/* * Infrastructure for profiling code inserted by 'gcc -pg'. * * Copyright (C) 2007-2008 Steven Rostedt * Copyright (C) 2004-2008 Ingo Molnar * * Originally ported from the -rt patch by: * Copyright (C) 2007 Arnaldo Carvalho de Melo * * Based on code in the latency_tracer, that is: * * Copyright (C) 2004-2006 Ingo Molnar * Copyright (C) 2004 William Lee Irwin III */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "trace_output.h" #include "trace_stat.h" #define FTRACE_WARN_ON(cond) \ do { \ if (WARN_ON(cond)) \ ftrace_kill(); \ } while (0) #define FTRACE_WARN_ON_ONCE(cond) \ do { \ if (WARN_ON_ONCE(cond)) \ ftrace_kill(); \ } while (0) /* hash bits for specific function selection */ #define FTRACE_HASH_BITS 7 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS) /* ftrace_enabled is a method to turn ftrace on or off */ int ftrace_enabled __read_mostly; static int last_ftrace_enabled; /* Quick disabling of function tracer. */ int function_trace_stop; /* List for set_ftrace_pid's pids. */ LIST_HEAD(ftrace_pids); struct ftrace_pid { struct list_head list; struct pid *pid; }; /* * ftrace_disabled is set when an anomaly is discovered. * ftrace_disabled is much stronger than ftrace_enabled. */ static int ftrace_disabled __read_mostly; static DEFINE_MUTEX(ftrace_lock); static struct ftrace_ops ftrace_list_end __read_mostly = { .func = ftrace_stub, }; static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end; ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub; ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub; static void ftrace_list_func(unsigned long ip, unsigned long parent_ip) { struct ftrace_ops *op = ftrace_list; /* in case someone actually ports this to alpha! */ read_barrier_depends(); while (op != &ftrace_list_end) { /* silly alpha */ read_barrier_depends(); op->func(ip, parent_ip); op = op->next; }; } static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip) { if (!test_tsk_trace_trace(current)) return; ftrace_pid_function(ip, parent_ip); } static void set_ftrace_pid_function(ftrace_func_t func) { /* do not set ftrace_pid_function to itself! */ if (func != ftrace_pid_func) ftrace_pid_function = func; } /** * clear_ftrace_function - reset the ftrace function * * This NULLs the ftrace function and in essence stops * tracing. There may be lag */ void clear_ftrace_function(void) { ftrace_trace_function = ftrace_stub; __ftrace_trace_function = ftrace_stub; ftrace_pid_function = ftrace_stub; } #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST /* * For those archs that do not test ftrace_trace_stop in their * mcount call site, we need to do it from C. */ static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip) { if (function_trace_stop) return; __ftrace_trace_function(ip, parent_ip); } #endif static int __register_ftrace_function(struct ftrace_ops *ops) { ops->next = ftrace_list; /* * We are entering ops into the ftrace_list but another * CPU might be walking that list. We need to make sure * the ops->next pointer is valid before another CPU sees * the ops pointer included into the ftrace_list. */ smp_wmb(); ftrace_list = ops; if (ftrace_enabled) { ftrace_func_t func; if (ops->next == &ftrace_list_end) func = ops->func; else func = ftrace_list_func; if (!list_empty(&ftrace_pids)) { set_ftrace_pid_function(func); func = ftrace_pid_func; } /* * For one func, simply call it directly. * For more than one func, call the chain. */ #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST ftrace_trace_function = func; #else __ftrace_trace_function = func; ftrace_trace_function = ftrace_test_stop_func; #endif } return 0; } static int __unregister_ftrace_function(struct ftrace_ops *ops) { struct ftrace_ops **p; /* * If we are removing the last function, then simply point * to the ftrace_stub. */ if (ftrace_list == ops && ops->next == &ftrace_list_end) { ftrace_trace_function = ftrace_stub; ftrace_list = &ftrace_list_end; return 0; } for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next) if (*p == ops) break; if (*p != ops) return -1; *p = (*p)->next; if (ftrace_enabled) { /* If we only have one func left, then call that directly */ if (ftrace_list->next == &ftrace_list_end) { ftrace_func_t func = ftrace_list->func; if (!list_empty(&ftrace_pids)) { set_ftrace_pid_function(func); func = ftrace_pid_func; } #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST ftrace_trace_function = func; #else __ftrace_trace_function = func; #endif } } return 0; } static void ftrace_update_pid_func(void) { ftrace_func_t func; if (ftrace_trace_function == ftrace_stub) return; #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST func = ftrace_trace_function; #else func = __ftrace_trace_function; #endif if (!list_empty(&ftrace_pids)) { set_ftrace_pid_function(func); func = ftrace_pid_func; } else { if (func == ftrace_pid_func) func = ftrace_pid_function; } #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST ftrace_trace_function = func; #else __ftrace_trace_function = func; #endif } #ifdef CONFIG_FUNCTION_PROFILER struct ftrace_profile { struct hlist_node node; unsigned long ip; unsigned long counter; #ifdef CONFIG_FUNCTION_GRAPH_TRACER unsigned long long time; #endif }; struct ftrace_profile_page { struct ftrace_profile_page *next; unsigned long index; struct ftrace_profile records[]; }; struct ftrace_profile_stat { atomic_t disabled; struct hlist_head *hash; struct ftrace_profile_page *pages; struct ftrace_profile_page *start; struct tracer_stat stat; }; #define PROFILE_RECORDS_SIZE \ (PAGE_SIZE - offsetof(struct ftrace_profile_page, records)) #define PROFILES_PER_PAGE \ (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile)) static int ftrace_profile_bits __read_mostly; static int ftrace_profile_enabled __read_mostly; /* ftrace_profile_lock - synchronize the enable and disable of the profiler */ static DEFINE_MUTEX(ftrace_profile_lock); static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats); #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */ static void * function_stat_next(void *v, int idx) { struct ftrace_profile *rec = v; struct ftrace_profile_page *pg; pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK); again: if (idx != 0) rec++; if ((void *)rec >= (void *)&pg->records[pg->index]) { pg = pg->next; if (!pg) return NULL; rec = &pg->records[0]; if (!rec->counter) goto again; } return rec; } static void *function_stat_start(struct tracer_stat *trace) { struct ftrace_profile_stat *stat = container_of(trace, struct ftrace_profile_stat, stat); if (!stat || !stat->start) return NULL; return function_stat_next(&stat->start->records[0], 0); } #ifdef CONFIG_FUNCTION_GRAPH_TRACER /* function graph compares on total time */ static int function_stat_cmp(void *p1, void *p2) { struct ftrace_profile *a = p1; struct ftrace_profile *b = p2; if (a->time < b->time) return -1; if (a->time > b->time) return 1; else return 0; } #else /* not function graph compares against hits */ static int function_stat_cmp(void *p1, void *p2) { struct ftrace_profile *a = p1; struct ftrace_profile *b = p2; if (a->counter < b->counter) return -1; if (a->counter > b->counter) return 1; else return 0; } #endif static int function_stat_headers(struct seq_file *m) { #ifdef CONFIG_FUNCTION_GRAPH_TRACER seq_printf(m, " Function " "Hit Time Avg\n" " -------- " "--- ---- ---\n"); #else seq_printf(m, " Function Hit\n" " -------- ---\n"); #endif return 0; } static int function_stat_show(struct seq_file *m, void *v) { struct ftrace_profile *rec = v; char str[KSYM_SYMBOL_LEN]; #ifdef CONFIG_FUNCTION_GRAPH_TRACER static DEFINE_MUTEX(mutex); static struct trace_seq s; unsigned long long avg; #endif kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); seq_printf(m, " %-30.30s %10lu", str, rec->counter); #ifdef CONFIG_FUNCTION_GRAPH_TRACER seq_printf(m, " "); avg = rec->time; do_div(avg, rec->counter); mutex_lock(&mutex); trace_seq_init(&s); trace_print_graph_duration(rec->time, &s); trace_seq_puts(&s, " "); trace_print_graph_duration(avg, &s); trace_print_seq(m, &s); mutex_unlock(&mutex); #endif seq_putc(m, '\n'); return 0; } static void ftrace_profile_reset(struct ftrace_profile_stat *stat) { struct ftrace_profile_page *pg; pg = stat->pages = stat->start; while (pg) { memset(pg->records, 