Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755386AbaBFFdi (ORCPT ); Thu, 6 Feb 2014 00:33:38 -0500 Received: from mail9.hitachi.co.jp ([133.145.228.44]:56245 "EHLO mail9.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752939AbaBFFcV (ORCPT ); Thu, 6 Feb 2014 00:32:21 -0500 Subject: [PATCH -tip v3 07/11] perf-probe: Find given address from offline dwarf To: Arnaldo Carvalho de Melo From: Masami Hiramatsu Cc: Srikar Dronamraju , David Ahern , linux-kernel@vger.kernel.org, "Steven Rostedt (Red Hat)" , Oleg Nesterov , Ingo Molnar , "David A. Long" , yrl.pp-manager.tt@hitachi.com, Namhyung Kim Date: Thu, 06 Feb 2014 05:32:18 +0000 Message-ID: <20140206053218.29635.74821.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp> In-Reply-To: <20140206053201.29635.99095.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp> References: <20140206053201.29635.99095.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp> User-Agent: StGit/0.16 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 Find the given address from offline dwarfs instead of online kernel dwarfs. On the KASLR enabled kernel, the kernel text section is loaded with random offset, and the debuginfo__new_online_kernel can't handle it. So let's move to the offline dwarf loader instead of using the online dwarf loader. As a result, since we don't need debuginfo__new_online_kernel any more, this also removes the functions related that. Without this change; # ./perf probe -l probe:t_show (on _stext+901288 with m v) probe:t_show_1 (on _stext+939624 with m v t) probe:t_show_2 (on _stext+980296 with m v fmt) probe:t_show_3 (on _stext+1014392 with m v file) With this change; # ./perf probe -l probe:t_show (on t_show@linux-3/kernel/trace/ftrace.c with m v) probe:t_show_1 (on t_show@linux-3/kernel/trace/trace.c with m v t) probe:t_show_2 (on t_show@kernel/trace/trace_printk.c with m v fmt) probe:t_show_3 (on t_show@kernel/trace/trace_events.c with m v file) Changes from v2: - Instead of retrying, directly opens offline dwarf. - Remove debuginfo__new_online_kernel and related functions. - Refer map->reloc to get the correct address of a symbol. - Add a special case for handling ref_reloc_sym based address. Signed-off-by: Masami Hiramatsu --- tools/perf/util/probe-event.c | 40 ++++++++++++------- tools/perf/util/probe-finder.c | 86 ---------------------------------------- tools/perf/util/probe-finder.h | 1 3 files changed, 26 insertions(+), 101 deletions(-) diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index 1ce2cb9..8e34c8d 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -248,6 +248,18 @@ static struct debuginfo *open_debuginfo(const char *module) return debuginfo__new(path); } +static struct ref_reloc_sym *__kernel_get_ref_reloc_sym(void) +{ + /* kmap->ref_reloc_sym should be set if host_machine is initialized */ + struct kmap *kmap; + + if (map__load(host_machine->vmlinux_maps[MAP__FUNCTION], NULL) < 0) + return NULL; + + kmap = map__kmap(host_machine->vmlinux_maps[MAP__FUNCTION]); + return kmap->ref_reloc_sym; +} + /* * Convert trace point to probe point with debuginfo * Currently only handles kprobes. @@ -256,18 +268,27 @@ static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp, struct perf_probe_point *pp) { struct symbol *sym; + struct ref_reloc_sym *reloc_sym; struct map *map; - u64 addr; + u64 addr = 0; int ret = -ENOENT; struct debuginfo *dinfo; - sym = __find_kernel_function_by_name(tp->symbol, &map); - if (sym) { - addr = map->unmap_ip(map, sym->start + tp->offset); + /* ref_reloc_sym is just a label. Need a special fix*/ + reloc_sym = __kernel_get_ref_reloc_sym(); + if (reloc_sym && strcmp(tp->symbol, reloc_sym->name) == 0) + addr = reloc_sym->unrelocated_addr + tp->offset; + else { + sym = __find_kernel_function_by_name(tp->symbol, &map); + if (sym) + addr = map->unmap_ip(map, sym->start + tp->offset) - + map->reloc; + } + if (addr) { pr_debug("try