diff options
Diffstat (limited to 'kernel/trace/trace_functions_graph.c')
| -rw-r--r-- | kernel/trace/trace_functions_graph.c | 1470 |
1 files changed, 1470 insertions, 0 deletions
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c new file mode 100644 index 000000000..a51e79688 --- /dev/null +++ b/kernel/trace/trace_functions_graph.c @@ -0,0 +1,1470 @@ +/* + * + * 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/uaccess.h> +#include <linux/ftrace.h> +#include <linux/slab.h> +#include <linux/fs.h> + +#include "trace.h" +#include "trace_output.h" + +static bool kill_ftrace_graph; + +/** + * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called + * + * ftrace_graph_stop() is called when a severe error is detected in + * the function graph tracing. This function is called by the critical + * paths of function graph to keep those paths from doing any more harm. + */ +bool ftrace_graph_is_dead(void) +{ + return kill_ftrace_graph; +} + +/** + * ftrace_graph_stop - set to permanently disable function graph tracincg + * + * In case of an error int function graph tracing, this is called + * to try to keep function graph tracing from causing any more harm. + * Usually this is pretty severe and this is called to try to at least + * get a warning out to the user. + */ +void ftrace_graph_stop(void) +{ + kill_ftrace_graph = true; +} + +/* 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 + +static unsigned int max_depth; + +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) }, + /* Display function name after trailing } */ + { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) }, + { } /* Empty entry */ +}; + +static struct tracer_flags tracer_flags = { + /* Don't display overruns, proc, or tail 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 { + FLAGS_FILL_FULL = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT, + FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT, + FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT, +}; + +static void +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 (unlikely(ftrace_graph_is_dead())) + return -EBUSY; + + 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; + } + + /* + * The curr_ret_stack is an index to ftrace return stack of + * current task. Its value should be in [0, FTRACE_RETFUNC_ + * DEPTH) when the function graph tracer is used. To support + * filtering out specific functions, it makes the index + * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH) + * so when it sees a negative index the ftrace will ignore + * the record. And the index gets recovered when returning + * from the filtered function by adding the FTRACE_NOTRACE_ + * DEPTH and then it'll continue to record functions normally. + * + * The curr_ret_stack is initialized to -1 and get increased + * in this function. So it can be less than -1 only if it was + * filtered out via ftrace_graph_notrace_addr() which can be + * set from set_graph_notrace file in tracefs by user. + */ + if (current->curr_ret_stack < -1) + return -EBUSY; + + calltime = trace_clock_local(); + + index = ++current->curr_ret_stack; + if (ftrace_graph_notrace_addr(func)) + current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH; + 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 = current->curr_ret_stack; + + 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; + + /* + * A negative index here means that it's just returned from a + * notrace'd function. Recover index to get an original + * return address. See ftrace_push_return_trace(). + * + * TODO: Need to check whether the stack gets corrupted. + */ + if (index < 0) + index += FTRACE_NOTRACE_DEPTH; + + if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) { + ftrace_graph_stop(); + WARN_ON(1); + /* Might as well panic, otherwise we have no where to go */ + *ret = (unsigned long)panic; + return; + } + +#if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY) + /* + * 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. + * + * Note, -mfentry does not use frame pointers, and this test + * is not needed if CC_USING_FENTRY is set. + */ + 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(); + barrier(); + current->curr_ret_stack--; + /* + * The curr_ret_stack can be less than -1 only if it was + * filtered out and it's about to return from the function. + * Recover the index and continue to trace normal functions. + */ + if (current->curr_ret_stack < -1) { + current->curr_ret_stack += FTRACE_NOTRACE_DEPTH; + return ret; + } + + /* + * The trace should run after decrementing the ret counter + * in case an interrupt were to come in. We don't want to + * lose the interrupt if max_depth is set. + */ + ftrace_graph_return(&trace); + + 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->trace_buffer.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 (!call_filter_check_discard(call, entry, buffer, event)) + __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()) || (trace->depth < 0) || + (max_depth && trace->depth >= max_depth)) + return 0; + + /* + * Do not trace a function if it's filtered by set_graph_notrace. + * Make the index of ret stack negative to indicate that it should + * ignore further functions. But it needs its own ret stack entry + * to recover the original index in order to continue tracing after + * returning from the function. + */ + if (ftrace_graph_notrace_addr(trace->func)) + return 1; + + local_irq_save(flags); + cpu = raw_smp_processor_id(); + data = per_cpu_ptr(tr->trace_buffer.