0, PROFILE_RECORDS_SIZE); pg->index = 0; pg = pg->next; } memset(stat->hash, 0, FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head)); } int ftrace_profile_pages_init(struct ftrace_profile_stat *stat) { struct ftrace_profile_page *pg; int functions; int pages; int i; /* If we already allocated, do nothing */ if (stat->pages) return 0; stat->pages = (void *)get_zeroed_page(GFP_KERNEL); if (!stat->pages) return -ENOMEM; #ifdef CONFIG_DYNAMIC_FTRACE functions = ftrace_update_tot_cnt; #else /* * We do not know the number of functions that exist because * dynamic tracing is what counts them. With past experience * we have around 20K functions. That should be more than enough. * It is highly unlikely we will execute every function in * the kernel. */ functions = 20000; #endif pg = stat->start = stat->pages; pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE); for (i = 0; i < pages; i++) { pg->next = (void *)get_zeroed_page(GFP_KERNEL); if (!pg->next) goto out_free; pg = pg->next; } return 0; out_free: pg = stat->start; while (pg) { unsigned long tmp = (unsigned long)pg; pg = pg->next; free_page(tmp); } free_page((unsigned long)stat->pages); stat->pages = NULL; stat->start = NULL; return -ENOMEM; } static int ftrace_profile_init_cpu(int cpu) { struct ftrace_profile_stat *stat; int size; stat = &per_cpu(ftrace_profile_stats, cpu); if (stat->hash) { /* If the profile is already created, simply reset it */ ftrace_profile_reset(stat); return 0; } /* * We are profiling all functions, but usually only a few thousand * functions are hit. We'll make a hash of 1024 items. */ size = FTRACE_PROFILE_HASH_SIZE; stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL); if (!stat->hash) return -ENOMEM; if (!ftrace_profile_bits) { size--; for (; size; size >>= 1) ftrace_profile_bits++; } /* Preallocate the function profiling pages */ if (ftrace_profile_pages_init(stat) < 0) { kfree(stat->hash); stat->hash = NULL; return -ENOMEM; } return 0; } static int ftrace_profile_init(void) { int cpu; int ret = 0; for_each_online_cpu(cpu) { ret = ftrace_profile_init_cpu(cpu); if (ret) break; } return ret; } /* interrupts must be disabled */ static struct ftrace_profile * ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip) { struct ftrace_profile *rec; struct hlist_head *hhd; struct hlist_node *n; unsigned long key; key = hash_long(ip, ftrace_profile_bits); hhd = &stat->hash[key]; if (hlist_empty(hhd)) return NULL; hlist_for_each_entry_rcu(rec, n, hhd, node) { if (rec->ip == ip) return rec; } return NULL; } static void ftrace_add_profile(struct ftrace_profile_stat *stat, struct ftrace_profile *rec) { unsigned long key; key = hash_long(rec->ip, ftrace_profile_bits); hlist_add_head_rcu(&rec->node, &stat->hash[key]); } /* * The memory is already allocated, this simply finds a new record to use. */ static struct ftrace_profile * ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip) { struct ftrace_profile *rec = NULL; /* prevent recursion (from NMIs) */ if (atomic_inc_return(&stat->disabled) != 1) goto out; /* * Try to find the function again since an NMI * could have added it */ rec = ftrace_find_profiled_func(stat, ip); if (rec) goto out; if (stat->pages->index == PROFILES_PER_PAGE) { if (!stat->pages->next) goto out; stat->pages = stat->pages->next; } rec = &stat->pages->records[stat->pages->index++]; rec->ip = ip; ftrace_add_profile(stat, rec); out: atomic_dec(&stat->disabled); return rec; } static void function_profile_call(unsigned long ip, unsigned long parent_ip) { struct ftrace_profile_stat *stat; struct ftrace_profile *rec; unsigned long flags; if (!ftrace_profile_enabled) return; local_irq_save(flags); stat = &__get_cpu_var(ftrace_profile_stats); if (!stat->hash || !ftrace_profile_enabled) goto out; rec = ftrace_find_profiled_func(stat, ip); if (!rec) { rec = ftrace_profile_alloc(stat, ip); if (!rec) goto out; } rec->counter++; out: local_irq_restore(flags); } #ifdef CONFIG_FUNCTION_GRAPH_TRACER static int profile_graph_entry(struct ftrace_graph_ent *trace) { function_profile_call(trace->func, 0); return 1; } static void profile_graph_return(struct ftrace_graph_ret *trace) { struct ftrace_profile_stat *stat; unsigned long long calltime; struct ftrace_profile *rec; unsigned long flags; local_irq_save(flags); stat = &__get_cpu_var(ftrace_profile_stats); if (!stat->hash || !ftrace_profile_enabled) goto out; calltime = trace->rettime - trace->calltime; if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) { int index; index = trace->depth; /* Append this call time to the parent time to subtract */ if (index) current->ret_stack[index - 1].subtime += calltime; if (current->ret_stack[index].subtime < calltime) calltime -= current->ret_stack[index].subtime; else calltime = 0; } rec = ftrace_find_profiled_func(stat, trace->func); if (rec) rec->time += calltime; out: local_irq_restore(flags); } static int register_ftrace_profiler(void) { return register_ftrace_graph(&profile_graph_return, &profile_graph_entry); } static void unregister_ftrace_profiler(void) { unregister_ftrace_graph(); } #else static struct ftrace_ops ftrace_profile_ops __read_mostly = { .func = function_profile_call, }; static int register_ftrace_profiler(void) { return register_ftrace_function(&ftrace_profile_ops); } static void unregister_ftrace_profiler(void) { unregister_ftrace_function(&ftrace_profile_ops); } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ static ssize_t ftrace_profile_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { unsigned long val; char buf[64]; /* big enough to hold a number */ int ret; if (cnt >= sizeof(buf)) return -EINVAL; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; buf[cnt] = 0; ret = strict_strtoul(buf, 10, &val); if (ret < 0) return ret; val = !!val; mutex_lock(&ftrace_profile_lock); if (ftrace_profile_enabled ^ val) { if (val) { ret = ftrace_profile_init(); if (ret < 0) { cnt = ret; goto out; } ret = register_ftrace_profiler(); if (ret < 0) { cnt = ret; goto out; } ftrace_profile_enabled = 1; } else { ftrace_profile_enabled = 0; /* * unregister_ftrace_profiler calls stop_machine * so this acts like an synchronize_sched. */ unregister_ftrace_profiler(); } } out: mutex_unlock(&ftrace_profile_lock); *ppos += cnt; return cnt; } static ssize_t ftrace_profile_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[64]; /* big enough to hold a number */ int r; r = sprintf(buf, "%u\n", ftrace_profile_enabled); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } static const struct file_operations ftrace_profile_fops = { .open = tracing_open_generic, .read = ftrace_profile_read, .write = ftrace_profile_write, }; /* used to initialize the real stat files */ static struct tracer_stat function_stats __initdata = { .name = "functions", .stat_start = function_stat_start, .stat_next = function_stat_next, .stat_cmp = function_stat_cmp, .stat_headers = function_stat_headers, .stat_show = function_stat_show }; static __init void ftrace_profile_debugfs(struct dentry *d_tracer) { struct ftrace_profile_stat *stat; struct dentry *entry; char *name; int ret; int cpu; for_each_possible_cpu(cpu) { stat = &per_cpu(ftrace_profile_stats, cpu); /* allocate enough for function name + cpu number */ name = kmalloc(32, GFP_KERNEL); if (!name) { /* * The files created are permanent, if something happens * we still do not free memory. */ WARN(1, "Could not allocate stat file for cpu %d\n", cpu); return; } stat->stat = function_stats; snprintf(name, 32, "function%d", cpu); stat->stat.name = name; ret = register_stat_tracer(&stat->stat); if (ret) { WARN(1, "Could not register function stat for cpu %d\n", cpu); kfree(name); return; } } entry = debugfs_create_file("function_profile_enabled", 0644, d_tracer, NULL, &ftrace_profile_fops); if (!entry) pr_warning("Could not create debugfs " "'function_profile_enabled' entry\n"); } #else /* CONFIG_FUNCTION_PROFILER */ static __init void ftrace_profile_debugfs(struct dentry *d_tracer) { } #endif /* CONFIG_FUNCTION_PROFILER */ static struct pid * const ftrace_swapper_pid = &init_struct_pid; #ifdef CONFIG_DYNAMIC_FTRACE #ifndef CONFIG_FTRACE_MCOUNT_RECORD # error Dynamic ftrace depends on MCOUNT_RECORD #endif static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly; struct ftrace_func_probe { struct hlist_node