From 405b2651e4bedf8d3932b64cad649b4d26b067f5 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 7 Oct 2009 18:27:40 -0400 Subject: tracing/kprobes: Add $ prefix to special variables Add $ prefix to the special variables(e.g. sa, rv) of kprobe-tracer. This resolves consistency issues between kprobe_events and perf-kprobe. The main goal is to avoid conflicts between local variable names of probed functions, used by perf probe, and special variables used in the kprobe event creation interface (stack values, etc...) and also available from perf probe. ie: we don't want rv (return value) to conflict with a local variable named rv in a probed function. Signed-off-by: Masami Hiramatsu 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 LKML-Reference: <20091007222740.1684.91170.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Frederic Weisbecker --- kernel/trace/trace_kprobe.c | 60 ++++++++++++++++++++++++++++----------------- 1 file changed, 37 insertions(+), 23 deletions(-) (limited to 'kernel/trace/trace_kprobe.c') diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 97309d4714f7..f63ead0cc5cf 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 -- cgit