mirror of https://gitee.com/openkylin/linux.git
1790 lines
43 KiB
C
1790 lines
43 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* trace_events_synth - synthetic trace events
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*
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* Copyright (C) 2015, 2020 Tom Zanussi <tom.zanussi@linux.intel.com>
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*/
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#include <linux/module.h>
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#include <linux/kallsyms.h>
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#include <linux/security.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <linux/stacktrace.h>
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#include <linux/rculist.h>
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#include <linux/tracefs.h>
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/* for gfp flag names */
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#include <linux/trace_events.h>
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#include <trace/events/mmflags.h>
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#include "trace_synth.h"
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static int create_synth_event(int argc, const char **argv);
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static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
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static int synth_event_release(struct dyn_event *ev);
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static bool synth_event_is_busy(struct dyn_event *ev);
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static bool synth_event_match(const char *system, const char *event,
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int argc, const char **argv, struct dyn_event *ev);
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static struct dyn_event_operations synth_event_ops = {
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.create = create_synth_event,
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.show = synth_event_show,
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.is_busy = synth_event_is_busy,
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.free = synth_event_release,
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.match = synth_event_match,
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};
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static bool is_synth_event(struct dyn_event *ev)
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{
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return ev->ops == &synth_event_ops;
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}
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static struct synth_event *to_synth_event(struct dyn_event *ev)
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{
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return container_of(ev, struct synth_event, devent);
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}
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static bool synth_event_is_busy(struct dyn_event *ev)
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{
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struct synth_event *event = to_synth_event(ev);
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return event->ref != 0;
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}
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static bool synth_event_match(const char *system, const char *event,
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int argc, const char **argv, struct dyn_event *ev)
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{
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struct synth_event *sev = to_synth_event(ev);
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return strcmp(sev->name, event) == 0 &&
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(!system || strcmp(system, SYNTH_SYSTEM) == 0);
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}
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struct synth_trace_event {
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struct trace_entry ent;
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u64 fields[];
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};
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static int synth_event_define_fields(struct trace_event_call *call)
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{
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struct synth_trace_event trace;
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int offset = offsetof(typeof(trace), fields);
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struct synth_event *event = call->data;
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unsigned int i, size, n_u64;
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char *name, *type;
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bool is_signed;
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int ret = 0;
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for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
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size = event->fields[i]->size;
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is_signed = event->fields[i]->is_signed;
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type = event->fields[i]->type;
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name = event->fields[i]->name;
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ret = trace_define_field(call, type, name, offset, size,
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is_signed, FILTER_OTHER);
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if (ret)
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break;
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event->fields[i]->offset = n_u64;
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if (event->fields[i]->is_string) {
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offset += STR_VAR_LEN_MAX;
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n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
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} else {
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offset += sizeof(u64);
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n_u64++;
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}
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}
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event->n_u64 = n_u64;
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return ret;
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}
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static bool synth_field_signed(char *type)
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{
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if (str_has_prefix(type, "u"))
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return false;
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if (strcmp(type, "gfp_t") == 0)
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return false;
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return true;
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}
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static int synth_field_is_string(char *type)
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{
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if (strstr(type, "char[") != NULL)
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return true;
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return false;
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}
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static int synth_field_string_size(char *type)
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{
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char buf[4], *end, *start;
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unsigned int len;
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int size, err;
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start = strstr(type, "char[");
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if (start == NULL)
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return -EINVAL;
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start += sizeof("char[") - 1;
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end = strchr(type, ']');
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if (!end || end < start)
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return -EINVAL;
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len = end - start;
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if (len > 3)
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return -EINVAL;
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strncpy(buf, start, len);
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buf[len] = '\0';
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err = kstrtouint(buf, 0, &size);
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if (err)
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return err;
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if (size > STR_VAR_LEN_MAX)
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return -EINVAL;
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return size;
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}
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static int synth_field_size(char *type)
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{
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int size = 0;
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if (strcmp(type, "s64") == 0)
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size = sizeof(s64);
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else if (strcmp(type, "u64") == 0)
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size = sizeof(u64);
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else if (strcmp(type, "s32") == 0)
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size = sizeof(s32);
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else if (strcmp(type, "u32") == 0)
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size = sizeof(u32);
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else if (strcmp(type, "s16") == 0)
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size = sizeof(s16);
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else if (strcmp(type, "u16") == 0)
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size = sizeof(u16);
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else if (strcmp(type, "s8") == 0)
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size = sizeof(s8);
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else if (strcmp(type, "u8") == 0)
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size = sizeof(u8);
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else if (strcmp(type, "char") == 0)
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size = sizeof(char);
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else if (strcmp(type, "unsigned char") == 0)
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size = sizeof(unsigned char);
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else if (strcmp(type, "int") == 0)
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size = sizeof(int);
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else if (strcmp(type, "unsigned int") == 0)
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size = sizeof(unsigned int);
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else if (strcmp(type, "long") == 0)
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size = sizeof(long);
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else if (strcmp(type, "unsigned long") == 0)
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size = sizeof(unsigned long);
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else if (strcmp(type, "pid_t") == 0)
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size = sizeof(pid_t);
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else if (strcmp(type, "gfp_t") == 0)
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size = sizeof(gfp_t);
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else if (synth_field_is_string(type))
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size = synth_field_string_size(type);
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return size;
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}
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static const char *synth_field_fmt(char *type)
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{
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const char *fmt = "%llu";
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if (strcmp(type, "s64") == 0)
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fmt = "%lld";
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else if (strcmp(type, "u64") == 0)
