/* * * Function graph tracer. * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com> * Mostly borrowed from function tracer which * is Copyright (c) Steven Rostedt <srostedt@redhat.com> * */ #include <linux/debugfs.h> #include <linux/uaccess.h> #include <linux/ftrace.h> #include <linux/slab.h> #include <linux/fs.h> #include "trace.h" #include "trace_output.h" /* When set, irq functions will be ignored */ static int ftrace_graph_skip_irqs; struct fgraph_cpu_data { pid_t last_pid; int depth; int depth_irq; int ignore; unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH]; }; struct fgraph_data { struct fgraph_cpu_data __percpu *cpu_data; /* Place to preserve last processed entry. */ struct ftrace_graph_ent_entry ent; struct ftrace_graph_ret_entry ret; int failed; int cpu; }; #define TRACE_GRAPH_INDENT 2 /* Flag options */ #define TRACE_GRAPH_PRINT_OVERRUN 0x1 #define TRACE_GRAPH_PRINT_CPU 0x2 #define TRACE_GRAPH_PRINT_OVERHEAD 0x4 #define TRACE_GRAPH_PRINT_PROC 0x8 #define TRACE_GRAPH_PRINT_DURATION 0x10 #define TRACE_GRAPH_PRINT_ABS_TIME 0x20 #define TRACE_GRAPH_PRINT_IRQS 0x40 static struct tracer_opt trace_opts[] = { /* Display overruns? (for self-debug purpose) */ { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) }, /* Display CPU ? */ { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) }, /* Display Overhead ? */ { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) }, /* Display proc name/pid */ { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) }, /* Display duration of execution */ { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) }, /* Display absolute time of an entry */ { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) }, /* Display interrupts */ { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) }, { } /* Empty entry */ }; static struct tracer_flags tracer_flags = { /* Don't display overruns and proc by default */ .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD | TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS, .opts = trace_opts }; static struct trace_array *graph_array; /* * DURATION column is being also used to display IRQ signs, * following values are used by print_graph_irq and others * to fill in space into DURATION column. */ enum { DURATION_FILL_FULL = -1, DURATION_FILL_START = -2, DURATION_FILL_END = -3, }; static enum print_line_t print_graph_duration(unsigned long long duration, struct trace_seq *s, u32 flags); /* Add a function return address to the trace stack on thread info.*/ int ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, unsigned long frame_pointer) { unsigned long long calltime; int index; if (!current->ret_stack) return -EBUSY; /* * We must make sure the ret_stack is tested before we read * anything else. */ smp_rmb(); /* The return trace stack is full */ if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) { atomic_inc(¤t->trace_overrun); return -EBUSY; } calltime = trace_clock_local(); index = ++current->curr_ret_stack; barrier(); current->ret_stack[index].ret = ret; current->ret_stack[index].func = func; current->ret_stack[index].calltime = calltime; current->ret_stack[index].subtime = 0; current->ret_stack[index].fp = frame_pointer; *depth = index; return 0; } /* Retrieve a function return address to the trace stack on thread info.*/ static void ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret, unsigned long frame_pointer) { int index; index = current->curr_ret_stack; if (unlikely(index < 0)) { ftrace_graph_stop(); WARN_ON(1); /* Might as well panic, otherwise we have no where to go */ *ret = (unsigned long)panic; return; } #ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST /* * The arch may choose to record the frame pointer used * and check it here to make sure that it is what we expect it * to be. If gcc does not set the place holder of the return * address in the frame pointer, and does a copy instead, then * the function graph trace will fail. This test detects this * case. * * Currently, x86_32 with optimize for size (-Os) makes the latest * gcc do the above. */ if (unlikely(current->ret_stack[index].fp != frame_pointer)) { ftrace_graph_stop(); WARN(1, "Bad frame pointer: expected %lx, received %lx\n" " from func %ps return to %lx\n", current->ret_stack[index].fp, frame_pointer, (void *)current->ret_stack[index].func, current->ret_stack[index].ret); *ret = (unsigned long)panic; return; } #endif *ret = current->ret_stack[index].ret; trace->func = current->ret_stack[index].func; trace->calltime = current->ret_stack[index].calltime; trace->overrun = atomic_read(¤t->trace_overrun); trace->depth = index; } /* * Send the trace to the ring-buffer. * @return the original return address. */ unsigned long ftrace_return_to_handler(unsigned long frame_pointer) { struct ftrace_graph_ret trace; unsigned long ret; ftrace_pop_return_trace(&trace, &ret, frame_pointer); trace.rettime = trace_clock_local(); ftrace_graph_return(&trace); barrier(); current->curr_ret_stack--; if (unlikely(!ret)) { ftrace_graph_stop(); WARN_ON(1); /* Might as well panic. What else to do? */ ret = (unsigned long)panic; } return ret; } int __trace_graph_entry(struct trace_array *tr, struct ftrace_graph_ent *trace, unsigned long flags, int pc) { struct ftrace_event_call *call = &event_funcgraph_entry; struct ring_buffer_event *event; struct ring_buffer *buffer = tr->buffer; struct ftrace_graph_ent_entry *entry; if (unlikely(__this_cpu_read(ftrace_cpu_disabled))) return 0; event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT, sizeof(*entry), flags, pc); if (!event) return 0; entry = ring_buffer_event_data(event); entry->graph_ent = *trace; if (!filter_current_check_discard(buffer, call, entry, event)) ring_buffer_unlock_commit(buffer, event); return 1; } static inline int ftrace_graph_ignore_irqs(void) { if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT)) return 0; return in_irq(); } int trace_graph_entry(struct ftrace_graph_ent *trace) { struct trace_array *tr = graph_array; struct trace_array_cpu *data; unsigned long flags; long disabled; int ret; int cpu; int pc; if (!ftrace_trace_task(current)) return 0; /* trace it when it is-nested-in or is a function enabled. */ if (!(trace->depth || ftrace_graph_addr(trace->func)) || ftrace_graph_ignore_irqs()) return 0; local_irq_save(flags); cpu = raw_smp_processor_id(); data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); if (likely(disabled == 1)) { pc = preempt_count(); ret = __trace_graph_entry(tr, trace, flags, pc); } else { ret = 0; } atomic_dec(&data->disabled); local_irq_restore(flags); return ret; } int trace_graph_thresh_entry(struct ftrace_graph_ent *trace) { if (tracing_thresh) return 1; else return trace_graph_entry(trace); } static void __trace_graph_function(struct trace_array *tr, unsigned long ip, unsigned long flags, int pc) { u64 time = trace_clock_local(); struct ftrace_graph_ent ent = { .func = ip, .depth = 0, }; struct ftrace_graph_ret ret = { .func = ip, .depth = 0, .calltime = time, .rettime = time, }; __trace_graph_entry(tr, &ent, flags, pc); __trace_graph_return(tr, &ret, flags, pc); } void trace_graph_function(struct trace_array *tr, unsigned long ip, unsigned long parent_ip, unsigned long flags, int pc) { __trace_graph_function(tr, ip, flags, pc); } void __trace_graph_return(struct trace_array *tr, struct ftrace_graph_ret *trace, unsigned long flags, int pc) { struct ftrace_event_call *call = &event_funcgraph_exit; struct ring_buffer_event *event; struct ring_buffer *buffer = tr->buffer; struct ftrace_graph_ret_entry *entry; if (unlikely(__this_cpu_read(ftrace_cpu_disabled))) return; event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET, sizeof(*entry), flags, pc); if (!event) return; entry = ring_buffer_event_data(event); entry->ret = *trace; if (!filter_current_check_discard(buffer, call, entry, event)) ring_buffer_unlock_commit(buffer, event); } void trace_graph_return(struct ftrace_graph_ret *trace) { struct trace_array *tr = graph_array; struct trace_array_cpu *data; unsigned long flags; long disabled; int cpu; int pc; local_irq_save(flags); cpu = raw_smp_processor_id(); data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); if (likely(disabled == 1)) { pc = preempt_count(); __trace_graph_return(tr, trace, flags, pc); } atomic_dec(&data->disabled); local_irq_restore(flags); } void set_graph_array(struct trace_array *tr) { graph_array = tr; /* Make graph_array visible before we start tracing */ smp_mb(); } void trace_graph_thresh_return(struct ftrace_graph_ret *trace) { if (tracing_thresh && (trace->rettime - trace->calltime < tracing_thresh)) return; else trace_graph_return(trace); } static int graph_trace_init(struct trace_array *tr) { int ret; set_graph_array(tr); if (tracing_thresh) ret = register_ftrace_graph(&trace_graph_thresh_return, &trace_graph_thresh_entry); else ret = register_ftrace_graph(&trace_graph_return, &trace_graph_entry); if (ret) return ret; tracing_start_cmdline_record(); return 0; } static void graph_trace_reset(struct trace_array *tr) { tracing_stop_cmdline_record(); unregister_ftrace_graph(); } static int max_bytes_for_cpu; static enum print_line_t print_graph_cpu(struct trace_seq *s, int cpu) { int ret; /* * Start with a space character - to make it stand out * to the right a bit when trace output is pasted into * email: */ ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } #define TRACE_GRAPH_PROCINFO_LENGTH 14 static enum print_line_t print_graph_proc(struct trace_seq *s, pid_t pid) { char comm[TASK_COMM_LEN]; /* sign + log10(MAX_INT) + '\0' */ char pid_str[11]; int spaces = 0; int ret; int len; int i; trace_find_cmdline(pid, comm); comm[7] = '\0'; sprintf(pid_str, "%d", pid); /* 1 stands for the "-" character */ len = strlen(comm) + strlen(pid_str) + 1; if (len < TRACE_GRAPH_PROCINFO_LENGTH) spaces = TRACE_GRAPH_PROCINFO_LENGTH - len; /* First spaces to align center */ for (i = 0; i < spaces / 2; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } ret = trace_seq_printf(s, "%s-%s", comm, pid_str); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* Last spaces to align center */ for (i = 0; i < spaces - (spaces / 2); i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } return TRACE_TYPE_HANDLED; } static enum print_line_t print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry) { if (!trace_seq_putc(s, ' ')) return 0; return trace_print_lat_fmt(s, entry); } /* If the pid changed since the last trace, output this event */ static enum print_line_t verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data) { pid_t prev_pid; pid_t *last_pid; int ret; if (!data) return TRACE_TYPE_HANDLED; last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid); if (*last_pid == pid) return TRACE_TYPE_HANDLED; prev_pid = *last_pid; *last_pid = pid; if (prev_pid == -1) return TRACE_TYPE_HANDLED; /* * Context-switch trace line: ------------------------------------------ | 1) migration/0--1 => sshd-1755 ------------------------------------------ */ ret = trace_seq_printf(s, " ------------------------------------------\n"); if (!ret) return TRACE_TYPE_PARTIAL_LINE; ret = print_graph_cpu(s, cpu); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; ret = print_graph_proc(s, prev_pid); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; ret = trace_seq_printf(s, " => "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; ret = print_graph_proc(s, pid); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; ret = trace_seq_printf(s, "\n ------------------------------------------\n\n"); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } static struct ftrace_graph_ret_entry * get_return_for_leaf(struct trace_iterator *iter, struct ftrace_graph_ent_entry *curr) { struct fgraph_data *data = iter->private; struct ring_buffer_iter *ring_iter = NULL; struct ring_buffer_event *event; struct ftrace_graph_ret_entry *next; /* * If the previous output failed to write to the seq buffer, * then we just reuse the data from before. */ if (data && data->failed) { curr = &data->ent; next = &data->ret; } else { ring_iter = iter->buffer_iter[iter->cpu]; /* First peek to compare current