--- /dev/null
+/*
+ *
+ * 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);
Code Review / kvmfornfv.git / blobdiff