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fmt = "%llu";
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else if (strcmp(type, "s32") == 0)
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fmt = "%d";
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else if (strcmp(type, "u32") == 0)
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fmt = "%u";
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else if (strcmp(type, "s16") == 0)
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fmt = "%d";
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else if (strcmp(type, "u16") == 0)
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fmt = "%u";
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else if (strcmp(type, "s8") == 0)
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fmt = "%d";
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else if (strcmp(type, "u8") == 0)
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fmt = "%u";
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else if (strcmp(type, "char") == 0)
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fmt = "%d";
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else if (strcmp(type, "unsigned char") == 0)
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fmt = "%u";
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else if (strcmp(type, "int") == 0)
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fmt = "%d";
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else if (strcmp(type, "unsigned int") == 0)
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fmt = "%u";
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else if (strcmp(type, "long") == 0)
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fmt = "%ld";
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else if (strcmp(type, "unsigned long") == 0)
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fmt = "%lu";
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else if (strcmp(type, "pid_t") == 0)
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fmt = "%d";
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else if (strcmp(type, "gfp_t") == 0)
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fmt = "%x";
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else if (synth_field_is_string(type))
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fmt = "%s";
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return fmt;
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}
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static void print_synth_event_num_val(struct trace_seq *s,
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char *print_fmt, char *name,
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int size, u64 val, char *space)
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{
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switch (size) {
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case 1:
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trace_seq_printf(s, print_fmt, name, (u8)val, space);
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break;
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case 2:
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trace_seq_printf(s, print_fmt, name, (u16)val, space);
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break;
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case 4:
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trace_seq_printf(s, print_fmt, name, (u32)val, space);
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break;
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default:
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trace_seq_printf(s, print_fmt, name, val, space);
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break;
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}
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}
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static enum print_line_t print_synth_event(struct trace_iterator *iter,
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int flags,
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struct trace_event *event)
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{
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struct trace_array *tr = iter->tr;
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struct trace_seq *s = &iter->seq;
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struct synth_trace_event *entry;
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struct synth_event *se;
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unsigned int i, n_u64;
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char print_fmt[32];
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const char *fmt;
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entry = (struct synth_trace_event *)iter->ent;
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se = container_of(event, struct synth_event, call.event);
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trace_seq_printf(s, "%s: ", se->name);
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for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
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if (trace_seq_has_overflowed(s))
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goto end;
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fmt = synth_field_fmt(se->fields[i]->type);
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/* parameter types */
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if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
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trace_seq_printf(s, "%s ", fmt);
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snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
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/* parameter values */
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if (se->fields[i]->is_string) {
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trace_seq_printf(s, print_fmt, se->fields[i]->name,
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(char *)&entry->fields[n_u64],
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i == se->n_fields - 1 ? "" : " ");
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n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
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} else {
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struct trace_print_flags __flags[] = {
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__def_gfpflag_names, {-1, NULL} };
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char *space = (i == se->n_fields - 1 ? "" : " ");
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print_synth_event_num_val(s, print_fmt,
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se->fields[i]->name,
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se->fields[i]->size,
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entry->fields[n_u64],
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space);
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if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
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trace_seq_puts(s, " (");
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trace_print_flags_seq(s, "|",
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entry->fields[n_u64],
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__flags);
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trace_seq_putc(s, ')');
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}
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n_u64++;
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}
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}
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end:
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trace_seq_putc(s, '\n');
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return trace_handle_return(s);
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}
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static struct trace_event_functions synth_event_funcs = {
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.trace = print_synth_event
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};
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static notrace void trace_event_raw_event_synth(void *__data,
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u64 *var_ref_vals,
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unsigned int *var_ref_idx)
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{
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struct trace_event_file *trace_file = __data;
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struct synth_trace_event *entry;
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struct trace_event_buffer fbuffer;
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struct trace_buffer *buffer;
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struct synth_event *event;
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unsigned int i, n_u64, val_idx;
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int fields_size = 0;
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event = trace_file->event_call->data;
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if (trace_trigger_soft_disabled(trace_file))
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return;
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fields_size = event->n_u64 * sizeof(u64);
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/*
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* Avoid ring buffer recursion detection, as this event
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* is being performed within another event.
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*/
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buffer = trace_file->tr->array_buffer.buffer;
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ring_buffer_nest_start(buffer);
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entry = trace_event_buffer_reserve(&fbuffer, trace_file,
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sizeof(*entry) + fields_size);
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if (!entry)
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goto out;
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for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
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val_idx = var_ref_idx[i];
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if (event->fields[i]->is_string) {
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char *str_val = (char *)(long)var_ref_vals[val_idx];
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char *str_field = (char *)&entry->fields[n_u64];
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strscpy(str_field, str_val, STR_VAR_LEN_MAX);
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n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
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} else {
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struct synth_field *field = event->fields[i];
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u64 val = var_ref_vals[val_idx];
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switch (field->size) {
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case 1:
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*(u8 *)&entry->fields[n_u64] = (u8)val;
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break;
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case 2:
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*(u16 *)&entry->fields[n_u64] = (u16)val;
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break;
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case 4:
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*(u32 *)&entry->fields[n_u64] = (u32)val;
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break;
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default:
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entry->fields[n_u64] = val;
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break;
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}
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n_u64++;
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}
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}
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trace_event_buffer_commit(&fbuffer);
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out:
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ring_buffer_nest_end(buffer);
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}
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static void free_synth_event_print_fmt(struct trace_event_call *call)
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{
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if (call) {
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kfree(call->print_fmt);