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; +} + +static 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->trace_buffer.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 (!call_filter_check_discard(call, entry, buffer, event)) + __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 = per_cpu_ptr(tr->trace_buffer.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(); +} + +static 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 graph_trace_update_thresh(struct trace_array *tr) +{ + graph_trace_reset(tr); + return graph_trace_init(tr); +} + +static int max_bytes_for_cpu; + +static void print_graph_cpu(struct trace_seq *s, int cpu) +{ + /* + * Start with a space character - to make it stand out + * to the right a bit when trace output is pasted into + * email: + */ + trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu); +} + +#define TRACE_GRAPH_PROCINFO_LENGTH 14 + +static void 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 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++) + trace_seq_putc(s, ' '); + + trace_seq_printf(s, "%s-%s", comm, pid_str); + + /* Last spaces to align center */ + for (i = 0; i < spaces - (spaces / 2); i++) + trace_seq_putc(s, ' '); +} + + +static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry) +{ + trace_seq_putc(s, ' '); + trace_print_lat_fmt(s, entry); +} + +/* If the pid changed since the last trace, output this event */ +static void +verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data) +{ + pid_t prev_pid; + pid_t *last_pid; + + if (!data) + return; + + last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid); + + if (*last_pid == pid) + return; + + prev_pid = *last_pid; + *last_pid = pid; + + if (prev_pid == -1) + return; +/* + * Context-switch trace line: + + ------------------------------------------ + | 1) migration/0--1 => sshd-1755 + ------------------------------------------ + + */ + trace_seq_puts(s, " ------------------------------------------\n"); + print_graph_cpu(s, cpu); + print_graph_proc(s, prev_pid); + trace_seq_puts(s, " => "); + print_graph_proc(s, pid); + trace_seq_puts(s, "\n ------------------------------------------\n\n"); +} + +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 = trace_buffer_iter(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->trace_buffer->buffer, iter->cpu, + NULL, NULL); + event = ring_buffer_peek(iter->trace_buffer->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 void 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; + + trace_seq_printf(s, "%5lu.%06lu | ", + (unsigned long)t, usecs_rem); +} + +static void +print_graph_irq(struct trace_iterator *iter, unsigned long addr, + enum trace_type type, int cpu, pid_t pid, u32 flags) +{ + struct trace_seq *s = &iter->seq; + struct trace_entry *ent = iter->ent; + + if (addr < (unsigned long)__irqentry_text_start || + addr >= (unsigned long)__irqentry_text_end) + return; + + if (trace_flags & TRACE_ITER_CONTEXT_INFO) { + /* Absolute time */ + if (flags & TRACE_GRAPH_PRINT_ABS_TIME) + print_graph_abs_time(iter->ts, s); + + /* Cpu */ + if (flags & TRACE_GRAPH_PRINT_CPU) + print_graph_cpu(s, cpu); + + /* Proc */ + if (flags & TRACE_GRAPH_PRINT_PROC) { + print_graph_proc(s, pid); + trace_seq_puts(s, " | "); + } + + /* Latency format */ + if (trace_flags & TRACE_ITER_LATENCY_FMT) + print_graph_lat_fmt(s, ent); + } + + /* No overhead */ + print_graph_duration(0, s, flags | FLAGS_FILL_START); + + if (type == TRACE_GRAPH_ENT) + trace_seq_puts(s, "==========>"); + else + trace_seq_puts(s, "<=========="); + + print_graph_duration(0, s, flags | FLAGS_FILL_END); + trace_seq_putc(s, '\n'); +} + +void +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 usecs_str[21]; + char nsecs_str[5]; + int len; + int i; + + sprintf(usecs_str, "%lu", (unsigned long) duration); + + /* Print msecs */ + trace_seq_printf(s, "%s", usecs_str); + + len = strlen(usecs_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); + trace_seq_printf(s, ".%s", nsecs_str); + len += strlen(nsecs_str); + } + + trace_seq_puts(s, " us "); + + /* Print remaining spaces to fit the row's width */ + for (i = len; i < 7; i++) + trace_seq_putc(s, ' '); +} + +static void +print_graph_duration(unsigned long long duration, struct trace_seq *s, + u32 flags) +{ + if (!(flags & TRACE_GRAPH_PRINT_DURATION) || + !(trace_flags & TRACE_ITER_CONTEXT_INFO)) + return; + + /* No real adata, just filling the column with spaces */ + switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) { + case FLAGS_FILL_FULL: + trace_seq_puts(s, " | "); + return; + case FLAGS_FILL_START: + trace_seq_puts(s, " "); + return; + case FLAGS_FILL_END: + trace_seq_puts(s, " |"); + return; + } + + /* Signal a overhead of time execution to the output */ + if (flags & TRACE_GRAPH_PRINT_OVERHEAD) + trace_seq_printf(s, "%c ", trace_find_mark(duration)); + else + trace_seq_puts(s, " "); + + trace_print_graph_duration(duration, s); + trace_seq_puts(s, "| "); +} + +/* 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 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 */ + print_graph_duration(duration, s, flags); + + /* Function */ + for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) + trace_seq_putc(s, ' '); + + trace_seq_printf(s, "%ps();\n", (void *)call->func); + + return trace_handle_return(s); +} + +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 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 */ + print_graph_duration(0, s, flags | FLAGS_FILL_FULL); + + /* Function */ + for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) + trace_seq_putc(s, ' '); + + trace_seq_printf(s, "%ps() {\n", (void *)call->func); + + if (trace_seq_has_overflowed(s)) + 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 void +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; + + /* Pid */ + verif_pid(s, ent->pid, cpu, data); + + if (type) + /* Interrupt */ + print_graph_irq(iter, addr, type, cpu, ent->pid, flags); + + if (!