entry and the next one */ if (ring_iter) event = ring_buffer_iter_peek(ring_iter, NULL); else { /* * We need to consume the current entry to see * the next one. */ ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL, NULL); event = ring_buffer_peek(iter->tr->buffer, iter->cpu, NULL, NULL); } if (!event) return NULL; next = ring_buffer_event_data(event); if (data) { /* * Save current and next entries for later reference * if the output fails. */ data->ent = *curr; /* * If the next event is not a return type, then * we only care about what type it is. Otherwise we can * safely copy the entire event. */ if (next->ent.type == TRACE_GRAPH_RET) data->ret = *next; else data->ret.ent.type = next->ent.type; } } if (next->ent.type != TRACE_GRAPH_RET) return NULL; if (curr->ent.pid != next->ent.pid || curr->graph_ent.func != next->ret.func) return NULL; /* this is a leaf, now advance the iterator */ if (ring_iter) ring_buffer_read(ring_iter, NULL); return next; } static int print_graph_abs_time(u64 t, struct trace_seq *s) { unsigned long usecs_rem; usecs_rem = do_div(t, NSEC_PER_SEC); usecs_rem /= 1000; return trace_seq_printf(s, "%5lu.%06lu | ", (unsigned long)t, usecs_rem); } static enum print_line_t print_graph_irq(struct trace_iterator *iter, unsigned long addr, enum trace_type type, int cpu, pid_t pid, u32 flags) { int ret; struct trace_seq *s = &iter->seq; if (addr < (unsigned long)__irqentry_text_start || addr >= (unsigned long)__irqentry_text_end) return TRACE_TYPE_UNHANDLED; if (trace_flags & TRACE_ITER_CONTEXT_INFO) { /* Absolute time */ if (flags & TRACE_GRAPH_PRINT_ABS_TIME) { ret = print_graph_abs_time(iter->ts, s); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* Cpu */ if (flags & TRACE_GRAPH_PRINT_CPU) { ret = print_graph_cpu(s, cpu); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; } /* Proc */ if (flags & TRACE_GRAPH_PRINT_PROC) { ret = print_graph_proc(s, pid); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; ret = trace_seq_printf(s, " | "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } } /* No overhead */ ret = print_graph_duration(DURATION_FILL_START, s, flags); if (ret != TRACE_TYPE_HANDLED) return ret; if (type == TRACE_GRAPH_ENT) ret = trace_seq_printf(s, "==========>"); else ret = trace_seq_printf(s, "<=========="); if (!ret) return TRACE_TYPE_PARTIAL_LINE; ret = print_graph_duration(DURATION_FILL_END, s, flags); if (ret != TRACE_TYPE_HANDLED) return ret; ret = trace_seq_printf(s, "\n"); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } enum print_line_t trace_print_graph_duration(unsigned long long duration, struct trace_seq *s) { unsigned long nsecs_rem = do_div(duration, 1000); /* log10(ULONG_MAX) + '\0' */ char msecs_str[21]; char nsecs_str[5]; int ret, len; int i; sprintf(msecs_str, "%lu", (unsigned long) duration); /* Print msecs */ ret = trace_seq_printf(s, "%s", msecs_str); if (!ret) return TRACE_TYPE_PARTIAL_LINE; len = strlen(msecs_str); /* Print nsecs (we don't want to exceed 7 numbers) */ if (len < 7) { size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len); snprintf(nsecs_str, slen, "%03lu", nsecs_rem); ret = trace_seq_printf(s, ".%s", nsecs_str); if (!ret) return TRACE_TYPE_PARTIAL_LINE; len += strlen(nsecs_str); } ret = trace_seq_printf(s, " us "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* Print remaining spaces to fit the row's width */ for (i = len; i < 7; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } return TRACE_TYPE_HANDLED; } static enum print_line_t print_graph_duration(unsigned long long duration, struct trace_seq *s, u32 flags) { int ret = -1; if (!(flags & TRACE_GRAPH_PRINT_DURATION) || !