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call->print_fmt = NULL;
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}
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}
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static int __set_synth_event_print_fmt(struct synth_event *event,
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char *buf, int len)
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{
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const char *fmt;
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int pos = 0;
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int i;
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/* When len=0, we just calculate the needed length */
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#define LEN_OR_ZERO (len ? len - pos : 0)
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pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
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for (i = 0; i < event->n_fields; i++) {
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fmt = synth_field_fmt(event->fields[i]->type);
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pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
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event->fields[i]->name, fmt,
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i == event->n_fields - 1 ? "" : ", ");
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}
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pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
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for (i = 0; i < event->n_fields; i++) {
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pos += snprintf(buf + pos, LEN_OR_ZERO,
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", REC->%s", event->fields[i]->name);
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}
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#undef LEN_OR_ZERO
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/* return the length of print_fmt */
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return pos;
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}
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static int set_synth_event_print_fmt(struct trace_event_call *call)
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{
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struct synth_event *event = call->data;
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char *print_fmt;
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int len;
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/* First: called with 0 length to calculate the needed length */
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len = __set_synth_event_print_fmt(event, NULL, 0);
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print_fmt = kmalloc(len + 1, GFP_KERNEL);
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if (!print_fmt)
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return -ENOMEM;
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/* Second: actually write the @print_fmt */
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__set_synth_event_print_fmt(event, print_fmt, len + 1);
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call->print_fmt = print_fmt;
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return 0;
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}
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static void free_synth_field(struct synth_field *field)
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{
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kfree(field->type);
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kfree(field->name);
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kfree(field);
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}
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static struct synth_field *parse_synth_field(int argc, const char **argv,
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int *consumed)
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{
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struct synth_field *field;
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const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
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int len, ret = 0;
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if (field_type[0] == ';')
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field_type++;
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if (!strcmp(field_type, "unsigned")) {
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if (argc < 3)
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return ERR_PTR(-EINVAL);
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prefix = "unsigned ";
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field_type = argv[1];
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field_name = argv[2];
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*consumed = 3;
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} else {
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field_name = argv[1];
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*consumed = 2;
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}
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field = kzalloc(sizeof(*field), GFP_KERNEL);
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if (!field)
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return ERR_PTR(-ENOMEM);
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len = strlen(field_name);
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array = strchr(field_name, '[');
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if (array)
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len -= strlen(array);
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else if (field_name[len - 1] == ';')
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len--;
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field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
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if (!field->name) {
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ret = -ENOMEM;
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goto free;
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}
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|
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if (field_type[0] == ';')
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field_type++;
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len = strlen(field_type) + 1;
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if (array)
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len += strlen(array);
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if (prefix)
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len += strlen(prefix);
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field->type = kzalloc(len, GFP_KERNEL);
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if (!field->type) {
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ret = -ENOMEM;
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goto free;
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}
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if (prefix)
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strcat(field->type, prefix);
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strcat(field->type, field_type);
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if (array) {
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strcat(field->type, array);
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if (field->type[len - 1] == ';')
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field->type[len - 1] = '\0';
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}
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field->size = synth_field_size(field->type);
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if (!field->size) {
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ret = -EINVAL;
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goto free;
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}
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|
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if (synth_field_is_string(field->type))
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field->is_string = true;
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field->is_signed = synth_field_signed(field->type);
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out:
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|
return field;
|
|
free:
|
|
free_synth_field(field);
|
|
field = ERR_PTR(ret);
|
|
goto out;
|
|
}
|
|
|
|
static void free_synth_tracepoint(struct tracepoint *tp)
|
|
{
|
|
if (!tp)
|
|
return;
|
|
|
|
kfree(tp->name);
|
|
kfree(tp);
|
|
}
|
|
|
|
static struct tracepoint *alloc_synth_tracepoint(char *name)
|
|
{
|
|
struct tracepoint *tp;
|
|
|
|
tp = kzalloc(sizeof(*tp), GFP_KERNEL);
|
|
if (!tp)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
tp->name = kstrdup(name, GFP_KERNEL);
|
|
if (!tp->name) {
|
|
kfree(tp);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
return tp;
|
|
}
|
|
|
|
struct synth_event *find_synth_event(const char *name)
|
|
{
|
|
struct dyn_event *pos;
|
|
struct synth_event *event;
|
|
|
|
for_each_dyn_event(pos) {
|
|
if (!is_synth_event(pos))
|
|
continue;
|
|
event = to_synth_event(pos);
|
|
if (strcmp(event->name, name) == 0)
|
|
return event;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static struct trace_event_fields synth_event_fields_array[] = {
|
|
{ .type = TRACE_FUNCTION_TYPE,
|
|
.define_fields = synth_event_define_fields },
|
|
{}
|
|
};
|
|
|
|
static int register_synth_event(struct synth_event *event)
|
|
{
|
|
struct trace_event_call *call = &event->call;
|
|
int ret = 0;
|
|
|
|
event->call.class = &event->class;
|
|
event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
|
|
if (!event->class.system) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
event->tp = alloc_synth_tracepoint(event->name);
|
|
if (IS_ERR(event->tp)) {
|
|
ret = PTR_ERR(event->tp);
|
|
event->tp = NULL;
|
|
goto out;
|
|
}
|
|
|
|
INIT_LIST_HEAD(&call->class->fields);
|
|
call->event.funcs = &synth_event_funcs;
|
|
call->class->fields_array = synth_event_fields_array;
|
|
|
|
ret = register_trace_event(&call->event);
|
|
if (!ret) {
|
|
ret = -ENODEV;
|
|
goto out;
|
|
}
|
|
call->flags = TRACE_EVENT_FL_TRACEPOINT;
|
|
call->class->reg = trace_event_reg;
|
|
call->class->probe = trace_event_raw_event_synth;
|
|
call->data = event;
|
|
call->tp = event->tp;
|
|
|
|
ret = trace_add_event_call(call);
|
|
if (ret) {
|
|
pr_warn("Failed to register synthetic event: %s\n",
|
|
trace_event_name(call));
|
|
goto err;
|
|
}
|
|
|
|
ret = set_synth_event_print_fmt(call);
|
|
if (ret < 0) {
|
|
trace_remove_event_call(call);
|
|
goto err;
|
|
}
|
|
out:
|
|
return ret;
|
|
err:
|
|
unregister_trace_event(&call->event);
|
|
goto out;
|
|
}
|
|
|
|
static int unregister_synth_event(struct synth_event *event)
|
|
{
|
|
struct trace_event_call *call = &event->call;
|
|
int ret;
|
|
|
|
ret = trace_remove_event_call(call);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void free_synth_event(struct synth_event *event)
|
|
{
|
|
unsigned int i;
|
|
|
|
if (!event)
|
|
return;
|
|
|
|
for (i = 0; i < event->n_fields; i++)
|
|
free_synth_field(event->fields[i]);
|
|
|
|
kfree(event->fields);
|
|
kfree(event->name);
|
|
kfree(event->class.system);
|
|
free_synth_tracepoint(event->tp);
|
|
free_synth_event_print_fmt(&event->call);
|
|
kfree(event);
|
|
}
|
|
|
|
static struct synth_event *alloc_synth_event(const char *name, int n_fields,
|
|
struct synth_field **fields)
|
|
{
|
|
struct synth_event *event;
|
|
unsigned int i;
|
|
|
|
event = kzalloc(sizeof(*event), GFP_KERNEL);
|
|
if (!event) {
|
|
event = ERR_PTR(-ENOMEM);
|
|
goto out;
|
|
}
|
|
|
|
event->name = kstrdup(name, GFP_KERNEL);
|
|
if (!event->name) {
|
|
kfree(event);
|
|
event = ERR_PTR(-ENOMEM);
|
|
goto out;
|
|
}
|
|
|
|
event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
|
|
if (!event->fields) {
|
|
free_synth_event(event);
|
|
event = ERR_PTR(-ENOMEM);
|
|
goto out;
|
|
}
|
|
|
|
dyn_event_init(&event->devent, &synth_event_ops);
|
|
|
|
for (i = 0; i < n_fields; i++)
|
|
event->fields[i] = fields[i];
|
|
|
|
event->n_fields = n_fields;
|
|
out:
|
|
return event;
|
|
}
|
|
|
|
static int synth_event_check_arg_fn(void *data)
|
|
{
|
|
struct dynevent_arg_pair *arg_pair = data;
|
|
int size;
|
|
|
|
size = synth_field_size((char *)arg_pair->lhs);
|
|
|
|
return size ? 0 : -EINVAL;
|
|
}
|
|
|
|
/**
|
|
* synth_event_add_field - Add a new field to a synthetic event cmd
|
|
* @cmd: A pointer to the dynevent_cmd struct representing the new event
|
|
* @type: The type of the new field to add
|
|
* @name: The name of the new field to add
|
|
*
|
|
* Add a new field to a synthetic event cmd object. Field ordering is in
|
|
* the same order the fields are added.