(trace_flags & TRACE_ITER_CONTEXT_INFO)) + return; + + /* Absolute time */ + if (flags & TRACE_GRAPH_PRINT_ABS_TIME) + print_graph_abs_time(iter->ts, s); + + /* Cpu */ + if (flags & TRACE_GRAPH_PRINT_CPU) + print_graph_cpu(s, cpu); + + /* Proc */ + if (flags & TRACE_GRAPH_PRINT_PROC) { + print_graph_proc(s, ent->pid); + trace_seq_puts(s, " | "); + } + + /* Latency format */ + if (trace_flags & TRACE_ITER_LATENCY_FMT) + print_graph_lat_fmt(s, ent); + + return; +} + +/* + * 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; + + print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags); + + 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 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; + } + } + + print_graph_prologue(iter, s, 0, 0, flags); + + /* Overhead and duration */ + print_graph_duration(duration, s, flags); + + /* Closing brace */ + for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) + trace_seq_putc(s, ' '); + + /* + * 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. Always do + * that if the funcgraph-tail option is enabled. + */ + if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL)) + trace_seq_puts(s, "}\n"); + else + trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func); + + /* Overrun */ + if (flags & TRACE_GRAPH_PRINT_OVERRUN) + trace_seq_printf(s, " (Overruns: %lu)\n", + trace->overrun); + + print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, + cpu, pid, flags); + + return trace_handle_return(s); +} + +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; + + print_graph_prologue(iter, s, 0, 0, flags); + + /* No time */ + print_graph_duration(0, s, flags | FLAGS_FILL_FULL); + + /* Indentation */ + if (depth > 0) + for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) + trace_seq_putc(s, ' '); + + /* The comment */ + trace_seq_puts(s, "/* "); + + 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; + } + + if (trace_seq_has_overflowed(s)) + goto out; + + /* Strip ending newline */ + if (s->buffer[s->seq.len - 1] == '\n') { + s->buffer[s->seq.len - 1] = '\0'; + s->seq.len--; + } + + trace_seq_puts(s, " */\n"); + out: + return trace_handle_return(s); +} + + +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_putc(s, '#'); + if (flags & TRACE_GRAPH_PRINT_ABS_TIME) + seq_puts(s, " TIME "); + if (flags & TRACE_GRAPH_PRINT_CPU) + seq_puts(s, " CPU"); + if (flags & TRACE_GRAPH_PRINT_PROC) + seq_puts(s, " TASK/PID "); + if (lat) + seq_puts(s, "||||"); + if (flags & TRACE_GRAPH_PRINT_DURATION) + seq_puts(s, " DURATION "); + seq_puts(s, " FUNCTION CALLS\n"); + + /* 2nd line */ + seq_putc(s, '#'); + if (flags & TRACE_GRAPH_PRINT_ABS_TIME) + seq_puts(s, " | "); + if (flags & TRACE_GRAPH_PRINT_CPU) + seq_puts(s, " | "); + if (flags & TRACE_GRAPH_PRINT_PROC) + seq_puts(s, " | | "); + if (lat) + seq_puts(s, "||||"); + if (flags & TRACE_GRAPH_PRINT_DURATION) + seq_puts(s, " | | "); + seq_puts(s, " | | | |\n"); +} + +static 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; + gfp_t gfpflags; + int cpu; + + iter->private = NULL; + + /* We can be called in atomic context via ftrace_dump() */ + gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL; + + data = kzalloc(sizeof(*data), gfpflags); + if (!data) + goto out_err; + + data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags); + 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(struct trace_array *tr, 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 __tracer_data = { + .name = "function_graph", + .update_thresh = graph_trace_update_thresh, + .open = graph_trace_open, + .pipe_open = graph_trace_open, + .close = graph_trace_close, + .pipe_close = graph_trace_close, + .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 ssize_t +graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt, + loff_t *ppos) +{ + unsigned long val; + int ret; + + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; + + max_depth = val; + + *ppos += cnt; + + return cnt; +} + +static ssize_t +graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt, + loff_t *ppos) +{ + char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/ + int n; + + n = sprintf(buf, "%d\n", max_depth); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, n); +} + +static const struct file_operations graph_depth_fops = { + .open = tracing_open_generic, + .write = graph_depth_write, + .read = graph_depth_read, + .llseek = generic_file_llseek, +}; + +static __init int init_graph_tracefs(void) +{ + struct dentry *d_tracer; + + d_tracer = tracing_init_dentry(); + if (IS_ERR(d_tracer)) + return 0; + + trace_create_file("max_graph_depth", 0644, d_tracer, + NULL, &graph_depth_fops); + + return 0; +} +fs_initcall(init_graph_tracefs); + +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); +} + +core_initcall(init_graph_trace); |