to find %s+%ld@%" PRIx64 "\n", tp->symbol, tp->offset, addr); - dinfo = debuginfo__new_online_kernel(addr); + dinfo = open_debuginfo(tp->module); if (dinfo) { ret = debuginfo__find_probe_point(dinfo, (unsigned long)addr, pp); @@ -383,15 +404,6 @@ static int add_module_to_probe_trace_events(struct probe_trace_event *tevs, return ret; } -static struct ref_reloc_sym *__kernel_get_ref_reloc_sym(void) -{ - /* kmap->ref_reloc_sym should be set if host_machine is initialized */ - struct kmap *kmap; - - kmap = map__kmap(host_machine->vmlinux_maps[MAP__FUNCTION]); - return kmap->ref_reloc_sym; -} - /* Post processing the probe events */ static int post_process_probe_trace_events(struct probe_trace_event *tevs, int ntevs, const char *module, diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index e5e589f..4f6e277 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -89,79 +89,6 @@ error: return -ENOENT; } -#if _ELFUTILS_PREREQ(0, 148) -/* This method is buggy if elfutils is older than 0.148 */ -static int __linux_kernel_find_elf(Dwfl_Module *mod, - void **userdata, - const char *module_name, - Dwarf_Addr base, - char **file_name, Elf **elfp) -{ - int fd; - const char *path = kernel_get_module_path(module_name); - - pr_debug2("Use file %s for %s\n", path, module_name); - if (path) { - fd = open(path, O_RDONLY); - if (fd >= 0) { - *file_name = strdup(path); - return fd; - } - } - /* If failed, try to call standard method */ - return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base, - file_name, elfp); -} - -static const Dwfl_Callbacks kernel_callbacks = { - .find_debuginfo = dwfl_standard_find_debuginfo, - .debuginfo_path = &debuginfo_path, - - .find_elf = __linux_kernel_find_elf, - .section_address = dwfl_linux_kernel_module_section_address, -}; - -/* Get a Dwarf from live kernel image */ -static int debuginfo__init_online_kernel_dwarf(struct debuginfo *dbg, - Dwarf_Addr addr) -{ - dbg->dwfl = dwfl_begin(&kernel_callbacks); - if (!dbg->dwfl) - return -EINVAL; - - /* Load the kernel dwarves: Don't care the result here */ - dwfl_linux_kernel_report_kernel(dbg->dwfl); - dwfl_linux_kernel_report_modules(dbg->dwfl); - - dbg->dbg = dwfl_addrdwarf(dbg->dwfl, addr, &dbg->bias); - /* Here, check whether we could get a real dwarf */ - if (!dbg->dbg) { - pr_debug("Failed to find kernel dwarf at %lx\n", - (unsigned long)addr); - dwfl_end(dbg->dwfl); - memset(dbg, 0, sizeof(*dbg)); - return -ENOENT; - } - - return 0; -} -#else -/* With older elfutils, this just support kernel module... */ -static int debuginfo__init_online_kernel_dwarf(struct debuginfo *dbg, - Dwarf_Addr addr __maybe_unused) -{ - const char *path = kernel_get_module_path("kernel"); - - if (!path) { - pr_err("Failed to find vmlinux path\n"); - return -ENOENT; - } - - pr_debug2("Use file %s for debuginfo\n", path); - return debuginfo__init_offline_dwarf(dbg, path); -} -#endif - struct debuginfo *debuginfo__new(const char *path) { struct debuginfo *dbg = zalloc(sizeof(*dbg)); @@ -174,19 +101,6 @@ struct debuginfo *debuginfo__new(const char *path) return dbg; } -struct debuginfo *debuginfo__new_online_kernel(unsigned long addr) -{ - struct debuginfo *dbg = zalloc(sizeof(*dbg)); - - if (!dbg) - return NULL; - - if (debuginfo__init_online_kernel_dwarf(dbg, (Dwarf_Addr)addr) < 0) - zfree(&dbg); - - return dbg; -} - void debuginfo__delete(struct debuginfo *dbg) { if (dbg) { diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h index 592c4da..3fc5973 100644 --- a/tools/perf/util/probe-finder.h +++ b/tools/perf/util/probe-finder.h @@ -31,7 +31,6 @@ struct debuginfo { }; extern struct debuginfo *debuginfo__new(const char *path); -extern struct debuginfo *debuginfo__new_online_kernel(unsigned long addr); extern void debuginfo__delete(struct debuginfo *dbg); /* Find probe_trace_events specified by perf_probe_event from debuginfo */ -- 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/