|
|
*
|
|
* See synth_field_size() for available types. If field_name contains
|
|
* [n] the field is considered to be an array.
|
|
*
|
|
* Return: 0 if successful, error otherwise.
|
|
*/
|
|
int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
|
|
const char *name)
|
|
{
|
|
struct dynevent_arg_pair arg_pair;
|
|
int ret;
|
|
|
|
if (cmd->type != DYNEVENT_TYPE_SYNTH)
|
|
return -EINVAL;
|
|
|
|
if (!type || !name)
|
|
return -EINVAL;
|
|
|
|
dynevent_arg_pair_init(&arg_pair, 0, ';');
|
|
|
|
arg_pair.lhs = type;
|
|
arg_pair.rhs = name;
|
|
|
|
ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (++cmd->n_fields > SYNTH_FIELDS_MAX)
|
|
ret = -EINVAL;
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_add_field);
|
|
|
|
/**
|
|
* synth_event_add_field_str - Add a new field to a synthetic event cmd
|
|
* @cmd: A pointer to the dynevent_cmd struct representing the new event
|
|
* @type_name: The type and name of the new field to add, as a single string
|
|
*
|
|
* Add a new field to a synthetic event cmd object, as a single
|
|
* string. The @type_name string is expected to be of the form 'type
|
|
* name', which will be appended by ';'. No sanity checking is done -
|
|
* what's passed in is assumed to already be well-formed. Field
|
|
* ordering is in the same order the fields are added.
|
|
*
|
|
* See synth_field_size() for available types. If field_name contains
|
|
* [n] the field is considered to be an array.
|
|
*
|
|
* Return: 0 if successful, error otherwise.
|
|
*/
|
|
int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
|
|
{
|
|
struct dynevent_arg arg;
|
|
int ret;
|
|
|
|
if (cmd->type != DYNEVENT_TYPE_SYNTH)
|
|
return -EINVAL;
|
|
|
|
if (!type_name)
|
|
return -EINVAL;
|
|
|
|
dynevent_arg_init(&arg, ';');
|
|
|
|
arg.str = type_name;
|
|
|
|
ret = dynevent_arg_add(cmd, &arg, NULL);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (++cmd->n_fields > SYNTH_FIELDS_MAX)
|
|
ret = -EINVAL;
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_add_field_str);
|
|
|
|
/**
|
|
* synth_event_add_fields - Add multiple fields to a synthetic event cmd
|
|
* @cmd: A pointer to the dynevent_cmd struct representing the new event
|
|
* @fields: An array of type/name field descriptions
|
|
* @n_fields: The number of field descriptions contained in the fields array
|
|
*
|
|
* Add a new set of fields to a synthetic event cmd object. The event
|
|
* fields that will be defined for the event should be passed in as an
|
|
* array of struct synth_field_desc, and the number of elements in the
|
|
* array passed in as n_fields. Field ordering will retain the
|
|
* ordering given in the fields array.
|
|
*
|
|
* See synth_field_size() for available types. If field_name contains
|
|
* [n] the field is considered to be an array.
|
|
*
|
|
* Return: 0 if successful, error otherwise.
|
|
*/
|
|
int synth_event_add_fields(struct dynevent_cmd *cmd,
|
|
struct synth_field_desc *fields,
|
|
unsigned int n_fields)
|
|
{
|
|
unsigned int i;
|
|
int ret = 0;
|
|
|
|
for (i = 0; i < n_fields; i++) {
|
|
if (fields[i].type == NULL || fields[i].name == NULL) {
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_add_fields);
|
|
|
|
/**
|
|
* __synth_event_gen_cmd_start - Start a synthetic event command from arg list
|
|
* @cmd: A pointer to the dynevent_cmd struct representing the new event
|
|
* @name: The name of the synthetic event
|
|
* @mod: The module creating the event, NULL if not created from a module
|
|
* @args: Variable number of arg (pairs), one pair for each field
|
|
*
|
|
* NOTE: Users normally won't want to call this function directly, but
|
|
* rather use the synth_event_gen_cmd_start() wrapper, which
|
|
* automatically adds a NULL to the end of the arg list. If this
|
|
* function is used directly, make sure the last arg in the variable
|
|
* arg list is NULL.
|
|
*
|
|
* Generate a synthetic event command to be executed by
|
|
* synth_event_gen_cmd_end(). This function can be used to generate
|
|
* the complete command or only the first part of it; in the latter
|
|
* case, synth_event_add_field(), synth_event_add_field_str(), or
|
|
* synth_event_add_fields() can be used to add more fields following
|
|
* this.
|
|
*
|
|
* There should be an even number variable args, each pair consisting
|
|
* of a type followed by a field name.
|
|
*
|
|
* See synth_field_size() for available types. If field_name contains
|
|
* [n] the field is considered to be an array.
|
|
*
|
|
* Return: 0 if successful, error otherwise.
|
|
*/
|
|
int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
|
|
struct module *mod, ...)
|
|
{
|
|
struct dynevent_arg arg;
|
|
va_list args;
|
|
int ret;
|
|
|
|
cmd->event_name = name;
|
|
cmd->private_data = mod;
|
|
|
|
if (cmd->type != DYNEVENT_TYPE_SYNTH)
|
|
return -EINVAL;
|
|
|
|
dynevent_arg_init(&arg, 0);
|
|
arg.str = name;
|
|
ret = dynevent_arg_add(cmd, &arg, NULL);
|
|
if (ret)
|
|
return ret;
|
|
|
|
va_start(args, mod);
|
|
for (;;) {
|
|
const char *type, *name;
|
|
|
|
type = va_arg(args, const char *);
|
|
if (!type)
|
|
break;
|
|
name = va_arg(args, const char *);
|
|
if (!name)
|
|
break;
|
|
|
|
if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
ret = synth_event_add_field(cmd, type, name);
|
|
if (ret)
|
|
break;
|
|
}
|
|
va_end(args);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
|
|
|
|
/**
|
|
* synth_event_gen_cmd_array_start - Start synthetic event command from an array
|
|
* @cmd: A pointer to the dynevent_cmd struct representing the new event
|
|
* @name: The name of the synthetic event
|
|
* @fields: An array of type/name field descriptions
|
|
* @n_fields: The number of field descriptions contained in the fields array
|
|
*
|
|
* Generate a synthetic event command to be executed by
|
|
* synth_event_gen_cmd_end(). This function can be used to generate
|
|
* the complete command or only the first part of it; in the latter
|
|
* case, synth_event_add_field(), synth_event_add_field_str(), or
|
|
* synth_event_add_fields() can be used to add more fields following
|
|
* this.