(trace_flags & TRACE_ITER_CONTEXT_INFO)) return TRACE_TYPE_HANDLED; /* No real adata, just filling the column with spaces */ switch (duration) { case DURATION_FILL_FULL: ret = trace_seq_printf(s, " | "); return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; case DURATION_FILL_START: ret = trace_seq_printf(s, " "); return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; case DURATION_FILL_END: ret = trace_seq_printf(s, " |"); return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; } /* Signal a overhead of time execution to the output */ if (flags & TRACE_GRAPH_PRINT_OVERHEAD) { /* Duration exceeded 100 msecs */ if (duration > 100000ULL) ret = trace_seq_printf(s, "! "); /* Duration exceeded 10 msecs */ else if (duration > 10000ULL) ret = trace_seq_printf(s, "+ "); } /* * The -1 means we either did not exceed the duration tresholds * or we dont want to print out the overhead. Either way we need * to fill out the space. */ if (ret == -1) ret = trace_seq_printf(s, " "); /* Catching here any failure happenned above */ if (!ret) return TRACE_TYPE_PARTIAL_LINE; ret = trace_print_graph_duration(duration, s); if (ret != TRACE_TYPE_HANDLED) return ret; ret = trace_seq_printf(s, "| "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } /* Case of a leaf function on its call entry */ static enum print_line_t print_graph_entry_leaf(struct trace_iterator *iter, struct ftrace_graph_ent_entry *entry, struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s, u32 flags) { struct fgraph_data *data = iter->private; struct ftrace_graph_ret *graph_ret; struct ftrace_graph_ent *call; unsigned long long duration; int ret; int i; graph_ret = &ret_entry->ret; call = &entry->graph_ent; duration = graph_ret->rettime - graph_ret->calltime; if (data) { struct fgraph_cpu_data *cpu_data; int cpu = iter->cpu; cpu_data = per_cpu_ptr(data->cpu_data, cpu); /* * Comments display at + 1 to depth. Since * this is a leaf function, keep the comments * equal to this depth. */ cpu_data->depth = call->depth - 1; /* No need to keep this function around for this depth */ if (call->depth < FTRACE_RETFUNC_DEPTH) cpu_data->enter_funcs[call->depth] = 0; } /* Overhead and duration */ ret = print_graph_duration(duration, s, flags); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; /* Function */ for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } ret = trace_seq_printf(s, "%ps();\n", (void *)call->func); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } static enum print_line_t print_graph_entry_nested(struct trace_iterator *iter, struct ftrace_graph_ent_entry *entry, struct trace_seq *s, int cpu, u32 flags) { struct ftrace_graph_ent *call = &entry->graph_ent; struct fgraph_data *data = iter->private; int ret; int i; if (data) { struct fgraph_cpu_data *cpu_data; int cpu = iter->cpu; cpu_data = per_cpu_ptr(data->cpu_data, cpu); cpu_data->depth = call->depth; /* Save this function pointer to see if the exit matches */ if (call->depth < FTRACE_RETFUNC_DEPTH) cpu_data->enter_funcs[call->depth] = call->func; } /* No time */ ret = print_graph_duration(DURATION_FILL_FULL, s, flags); if (ret != TRACE_TYPE_HANDLED) return ret; /* Function */ for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* * we already consumed the current entry to check the next one * and see if this is a leaf. */ return TRACE_TYPE_NO_CONSUME; } static enum print_line_t print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s, int type, unsigned long addr, u32 flags) { struct fgraph_data *data = iter->private; struct trace_entry *ent = iter->ent; int cpu = iter->cpu; int ret; /* Pid */ if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; if (type) { /* Interrupt */ ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; } if (!(trace_flags & TRACE_ITER_CONTEXT_INFO)) return 0; /* Absolute time */ if (flags & TRACE_GRAPH_PRINT_ABS_TIME) { ret = print_graph_abs_time(iter->ts, s); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* Cpu */ if (flags & TRACE_GRAPH_PRINT_CPU) { ret = print_graph_cpu(s, cpu); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; } /* Proc */ if (flags & TRACE_GRAPH_PRINT_PROC) { ret = print_graph_proc(s, ent->pid); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; ret = trace_seq_printf(s, " | "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* Latency format */ if (trace_flags & TRACE_ITER_LATENCY_FMT) { ret = print_graph_lat_fmt(s, ent); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; } return 