diff options
| -rw-r--r-- | Documentation/trace/uprobetracer.txt | 25 | ||||
| -rw-r--r-- | kernel/trace/trace_probe.c | 34 |
2 files changed, 47 insertions, 12 deletions
diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.txt index 8f1a8b8956fc..6e5cff263e2b 100644 --- a/Documentation/trace/uprobetracer.txt +++ b/Documentation/trace/uprobetracer.txt @@ -31,6 +31,31 @@ Synopsis of uprobe_tracer FETCHARGS : Arguments. Each probe can have up to 128 args. %REG : Fetch register REG + @ADDR : Fetch memory at ADDR (ADDR should be in userspace) + $stackN : Fetch Nth entry of stack (N >= 0) + $stack : Fetch stack address. + $retval : Fetch return value.(*) + +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**) + NAME=FETCHARG : Set NAME as the argument name of FETCHARG. + FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types + (u8/u16/u32/u64/s8/s16/s32/s64), "string" and bitfield + are supported. + + (*) only for return probe. + (**) this is useful for fetching a field of data structures. + +Types +----- +Several types are supported for fetch-args. Uprobe tracer will access memory +by given type. Prefix 's' and 'u' means those types are signed and unsigned +respectively. Traced arguments are shown in decimal (signed) or hex (unsigned). +String type is a special type, which fetches a "null-terminated" string from +user space. +Bitfield is another special type, which takes 3 parameters, bit-width, bit- +offset, and container-size (usually 32). The syntax is; + + b<bit-width>@<bit-offset>/<container-size> + Event Profiling --------------- diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 8f7a2b6d389d..a130d612e705 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -255,12 +255,18 @@ fail: } /* Special function : only accept unsigned long */ -static __kprobes void fetch_stack_address(struct pt_regs *regs, - void *dummy, void *dest) +static __kprobes void fetch_kernel_stack_address(struct pt_regs *regs, + void *dummy, void *dest) { *(unsigned long *)dest = kernel_stack_pointer(regs); } +static __kprobes void fetch_user_stack_address(struct pt_regs *regs, + void *dummy, void *dest) +{ + *(unsigned long *)dest = user_stack_pointer(regs); +} + static fetch_func_t get_fetch_size_function(const struct fetch_type *type, fetch_func_t orig_fn, const struct fetch_type *ftbl) @@ -305,7 +311,8 @@ int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset) #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long)) static int parse_probe_vars(char *arg, const struct fetch_type *t, - struct fetch_param *f, bool is_return) + struct fetch_param *f, bool is_return, + bool is_kprobe) { int ret = 0; unsigned long param; @@ -317,13 +324,16 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t, ret = -EINVAL; } else if (strncmp(arg, "stack", 5) == 0) { if (arg[5] == '\0') { - if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0) - f->fn = fetch_stack_address; + if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR)) + return -EINVAL; + + if (is_kprobe) + f->fn = fetch_kernel_stack_address; else - ret = -EINVAL; + f->fn = fetch_user_stack_address; } else if (isdigit(arg[5])) { ret = kstrtoul(arg + 5, 10, ¶m); - if (ret || param > PARAM_MAX_STACK) + if (ret || (is_kprobe && param > PARAM_MAX_STACK)) ret = -EINVAL; else { f->fn = t->fetch[FETCH_MTD_stack]; @@ -350,13 +360,9 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table; BUG_ON(ftbl == NULL); - /* Until uprobe_events supports only reg arguments */ - if (!is_kprobe && arg[0] != '%') - return -EINVAL; - switch (arg[0]) { case '$': - ret = parse_probe_vars(arg + 1, t, f, is_return); + ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe); break; case '%': /* named register */ @@ -377,6 +383,10 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, f->fn = t->fetch[FETCH_MTD_memory]; f->data = (void *)param; } else { + /* uprobes don't support symbols */ + if (!is_kprobe) + return -EINVAL; + ret = traceprobe_split_symbol_offset(arg + 1, &offset); if (ret) break; |