|
|
*
|
|
* The event fields that will be defined for the event should be
|
|
* passed in as an array of struct synth_field_desc, and the number of
|
|
* elements in the array passed in as n_fields. Field ordering will
|
|
* retain the ordering given in the fields array.
|
|
*
|
|
* See synth_field_size() for available types. If field_name contains
|
|
* [n] the field is considered to be an array.
|
|
*
|
|
* Return: 0 if successful, error otherwise.
|
|
*/
|
|
int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
|
|
struct module *mod,
|
|
struct synth_field_desc *fields,
|
|
unsigned int n_fields)
|
|
{
|
|
struct dynevent_arg arg;
|
|
unsigned int i;
|
|
int ret = 0;
|
|
|
|
cmd->event_name = name;
|
|
cmd->private_data = mod;
|
|
|
|
if (cmd->type != DYNEVENT_TYPE_SYNTH)
|
|
return -EINVAL;
|
|
|
|
if (n_fields > SYNTH_FIELDS_MAX)
|
|
return -EINVAL;
|
|
|
|
dynevent_arg_init(&arg, 0);
|
|
arg.str = name;
|
|
ret = dynevent_arg_add(cmd, &arg, NULL);
|
|
if (ret)
|
|
return ret;
|
|
|
|
for (i = 0; i < n_fields; i++) {
|
|
if (fields[i].type == NULL || fields[i].name == NULL)
|
|
return -EINVAL;
|
|
|
|
ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
|
|
|
|
static int __create_synth_event(int argc, const char *name, const char **argv)
|
|
{
|
|
struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
|
|
struct synth_event *event = NULL;
|
|
int i, consumed = 0, n_fields = 0, ret = 0;
|
|
|
|
/*
|
|
* Argument syntax:
|
|
* - Add synthetic event: <event_name> field[;field] ...
|
|
* - Remove synthetic event: !<event_name> field[;field] ...
|
|
* where 'field' = type field_name
|
|
*/
|
|
|
|
if (name[0] == '\0' || argc < 1)
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&event_mutex);
|
|
|
|
event = find_synth_event(name);
|
|
if (event) {
|
|
ret = -EEXIST;
|
|
goto out;
|
|
}
|
|
|
|
for (i = 0; i < argc - 1; i++) {
|
|
if (strcmp(argv[i], ";") == 0)
|
|
continue;
|
|
if (n_fields == SYNTH_FIELDS_MAX) {
|
|
ret = -EINVAL;
|
|
goto err;
|
|
}
|
|
|
|
field = parse_synth_field(argc - i, &argv[i], &consumed);
|
|
if (IS_ERR(field)) {
|
|
ret = PTR_ERR(field);
|
|
goto err;
|
|
}
|
|
fields[n_fields++] = field;
|
|
i += consumed - 1;
|
|
}
|
|
|
|
if (i < argc && strcmp(argv[i], ";") != 0) {
|
|
ret = -EINVAL;
|
|
goto err;
|
|
}
|
|
|
|
event = alloc_synth_event(name, n_fields, fields);
|
|
if (IS_ERR(event)) {
|
|
ret = PTR_ERR(event);
|
|
event = NULL;
|
|
goto err;
|
|
}
|
|
ret = register_synth_event(event);
|
|
if (!ret)
|
|
dyn_event_add(&event->devent);
|
|
else
|
|
free_synth_event(event);
|
|
out:
|
|
mutex_unlock(&event_mutex);
|
|
|
|
return ret;
|
|
err:
|
|
for (i = 0; i < n_fields; i++)
|
|
free_synth_field(fields[i]);
|
|
|
|
goto out;
|
|
}
|
|
|
|
/**
|
|
* synth_event_create - Create a new synthetic event
|
|
* @name: The name of the new sythetic event
|
|
* @fields: An array of type/name field descriptions
|
|
* @n_fields: The number of field descriptions contained in the fields array
|
|
* @mod: The module creating the event, NULL if not created from a module
|
|
*
|
|
* Create a new synthetic event with the given name under the
|
|
* trace/events/synthetic/ directory. The event fields that will be
|
|
* defined for the event should be passed in as an array of struct
|
|
* synth_field_desc, and the number elements in the array passed in as
|
|
* n_fields. Field ordering will retain the ordering given in the
|
|
* fields array.
|
|
*
|
|
* If the new synthetic event is being created from a module, the mod
|
|
* param must be non-NULL. This will ensure that the trace buffer
|
|
* won't contain unreadable events.
|
|
*
|
|
* The new synth event should be deleted using synth_event_delete()
|
|
* function. The new synthetic event can be generated from modules or
|
|
* other kernel code using trace_synth_event() and related functions.
|
|
*
|
|
* Return: 0 if successful, error otherwise.
|
|
*/
|
|
int synth_event_create(const char *name, struct synth_field_desc *fields,
|
|
unsigned int n_fields, struct module *mod)
|
|
{
|
|
struct dynevent_cmd cmd;
|
|
char *buf;
|
|
int ret;
|
|
|
|
buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
|
|
if (!buf)
|
|
return -ENOMEM;
|
|
|
|
synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
|
|
|
|
ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
|
|
fields, n_fields);
|
|
if (ret)
|
|
goto out;
|
|
|
|
ret = synth_event_gen_cmd_end(&cmd);
|
|
out:
|
|
kfree(buf);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_create);
|
|
|
|
static int destroy_synth_event(struct synth_event *se)
|
|
{
|
|
int ret;
|
|
|
|
if (se->ref)
|
|
ret = -EBUSY;
|
|
else {
|
|
ret = unregister_synth_event(se);
|
|
if (!ret) {
|
|
dyn_event_remove(&se->devent);
|
|
free_synth_event(se);
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* synth_event_delete - Delete a synthetic event
|
|
* @event_name: The name of the new sythetic event
|
|
*
|
|
* Delete a synthetic event that was created with synth_event_create().
|
|
*
|
|
* Return: 0 if successful, error otherwise.
|
|
*/
|
|
int synth_event_delete(const char *event_name)
|
|
{
|
|
struct synth_event *se = NULL;
|
|
struct module *mod = NULL;
|
|
int ret = -ENOENT;
|
|
|
|
mutex_lock(&event_mutex);
|
|
se = find_synth_event(event_name);
|
|
if (se) {
|
|
mod = se->mod;
|
|
ret = destroy_synth_event(se);
|
|
}
|
|
mutex_unlock(&event_mutex);
|
|
|
|
if (mod) {
|
|
mutex_lock(&trace_types_lock);
|
|
/*
|
|
* It is safest to reset the ring buffer if the module
|
|
* being unloaded registered any events that were
|
|
* used. The only worry is if a new module gets
|
|
* loaded, and takes on the same id as the events of
|
|
* this module. When printing out the buffer, traced
|
|
* events left over from this module may be passed to
|
|
* the new module events and unexpected results may
|
|
* occur.