node; struct ftrace_probe_ops *ops; unsigned long flags; unsigned long ip; void *data; struct rcu_head rcu; }; enum { FTRACE_ENABLE_CALLS = (1 << 0), FTRACE_DISABLE_CALLS = (1 << 1), FTRACE_UPDATE_TRACE_FUNC = (1 << 2), FTRACE_ENABLE_MCOUNT = (1 << 3), FTRACE_DISABLE_MCOUNT = (1 << 4), FTRACE_START_FUNC_RET = (1 << 5), FTRACE_STOP_FUNC_RET = (1 << 6), }; static int ftrace_filtered; static struct dyn_ftrace *ftrace_new_addrs; static DEFINE_MUTEX(ftrace_regex_lock); struct ftrace_page { struct ftrace_page *next; int index; struct dyn_ftrace records[]; }; #define ENTRIES_PER_PAGE \ ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace)) /* estimate from running different kernels */ #define NR_TO_INIT 10000 static struct ftrace_page *ftrace_pages_start; static struct ftrace_page *ftrace_pages; static struct dyn_ftrace *ftrace_free_records; /* * This is a double for. Do not use 'break' to break out of the loop, * you must use a goto. */ #define do_for_each_ftrace_rec(pg, rec) \ for (pg = ftrace_pages_start; pg; pg = pg->next) { \ int _____i; \ for (_____i = 0; _____i < pg->index; _____i++) { \ rec = &pg->records[_____i]; #define while_for_each_ftrace_rec() \ } \ } static void ftrace_free_rec(struct dyn_ftrace *rec) { rec->freelist = ftrace_free_records; ftrace_free_records = rec; rec->flags |= FTRACE_FL_FREE; } static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip) { struct dyn_ftrace *rec; /* First check for freed records */ if (ftrace_free_records) { rec = ftrace_free_records; if (unlikely(!(rec->flags & FTRACE_FL_FREE))) { FTRACE_WARN_ON_ONCE(1); ftrace_free_records = NULL; return NULL; } ftrace_free_records = rec->freelist; memset(rec, 0, sizeof(*rec)); return rec; } if (ftrace_pages->index == ENTRIES_PER_PAGE) { if (!ftrace_pages->next) { /* allocate another page */ ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL); if (!ftrace_pages->next) return NULL; } ftrace_pages = ftrace_pages->next; } return &ftrace_pages->records[ftrace_pages->index++]; } static struct dyn_ftrace * ftrace_record_ip(unsigned long ip) { struct dyn_ftrace *rec; if (ftrace_disabled) return NULL; rec = ftrace_alloc_dyn_node(ip); if (!rec) return NULL; rec->ip = ip; rec->newlist = ftrace_new_addrs; ftrace_new_addrs = rec; return rec; } static void print_ip_ins(const char *fmt, unsigned char *p) { int i; printk(KERN_CONT "%s", fmt); for (i = 0; i < MCOUNT_INSN_SIZE; i++) printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]); } static void ftrace_bug(int failed, unsigned long ip) { switch (failed) { case -EFAULT: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace faulted on modifying "); print_ip_sym(ip); break; case -EINVAL: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace failed to modify "); print_ip_sym(ip); print_ip_ins(" actual: ", (unsigned char *)ip); printk(KERN_CONT "\n"); break; case -EPERM: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace faulted on writing "); print_ip_sym(ip); break; default: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace faulted on unknown error "); print_ip_sym(ip); } } /* Return 1 if the address range is reserved for ftrace */ int ftrace_text_reserved(void *start, void *end) { struct dyn_ftrace *rec; struct ftrace_page *pg; do_for_each_ftrace_rec(pg, rec) { if (rec->ip <= (unsigned long)end && rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start) return 1; } while_for_each_ftrace_rec(); return 0; } static int __ftrace_replace_code(struct dyn_ftrace *rec, int enable) { unsigned long ftrace_addr; unsigned long flag = 0UL; ftrace_addr = (unsigned long)FTRACE_ADDR; /* * If this record is not to be traced or we want to disable it, * then disable it. * * If we want to enable it and filtering is off, then enable it. * * If we want to enable it and filtering is on, enable it only if * it's filtered */ if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) { if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER)) flag = FTRACE_FL_ENABLED; } /* If the state of this record hasn't changed, then do nothing */ if ((rec->flags & FTRACE_FL_ENABLED) == flag) return 0; if (flag) { rec->flags |= FTRACE_FL_ENABLED; return ftrace_make_call(rec, ftrace_addr); } rec->flags &= ~FTRACE_FL_ENABLED; return ftrace_make_nop(NULL, rec, ftrace_addr); } static void ftrace_replace_code(int enable) { struct dyn_ftrace *rec; struct ftrace_page *pg; int failed; do_for_each_ftrace_rec(pg, rec) { /* * Skip over free records, records that have * failed and not converted. */ if (rec->flags & FTRACE_FL_FREE || rec->flags & FTRACE_FL_FAILED || !(rec->flags & FTRACE_FL_CONVERTED)) continue; failed = __ftrace_replace_code(rec, enable); if (failed) { rec->flags |= FTRACE_FL_FAILED; ftrace_bug(failed, rec->ip); /* Stop processing */ return; } } while_for_each_ftrace_rec(); } static int ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec) { unsigned long ip; int ret; ip = rec->ip; ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR); if (ret) { ftrace_bug(ret, ip); rec->flags |= FTRACE_FL_FAILED; return 0; } return 1; } /* * archs can override this function if they must do something * before the modifying code is performed. */ int __weak ftrace_arch_code_modify_prepare(void) { return 0; } /* * archs can override this function if they must do something * after the modifying code is performed. */ int __weak ftrace_arch_code_modify_post_process(void) { return 0; } static int __ftrace_modify_code(void *data) { int *command = data; if (*command & FTRACE_ENABLE_CALLS) ftrace_replace_code(1); else if (*command & FTRACE_DISABLE_CALLS) ftrace_replace_code(0); if (*command & FTRACE_UPDATE_TRACE_FUNC) ftrace_update_ftrace_func(ftrace_trace_function); if (*command & FTRACE_START_FUNC_RET) ftrace_enable_ftrace_graph_caller(); else if (*command & FTRACE_STOP_FUNC_RET) ftrace_disable_ftrace_graph_caller(); return 0; } static void ftrace_run_update_code(int command) { int ret; ret = ftrace_arch_code_modify_prepare(); FTRACE_WARN_ON(ret); if (ret) return; stop_machine(__ftrace_modify_code, &command, NULL); ret = ftrace_arch_code_modify_post_process(); FTRACE_WARN_ON(ret); } static ftrace_func_t saved_ftrace_func; static int ftrace_start_up; static void ftrace_startup_enable(int command) { if (saved_ftrace_func != ftrace_trace_function) { saved_ftrace_func = ftrace_trace_function; command |= FTRACE_UPDATE_TRACE_FUNC; } if (!command || !ftrace_enabled) return; ftrace_run_update_code(command); } static void ftrace_startup(int command) { if (unlikely(ftrace_disabled)) return; ftrace_start_up++; command |= FTRACE_ENABLE_CALLS; ftrace_startup_enable(command); } static void ftrace_shutdown(int command) { if (unlikely(ftrace_disabled)) return; ftrace_start_up--; /* * Just warn in case of unbalance, no need to kill ftrace, it's not * critical but the ftrace_call callers may be never nopped again after * further ftrace uses. */ WARN_ON_ONCE(ftrace_start_up < 0); if (!ftrace_start_up) command |= FTRACE_DISABLE_CALLS; if (saved_ftrace_func != ftrace_trace_function) { saved_ftrace_func = ftrace_trace_function; command |= FTRACE_UPDATE_TRACE_FUNC; } if (!command || !ftrace_enabled) return; ftrace_run_update_code(command); } static void ftrace_startup_sysctl(void) { int command = FTRACE_ENABLE_MCOUNT; if (unlikely(ftrace_disabled)) return; /* Force update next time */ saved_ftrace_func = NULL; /* ftrace_start_up is true if we want ftrace running */ if (ftrace_start_up) command |= FTRACE_ENABLE_CALLS; ftrace_run_update_code(command); } static void ftrace_shutdown_sysctl(void) { int command = FTRACE_DISABLE_MCOUNT; if (unlikely(ftrace_disabled)) return; /* ftrace_start_up is true if ftrace is running */ if (ftrace_start_up) command |= FTRACE_DISABLE_CALLS; ftrace_run_update_code(command); } static cycle_t ftrace_update_time; static unsigned long ftrace_update_cnt; unsigned long ftrace_update_tot_cnt; static int ftrace_update_code(struct module *mod) { struct dyn_ftrace *p; cycle_t start, stop; start = ftrace_now(raw_smp_processor_id()); ftrace_update_cnt = 0; while (ftrace_new_addrs) { /* If something went wrong, bail without enabling anything */ if (unlikely(ftrace_disabled)) return -1; p = ftrace_new_addrs; ftrace_new_addrs = p->newlist; p->flags = 0L; /* * Do the initial record convertion from mcount jump * to the