Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755780AbZJGWiD (ORCPT ); Wed, 7 Oct 2009 18:38:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755749AbZJGWiC (ORCPT ); Wed, 7 Oct 2009 18:38:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51636 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755742AbZJGWh7 (ORCPT ); Wed, 7 Oct 2009 18:37:59 -0400 From: Masami Hiramatsu Subject: [PATCH tracing/kprobes v3 1/7] tracing/kprobes: Add $ prefix to special variables To: Frederic Weisbecker , Steven Rostedt , Ingo Molnar , lkml Cc: systemtap , DLE , Masami Hiramatsu , Frederic Weisbecker , Ingo Molnar , Thomas Gleixner , Arnaldo Carvalho de Melo , Steven Rostedt , Mike Galbraith , Paul Mackerras , Peter Zijlstra , Christoph Hellwig , Ananth N Mavinakayanahalli , Jim Keniston , "Frank Ch. Eigler" Date: Wed, 07 Oct 2009 18:27:40 -0400 Message-ID: <20091007222740.1684.91170.stgit@dhcp-100-2-132.bos.redhat.com> In-Reply-To: <20091007222733.1684.32035.stgit@dhcp-100-2-132.bos.redhat.com> References: <20091007222733.1684.32035.stgit@dhcp-100-2-132.bos.redhat.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8567 Lines: 213 Add $ prefix to the special variables(e.g. sa, rv) of kprobe-tracer. This resolves consistency issue between kprobe_events and perf-kprobe. Signed-off-by: Masami Hiramatsu Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Arnaldo Carvalho de Melo Cc: Steven Rostedt Cc: Mike Galbraith Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Christoph Hellwig Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Frank Ch. Eigler --- Documentation/trace/kprobetrace.txt | 20 ++++++------ kernel/trace/trace_kprobe.c | 60 ++++++++++++++++++++++------------- 2 files changed, 47 insertions(+), 33 deletions(-) diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index 9b8f7c6..33f5318 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -36,13 +36,13 @@ Synopsis of kprobe_events FETCHARGS : Arguments. Each probe can have up to 128 args. %REG : Fetch register REG - sN : Fetch Nth entry of stack (N >= 0) - sa : Fetch stack address. @ADDR : Fetch memory at ADDR (ADDR should be in kernel) @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol) - aN : Fetch function argument. (N >= 0)(*) - rv : Fetch return value.(**) - ra : Fetch return address.(**) + $sN : Fetch Nth entry of stack (N >= 0) + $sa : Fetch stack address. + $aN : Fetch function argument. (N >= 0)(*) + $rv : Fetch return value.(**) + $ra : Fetch return address.(**) +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***) NAME=FETCHARG: Set NAME as the argument name of FETCHARG. @@ -85,13 +85,13 @@ Usage examples To add a probe as a new event, write a new definition to kprobe_events as below. - echo p:myprobe do_sys_open dfd=a0 filename=a1 flags=a2 mode=a3 > /sys/kernel/debug/tracing/kprobe_events + echo p:myprobe do_sys_open dfd=$a0 filename=$a1 flags=$a2 mode=$a3 > /sys/kernel/debug/tracing/kprobe_events This sets a kprobe on the top of do_sys_open() function with recording 1st to 4th arguments as "myprobe" event. As this example shows, users can choose more familiar names for each arguments. - echo r:myretprobe do_sys_open rv ra >> /sys/kernel/debug/tracing/kprobe_events + echo r:myretprobe do_sys_open $rv $ra >> /sys/kernel/debug/tracing/kprobe_events This sets a kretprobe on the return point of do_sys_open() function with recording return value and return address as "myretprobe" event. @@ -138,11 +138,11 @@ events, you need to enable it. # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <...>-1447 [001] 1038282.286875: myprobe: (do_sys_open+0x0/0xd6) dfd=3 filename=7fffd1ec4440 flags=8000 mode=0 - <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) rv=fffffffffffffffe ra=ffffffff81367a3a + <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $rv=fffffffffffffffe $ra=ffffffff81367a3a <...>-1447 [001] 1038282.286885: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=40413c flags=8000 mode=1b6 - <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) rv=3 ra=ffffffff81367a3a + <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 $ra=ffffffff81367a3a <...