|
|
*/
|
|
tracing_reset_all_online_cpus();
|
|
mutex_unlock(&trace_types_lock);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_delete);
|
|
|
|
static int create_or_delete_synth_event(int argc, char **argv)
|
|
{
|
|
const char *name = argv[0];
|
|
int ret;
|
|
|
|
/* trace_run_command() ensures argc != 0 */
|
|
if (name[0] == '!') {
|
|
ret = synth_event_delete(name + 1);
|
|
return ret;
|
|
}
|
|
|
|
ret = __create_synth_event(argc - 1, name, (const char **)argv + 1);
|
|
return ret == -ECANCELED ? -EINVAL : ret;
|
|
}
|
|
|
|
static int synth_event_run_command(struct dynevent_cmd *cmd)
|
|
{
|
|
struct synth_event *se;
|
|
int ret;
|
|
|
|
ret = trace_run_command(cmd->seq.buffer, create_or_delete_synth_event);
|
|
if (ret)
|
|
return ret;
|
|
|
|
se = find_synth_event(cmd->event_name);
|
|
if (WARN_ON(!se))
|
|
return -ENOENT;
|
|
|
|
se->mod = cmd->private_data;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* synth_event_cmd_init - Initialize a synthetic event command object
|
|
* @cmd: A pointer to the dynevent_cmd struct representing the new event
|
|
* @buf: A pointer to the buffer used to build the command
|
|
* @maxlen: The length of the buffer passed in @buf
|
|
*
|
|
* Initialize a synthetic event command object. Use this before
|
|
* calling any of the other dyenvent_cmd functions.
|
|
*/
|
|
void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
|
|
{
|
|
dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
|
|
synth_event_run_command);
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_cmd_init);
|
|
|
|
static inline int
|
|
__synth_event_trace_start(struct trace_event_file *file,
|
|
struct synth_event_trace_state *trace_state)
|
|
{
|
|
int entry_size, fields_size = 0;
|
|
int ret = 0;
|
|
|
|
memset(trace_state, '\0', sizeof(*trace_state));
|
|
|
|
/*
|
|
* Normal event tracing doesn't get called at all unless the
|
|
* ENABLED bit is set (which attaches the probe thus allowing
|
|
* this code to be called, etc). Because this is called
|
|
* directly by the user, we don't have that but we still need
|
|
* to honor not logging when disabled. For the the iterated
|
|
* trace case, we save the enabed state upon start and just
|
|
* ignore the following data calls.
|
|
*/
|
|
if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
|
|
trace_trigger_soft_disabled(file)) {
|
|
trace_state->disabled = true;
|
|
ret = -ENOENT;
|
|
goto out;
|
|
}
|
|
|
|
trace_state->event = file->event_call->data;
|
|
|
|
fields_size = trace_state->event->n_u64 * sizeof(u64);
|
|
|
|
/*
|
|
* Avoid ring buffer recursion detection, as this event
|
|
* is being performed within another event.
|
|
*/
|
|
trace_state->buffer = file->tr->array_buffer.buffer;
|
|
ring_buffer_nest_start(trace_state->buffer);
|
|
|
|
entry_size = sizeof(*trace_state->entry) + fields_size;
|
|
trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
|
|
file,
|
|
entry_size);
|
|
if (!trace_state->entry) {
|
|
ring_buffer_nest_end(trace_state->buffer);
|
|
ret = -EINVAL;
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static inline void
|
|
__synth_event_trace_end(struct synth_event_trace_state *trace_state)
|
|
{
|
|
trace_event_buffer_commit(&trace_state->fbuffer);
|
|
|
|
ring_buffer_nest_end(trace_state->buffer);
|
|
}
|
|
|
|
/**
|
|
* synth_event_trace - Trace a synthetic event
|
|
* @file: The trace_event_file representing the synthetic event
|
|
* @n_vals: The number of values in vals
|
|
* @args: Variable number of args containing the event values
|
|
*
|
|
* Trace a synthetic event using the values passed in the variable
|
|
* argument list.
|
|
*
|
|
* The argument list should be a list 'n_vals' u64 values. The number
|
|
* of vals must match the number of field in the synthetic event, and
|
|
* must be in the same order as the synthetic event fields.
|
|
*
|
|
* All vals should be cast to u64, and string vals are just pointers
|
|
* to strings, cast to u64. Strings will be copied into space
|
|
* reserved in the event for the string, using these pointers.
|
|
*
|
|
* Return: 0 on success, err otherwise.
|
|
*/
|
|
int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
|
|
{
|
|
struct synth_event_trace_state state;
|
|
unsigned int i, n_u64;
|
|
va_list args;
|
|
int ret;
|
|
|
|
ret = __synth_event_trace_start(file, &state);
|
|
if (ret) {
|
|
if (ret == -ENOENT)
|
|
ret = 0; /* just disabled, not really an error */
|
|
return ret;
|
|
}
|
|
|
|
if (n_vals != state.event->n_fields) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
va_start(args, n_vals);
|
|
for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
|
|
u64 val;
|
|
|
|
val = va_arg(args, u64);
|
|
|
|
if (state.event->fields[i]->is_string) {
|
|
char *str_val = (char *)(long)val;
|
|
char *str_field = (char *)&state.entry->fields[n_u64];
|
|
|
|
strscpy(str_field, str_val, STR_VAR_LEN_MAX);
|
|
n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
|
|
} else {
|
|
struct synth_field *field = state.event->fields[i];
|
|
|
|
switch (field->size) {
|
|
case 1:
|
|
*(u8 *)&state.entry->fields[n_u64] = (u8)val;
|
|
break;
|
|
|
|
case 2:
|
|
*(u16 *)&state.entry->fields[n_u64] = (u16)val;
|
|
break;
|
|
|
|
case 4:
|
|
*(u32 *)&state.entry->fields[n_u64] = (u32)val;
|
|
break;
|
|
|
|
default:
|
|
state.entry->fields[n_u64] = val;
|
|
break;
|
|
}
|
|
n_u64++;
|
|
}
|
|
}
|
|
va_end(args);
|
|
out:
|
|
__synth_event_trace_end(&state);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_trace);
|
|
|
|
/**
|
|
* synth_event_trace_array - Trace a synthetic event from an array
|
|
* @file: The trace_event_file representing the synthetic event
|
|
* @vals: Array of values
|
|
* @n_vals: The number of values in vals
|
|
*
|
|
* Trace a synthetic event using the values passed in as 'vals'.