NOP instructions. */ if (!ftrace_code_disable(mod, p)) { ftrace_free_rec(p); continue; } p->flags |= FTRACE_FL_CONVERTED; ftrace_update_cnt++; /* * If the tracing is enabled, go ahead and enable the record. * * The reason not to enable the record immediatelly is the * inherent check of ftrace_make_nop/ftrace_make_call for * correct previous instructions. Making first the NOP * conversion puts the module to the correct state, thus * passing the ftrace_make_call check. */ if (ftrace_start_up) { int failed = __ftrace_replace_code(p, 1); if (failed) { ftrace_bug(failed, p->ip); ftrace_free_rec(p); } } } stop = ftrace_now(raw_smp_processor_id()); ftrace_update_time = stop - start; ftrace_update_tot_cnt += ftrace_update_cnt; return 0; } static int __init ftrace_dyn_table_alloc(unsigned long num_to_init) { struct ftrace_page *pg; int cnt; int i; /* allocate a few pages */ ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL); if (!ftrace_pages_start) return -1; /* * Allocate a few more pages. * * TODO: have some parser search vmlinux before * final linking to find all calls to ftrace. * Then we can: * a) know how many pages to allocate. * and/or * b) set up the table then. * * The dynamic code is still necessary for * modules. */ pg = ftrace_pages = ftrace_pages_start; cnt = num_to_init / ENTRIES_PER_PAGE; pr_info("ftrace: allocating %ld entries in %d pages\n", num_to_init, cnt + 1); for (i = 0; i < cnt; i++) { pg->next = (void *)get_zeroed_page(GFP_KERNEL); /* If we fail, we'll try later anyway */ if (!pg->next) break; pg = pg->next; } return 0; } enum { FTRACE_ITER_FILTER = (1 << 0), FTRACE_ITER_NOTRACE = (1 << 1), FTRACE_ITER_FAILURES = (1 << 2), FTRACE_ITER_PRINTALL = (1 << 3), FTRACE_ITER_HASH = (1 << 4), }; #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ struct ftrace_iterator { struct ftrace_page *pg; int hidx; int idx; unsigned flags; struct trace_parser parser; }; static void * t_hash_next(struct seq_file *m, void *v, loff_t *pos) { struct ftrace_iterator *iter = m->private; struct hlist_node *hnd = v; struct hlist_head *hhd; WARN_ON(!(iter->flags & FTRACE_ITER_HASH)); (*pos)++; retry: if (iter->hidx >= FTRACE_FUNC_HASHSIZE) return NULL; hhd = &ftrace_func_hash[iter->hidx]; if (hlist_empty(hhd)) { iter->hidx++; hnd = NULL; goto retry; } if (!hnd) hnd = hhd->first; else { hnd = hnd->next; if (!hnd) { iter->hidx++; goto retry; } } return hnd; } static void *t_hash_start(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; void *p = NULL; loff_t l; if (!(iter->flags & FTRACE_ITER_HASH)) *pos = 0; iter->flags |= FTRACE_ITER_HASH; iter->hidx = 0; for (l = 0; l <= *pos; ) { p = t_hash_next(m, p, &l); if (!p) break; } return p; } static int t_hash_show(struct seq_file *m, void *v) { struct ftrace_func_probe *rec; struct hlist_node *hnd = v; rec = hlist_entry(hnd, struct ftrace_func_probe, node); if (rec->ops->print) return rec->ops->print(m, rec->ip, rec->ops, rec->data); seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func); if (rec->data) seq_printf(m, ":%p", rec->data); seq_putc(m, '\n'); return 0; } static void * t_next(struct seq_file *m, void *v, loff_t *pos) { struct ftrace_iterator *iter = m->private; struct dyn_ftrace *rec = NULL; if (iter->flags & FTRACE_ITER_HASH) return t_hash_next(m, v, pos); (*pos)++; if (iter->flags & FTRACE_ITER_PRINTALL) return NULL; retry: if (iter->idx >= iter->pg->index) { if (iter->pg->next) { iter->pg = iter->pg->next; iter->idx = 0; goto retry; } } else { rec = &iter->pg->records[iter->idx++]; if ((rec->flags & FTRACE_FL_FREE) || (!(iter->flags & FTRACE_ITER_FAILURES) && (rec->flags & FTRACE_FL_FAILED)) || ((iter->flags & FTRACE_ITER_FAILURES) && !(rec->flags & FTRACE_FL_FAILED)) || ((iter->flags & FTRACE_ITER_FILTER) && !(rec->flags & FTRACE_FL_FILTER)) || ((iter->flags & FTRACE_ITER_NOTRACE) && !(rec->flags & FTRACE_FL_NOTRACE))) { rec = NULL; goto retry; } } return rec; } static void *t_start(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; void *p = NULL; loff_t l; mutex_lock(&ftrace_lock); /* * For set_ftrace_filter reading, if we have the filter * off, we can short cut and just print out that all * functions are enabled. */ if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) { if (*pos > 0) return t_hash_start(m, pos); iter->flags |= FTRACE_ITER_PRINTALL; return iter; } if (iter->flags & FTRACE_ITER_HASH) return t_hash_start(m, pos); iter->pg = ftrace_pages_start; iter->idx = 0; for (l = 0; l <= *pos; ) { p = t_next(m, p, &l); if (!p) break; } if (!p && iter->flags & FTRACE_ITER_FILTER) return t_hash_start(m, pos); return p; } static void t_stop(struct seq_file *m, void *p) { mutex_unlock(&ftrace_lock); } static int t_show(struct seq_file *m, void *v) { struct ftrace_iterator *iter = m->private; struct dyn_ftrace *rec = v; if (iter->flags & FTRACE_ITER_HASH) return t_hash_show(m, v); if (iter->flags & FTRACE_ITER_PRINTALL) { seq_printf(m, "#### all functions enabled ####\n"); return 0; } if (!rec) return 0; seq_printf(m, "%ps\n", (void *)rec->ip); return 0; } static const struct seq_operations show_ftrace_seq_ops = { .start = t_start, .next = t_next, .stop = t_stop, .show = t_show, }; static int ftrace_avail_open(struct inode *inode, struct file *file) { struct ftrace_iterator *iter; int ret; if (unlikely(ftrace_disabled)) return -ENODEV; iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) return -ENOMEM; iter->pg = ftrace_pages_start; ret = seq_open(file, &show_ftrace_seq_ops); if (!ret) { struct seq_file *m = file->private_data; m->private = iter; } else { kfree(iter); } return ret; } static int ftrace_failures_open(struct inode *inode, struct file *file) { int ret; struct seq_file *m; struct ftrace_iterator *iter; ret = ftrace_avail_open(inode, file); if (!ret) { m = (struct seq_file *)file->private_data; iter = (struct ftrace_iterator *)m->private; iter->flags = FTRACE_ITER_FAILURES; } return ret; } static void ftrace_filter_reset(int enable) { struct ftrace_page *pg; struct dyn_ftrace *rec; unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE; mutex_lock(&ftrace_lock); if (enable) ftrace_filtered = 0; do_for_each_ftrace_rec(pg, rec) { if (rec->flags & FTRACE_FL_FAILED) continue; rec->flags &= ~type; } while_for_each_ftrace_rec(); mutex_unlock(&ftrace_lock); } static int ftrace_regex_open(struct inode *inode, struct file *file, int enable) { struct ftrace_iterator *iter; int ret = 0; if (unlikely(ftrace_disabled)) return -ENODEV; iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) return -ENOMEM; if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) { kfree(iter); return -ENOMEM; } mutex_lock(&ftrace_regex_lock); if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) ftrace_filter_reset(enable); if (file->f_mode & FMODE_READ) { iter->pg = ftrace_pages_start; iter->flags = enable ? FTRACE_ITER_FILTER : FTRACE_ITER_NOTRACE; ret = seq_open(file, &show_ftrace_seq_ops); if (!ret) { struct seq_file *m = file->private_data; m->private = iter; } else { trace_parser_put(&iter->parser); kfree(iter); } } else file->private_data = iter; mutex_unlock(&ftrace_regex_lock); return ret; } static int ftrace_filter_open(struct inode *inode, struct file *file) { return ftrace_regex_open(inode, file, 1); } static int ftrace_notrace_open(struct inode *inode, struct file *file) { return ftrace_regex_open(inode, file, 0); } static loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int origin) { loff_t ret; if (file->f_mode & FMODE_READ) ret = seq_lseek(file, offset, origin); else file->f_pos = ret = 1; return ret; } static int ftrace_match(char *str, char *regex, int len, int type) { int matched = 0; int slen; switch (type) { case MATCH_FULL: if (strcmp(str, regex) == 0) matched = 1; break; case MATCH_FRONT_ONLY: if (strncmp(str, regex, len) == 0) matched = 1; break; case MATCH_MIDDLE_ONLY: if (strstr(str, regex)) matched = 1; break; case MATCH_END_ONLY: slen = strlen(str); if (slen >= len && memcmp(str + slen - len, regex, len) == 0) matched = 1; break; } return matched; } static int ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type) { char str[KSYM_SYMBOL_LEN]; kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); return ftrace_match(str, regex, len, type); } static int ftrace_match_records(char *buff, int len, int enable) { unsigned