diff options
Diffstat (limited to 'kernel/trace/trace_kprobe.c')
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 238 |
1 files changed, 204 insertions, 34 deletions
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index aa515d578c5b..d8264ebb9581 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -22,7 +22,6 @@ #define KPROBE_EVENT_SYSTEM "kprobes" #define KRETPROBE_MAXACTIVE_MAX 4096 -#define MAX_KPROBE_CMDLINE_SIZE 1024 /* Kprobe early definition from command line */ static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata; @@ -902,6 +901,167 @@ static int create_or_delete_trace_kprobe(int argc, char **argv) return ret == -ECANCELED ? -EINVAL : ret; } +static int trace_kprobe_run_command(struct dynevent_cmd *cmd) +{ + return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe); +} + +/** + * kprobe_event_cmd_init - Initialize a kprobe 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 kprobe_event functions. + */ +void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen) +{ + dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE, + trace_kprobe_run_command); +} +EXPORT_SYMBOL_GPL(kprobe_event_cmd_init); + +/** + * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @name: The name of the kprobe event + * @loc: The location of the kprobe event + * @kretprobe: Is this a return probe? + * @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 kprobe_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 kprobe event command to be executed by + * kprobe_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, + * kprobe_event_add_fields() can be used to add more fields following this. + * + * Return: 0 if successful, error otherwise. + */ +int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe, + const char *name, const char *loc, ...) +{ + char buf[MAX_EVENT_NAME_LEN]; + struct dynevent_arg arg; + va_list args; + int ret; + + if (cmd->type != DYNEVENT_TYPE_KPROBE) + return -EINVAL; + + if (kretprobe) + snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name); + else + snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name); + + ret = dynevent_str_add(cmd, buf); + if (ret) + return ret; + + dynevent_arg_init(&arg, 0); + arg.str = loc; + ret = dynevent_arg_add(cmd, &arg, NULL); + if (ret) + return ret; + + va_start(args, loc); + for (;;) { + const char *field; + + field = va_arg(args, const char *); + if (!field) + break; + + if (++cmd->n_fields > MAX_TRACE_ARGS) { + ret = -EINVAL; + break; + } + + arg.str = field; + ret = dynevent_arg_add(cmd, &arg, NULL); + if (ret) + break; + } + va_end(args); + + return ret; +} +EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start); + +/** + * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @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 kprobe_event_add_fields() 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. + * + * Add probe fields to an existing kprobe command using a variable + * list of args. Fields are added in the same order they're listed. + * + * Return: 0 if successful, error otherwise. + */ +int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...) +{ + struct dynevent_arg arg; + va_list args; + int ret; + + if (cmd->type != DYNEVENT_TYPE_KPROBE) + return -EINVAL; + + dynevent_arg_init(&arg, 0); + + va_start(args, cmd); + for (;;) { + const char *field; + + field = va_arg(args, const char *); + if (!field) + break; + + if (++cmd->n_fields > MAX_TRACE_ARGS) { + ret = -EINVAL; + break; + } + + arg.str = field; + ret = dynevent_arg_add(cmd, &arg, NULL); + if (ret) + break; + } + va_end(args); + + return ret; +} +EXPORT_SYMBOL_GPL(__kprobe_event_add_fields); + +/** + * kprobe_event_delete - Delete a kprobe event + * @name: The name of the kprobe event to delete + * + * Delete a kprobe event with the give @name from kernel code rather + * than directly from the command line. + * + * Return: 0 if successful, error otherwise. + */ +int kprobe_event_delete(const char *name) +{ + char buf[MAX_EVENT_NAME_LEN]; + + snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name); + + return