|
|
*
|
|
* The 'vals' array is just an array of 'n_vals' u64. The number of
|
|
* vals must match the number of field in the synthetic event, and
|
|
* must be in the same order as the synthetic event fields.
|
|
*
|
|
* All vals should be cast to u64, and string vals are just pointers
|
|
* to strings, cast to u64. Strings will be copied into space
|
|
* reserved in the event for the string, using these pointers.
|
|
*
|
|
* Return: 0 on success, err otherwise.
|
|
*/
|
|
int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
|
|
unsigned int n_vals)
|
|
{
|
|
struct synth_event_trace_state state;
|
|
unsigned int i, n_u64;
|
|
int ret;
|
|
|
|
ret = __synth_event_trace_start(file, &state);
|
|
if (ret) {
|
|
if (ret == -ENOENT)
|
|
ret = 0; /* just disabled, not really an error */
|
|
return ret;
|
|
}
|
|
|
|
if (n_vals != state.event->n_fields) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
|
|
if (state.event->fields[i]->is_string) {
|
|
char *str_val = (char *)(long)vals[i];
|
|
char *str_field = (char *)&state.entry->fields[n_u64];
|
|
|
|
strscpy(str_field, str_val, STR_VAR_LEN_MAX);
|
|
n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
|
|
} else {
|
|
struct synth_field *field = state.event->fields[i];
|
|
u64 val = vals[i];
|
|
|
|
switch (field->size) {
|
|
case 1:
|
|
*(u8 *)&state.entry->fields[n_u64] = (u8)val;
|
|
break;
|
|
|
|
case 2:
|
|
*(u16 *)&state.entry->fields[n_u64] = (u16)val;
|
|
break;
|
|
|
|
case 4:
|
|
*(u32 *)&state.entry->fields[n_u64] = (u32)val;
|
|
break;
|
|
|
|
default:
|
|
state.entry->fields[n_u64] = val;
|
|
break;
|
|
}
|
|
n_u64++;
|
|
}
|
|
}
|
|
out:
|
|
__synth_event_trace_end(&state);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_trace_array);
|
|
|
|
/**
|
|
* synth_event_trace_start - Start piecewise synthetic event trace
|
|
* @file: The trace_event_file representing the synthetic event
|
|
* @trace_state: A pointer to object tracking the piecewise trace state
|
|
*
|
|
* Start the trace of a synthetic event field-by-field rather than all
|
|
* at once.
|
|
*
|
|
* This function 'opens' an event trace, which means space is reserved
|
|
* for the event in the trace buffer, after which the event's
|
|
* individual field values can be set through either
|
|
* synth_event_add_next_val() or synth_event_add_val().
|
|
*
|
|
* A pointer to a trace_state object is passed in, which will keep
|
|
* track of the current event trace state until the event trace is
|
|
* closed (and the event finally traced) using
|
|
* synth_event_trace_end().
|
|
*
|
|
* Note that synth_event_trace_end() must be called after all values
|
|
* have been added for each event trace, regardless of whether adding
|
|
* all field values succeeded or not.
|
|
*
|
|
* Note also that for a given event trace, all fields must be added
|
|
* using either synth_event_add_next_val() or synth_event_add_val()
|
|
* but not both together or interleaved.
|
|
*
|
|
* Return: 0 on success, err otherwise.
|
|
*/
|
|
int synth_event_trace_start(struct trace_event_file *file,
|
|
struct synth_event_trace_state *trace_state)
|
|
{
|
|
int ret;
|
|
|
|
if (!trace_state)
|
|
return -EINVAL;
|
|
|
|
ret = __synth_event_trace_start(file, trace_state);
|
|
if (ret == -ENOENT)
|
|
ret = 0; /* just disabled, not really an error */
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_trace_start);
|
|
|
|
static int __synth_event_add_val(const char *field_name, u64 val,
|
|
struct synth_event_trace_state *trace_state)
|
|
{
|
|
struct synth_field *field = NULL;
|
|
struct synth_trace_event *entry;
|
|
struct synth_event *event;
|
|
int i, ret = 0;
|
|
|
|
if (!trace_state) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* can't mix add_next_synth_val() with add_synth_val() */
|
|
if (field_name) {
|
|
if (trace_state->add_next) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
trace_state->add_name = true;
|
|
} else {
|
|
if (trace_state->add_name) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
trace_state->add_next = true;
|
|
}
|
|
|
|
if (trace_state->disabled)
|
|
goto out;
|
|
|
|
event = trace_state->event;
|
|
if (trace_state->add_name) {
|
|
for (i = 0; i < event->n_fields; i++) {
|
|
field = event->fields[i];
|
|
if (strcmp(field->name, field_name) == 0)
|
|
break;
|
|
}
|
|
if (!field) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
} else {
|
|
if (trace_state->cur_field >= event->n_fields) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
field = event->fields[trace_state->cur_field++];
|
|
}
|
|
|
|
entry = trace_state->entry;
|
|
if (field->is_string) {
|
|
char *str_val = (char *)(long)val;
|
|
char *str_field;
|
|
|
|
if (!str_val) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
str_field = (char *)&entry->fields[field->offset];
|
|
strscpy(str_field, str_val, STR_VAR_LEN_MAX);
|
|
} else {
|
|
switch (field->size) {
|
|
case 1:
|
|
*(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
|
|
break;
|
|
|
|
case 2:
|
|
*(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
|
|
break;
|
|
|
|
case 4:
|
|
*(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
|
|
break;
|
|
|
|
default:
|
|
trace_state->entry->fields[field->offset] = val;
|
|
break;
|
|
}
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* synth_event_add_next_val - Add the next field's value to an open synth trace
|
|
* @val: The value to set the next field to
|
|
* @trace_state: A pointer to object tracking the piecewise trace state
|
|
*
|
|
* Set the value of the next field in an event that's been opened by
|
|
* synth_event_trace_start().
|
|
*
|
|
* The val param should be the value cast to u64. If the value points
|
|
* to a string, the val param should be a char * cast to u64.
|
|
*
|
|
* This function assumes all the fields in an event are to be set one
|
|
* after another - successive calls to this function are made, one for
|
|
* each field, in the order of the fields in the event, until all
|
|
* fields have been set. If you'd rather set each field individually
|
|
* without regard to ordering, synth_event_add_val() can be used
|
|
* instead.
|
|
*
|
|
* Note however that synth_event_add_next_val() and
|
|
* synth_event_add_val() can't be intermixed for a given event trace -
|
|
* one or the other but not both can be used at the same time.
|
|
*
|
|
* Note also that synth_event_trace_end() must be called after all
|
|
* values have been added for each event trace, regardless of whether
|
|
* adding all field values succeeded or not.
|
|
*
|
|
* Return: 0 on success, err otherwise.
