From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754260AbcBBI5g (ORCPT ); Tue, 2 Feb 2016 03:57:36 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:31812 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754232AbcBBI5e (ORCPT ); Tue, 2 Feb 2016 03:57:34 -0500 From: Wang Nan To: , , , , CC: , Wang Nan , "Arnaldo Carvalho de Melo" , Jiri Olsa , "Masami Hiramatsu" , Namhyung Kim , Li Zefan , Subject: [PATCH 1/2] perf tools: Record text offset in dso to calculate objdump address Date: Tue, 2 Feb 2016 08:56:05 +0000 Message-ID: <1454403366-27055-2-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1454403366-27055-1-git-send-email-wangnan0@huawei.com> References: <1454403366-27055-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020202.56B06F39.017E,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: fc0fc2d2a1c32a3100a5d201b3ac7b27 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In this patch, the offset of '.text' section is stored into dso and used here to re-calculate address to objdump. In most of the cases, executable code is in '.text' section, so the adjustment made to a symbol in dso__load_sym (using sym.st_value -= shdr.sh_addr - shdr.sh_offset) should equal to 'sym.st_value -= dso->text_offset'. Therefore, adding text_offset back get objdump address from symbol address (rip). However, it is not true for kernel and kernel module since there could be multiple executable sections with different offset. Exclude kernel for this reason. After this patch, even dso->adjust_symbols is set to true for shared objects, map__rip_2objdump() and map__objdump_2mem() would return correct result, so perf behavior of annotate won't be changed. Signed-off-by: Wang Nan Cc: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Cody P Schafer Cc: He Kuang Cc: Jiri Olsa Cc: Kirill Smelkov Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Li Zefan Cc: pi3orama@163.com --- tools/perf/util/dso.h | 1 + tools/perf/util/map.c | 14 ++++++++++++++ tools/perf/util/symbol-elf.c | 12 ++++++------ 3 files changed, 21 insertions(+), 6 deletions(-) diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h index 45ec4d0..ef3dbc9 100644 --- a/tools/perf/util/dso.h +++ b/tools/perf/util/dso.h @@ -162,6 +162,7 @@ struct dso { u8 loaded; u8 rel; u8 build_id[BUILD_ID_SIZE]; + u64 text_offset; const char *short_name; const char *long_name; u16 long_name_len; diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c index 171b6d1..02c3186 100644 --- a/tools/perf/util/map.c +++ b/tools/perf/util/map.c @@ -431,6 +431,13 @@ u64 map__rip_2objdump(struct map *map, u64 rip) if (map->dso->rel) return rip - map->pgoff; + /* + * kernel modules also have DSO_TYPE_USER in dso->kernel, + * but all kernel modules are ET_REL, so won't get here. + */ + if (map->dso->kernel == DSO_TYPE_USER) + return rip + map->dso->text_offset; + return map->unmap_ip(map, rip) - map->reloc; } @@ -454,6 +461,13 @@ u64 map__objdump_2mem(struct map *map, u64 ip) if (map->dso->rel) return map->unmap_ip(map, ip + map->pgoff); + /* + * kernel modules also have DSO_TYPE_USER in dso->kernel, + * but all kernel modules are ET_REL, so won't get here. + */ + if (map->dso->kernel == DSO_TYPE_USER) + return map->unmap_ip(map, ip - map->dso->text_offset); + return ip + map->reloc; } diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 562b8eb..5227186 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -792,6 +792,7 @@ int dso__load_sym(struct dso *dso, struct map *map, uint32_t idx; GElf_Ehdr ehdr; GElf_Shdr shdr; + GElf_Shdr tshdr; Elf_Data *syms, *opddata = NULL; GElf_Sym sym; Elf_Scn *sec, *sec_strndx; @@ -831,6 +832,9 @@ int dso__load_sym(struct dso *dso, struct map *map, sec = syms_ss->symtab; shdr = syms_ss->symshdr; + if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL)) + dso->text_offset = tshdr.sh_addr - tshdr.sh_offset; + if (runtime_ss->opdsec) opddata = elf_rawdata(runtime_ss->opdsec, NULL); @@ -879,12 +883,8 @@ int dso__load_sym(struct dso *dso, struct map *map, * Handle any relocation of vdso necessary because older kernels * attempted to prelink vdso to its virtual address. */ - if (dso__is_vdso(dso)) { - GElf_Shdr tshdr; - - if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL)) - map->reloc = map->start - tshdr.sh_addr + tshdr.sh_offset; - } + if (dso__is_vdso(dso)) + map->reloc = map->start - dso->text_offset; dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap); /* -- 1.8.3.4