>-1447 [001] 1038282.286969: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=4041c6 flags=98800 mode=10 - <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) rv=3 ra=ffffffff81367a3a + <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 $ra=ffffffff81367a3a Each line shows when the kernel hits an event, and <- SYMBOL means kernel diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 97309d4..f63ead0 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -220,24 +220,24 @@ static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff) int ret = -EINVAL; if (ff->func == fetch_argument) - ret = snprintf(buf, n, "a%lu", (unsigned long)ff->data); + ret = snprintf(buf, n, "$a%lu", (unsigned long)ff->data); else if (ff->func == fetch_register) { const char *name; name = regs_query_register_name((unsigned int)((long)ff->data)); ret = snprintf(buf, n, "%%%s", name); } else if (ff->func == fetch_stack) - ret = snprintf(buf, n, "s%lu", (unsigned long)ff->data); + ret = snprintf(buf, n, "$s%lu", (unsigned long)ff->data); else if (ff->func == fetch_memory) ret = snprintf(buf, n, "@0x%p", ff->data); else if (ff->func == fetch_symbol) { struct symbol_cache *sc = ff->data; ret = snprintf(buf, n, "@%s%+ld", sc->symbol, sc->offset); } else if (ff->func == fetch_retvalue) - ret = snprintf(buf, n, "rv"); + ret = snprintf(buf, n, "$rv"); else if (ff->func == fetch_ip) - ret = snprintf(buf, n, "ra"); + ret = snprintf(buf, n, "$ra"); else if (ff->func == fetch_stack_address) - ret = snprintf(buf, n, "sa"); + ret = snprintf(buf, n, "$sa"); else if (ff->func == fetch_indirect) { struct indirect_fetch_data *id = ff->data; size_t l = 0; @@ -429,12 +429,10 @@ static int split_symbol_offset(char *symbol, unsigned long *offset) #define PARAM_MAX_ARGS 16 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long)) -static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return) +static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return) { int ret = 0; unsigned long param; - long offset; - char *tmp; switch (arg[0]) { case 'a': /* argument */ @@ -456,14 +454,6 @@ static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return) } else ret = -EINVAL; break; - case '%': /* named register */ - ret = regs_query_register_offset(arg + 1); - if (ret >= 0) { - ff->func = fetch_register; - ff->data = (void *)(unsigned long)ret; - ret = 0; - } - break; case 's': /* stack */ if (arg[1] == 'a') { ff->func = fetch_stack_address; @@ -478,6 +468,31 @@ static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return) } } break; + default: + ret = -EINVAL; + } + return ret; +} + +static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return) +{ + int ret = 0; + unsigned long param; + long offset; + char *tmp; + + switch (arg[0]) { + case '$': + ret = parse_probe_vars(arg + 1, ff, is_return); + break; + case '%': /* named register */ + ret = regs_query_register_offset(arg + 1); + if (ret >= 0) { + ff->func = fetch_register; + ff->data = (void *)(unsigned long)ret; + ret = 0; + } + break; case '@': /* memory or symbol */ if (isdigit(arg[1])) { ret = strict_strtoul(arg + 1, 0, ¶m); @@ -489,8 +504,7 @@ static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return) ret = split_symbol_offset(arg + 1, &offset); if (ret) break; - ff->data = alloc_symbol_cache(arg + 1, - offset); + ff->data = alloc_symbol_cache(arg + 1, offset); if (ff->data) ff->func = fetch_symbol; else @@ -544,11 +558,11 @@ static int create_trace_probe(int argc, char **argv) * - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS] * - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS] * Fetch args: - * aN : fetch Nth of function argument. (N:0-) - * rv : fetch return value - * ra : fetch return address - * sa : fetch stack address - * sN : fetch Nth of stack (N:0-) + * $aN : fetch Nth of function argument. (N:0-) + * $rv : fetch return value + * $ra : fetch return address + * $sa : fetch stack address + * $sN : fetch Nth of stack (N:0-) * @ADDR : fetch memory at ADDR (ADDR should be in kernel) * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) * %REG : fetch register REG -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America), Inc. Software Solutions Division e-mail: mhiramat@redhat.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/