trace_run_command(buf, create_or_delete_trace_kprobe); +} +EXPORT_SYMBOL_GPL(kprobe_event_delete); + static int trace_kprobe_release(struct dyn_event *ev) { struct trace_kprobe *tk = to_trace_kprobe(ev); @@ -1175,35 +1335,35 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, struct trace_event_file *trace_file) { struct kprobe_trace_entry_head *entry; - struct ring_buffer_event *event; - struct ring_buffer *buffer; - int size, dsize, pc; - unsigned long irq_flags; struct trace_event_call *call = trace_probe_event_call(&tk->tp); + struct trace_event_buffer fbuffer; + int dsize; WARN_ON(call != trace_file->event_call); if (trace_trigger_soft_disabled(trace_file)) return; - local_save_flags(irq_flags); - pc = preempt_count(); + local_save_flags(fbuffer.flags); + fbuffer.pc = preempt_count(); + fbuffer.trace_file = trace_file; dsize = __get_data_size(&tk->tp, regs); - size = sizeof(*entry) + tk->tp.size + dsize; - event = trace_event_buffer_lock_reserve(&buffer, trace_file, - call->event.type, - size, irq_flags, pc); - if (!event) + fbuffer.event = + trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file, + call->event.type, + sizeof(*entry) + tk->tp.size + dsize, + fbuffer.flags, fbuffer.pc); + if (!fbuffer.event) return; - entry = ring_buffer_event_data(event); + fbuffer.regs = regs; + entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); entry->ip = (unsigned long)tk->rp.kp.addr; store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); - event_trigger_unlock_commit_regs(trace_file, buffer, event, - entry, irq_flags, pc, regs); + trace_event_buffer_commit(&fbuffer); } static void @@ -1223,36 +1383,35 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, struct trace_event_file *trace_file) { struct kretprobe_trace_entry_head *entry; - struct ring_buffer_event *event; - struct ring_buffer *buffer; - int size, pc, dsize; - unsigned long irq_flags; + struct trace_event_buffer fbuffer; struct trace_event_call *call = trace_probe_event_call(&tk->tp); + int dsize; WARN_ON(call != trace_file->event_call); if (trace_trigger_soft_disabled(trace_file)) return; - local_save_flags(irq_flags); - pc = preempt_count(); + local_save_flags(fbuffer.flags); + fbuffer.pc = preempt_count(); + fbuffer.trace_file = trace_file; dsize = __get_data_size(&tk->tp, regs); - size = sizeof(*entry) + tk->tp.size + dsize; - - event = trace_event_buffer_lock_reserve(&buffer, trace_file, - call->event.type, - size, irq_flags, pc); - if (!event) + fbuffer.event = + trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file, + call->event.type, + sizeof(*entry) + tk->tp.size + dsize, + fbuffer.flags, fbuffer.pc); + if (!fbuffer.event) return; - entry = ring_buffer_event_data(event); + fbuffer.regs = regs; + entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); entry->func = (unsigned long)tk->rp.kp.addr; entry->ret_ip = (unsigned long)ri->ret_addr; store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); - event_trigger_unlock_commit_regs(trace_file, buffer, event, - entry, irq_flags, pc, regs); + trace_event_buffer_commit(&fbuffer); } static void @@ -1698,11 +1857,12 @@ static __init void setup_boot_kprobe_events(void) enable_boot_kprobe_events(); } -/* Make a tracefs interface for controlling probe points */ -static __init int init_kprobe_trace(void) +/* + * Register dynevent at subsys_initcall. This allows kernel to setup kprobe + * events in fs_initcall without tracefs. + */ +static __init int init_kprobe_trace_early(void) { - struct dentry *d_tracer; - struct dentry *entry; int ret; ret = dyn_event_register(&trace_kprobe_ops); @@ -1712,6 +1872,16 @@ static __init int init_kprobe_trace(void) if (register_module_notifier(&trace_kprobe_module_nb)) return -EINVAL; + return 0; +} +subsys_initcall(init_kprobe_trace_early); + +/* Make a tracefs interface for controlling probe points */ +static __init int init_kprobe_trace(void) +{ + struct dentry *d_tracer; + struct dentry *entry; + d_tracer = tracing_init_dentry(); if (IS_ERR(d_tracer)) return 0; |