Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752203AbbEHFwc (ORCPT ); Fri, 8 May 2015 01:52:32 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:10241 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751493AbbEHFwb (ORCPT ); Fri, 8 May 2015 01:52:31 -0400 From: Hou Pengyang To: , , , , CC: , , , Subject: [PATCH v4 2/2] arm64: perf: Fix callchain parse error with kernel tracepoint events Date: Fri, 8 May 2015 05:43:04 +0000 Message-ID: <1431063784-137600-3-git-send-email-houpengyang@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1431063784-137600-1-git-send-email-houpengyang@huawei.com> References: <1431063784-137600-1-git-send-email-houpengyang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.210] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2256 Lines: 60 For ARM64, when tracing with tracepoint events, the IP and pstate are set to 0, preventing the perf code parsing the callchain and resolving the symbols correctly. ./perf record -e sched:sched_switch -g --call-graph dwarf ls [ perf record: Captured and wrote 0.146 MB perf.data ] ./perf report -f Samples: 194 of event 'sched:sched_switch', Event count (approx.): 194 Children Self Command Shared Object Symbol 100.00% 100.00% ls [unknown] [.] 0000000000000000 The fix is to implement perf_arch_fetch_caller_regs for ARM64, which fills several necessary registers used for callchain unwinding, including pc,sp, fp and spsr . With this patch, callchain can be parsed correctly as follows: ...... + 2.63% 0.00% ls [kernel.kallsyms] [k] vfs_symlink + 2.63% 0.00% ls [kernel.kallsyms] [k] follow_down + 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_get + 2.63% 0.00% ls [kernel.kallsyms] [k] do_execveat_common.isra.33 - 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_send_policy_notify pfkey_send_policy_notify pfkey_get v9fs_vfs_rename page_follow_link_light link_path_walk el0_svc_naked ....... Signed-off-by: Hou Pengyang --- arch/arm64/include/asm/perf_event.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h index d26d1d5..6471773 100644 --- a/arch/arm64/include/asm/perf_event.h +++ b/arch/arm64/include/asm/perf_event.h @@ -24,4 +24,11 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs); #define perf_misc_flags(regs) perf_misc_flags(regs) #endif +#define perf_arch_fetch_caller_regs(regs, __ip) { \ + (regs)->pc = (__ip); \ + (regs)->regs[AARCH64_INSN_REG_FP] = (unsigned long) __builtin_frame_address(0); \ + (regs)->sp = current_stack_pointer; \ + (regs)->pstate = PSR_MODE_EL1h; \ +} + #endif -- 1.8.3.4 -- 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/