int search_len; struct ftrace_page *pg; struct dyn_ftrace *rec; unsigned long flag; char *search; int type; int not; int found = 0; flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE; type = filter_parse_regex(buff, len, &search, ¬); search_len = strlen(search); mutex_lock(&ftrace_lock); do_for_each_ftrace_rec(pg, rec) { if (rec->flags & FTRACE_FL_FAILED) continue; if (ftrace_match_record(rec, search, search_len, type)) { if (not) rec->flags &= ~flag; else rec->flags |= flag; found = 1; } /* * Only enable filtering if we have a function that * is filtered on. */ if (enable && (rec->flags & FTRACE_FL_FILTER)) ftrace_filtered = 1; } while_for_each_ftrace_rec(); mutex_unlock(&ftrace_lock); return found; } static int ftrace_match_module_record(struct dyn_ftrace *rec, char *mod, char *regex, int len, int type) { char str[KSYM_SYMBOL_LEN]; char *modname; kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); if (!modname || strcmp(modname, mod)) return 0; /* blank search means to match all funcs in the mod */ if (len) return ftrace_match(str, regex, len, type); else return 1; } static int ftrace_match_module_records(char *buff, char *mod, int enable) { unsigned search_len = 0; struct ftrace_page *pg; struct dyn_ftrace *rec; int type = MATCH_FULL; char *search = buff; unsigned long flag; int not = 0; int found = 0; flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE; /* blank or '*' mean the same */ if (strcmp(buff, "*") == 0) buff[0] = 0; /* handle the case of 'dont filter this module' */ if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) { buff[0] = 0; not = 1; } if (strlen(buff)) { type = filter_parse_regex(buff, strlen(buff), &search, ¬); search_len = strlen(search); } mutex_lock(&ftrace_lock); do_for_each_ftrace_rec(pg, rec) { if (rec->flags & FTRACE_FL_FAILED) continue; if (ftrace_match_module_record(rec, mod, search, search_len, type)) { if (not) rec->flags &= ~flag; else rec->flags |= flag; found = 1; } if (enable && (rec->flags & FTRACE_FL_FILTER)) ftrace_filtered = 1; } while_for_each_ftrace_rec(); mutex_unlock(&ftrace_lock); return found; } /* * We register the module command as a template to show others how * to register the a command as well. */ static int ftrace_mod_callback(char *func, char *cmd, char *param, int enable) { char *mod; /* * cmd == 'mod' because we only registered this func * for the 'mod' ftrace_func_command. * But if you register one func with multiple commands, * you can tell which command was used by the cmd * parameter. */ /* we must have a module name */ if (!param) return -EINVAL; mod = strsep(¶m, ":"); if (!strlen(mod)) return -EINVAL; if (ftrace_match_module_records(func, mod, enable)) return 0; return -EINVAL; } static struct ftrace_func_command ftrace_mod_cmd = { .name = "mod", .func = ftrace_mod_callback, }; static int __init ftrace_mod_cmd_init(void) { return register_ftrace_command(&ftrace_mod_cmd); } device_initcall(ftrace_mod_cmd_init); static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip) { struct ftrace_func_probe *entry; struct hlist_head *hhd; struct hlist_node *n; unsigned long key; int resched; key = hash_long(ip, FTRACE_HASH_BITS); hhd = &ftrace_func_hash[key]; if (hlist_empty(hhd)) return; /* * Disable preemption for these calls to prevent a RCU grace * period. This syncs the hash iteration and freeing of items * on the hash. rcu_read_lock is too dangerous here. */ resched = ftrace_preempt_disable(); hlist_for_each_entry_rcu(entry, n, hhd, node) { if (entry->ip == ip) entry->ops->func(ip, parent_ip, &entry->data); } ftrace_preempt_enable(resched); } static struct ftrace_ops trace_probe_ops __read_mostly = { .func = function_trace_probe_call, }; static int ftrace_probe_registered; static void __enable_ftrace_function_probe(void) { int i; if (ftrace_probe_registered) return; for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) { struct hlist_head *hhd = &ftrace_func_hash[i]; if (hhd->first) break; } /* Nothing registered? */ if (i == FTRACE_FUNC_HASHSIZE) return; __register_ftrace_function(&trace_probe_ops); ftrace_startup(0); ftrace_probe_registered = 1; } static void __disable_ftrace_function_probe(void) { int i; if (!ftrace_probe_registered) return; for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) { struct hlist_head *hhd = &ftrace_func_hash[i]; if (hhd->first) return; } /* no more funcs left */ __unregister_ftrace_function(&trace_probe_ops); ftrace_shutdown(0); ftrace_probe_registered = 0; } static void ftrace_free_entry_rcu(struct rcu_head *rhp) { struct ftrace_func_probe *entry = container_of(rhp, struct ftrace_func_probe, rcu); if (entry->ops->free) entry->ops->free(&entry->data); kfree(entry); } int register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, void *data) { struct ftrace_func_probe *entry; struct ftrace_page *pg; struct dyn_ftrace *rec; int type, len, not; unsigned long key; int count = 0; char *search; type = filter_parse_regex(glob, strlen(glob), &search, ¬); len = strlen(search); /* we do not support '!' for function probes */ if (WARN_ON(not)) return -EINVAL; mutex_lock(&ftrace_lock); do_for_each_ftrace_rec(pg, rec) { if (rec->flags & FTRACE_FL_FAILED) continue; if (!ftrace_match_record(rec, search, len, type)) continue; entry = kmalloc(sizeof(*entry), GFP_KERNEL); if (!entry) { /* If we did not process any, then return error */ if (!count) count = -ENOMEM; goto out_unlock; } count++; entry->data = data; /* * The caller might want to do something special * for each function we find. We call the callback * to give the caller an opportunity to do so. */ if (ops->callback) { if (ops->callback(rec->ip, &entry->data) < 0) { /* caller does not like this func */ kfree(entry); continue; } } entry->ops = ops; entry->ip = rec->ip; key = hash_long(entry->ip, FTRACE_HASH_BITS); hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]); } while_for_each_ftrace_rec(); __enable_ftrace_function_probe(); out_unlock: mutex_unlock(&ftrace_lock); return count; } enum { PROBE_TEST_FUNC = 1, PROBE_TEST_DATA = 2 }; static void __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, void *data, int flags) { struct ftrace_func_probe *entry; struct hlist_node *n, *tmp; char str[KSYM_SYMBOL_LEN]; int type = MATCH_FULL; int i, len = 0; char *search; if (glob && (strcmp(glob, "*") == 0 || !strlen(glob))) glob = NULL; else if (glob) { int not; type = filter_parse_regex(glob, strlen(glob), &search, ¬); len = strlen(search); /* we do not support '!' for function probes */ if (WARN_ON(not)) return; } mutex_lock(&ftrace_lock); for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) { struct hlist_head *hhd = &ftrace_func_hash[i]; hlist_for_each_entry_safe(entry, n, tmp, hhd, node) { /* break up if statements for readability */ if ((flags & PROBE_TEST_FUNC) && entry->ops != ops) continue; if ((flags & PROBE_TEST_DATA) && entry->data != data) continue; /* do this last, since it is the most expensive */ if (glob) { kallsyms_lookup(entry->ip, NULL, NULL, NULL, str); if (!ftrace_match(str, glob, len, type)) continue; } hlist_del(&entry->node); call_rcu(&entry->rcu, ftrace_free_entry_rcu); } } __disable_ftrace_function_probe(); mutex_unlock(&ftrace_lock); } void unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, void *data) { __unregister_ftrace_function_probe(glob, ops, data, PROBE_TEST_FUNC | PROBE_TEST_DATA); } void unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops) { __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC); } void unregister_ftrace_function_probe_all(char *glob) { __unregister_ftrace_function_probe(glob, NULL, NULL, 0); } static LIST_HEAD(ftrace_commands); static DEFINE_MUTEX(ftrace_cmd_mutex); int register_ftrace_command(struct ftrace_func_command *cmd) { struct ftrace_func_command *p; int ret = 0; mutex_lock(&ftrace_cmd_mutex); list_for_each_entry(p, &ftrace_commands, list) { if (strcmp(cmd->name, p->name) == 0) { ret = -EBUSY; goto out_unlock; } } list_add(&cmd->list, &ftrace_commands); out_unlock: mutex_unlock(&ftrace_cmd_mutex); return ret; } int unregister_ftrace_command(struct ftrace_func_command *cmd) { struct ftrace_func_command *p, *n; int ret = -ENODEV; mutex_lock(&ftrace_cmd_mutex); list_for_each_entry_safe(p, n, &ftrace_commands, list) { if (strcmp(cmd->name, p->name) == 