|
|
*/
|
|
int synth_event_add_next_val(u64 val,
|
|
struct synth_event_trace_state *trace_state)
|
|
{
|
|
return __synth_event_add_val(NULL, val, trace_state);
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_add_next_val);
|
|
|
|
/**
|
|
* synth_event_add_val - Add a named field's value to an open synth trace
|
|
* @field_name: The name of the synthetic event field value to set
|
|
* @val: The value to set the next field to
|
|
* @trace_state: A pointer to object tracking the piecewise trace state
|
|
*
|
|
* Set the value of the named field in an event that's been opened by
|
|
* synth_event_trace_start().
|
|
*
|
|
* The val param should be the value cast to u64. If the value points
|
|
* to a string, the val param should be a char * cast to u64.
|
|
*
|
|
* This function looks up the field name, and if found, sets the field
|
|
* to the specified value. This lookup makes this function more
|
|
* expensive than synth_event_add_next_val(), so use that or the
|
|
* none-piecewise synth_event_trace() instead if efficiency is more
|
|
* important.
|
|
*
|
|
* Note however that synth_event_add_next_val() and
|
|
* synth_event_add_val() can't be intermixed for a given event trace -
|
|
* one or the other but not both can be used at the same time.
|
|
*
|
|
* Note also that synth_event_trace_end() must be called after all
|
|
* values have been added for each event trace, regardless of whether
|
|
* adding all field values succeeded or not.
|
|
*
|
|
* Return: 0 on success, err otherwise.
|
|
*/
|
|
int synth_event_add_val(const char *field_name, u64 val,
|
|
struct synth_event_trace_state *trace_state)
|
|
{
|
|
return __synth_event_add_val(field_name, val, trace_state);
|
|
}
|
|
EXPORT_SYMBOL_GPL(synth_event_add_val);
|
|
|
|
/**
|
|
* synth_event_trace_end - End piecewise synthetic event trace
|
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* @trace_state: A pointer to object tracking the piecewise trace state
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*
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* End the trace of a synthetic event opened by
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* synth_event_trace__start().
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*
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* This function 'closes' an event trace, which basically means that
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* it commits the reserved event and cleans up other loose ends.
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*
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* A pointer to a trace_state object is passed in, which will keep
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* track of the current event trace state opened with
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* synth_event_trace_start().
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*
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* Note that this function must be called after all values have been
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* added for each event trace, regardless of whether adding all field
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* values succeeded or not.
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*
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* Return: 0 on success, err otherwise.
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*/
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int synth_event_trace_end(struct synth_event_trace_state *trace_state)
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{
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if (!trace_state)
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return -EINVAL;
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__synth_event_trace_end(trace_state);
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return 0;
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}
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EXPORT_SYMBOL_GPL(synth_event_trace_end);
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static int create_synth_event(int argc, const char **argv)
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{
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const char *name = argv[0];
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int len;
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if (name[0] != 's' || name[1] != ':')
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return -ECANCELED;
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name += 2;
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/* This interface accepts group name prefix */
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if (strchr(name, '/')) {
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len = str_has_prefix(name, SYNTH_SYSTEM "/");
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if (len == 0)
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return -EINVAL;
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name += len;
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}
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return __create_synth_event(argc - 1, name, argv + 1);
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}
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static int synth_event_release(struct dyn_event *ev)
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{
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struct synth_event *event = to_synth_event(ev);
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int ret;
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if (event->ref)
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return -EBUSY;
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ret = unregister_synth_event(event);
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if (ret)
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return ret;
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dyn_event_remove(ev);
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free_synth_event(event);
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return 0;
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}
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static int __synth_event_show(struct seq_file *m, struct synth_event *event)
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{
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struct synth_field *field;
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unsigned int i;
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seq_printf(m, "%s\t", event->name);
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for (i = 0; i < event->n_fields; i++) {
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field = event->fields[i];
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/* parameter values */
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seq_printf(m, "%s %s%s", field->type, field->name,
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i == event->n_fields - 1 ? "" : "; ");
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}
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seq_putc(m, '\n');
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return 0;
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}
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static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
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{
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struct synth_event *event = to_synth_event(ev);
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seq_printf(m, "s:%s/", event->class.system);
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return __synth_event_show(m, event);
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}
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static int synth_events_seq_show(struct seq_file *m, void *v)
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{
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struct dyn_event *ev = v;
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if (!is_synth_event(ev))
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return 0;
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return __synth_event_show(m, to_synth_event(ev));
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}
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static const struct seq_operations synth_events_seq_op = {
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.start = dyn_event_seq_start,
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.next = dyn_event_seq_next,
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.stop = dyn_event_seq_stop,
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.show = synth_events_seq_show,
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};
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static int synth_events_open(struct inode *inode, struct file *file)
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|
{
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|
int ret;
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|
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|
ret = security_locked_down(LOCKDOWN_TRACEFS);
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|
if (ret)
|
|
return ret;
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|
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if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
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|
ret = dyn_events_release_all(&synth_event_ops);
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|
if (ret < 0)
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|
return ret;
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|
}
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|
|
|
return seq_open(file, &synth_events_seq_op);
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|
}
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|
|
|
static ssize_t synth_events_write(struct file *file,
|
|
const char __user *buffer,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
return trace_parse_run_command(file, buffer, count, ppos,
|
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create_or_delete_synth_event);
|
|
}
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|
|
|
static const struct file_operations synth_events_fops = {
|
|
.open = synth_events_open,
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|
.write = synth_events_write,
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|
.read = seq_read,
|
|
.llseek = seq_lseek,
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|
.release = seq_release,
|
|
};
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|
|
|
static __init int trace_events_synth_init(void)
|
|
{
|
|
struct dentry *entry = NULL;
|
|
struct dentry *d_tracer;
|
|
int err = 0;
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|
|
|
err = dyn_event_register(&synth_event_ops);
|
|
if (err) {
|
|
pr_warn("Could not register synth_event_ops\n");
|
|
return err;
|
|
}
|
|
|
|
d_tracer = tracing_init_dentry();
|
|
if (IS_ERR(d_tracer)) {
|
|
err = PTR_ERR(d_tracer);
|
|
goto err;
|
|
}
|
|
|
|
entry = tracefs_create_file("synthetic_events", 0644, d_tracer,
|
|
NULL, &synth_events_fops);
|
|
if (!entry) {
|
|
err = -ENODEV;
|
|
goto err;
|
|
}
|
|
|
|
return err;
|
|
err:
|
|
pr_warn("Could not create tracefs 'synthetic_events' entry\n");
|
|
|
|
return err;
|
|
}
|
|
|
|
fs_initcall(trace_events_synth_init);
|