0; } /* * Entry check for irq code * * returns 1 if * - we are inside irq code * - we just entered irq code * * retunns 0 if * - funcgraph-interrupts option is set * - we are not inside irq code */ static int check_irq_entry(struct trace_iterator *iter, u32 flags, unsigned long addr, int depth) { int cpu = iter->cpu; int *depth_irq; struct fgraph_data *data = iter->private; /* * If we are either displaying irqs, or we got called as * a graph event and private data does not exist, * then we bypass the irq check. */ if ((flags & TRACE_GRAPH_PRINT_IRQS) || (!data)) return 0; depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq); /* * We are inside the irq code */ if (*depth_irq >= 0) return 1; if ((addr < (unsigned long)__irqentry_text_start) || (addr >= (unsigned long)__irqentry_text_end)) return 0; /* * We are entering irq code. */ *depth_irq = depth; return 1; } /* * Return check for irq code * * returns 1 if * - we are inside irq code * - we just left irq code * * returns 0 if * - funcgraph-interrupts option is set * - we are not inside irq code */ static int check_irq_return(struct trace_iterator *iter, u32 flags, int depth) { int cpu = iter->cpu; int *depth_irq; struct fgraph_data *data = iter->private; /* * If we are either displaying irqs, or we got called as * a graph event and private data does not exist, * then we bypass the irq check. */ if ((flags & TRACE_GRAPH_PRINT_IRQS) || (!data)) return 0; depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq); /* * We are not inside the irq code. */ if (*depth_irq == -1) return 0; /* * We are inside the irq code, and this is returning entry. * Let's not trace it and clear the entry depth, since * we are out of irq code. * * This condition ensures that we 'leave the irq code' once * we are out of the entry depth. Thus protecting us from * the RETURN entry loss. */ if (*depth_irq >= depth) { *depth_irq = -1; return 1; } /* * We are inside the irq code, and this is not the entry. */ return 1; } static enum print_line_t print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s, struct trace_iterator *iter, u32 flags) { struct fgraph_data *data = iter->private; struct ftrace_graph_ent *call = &field->graph_ent; struct ftrace_graph_ret_entry *leaf_ret; static enum print_line_t ret; int cpu = iter->cpu; if (check_irq_entry(iter, flags, call->func, call->depth)) return TRACE_TYPE_HANDLED; if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags)) return TRACE_TYPE_PARTIAL_LINE; leaf_ret = get_return_for_leaf(iter, field); if (leaf_ret) ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags); else ret = print_graph_entry_nested(iter, field, s, cpu, flags); if (data) { /* * If we failed to write our output, then we need to make * note of it. Because we already consumed our entry. */ if (s->full) { data->failed = 1; data->cpu = cpu; } else data->failed = 0; } return ret; } static enum print_line_t print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, struct trace_entry *ent, struct trace_iterator *iter, u32 flags) { unsigned long long duration = trace->rettime - trace->calltime; struct fgraph_data *data = iter->private; pid_t pid = ent->pid; int cpu = iter->cpu; int func_match = 1; int ret; int i; if (check_irq_return(iter, flags, trace->depth)) return TRACE_TYPE_HANDLED; if (data) { struct fgraph_cpu_data *cpu_data; int cpu = iter->cpu; cpu_data = per_cpu_ptr(data->cpu_data, cpu); /* * Comments display at + 1 to depth. This is the * return from a function, we now want the comments * to display at the same level of the bracket. */ cpu_data->depth = trace->depth - 1; if (trace->depth < FTRACE_RETFUNC_DEPTH) { if (cpu_data->enter_funcs[trace->depth] != trace->func) func_match = 0; cpu_data->enter_funcs[trace->depth] = 0; } } if (print_graph_prologue(iter, s, 0, 0, flags)) return TRACE_TYPE_PARTIAL_LINE; /* Overhead and duration */ ret = print_graph_duration(duration, s, flags); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; /* Closing brace */ for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* * If the return function does not have a matching entry, * then the entry was lost. Instead of just printing * the '}' and letting the user guess what function this * belongs to, write out the function name. */ if (func_match) { ret = trace_seq_printf(s, "}\n"); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } else { ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* Overrun */ if (flags & TRACE_GRAPH_PRINT_OVERRUN) { ret = trace_seq_printf(s, " (Overruns: %lu)\n", trace->overrun); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid, flags); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } static enum print_line_t print_graph_comment(struct trace_seq *s, struct trace_entry *ent, struct trace_iterator *iter, u32 flags) { unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK); struct fgraph_data *data = iter->private; struct trace_event *event; int depth = 0; int ret; int i; if (data) depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth; if (print_graph_prologue(iter, s, 0, 0, flags)) return TRACE_TYPE_PARTIAL_LINE; /* No time */ ret = print_graph_duration(DURATION_FILL_FULL, s, flags); if (ret != TRACE_TYPE_HANDLED) return ret; /* Indentation */ if (depth > 0) for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* The comment */ ret = trace_seq_printf(s, "/* "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; switch (iter->ent->type) { case TRACE_BPRINT: ret = trace_print_bprintk_msg_only(iter); if (ret != TRACE_TYPE_HANDLED) return ret; break; case TRACE_PRINT: ret = trace_print_printk_msg_only(iter); if (ret != TRACE_TYPE_HANDLED) return ret; break; default: event = ftrace_find_event(ent->type); if (!event) return TRACE_TYPE_UNHANDLED; ret = event->funcs->trace(iter, sym_flags, event); if (ret != TRACE_TYPE_HANDLED) return ret; } /* Strip ending newline */ if (s->buffer[s->len - 1] == '\n') { s->buffer[s->len - 1] = '\0'; s->len--; } ret = trace_seq_printf(s, " */\n"); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } enum print_line_t print_graph_function_flags(struct trace_iterator *iter, u32 flags) { struct ftrace_graph_ent_entry *field; struct fgraph_data *data = iter->private; struct trace_entry *entry = iter->ent; struct trace_seq *s = &iter->seq; int cpu = iter->cpu; int ret; if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) { per_cpu_ptr(data->cpu_data, cpu)->ignore = 0; return TRACE_TYPE_HANDLED; } /* * If the last output failed, there's a possibility we need * to print out the missing entry which would never go out. */ if (data && data->failed) { field = &data->ent; iter->cpu = data->cpu; ret = print_graph_entry(field, s, iter, flags); if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) { per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1; ret = TRACE_TYPE_NO_CONSUME; } iter->cpu = cpu; return ret; } switch (entry->type) { case TRACE_GRAPH_ENT: { /* * print_graph_entry() may consume the current event, * thus @field may become invalid, so we need to save it. * sizeof(struct ftrace_graph_ent_entry) is very small, * it can be safely saved at the stack. */ struct ftrace_graph_ent_entry saved; trace_assign_type(field, entry); saved = *field; return print_graph_entry(&saved, s, iter, flags); } case TRACE_GRAPH_RET: { struct ftrace_graph_ret_entry *field; trace_assign_type(field, entry); return print_graph_return(&field->ret, s, entry, iter, flags); } case TRACE_STACK: case TRACE_FN: /* dont trace stack and functions as comments */ return TRACE_TYPE_UNHANDLED; default: return print_graph_comment(s, entry, iter, flags); } return TRACE_TYPE_HANDLED; } static enum print_line_t print_graph_function(struct trace_iterator *iter) { return print_graph_function_flags(iter, tracer_flags.val); } static enum print_line_t print_graph_function_event(struct trace_iterator *iter, int flags, struct trace_event *event) { return print_graph_function(iter); } static void print_lat_header(struct seq_file *s, u32 flags) { static const char spaces[] = " " /* 16 spaces */ " " /* 4 spaces */ " "; /* 17 spaces */ int size = 0; if (flags & TRACE_GRAPH_PRINT_ABS_TIME) size += 16; if (flags & TRACE_GRAPH_PRINT_CPU) size += 4; if (flags & TRACE_GRAPH_PRINT_PROC) size += 17; seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces); seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces); seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces); seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces); seq_printf(s, "#%.