Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751463AbbD3N7c (ORCPT ); Thu, 30 Apr 2015 09:59:32 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:10789 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751102AbbD3N7a (ORCPT ); Thu, 30 Apr 2015 09:59:30 -0400 From: Hou Pengyang To: , , , , CC: , , , Subject: [PATCH v2] arm & arm64: perf: Fix callchain parse error with kernel tracepoint events Date: Thu, 30 Apr 2015 13:58:52 +0000 Message-ID: <1430402332-52750-1-git-send-email-houpengyang@huawei.com> X-Mailer: git-send-email 1.8.3.4 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: 3053 Lines: 80 For ARM & ARM64, when tracing with tracepoint events, the IP and cpsr 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 psr . 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 ....... Jean Pihet found this in ARM and come up with a patch: http://thread.gmane.org/gmane.linux.kernel/1734283/focus=1734280 Signed-off-by: Hou Pengyang --- arch/arm/include/asm/perf_event.h | 7 +++++++ arch/arm64/include/asm/perf_event.h | 7 +++++++ 2 files changed, 14 insertions(+) diff --git a/arch/arm/include/asm/perf_event.h b/arch/arm/include/asm/perf_event.h index d9cf138..17705e2b 100644 --- a/arch/arm/include/asm/perf_event.h +++ b/arch/arm/include/asm/perf_event.h @@ -19,4 +19,11 @@ 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)->ARM_pc = (__ip); \ + (regs)->ARM_fp = (unsigned long) __builtin_frame_address(0); \ + (regs)->ARM_sp = current_stack_pointer; \ + (regs)->ARM_cpsr |= SYSTEM_MODE; \ +} + #endif /* __ARM_PERF_EVENT_H__ */ diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h index d26d1d5..e6911a4 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)->ARM_pc = (__ip); \ + (regs)->ARM_fp = (unsigned long) __builtin_frame_address(0); \ + (regs)->ARM_sp = current_stack_pointer; \ + (regs)->ARM_cpsr |= PSR_MODE_EL1h; \ +} + #endif -- 1.8.5.2 -- 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/