macro instead of inline. + */ +#define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; }) +#define ftrace_set_early_filter(ops, buf, enable) do { } while (0) +#define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; }) +#define ftrace_set_filter_ips(ops, ips, cnt, remove, reset) ({ -ENODEV; }) +#define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; }) +#define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; }) +#define ftrace_free_filter(ops) do { } while (0) +#define ftrace_ops_set_global_filter(ops) do { } while (0) + +static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, + size_t cnt, loff_t *ppos) { return -ENODEV; } +static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, + size_t cnt, loff_t *ppos) { return -ENODEV; } +static inline int +ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; } + +static inline bool is_ftrace_trampoline(unsigned long addr) +{ + return false; +} +#endif /* CONFIG_DYNAMIC_FTRACE */ + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +#ifndef ftrace_graph_func +#define ftrace_graph_func ftrace_stub +#define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB +#else +#define FTRACE_OPS_GRAPH_STUB 0 +#endif +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +/* totally disable ftrace - can not re-enable after this */ +void ftrace_kill(void); + +static inline void tracer_disable(void) +{ +#ifdef CONFIG_FUNCTION_TRACER + ftrace_enabled = 0; +#endif +} + +/* + * Ftrace disable/restore without lock. Some synchronization mechanism + * must be used to prevent ftrace_enabled to be changed between + * disable/restore. + */ +static inline int __ftrace_enabled_save(void) +{ +#ifdef CONFIG_FUNCTION_TRACER + int saved_ftrace_enabled = ftrace_enabled; + ftrace_enabled = 0; + return saved_ftrace_enabled; +#else + return 0; +#endif +} + +static inline void __ftrace_enabled_restore(int enabled) +{ +#ifdef CONFIG_FUNCTION_TRACER + ftrace_enabled = enabled; +#endif +} + +/* All archs should have this, but we define it for consistency */ +#ifndef ftrace_return_address0 +# define ftrace_return_address0 __builtin_return_address(0) +#endif + +/* Archs may use other ways for ADDR1 and beyond */ +#ifndef ftrace_return_address +# ifdef CONFIG_FRAME_POINTER +# define ftrace_return_address(n) __builtin_return_address(n) +# else +# define ftrace_return_address(n) 0UL +# endif +#endif + +#define CALLER_ADDR0 ((unsigned long)ftrace_return_address0) +#define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1)) +#define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2)) +#define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3)) +#define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4)) +#define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5)) +#define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6)) + +static __always_inline unsigned long get_lock_parent_ip(void) +{ + unsigned long addr = CALLER_ADDR0; + + if (!in_lock_functions(addr)) + return addr; + addr = CALLER_ADDR1; + if (!in_lock_functions(addr)) + return addr; + return CALLER_ADDR2; +} + +#ifdef CONFIG_TRACE_PREEMPT_TOGGLE + extern void trace_preempt_on(unsigned long a0, unsigned long a1); + extern void trace_preempt_off(unsigned long a0, unsigned long a1); +#else +/* + * Use defines instead of static inlines because some arches will make code out + * of the CALLER_ADDR, when we really want these to be a real nop. + */ +# define trace_preempt_on(a0, a1) do { } while (0) +# define trace_preempt_off(a0, a1) do { } while (0) +#endif + +#ifdef CONFIG_FTRACE_MCOUNT_RECORD +extern void ftrace_init(void); +#ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY +#define FTRACE_CALLSITE_SECTION "__patchable_function_entries" +#else +#define FTRACE_CALLSITE_SECTION "__mcount_loc" +#endif +#else +static inline void ftrace_init(void) { } +#endif + +/* + * Structure that defines an entry function trace. + * It's already packed but the attribute "packed" is needed + * to remove extra padding at the end. + */ +struct ftrace_graph_ent { + unsigned long func; /* Current function */ + int depth; +} __packed; + +/* + * Structure that defines a return function trace. + * It's already packed but the attribute "packed" is needed + * to remove extra padding at the end. + */ +struct ftrace_graph_ret { + unsigned long func; /* Current function */ +#ifdef CONFIG_FUNCTION_GRAPH_RETVAL + unsigned long retval; +#endif + int depth; + /* Number of functions that overran the depth limit for current task */ + unsigned int overrun; + unsigned long long calltime; + unsigned long long rettime; +} __packed; + +/* Type of the callback handlers for tracing function graph*/ +typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */ +typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */ + +extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace); + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + +struct fgraph_ops { + trace_func_graph_ent_t entryfunc; + trace_func_graph_ret_t retfunc; +}; + +/* + * Stack of return addresses for functions + * of a thread. + * Used in struct thread_info + */ +struct ftrace_ret_stack { + unsigned long ret; + unsigned long func; + unsigned long long calltime; +#ifdef CONFIG_FUNCTION_PROFILER + unsigned long long subtime; +#endif +#ifdef HAVE_FUNCTION_GRAPH_FP_TEST + unsigned long fp; +#endif +#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR + unsigned long *retp; +#endif +}; + +/* + * Primary handler of a function return. + * It relays on ftrace_return_to_handler. + * Defined in entry_32/64.S + */ +extern void return_to_handler(void); + +extern int +function_graph_enter(unsigned long ret, unsigned long func, + unsigned long frame_pointer, unsigned long *retp); + +struct ftrace_ret_stack * +ftrace_graph_get_ret_stack(struct task_struct *task, int idx); + +unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, + unsigned long ret, unsigned long *retp); + +/* + * Sometimes we don't want to trace a function with the function + * graph tracer but we want them to keep traced by the usual function + * tracer if the function graph tracer is not configured. + */ +#define __notrace_funcgraph notrace + +#define FTRACE_RETFUNC_DEPTH 50 +#define FTRACE_RETSTACK_ALLOC_SIZE 32 + +extern int register_ftrace_graph(struct fgraph_ops *ops); +extern void unregister_ftrace_graph(struct fgraph_ops *ops); + +/** + * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called + * + * ftrace_graph_stop() is called when a severe error is detected in + * the function graph tracing. This function is called by the critical + * paths of function graph to keep those paths from doing any more harm. + */ +DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph); + +static inline bool ftrace_graph_is_dead(void) +{ + return static_branch_unlikely(&kill_ftrace_graph); +} + +extern void ftrace_graph_stop(void); + +/* The current handlers in use */ +extern trace_func_graph_ret_t ftrace_graph_return; +extern trace_func_graph_ent_t ftrace_graph_entry; + +extern void ftrace_graph_init_task(struct task_struct *t); +extern void ftrace_graph_exit_task(struct task_struct *t); +extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu); + +static inline void pause_graph_tracing(void) +{ + atomic_inc(¤t->tracing_graph_pause); +} + +static inline void unpause_graph_tracing(void) +{ + atomic_dec(¤t->tracing_graph_pause); +} +#else /* !CONFIG_FUNCTION_GRAPH_TRACER */ + +#define __notrace_funcgraph + +static inline void ftrace_graph_init_task(struct task_struct *t) { } +static inline void ftrace_graph_exit_task(struct task_struct *t) { } +static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { } + +/* Define as macros as fgraph_ops may not be defined */ +#define register_ftrace_graph(ops) ({ -1; }) +#define unregister_ftrace_graph(ops) do { } while (0) + +static inline unsigned long +ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret, + unsigned long *retp) +{ + return ret; +} + +static inline void pause_graph_tracing(void) { } +static inline void unpause_graph_tracing(void) { } +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +#ifdef CONFIG_TRACING +enum ftrace_dump_mode; + +extern enum ftrace_dump_mode ftrace_dump_on_oops; +extern int tracepoint_printk; + +extern void disable_trace_on_warning(void); +extern int __disable_trace_on_warning; + +int tracepoint_printk_sysctl(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos); + +#else /* CONFIG_TRACING */ +static inline void disable_trace_on_warning(void) { } +#endif /* CONFIG_TRACING */ + +#ifdef CONFIG_FTRACE_SYSCALLS + +unsigned long arch_syscall_addr(int nr); + +#endif /* CONFIG_FTRACE_SYSCALLS */ + +#endif /* _LINUX_FTRACE_H */ |