*s||| / \n", size, spaces); } static void __print_graph_headers_flags(struct seq_file *s, u32 flags) { int lat = trace_flags & TRACE_ITER_LATENCY_FMT; if (lat) print_lat_header(s, flags); /* 1st line */ seq_printf(s, "#"); if (flags & TRACE_GRAPH_PRINT_ABS_TIME) seq_printf(s, " TIME "); if (flags & TRACE_GRAPH_PRINT_CPU) seq_printf(s, " CPU"); if (flags & TRACE_GRAPH_PRINT_PROC) seq_printf(s, " TASK/PID "); if (lat) seq_printf(s, "||||"); if (flags & TRACE_GRAPH_PRINT_DURATION) seq_printf(s, " DURATION "); seq_printf(s, " FUNCTION CALLS\n"); /* 2nd line */ seq_printf(s, "#"); if (flags & TRACE_GRAPH_PRINT_ABS_TIME) seq_printf(s, " | "); if (flags & TRACE_GRAPH_PRINT_CPU) seq_printf(s, " | "); if (flags & TRACE_GRAPH_PRINT_PROC) seq_printf(s, " | | "); if (lat) seq_printf(s, "||||"); if (flags & TRACE_GRAPH_PRINT_DURATION) seq_printf(s, " | | "); seq_printf(s, " | | | |\n"); } void print_graph_headers(struct seq_file *s) { print_graph_headers_flags(s, tracer_flags.val); } void print_graph_headers_flags(struct seq_file *s, u32 flags) { struct trace_iterator *iter = s->private; if (!(trace_flags & TRACE_ITER_CONTEXT_INFO)) return; if (trace_flags & TRACE_ITER_LATENCY_FMT) { /* print nothing if the buffers are empty */ if (trace_empty(iter)) return; print_trace_header(s, iter); } __print_graph_headers_flags(s, flags); } void graph_trace_open(struct trace_iterator *iter) { /* pid and depth on the last trace processed */ struct fgraph_data *data; int cpu; iter->private = NULL; data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) goto out_err; data->cpu_data = alloc_percpu(struct fgraph_cpu_data); if (!data->cpu_data) goto out_err_free; for_each_possible_cpu(cpu) { pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid); int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore); int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq); *pid = -1; *depth = 0; *ignore = 0; *depth_irq = -1; } iter->private = data; return; out_err_free: kfree(data); out_err: pr_warning("function graph tracer: not enough memory\n"); } void graph_trace_close(struct trace_iterator *iter) { struct fgraph_data *data = iter->private; if (data) { free_percpu(data->cpu_data); kfree(data); } } static int func_graph_set_flag(u32 old_flags, u32 bit, int set) { if (bit == TRACE_GRAPH_PRINT_IRQS) ftrace_graph_skip_irqs = !set; return 0; } static struct trace_event_functions graph_functions = { .trace = print_graph_function_event, }; static struct trace_event graph_trace_entry_event = { .type = TRACE_GRAPH_ENT, .funcs = &graph_functions, }; static struct trace_event graph_trace_ret_event = { .type = TRACE_GRAPH_RET, .funcs = &graph_functions }; static struct tracer graph_trace __read_mostly = { .name = "function_graph", .open = graph_trace_open, .pipe_open = graph_trace_open, .close = graph_trace_close, .pipe_close = graph_trace_close, .wait_pipe = poll_wait_pipe, .init = graph_trace_init, .reset = graph_trace_reset, .print_line = print_graph_function, .print_header = print_graph_headers, .flags = &tracer_flags, .set_flag = func_graph_set_flag, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_function_graph, #endif }; static __init int init_graph_trace(void) { max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1); if (!register_ftrace_event(&graph_trace_entry_event)) { pr_warning("Warning: could not register graph trace events\n"); return 1; } if (!register_ftrace_event(&graph_trace_ret_event)) { pr_warning("Warning: could not register graph trace events\n"); return 1; } return register_tracer(&graph_trace); } device_initcall(init_graph_trace);