0) { ret = 0; list_del_init(&p->list); goto out_unlock; } } out_unlock: mutex_unlock(&ftrace_cmd_mutex); return ret; } static int ftrace_process_regex(char *buff, int len, int enable) { char *func, *command, *next = buff; struct ftrace_func_command *p; int ret = -EINVAL; func = strsep(&next, ":"); if (!next) { if (ftrace_match_records(func, len, enable)) return 0; return ret; } /* command found */ command = strsep(&next, ":"); mutex_lock(&ftrace_cmd_mutex); list_for_each_entry(p, &ftrace_commands, list) { if (strcmp(p->name, command) == 0) { ret = p->func(func, command, next, enable); goto out_unlock; } } out_unlock: mutex_unlock(&ftrace_cmd_mutex); return ret; } static ssize_t ftrace_regex_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos, int enable) { struct ftrace_iterator *iter; struct trace_parser *parser; ssize_t ret, read; if (!cnt) return 0; mutex_lock(&ftrace_regex_lock); if (file->f_mode & FMODE_READ) { struct seq_file *m = file->private_data; iter = m->private; } else iter = file->private_data; parser = &iter->parser; read = trace_get_user(parser, ubuf, cnt, ppos); if (read >= 0 && trace_parser_loaded(parser) && !trace_parser_cont(parser)) { ret = ftrace_process_regex(parser->buffer, parser->idx, enable); trace_parser_clear(parser); if (ret) goto out_unlock; } ret = read; out_unlock: mutex_unlock(&ftrace_regex_lock); return ret; } static ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { return ftrace_regex_write(file, ubuf, cnt, ppos, 1); } static ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { return ftrace_regex_write(file, ubuf, cnt, ppos, 0); } static void ftrace_set_regex(unsigned char *buf, int len, int reset, int enable) { if (unlikely(ftrace_disabled)) return; mutex_lock(&ftrace_regex_lock); if (reset) ftrace_filter_reset(enable); if (buf) ftrace_match_records(buf, len, enable); mutex_unlock(&ftrace_regex_lock); } /** * ftrace_set_filter - set a function to filter on in ftrace * @buf - the string that holds the function filter text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. * * Filters denote which functions should be enabled when tracing is enabled. * If @buf is NULL and reset is set, all functions will be enabled for tracing. */ void ftrace_set_filter(unsigned char *buf, int len, int reset) { ftrace_set_regex(buf, len, reset, 1); } /** * ftrace_set_notrace - set a function to not trace in ftrace * @buf - the string that holds the function notrace text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. * * Notrace Filters denote which functions should not be enabled when tracing * is enabled. If @buf is NULL and reset is set, all functions will be enabled * for tracing. */ void ftrace_set_notrace(unsigned char *buf, int len, int reset) { ftrace_set_regex(buf, len, reset, 0); } /* * command line interface to allow users to set filters on boot up. */ #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata; static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata; static int __init set_ftrace_notrace(char *str) { strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_notrace=", set_ftrace_notrace); static int __init set_ftrace_filter(char *str) { strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_filter=", set_ftrace_filter); #ifdef CONFIG_FUNCTION_GRAPH_TRACER static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; static int ftrace_set_func(unsigned long *array, int *idx, char *buffer); static int __init set_graph_function(char *str) { strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_graph_filter=", set_graph_function); static void __init set_ftrace_early_graph(char *buf) { int ret; char *func; while (buf) { func = strsep(&buf, ","); /* we allow only one expression at a time */ ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count, func); if (ret) printk(KERN_DEBUG "ftrace: function %s not " "traceable\n", func); } } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ static void __init set_ftrace_early_filter(char *buf, int enable) { char *func; while (buf) { func = strsep(&buf, ","); ftrace_set_regex(func, strlen(func), 0, enable); } } static void __init set_ftrace_early_filters(void) { if (ftrace_filter_buf[0]) set_ftrace_early_filter(ftrace_filter_buf, 1); if (ftrace_notrace_buf[0]) set_ftrace_early_filter(ftrace_notrace_buf, 0); #ifdef CONFIG_FUNCTION_GRAPH_TRACER if (ftrace_graph_buf[0]) set_ftrace_early_graph(ftrace_graph_buf); #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ } static int ftrace_regex_release(struct inode *inode, struct file *file, int enable) { struct seq_file *m = (struct seq_file *)file->private_data; struct ftrace_iterator *iter; struct trace_parser *parser; mutex_lock(&ftrace_regex_lock); if (file->f_mode & FMODE_READ) { iter = m->private; seq_release(inode, file); } else iter = file->private_data; parser = &iter->parser; if (trace_parser_loaded(parser)) { parser->buffer[parser->idx] = 0; ftrace_match_records(parser->buffer, parser->idx, enable); } mutex_lock(&ftrace_lock); if (ftrace_start_up && ftrace_enabled) ftrace_run_update_code(FTRACE_ENABLE_CALLS); mutex_unlock(&ftrace_lock); trace_parser_put(parser); kfree(iter); mutex_unlock(&ftrace_regex_lock); return 0; } static int ftrace_filter_release(struct inode *inode, struct file *file) { return ftrace_regex_release(inode, file, 1); } static int ftrace_notrace_release(struct inode *inode, struct file *file) { return ftrace_regex_release(inode, file, 0); } static const struct file_operations ftrace_avail_fops = { .open = ftrace_avail_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_private, }; static const struct file_operations ftrace_failures_fops = { .open = ftrace_failures_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_private, }; static const struct file_operations ftrace_filter_fops = { .open = ftrace_filter_open, .read = seq_read, .write = ftrace_filter_write, .llseek = ftrace_regex_lseek, .release = ftrace_filter_release, }; static const struct file_operations ftrace_notrace_fops = { .open = ftrace_notrace_open, .read = seq_read, .write = ftrace_notrace_write, .llseek = ftrace_regex_lseek, .release = ftrace_notrace_release, }; #ifdef CONFIG_FUNCTION_GRAPH_TRACER static DEFINE_MUTEX(graph_lock); int ftrace_graph_count; int ftrace_graph_filter_enabled; unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly; static void * __g_next(struct seq_file *m, loff_t *pos) { if (*pos >= ftrace_graph_count) return NULL; return &ftrace_graph_funcs[*pos]; } static void * g_next(struct seq_file *m, void *v, loff_t *pos) { (*pos)++; return __g_next(m, pos); } static void *g_start(struct seq_file *m, loff_t *pos) { mutex_lock(&graph_lock); /* Nothing, tell g_show to print all functions are enabled */ if (!ftrace_graph_filter_enabled && !*pos) return (void *)1; return __g_next(m, pos); } static void g_stop(struct seq_file *m, void *p) { mutex_unlock(&graph_lock); } static int g_show(struct seq_file *m, void *v) { unsigned long *ptr = v; if (!ptr) return 0; if (ptr == (unsigned long *)1) { seq_printf(m, "#### all functions enabled ####\n"); return 0; } seq_printf(m, "%ps\n", (void *)*ptr); return 0; } static const struct seq_operations ftrace_graph_seq_ops = { .start = g_start, .next = g_next, .stop = g_stop, .show = g_show, }; static int ftrace_graph_open(struct inode *inode, struct file *file) { int ret = 0; if (unlikely(ftrace_disabled)) return -ENODEV; mutex_lock(&graph_lock); if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { ftrace_graph_filter_enabled = 0; ftrace_graph_count = 0; memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs)); } mutex_unlock(&graph_lock); if (file->f_mode & FMODE_READ) ret = seq_open(file, &ftrace_graph_seq_ops); return ret; } static int ftrace_graph_release(struct inode *inode, struct file *file) { if (file->f_mode & FMODE_READ) seq_release(inode, file); return 0; } static int ftrace_set_func(unsigned long *array, int *idx, char *buffer) { struct dyn_ftrace *rec; struct ftrace_page *pg; int search_len; int fail = 1; int type, not; char *search; bool exists; int i; if (ftrace_disabled) return -ENODEV; /* decode regex */ type = filter_parse_regex(buffer, strlen(buffer), &search, ¬); if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS) return -EBUSY; search_len = strlen(search); mutex_lock(&ftrace_lock); do_for_each_ftrace_rec(pg, rec) { if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE)) continue; if (ftrace_match_record(rec, search, search_len, type)) { /* if it is in the array */ exists = false; for (i = 0; i < *idx; i++) { if (array[i] == rec->ip) { exists = true; break; } } if (!not) { fail = 0; if (!exists) { array[(*idx)++] = rec->ip; if (*idx >= FTRACE_GRAPH_MAX_FUNCS) goto out; } } else { if (exists) { array[i] = array[--(*idx)]; array[*idx] = 0; fail = 0; } } } } while_for_each_ftrace_rec(); out: mutex_unlock(&ftrace_lock); if (fail) return -EINVAL; ftrace_graph_filter_enabled = 1; return 0; } static ssize_t ftrace_graph_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_parser parser; ssize_t read, ret; if (!cnt) return 0; mutex_lock(&graph_lock); if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) { ret = -ENOMEM; goto out_unlock; } read = trace_get_user(&parser, ubuf, cnt, ppos); if (read >= 0 && trace_parser_loaded((&parser))) { parser.buffer[parser.idx] = 0; /* we allow only one expression at a time */ ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count, parser.buffer); if (ret) goto out_free; } ret = read; out_free: trace_parser_put(&parser); out_unlock: mutex_unlock(&graph_lock); return ret; } static const struct file_operations ftrace_graph_fops = { .open = ftrace_graph_open, .read = seq_read, .write = ftrace_graph_write, .release = ftrace_graph_release, }; #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { trace_create_file("available_filter_functions", 0444, d_tracer, NULL, &ftrace_avail_fops); trace_create_file("failures", 0444, d_tracer, NULL, &ftrace_failures_fops); trace_create_file("set_ftrace_filter", 0644, d_tracer, NULL, &ftrace_filter_fops); trace_create_file("set_ftrace_notrace", 0644, d_tracer, NULL, &ftrace_notrace_fops); #ifdef CONFIG_FUNCTION_GRAPH_TRACER trace_create_file("set_graph_function", 0444, d_tracer, NULL, &ftrace_graph_fops); #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ return 0; } static int ftrace_process_locs(struct module *mod, unsigned long *start, unsigned long *end) { unsigned long *p; unsigned long addr; unsigned long flags; mutex_lock(&ftrace_lock); p = start; while (p < end) { addr = ftrace_call_adjust(*p++); /* * Some architecture linkers will pad between * the different mcount_loc sections of different * object files to satisfy alignments. * Skip any NULL pointers. */ if (!addr) continue; ftrace_record_ip(addr); } /* disable interrupts to prevent kstop machine */ local_irq_save(flags); ftrace_update_code(mod); local_irq_restore(flags); mutex_unlock(&ftrace_lock); return 0; } #ifdef CONFIG_MODULES void ftrace_release_mod(struct module *mod) { struct dyn_ftrace *rec; struct ftrace_page *pg; if (ftrace_disabled) return; mutex_lock(&ftrace_lock); do_for_each_ftrace_rec(pg, rec) { if (within_module_core(rec->ip, mod)) { /* * rec->ip is changed in ftrace_free_rec() * It should not between s and e if record was freed. */ FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE); ftrace_free_rec(rec); } } while_for_each_ftrace_rec(); mutex_unlock(&ftrace_lock); } static void ftrace_init_module(struct module *mod, unsigned long *start, unsigned long *end) { if (ftrace_disabled || start == end) return; ftrace_process_locs(mod, start, end); } static int ftrace_module_notify(struct notifier_block *self, unsigned long val, void *data) { struct module *mod = data; switch (val) { case MODULE_STATE_COMING: ftrace_init_module(mod, mod->ftrace_callsites, mod->ftrace_callsites + mod->num_ftrace_callsites); break; case MODULE_STATE_GOING: ftrace_release_mod(mod); break; } return 0; } #else static int ftrace_module_notify(struct notifier_block *self, unsigned long val, void *data) { return 0; } #endif /* CONFIG_MODULES */ struct notifier_block ftrace_module_nb = { .notifier_call = ftrace_module_notify, .priority = 0, }; extern unsigned long __start_mcount_loc[]; extern unsigned long __stop_mcount_loc[]; void __init ftrace_init(void) { unsigned long count, addr, flags; int ret; /* Keep the ftrace pointer to the stub */ addr = (unsigned long)ftrace_stub; local_irq_save(flags); ftrace_dyn_arch_init(&addr); local_irq_restore(flags); /* ftrace_dyn_arch_init places the return code in addr */ if (addr) goto failed; count = __stop_mcount_loc - __start_mcount_loc; ret = ftrace_dyn_table_alloc(count); if (ret) goto failed; last_ftrace_enabled = ftrace_enabled = 1; ret = ftrace_process_locs(NULL, __start_mcount_loc, __stop_mcount_loc); ret = register_module_notifier(&ftrace_module_nb); if (ret) pr_warning("Failed to register trace ftrace module notifier\n"); set_ftrace_early_filters(); return; failed: ftrace_disabled = 1; } #else static int __init ftrace_nodyn_init(void) { ftrace_enabled = 1; return 0; } device_initcall(ftrace_nodyn_init); static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; } static inline void ftrace_startup_enable(int command) { } /* Keep as macros so we do not need to define the commands */ # define ftrace_startup(command) do { } while (0) # define ftrace_shutdown(command) do { } while (0) # define ftrace_startup_sysctl() do { } while (0) # define ftrace_shutdown_sysctl() do { } while (0) #endif /* CONFIG_DYNAMIC_FTRACE */ static void clear_ftrace_swapper(void) { struct task_struct *p; int cpu; get_online_cpus(); for_each_online_cpu(cpu) { p = idle_task(cpu); clear_tsk_trace_trace(p); } put_online_cpus(); } static void set_ftrace_swapper(void) { struct task_struct *p; int cpu; get_online_cpus(); for_each_online_cpu(cpu) { p = idle_task(cpu); set_tsk_trace_trace(p); } put_online_cpus(); } static void clear_ftrace_pid(struct pid *pid) { struct task_struct *p; rcu_read_lock(); do_each_pid_task(pid, PIDTYPE_PID, p) { clear_tsk_trace_trace(p); } while_each_pid_task(pid, PIDTYPE_PID, p); rcu_read_unlock(); put_pid(pid); } static void set_ftrace_pid(struct pid *pid) { struct task_struct *p; rcu_read_lock(); do_each_pid_task(pid, PIDTYPE_PID, p) { set_tsk_trace_trace(p); } while_each_pid_task(pid, PIDTYPE_PID, p); rcu_read_unlock(); } static void clear_ftrace_pid_task(struct pid *pid) { if (pid == ftrace_swapper_pid) clear_ftrace_swapper(); else clear_ftrace_pid(pid); } static void set_ftrace_pid_task(struct pid *pid) { if (pid == ftrace_swapper_pid) set_ftrace_swapper(); else set_ftrace_pid(pid); } static int ftrace_pid_add(int p) { struct pid *pid; struct ftrace_pid *fpid; int ret = -EINVAL; mutex_lock(&ftrace_lock); if (!p) pid = ftrace_swapper_pid; else pid = find_get_pid(p); if (!pid) goto out; ret = 0; list_for_each_entry(fpid, &ftrace_pids, list) if (fpid->pid == pid) goto out_put; ret = -ENOMEM; fpid = kmalloc(sizeof(*fpid), GFP_KERNEL); if (!fpid) goto out_put; list_add(&fpid->list, &ftrace_pids); fpid->pid = pid; set_ftrace_pid_task(pid); ftrace_update_pid_func(); ftrace_startup_enable(0); mutex_unlock(&ftrace_lock); return 0; out_put: if (pid != ftrace_swapper_pid) put_pid(pid); out: mutex_unlock(&ftrace_lock); return ret; } static void ftrace_pid_reset(void) { struct ftrace_pid *fpid, *safe; mutex_lock(&ftrace_lock); list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) { struct pid *pid = fpid->pid; clear_ftrace_pid_task(pid); list_del(&fpid->list); kfree(fpid); } ftrace_update_pid_func(); ftrace_startup_enable(0); mutex_unlock(&ftrace_lock); } static void *fpid_start(struct seq_file *m, loff_t *pos) { mutex_lock(&ftrace_lock); if (list_empty(&ftrace_pids) && (!