Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759756Ab3ICJsu (ORCPT ); Tue, 3 Sep 2013 05:48:50 -0400 Received: from mail9.hitachi.co.jp ([133.145.228.44]:43121 "EHLO mail9.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753493Ab3ICJss (ORCPT ); Tue, 3 Sep 2013 05:48:48 -0400 Message-ID: <5225B07C.9020102@hitachi.com> Date: Tue, 03 Sep 2013 18:48:44 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Namhyung Kim Cc: Steven Rostedt , Namhyung Kim , Hyeoncheol Lee , LKML , Srikar Dronamraju , Oleg Nesterov , "zhangwei(Jovi)" , Arnaldo Carvalho de Melo Subject: Re: [PATCH 13/13] tracing/uprobes: Add support for full argument access methods References: <1378187054-27401-1-git-send-email-namhyung@kernel.org> <1378187054-27401-14-git-send-email-namhyung@kernel.org> In-Reply-To: <1378187054-27401-14-git-send-email-namhyung@kernel.org> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6626 Lines: 182 (2013/09/03 14:44), Namhyung Kim wrote: > From: Namhyung Kim > > 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. Look good for me :) Acked-by: Masami Hiramatsu Thank you! > > Original-patch-by: Hyeoncheol Lee > Cc: Masami Hiramatsu > Cc: Srikar Dronamraju > Cc: Oleg Nesterov > Cc: zhangwei(Jovi) > Cc: Arnaldo Carvalho de Melo > Signed-off-by: Namhyung Kim > --- > Documentation/trace/uprobetracer.txt | 25 +++++++++++++++++++++++++ > kernel/trace/trace_probe.c | 36 +++++++++++++++++++++++------------- > 2 files changed, 48 insertions(+), 13 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@/ > + > > Event Profiling > --------------- > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c > index 70cd3bfde5a6..8c77825e87e6 100644 > --- a/kernel/trace/trace_probe.c > +++ b/kernel/trace/trace_probe.c > @@ -253,12 +253,18 @@ fail: > } > > /* Special function : only accept unsigned long */ > -static __kprobes void fetch_stack_address(struct pt_regs *regs, > +static __kprobes void fetch_kernel_stack_address(struct pt_regs *regs, > void *dummy, void *dest, void *priv) > { > *(unsigned long *)dest = kernel_stack_pointer(regs); > } > > +static __kprobes void fetch_user_stack_address(struct pt_regs *regs, > + void *dummy, void *dest, void *priv) > +{ > + *(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 *ttbl) > @@ -303,7 +309,8 @@ 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; > @@ -315,13 +322,16 @@ 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]; > @@ -345,17 +355,13 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, > int ret; > const struct fetch_type *ttbl; > > - ttbl = kprobes_fetch_type_table; > + ttbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table; > > ret = 0; > > - /* 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 */ > @@ -376,6 +382,10 @@ 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; > @@ -482,7 +492,7 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, > int ret; > const struct fetch_type *ttbl; > > - ttbl = kprobes_fetch_type_table; > + ttbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table; > > if (strlen(arg) > MAX_ARGSTR_LEN) { > pr_info("Argument is too long.: %s\n", arg); > -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/