Messages in this thread | | | Date | Thu, 2 Jan 2014 15:58:27 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH 15/17] tracing/uprobes: Add support for full argument access methods |
| |
On Mon, 16 Dec 2013 13:32:14 +0900 Namhyung Kim <namhyung@kernel.org> wrote:
> From: Namhyung Kim <namhyung.kim@lge.com> > > Enable to fetch other types of argument for the uprobes. IOW, we can > access stack, memory, deref, bitfield and retval from uprobes now. > > The format for the argument types are same as kprobes (but @SYMBOL > type is not supported for uprobes), i.e: > > @ADDR : Fetch memory at ADDR > $stackN : Fetch Nth entry of stack (N >= 0) > $stack : Fetch stack address > $retval : Fetch return value > +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address > > Note that the retval only can be used with uretprobes. > > Original-patch-by: Hyeoncheol Lee <cheol.lee@lge.com>
Where was the original patch posted? And can we get Hyeoncheol's SOB for this?
Thanks!
-- Steve
> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> > Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> > Cc: Oleg Nesterov <oleg@redhat.com> > Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com> > Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> > Signed-off-by: Namhyung Kim <namhyung@kernel.org> > --- > Documentation/trace/uprobetracer.txt | 25 +++++++++++++++++++++++++ > 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;
| |