*pos)) return (void *) 1; return seq_list_start(&ftrace_pids, *pos); } static void *fpid_next(struct seq_file *m, void *v, loff_t *pos) { if (v == (void *)1) return NULL; return seq_list_next(v, &ftrace_pids, pos); } static void fpid_stop(struct seq_file *m, void *p) { mutex_unlock(&ftrace_lock); } static int fpid_show(struct seq_file *m, void *v) { const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list); if (v == (void *)1) { seq_printf(m, "no pid\n"); return 0; } if (fpid->pid == ftrace_swapper_pid) seq_printf(m, "swapper tasks\n"); else seq_printf(m, "%u\n", pid_vnr(fpid->pid)); return 0; } static const struct seq_operations ftrace_pid_sops = { .start = fpid_start, .next = fpid_next, .stop = fpid_stop, .show = fpid_show, }; static int ftrace_pid_open(struct inode *inode, struct file *file) { int ret = 0; if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) ftrace_pid_reset(); if (file->f_mode & FMODE_READ) ret = seq_open(file, &ftrace_pid_sops); return ret; } static ssize_t ftrace_pid_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[64], *tmp; long val; int ret; if (cnt >= sizeof(buf)) return -EINVAL; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; buf[cnt] = 0; /* * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid" * to clean the filter quietly. */ tmp = strstrip(buf); if (strlen(tmp) == 0) return 1; ret = strict_strtol(tmp, 10, &val); if (ret < 0) return ret; ret = ftrace_pid_add(val); return ret ? ret : cnt; } static int ftrace_pid_release(struct inode *inode, struct file *file) { if (file->f_mode & FMODE_READ) seq_release(inode, file); return 0; } static const struct file_operations ftrace_pid_fops = { .open = ftrace_pid_open, .write = ftrace_pid_write, .read = seq_read, .llseek = seq_lseek, .release = ftrace_pid_release, }; static __init int ftrace_init_debugfs(void) { struct dentry *d_tracer; d_tracer = tracing_init_dentry(); if (!d_tracer) return 0; ftrace_init_dyn_debugfs(d_tracer); trace_create_file("set_ftrace_pid", 0644, d_tracer, NULL, &ftrace_pid_fops); ftrace_profile_debugfs(d_tracer); return 0; } fs_initcall(ftrace_init_debugfs); /** * ftrace_kill - kill ftrace * * This function should be used by panic code. It stops ftrace * but in a not so nice way. If you need to simply kill ftrace * from a non-atomic section, use ftrace_kill. */ void ftrace_kill(void) { ftrace_disabled = 1; ftrace_enabled = 0; clear_ftrace_function(); } /** * register_ftrace_function - register a function for profiling * @ops - ops structure that holds the function for profiling. * * Register a function to be called by all functions in the * kernel. * * Note: @ops->func and all the functions it calls must be labeled * with "notrace", otherwise it will go into a * recursive loop. */ int register_ftrace_function(struct ftrace_ops *ops) { int ret; if (unlikely(ftrace_disabled)) return -1; mutex_lock(&ftrace_lock); ret = __register_ftrace_function(ops); ftrace_startup(0); mutex_unlock(&ftrace_lock); return ret; } /** * unregister_ftrace_function - unregister a function for profiling. * @ops - ops structure that holds the function to unregister * * Unregister a function that was added to be called by ftrace profiling. */ int unregister_ftrace_function(struct ftrace_ops *ops) { int ret; mutex_lock(&ftrace_lock); ret = __unregister_ftrace_function(ops); ftrace_shutdown(0); mutex_unlock(&ftrace_lock); return ret; } int ftrace_enable_sysctl(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { int ret; if (unlikely(ftrace_disabled)) return -ENODEV; mutex_lock(&ftrace_lock); ret = proc_dointvec(table, write, buffer, lenp, ppos); if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) goto out; last_ftrace_enabled = !!ftrace_enabled; if (ftrace_enabled) { ftrace_startup_sysctl(); /* we are starting ftrace again */ if (ftrace_list != &ftrace_list_end) { if (ftrace_list->next == &ftrace_list_end) ftrace_trace_function = ftrace_list->func; else ftrace_trace_function = ftrace_list_func; } } else { /* stopping ftrace calls (just send to ftrace_stub) */ ftrace_trace_function = ftrace_stub; ftrace_shutdown_sysctl(); } out: mutex_unlock(&ftrace_lock); return ret; } #ifdef CONFIG_FUNCTION_GRAPH_TRACER static int ftrace_graph_active; static struct notifier_block ftrace_suspend_notifier; int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace) { return 0; } /* The callbacks that hook a function */ trace_func_graph_ret_t ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub; trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub; /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) { int i; int ret = 0; unsigned long flags; int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE; struct task_struct *g, *t; for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) { ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH * sizeof(struct ftrace_ret_stack), GFP_KERNEL); if (!ret_stack_list[i]) { start = 0; end = i; ret = -ENOMEM; goto free; } } read_lock_irqsave(&tasklist_lock, flags); do_each_thread(g, t) { if (start == end) { ret = -EAGAIN; goto unlock; } if (t->ret_stack == NULL) { atomic_set(&t->tracing_graph_pause, 0); atomic_set(&t->trace_overrun, 0); t->curr_ret_stack = -1; /* Make sure the tasks see the -1 first: */ smp_wmb(); t->ret_stack = ret_stack_list[start++]; } } while_each_thread(g, t); unlock: read_unlock_irqrestore(&tasklist_lock, flags); free: for (i = start; i < end; i++) kfree(ret_stack_list[i]); return ret; } static void ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev, struct task_struct *next) { unsigned long long timestamp; int index; /* * Does the user want to count the time a function was asleep. * If so, do not update the time stamps. */ if (trace_flags & TRACE_ITER_SLEEP_TIME) return; timestamp = trace_clock_local(); prev->ftrace_timestamp = timestamp; /* only process tasks that we timestamped */ if (!next->ftrace_timestamp) return; /* * Update all the counters in next to make up for the * time next was sleeping. */ timestamp -= next->ftrace_timestamp; for (index = next->curr_ret_stack; index >= 0; index--) next->ret_stack[index].calltime += timestamp; } /* Allocate a return stack for each task */ static int start_graph_tracing(void) { struct ftrace_ret_stack **ret_stack_list; int ret, cpu; ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE * sizeof(struct ftrace_ret_stack *), GFP_KERNEL); if (!ret_stack_list) return -ENOMEM; /* The cpu_boot init_task->ret_stack will never be freed */ for_each_online_cpu(cpu) { if (!idle_task(cpu)->ret_stack) ftrace_graph_init_task(idle_task(cpu)); } do { ret = alloc_retstack_tasklist(ret_stack_list); } while (ret == -EAGAIN); if (!ret) { ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch); if (ret) pr_info("ftrace_graph: Couldn't activate tracepoint" " probe to kernel_sched_switch\n"); } kfree(ret_stack_list); return ret; } /* * Hibernation protection. * The state of the current task is too much unstable during * suspend/restore to disk. We want to protect against that. */ static int ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state, void *unused) { switch (state) { case PM_HIBERNATION_PREPARE: pause_graph_tracing(); break; case PM_POST_HIBERNATION: unpause_graph_tracing(); break; } return NOTIFY_DONE; } int register_ftrace_graph(trace_func_graph_ret_t retfunc, trace_func_graph_ent_t entryfunc) { int ret = 0; mutex_lock(&ftrace_lock); /* we currently allow only one tracer registered at a time */ if (ftrace_graph_active) { ret = -EBUSY; goto out; } ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call; register_pm_notifier(&ftrace_suspend_notifier); ftrace_graph_active++; ret = start_graph_tracing(); if (ret) { ftrace_graph_active--; goto out; } ftrace_graph_return = retfunc; ftrace_graph_entry = entryfunc; ftrace_startup(FTRACE_START_FUNC_RET); out: mutex_unlock(&ftrace_lock); return ret; } void unregister_ftrace_graph(void) { mutex_lock(&ftrace_lock); if (unlikely(!ftrace_graph_active)) goto out; ftrace_graph_active--; unregister_trace_sched_switch(ftrace_graph_probe_sched_switch); ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub; ftrace_graph_entry = ftrace_graph_entry_stub; ftrace_shutdown(FTRACE_STOP_FUNC_RET); unregister_pm_notifier(&ftrace_suspend_notifier); out: mutex_unlock(&ftrace_lock); } /* Allocate a return stack for newly created task */ void ftrace_graph_init_task(struct task_struct *t) { /* Make sure we do not use the parent ret_stack */ t->ret_stack = NULL; t->curr_ret_stack = -1; if (ftrace_graph_active) { struct ftrace_ret_stack *ret_stack; ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH * sizeof(struct ftrace_ret_stack), GFP_KERNEL); if (!ret_stack) return; atomic_set(&t->tracing_graph_pause, 0); atomic_set(&t->trace_overrun, 0); t->ftrace_timestamp = 0; /* make curr_ret_stack visable before we add the ret_stack */ smp_wmb(); t->ret_stack = ret_stack; } } void ftrace_graph_exit_task(struct task_struct *t) { struct ftrace_ret_stack *ret_stack = t->ret_stack; t->ret_stack = NULL; /* NULL must become visible to IRQs before we free it: */ barrier(); kfree(ret_stack); } void ftrace_graph_stop(void) { ftrace_stop(); } #endif