From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752843AbbADSgf (ORCPT ); Sun, 4 Jan 2015 13:36:35 -0500 Received: from mail-pd0-f178.google.com ([209.85.192.178]:35346 "EHLO mail-pd0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752680AbbADSgc (ORCPT ); Sun, 4 Jan 2015 13:36:32 -0500 From: Andy Lutomirski To: Jiri Olsa , Ingo Molnar , Peter Zijlstra , =?utf-8?B?56em5om/5YiaKOaJv+WImik=?= Cc: Andy Lutomirski , Stephane Eranian , root , Andrew Morton , =?utf-8?B?56em5om/5YiaKOaJv+WImik=?= , Wu Fengguang , Namhyung Kim , Mike Galbraith , Arjan van de Ven , linux-kernel , David Ahern , Paul Mackerras , Yanmin Zhang Subject: [PATCH 1/2] perf: Move task_pt_regs sampling into arch code Date: Sun, 4 Jan 2015 10:36:19 -0800 Message-Id: X-Mailer: git-send-email 2.1.0 In-Reply-To: References: <20150104174105.GA29388@krava.brq.redhat.com> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On x86_64, at least, task_pt_regs may be only partially initialized in many contexts, so x86_64 should not use it without extra care from interrupt context, let alone NMI context. This will allow x86_64 to override the logic and will supply some scratch space to use to make a cleaner copy of user regs. Signed-off-by: Andy Lutomirski --- arch/arm/kernel/perf_regs.c | 8 ++++++++ arch/arm64/kernel/perf_regs.c | 8 ++++++++ arch/x86/kernel/perf_regs.c | 16 ++++++++++++++++ include/linux/perf_event.h | 12 +++++++----- include/linux/perf_regs.h | 16 ++++++++++++++++ kernel/events/core.c | 19 ++++++++----------- 6 files changed, 63 insertions(+), 16 deletions(-) diff --git a/arch/arm/kernel/perf_regs.c b/arch/arm/kernel/perf_regs.c index 6e4379c67cbc..592dda3f21ff 100644 --- a/arch/arm/kernel/perf_regs.c +++ b/arch/arm/kernel/perf_regs.c @@ -28,3 +28,11 @@ u64 perf_reg_abi(struct task_struct *task) { return PERF_SAMPLE_REGS_ABI_32; } + +void perf_get_regs_user(struct perf_regs *regs_user, + struct pt_regs *regs, + struct pt_regs *regs_user_copy) +{ + regs_user->regs = task_pt_regs(current); + regs_user->abi = perf_reg_abi(current); +} diff --git a/arch/arm64/kernel/perf_regs.c b/arch/arm64/kernel/perf_regs.c index 6762ad705587..3f62b35fb6f1 100644 --- a/arch/arm64/kernel/perf_regs.c +++ b/arch/arm64/kernel/perf_regs.c @@ -50,3 +50,11 @@ u64 perf_reg_abi(struct task_struct *task) else return PERF_SAMPLE_REGS_ABI_64; } + +void perf_get_regs_user(struct perf_regs *regs_user, + struct pt_regs *regs, + struct pt_regs *regs_user_copy) +{ + regs_user->regs = task_pt_regs(current); + regs_user->abi = perf_reg_abi(current); +} diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c index e309cc5c276e..3bbbb1a4fb52 100644 --- a/arch/x86/kernel/perf_regs.c +++ b/arch/x86/kernel/perf_regs.c @@ -78,6 +78,14 @@ u64 perf_reg_abi(struct task_struct *task) { return PERF_SAMPLE_REGS_ABI_32; } + +void perf_get_regs_user(struct perf_regs *regs_user, + struct pt_regs *regs, + struct pt_regs *regs_user_copy) +{ + regs_user->regs = task_pt_regs(current); + regs_user->abi = perf_reg_abi(current); +} #else /* CONFIG_X86_64 */ #define REG_NOSUPPORT ((1ULL << PERF_REG_X86_DS) | \ (1ULL << PERF_REG_X86_ES) | \ @@ -102,4 +110,12 @@ u64 perf_reg_abi(struct task_struct *task) else return PERF_SAMPLE_REGS_ABI_64; } + +void perf_get_regs_user(struct perf_regs *regs_user, + struct pt_regs *regs, + struct pt_regs *regs_user_copy) +{ + regs_user->regs = task_pt_regs(current); + regs_user->abi = perf_reg_abi(current); +} #endif /* CONFIG_X86_32 */ diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 486e84ccb1f9..4f7a61ca4b39 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -79,11 +79,6 @@ struct perf_branch_stack { struct perf_branch_entry entries[0]; }; -struct perf_regs { - __u64 abi; - struct pt_regs *regs; -}; - struct task_struct; /* @@ -610,7 +605,14 @@ struct perf_sample_data { u32 reserved; } cpu_entry; struct perf_callchain_entry *callchain; + + /* + * regs_user may point to task_pt_regs or to regs_user_copy, depending + * on arch details. + */ struct perf_regs regs_user; + struct pt_regs regs_user_copy; + struct perf_regs regs_intr; u64 stack_user_size; } ____cacheline_aligned; diff --git a/include/linux/perf_regs.h b/include/linux/perf_regs.h index 3c73d5fe18be..a5f98d53d732 100644 --- a/include/linux/perf_regs.h +++ b/include/linux/perf_regs.h @@ -1,11 +1,19 @@ #ifndef _LINUX_PERF_REGS_H #define _LINUX_PERF_REGS_H +struct perf_regs { + __u64 abi; + struct pt_regs *regs; +}; + #ifdef CONFIG_HAVE_PERF_REGS #include u64 perf_reg_value(struct pt_regs *regs, int idx); int perf_reg_validate(u64 mask); u64 perf_reg_abi(struct task_struct *task); +void perf_get_regs_user(struct perf_regs *regs_user, + struct pt_regs *regs, + struct pt_regs *regs_user_copy); #else static inline u64 perf_reg_value(struct pt_regs *regs, int idx) { @@ -21,5 +29,13 @@ static inline u64 perf_reg_abi(struct task_struct *task) { return PERF_SAMPLE_REGS_ABI_NONE; } + +static inline void perf_get_regs_user(struct perf_regs *regs_user, + struct pt_regs *regs, + struct pt_regs *regs_user_copy) +{ + regs_user->regs = task_pt_regs(current); + regs_user->abi = perf_reg_abi(current); +} #endif /* CONFIG_HAVE_PERF_REGS */ #endif /* _LINUX_PERF_REGS_H */ diff --git a/kernel/events/core.c b/kernel/events/core.c index 4c1ee7f2bebc..882f835a0d85 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4461,18 +4461,14 @@ perf_output_sample_regs(struct perf_output_handle *handle, } static void perf_sample_regs_user(struct perf_regs *regs_user, - struct pt_regs *regs) + struct pt_regs *regs, + struct pt_regs *regs_user_copy) { - if (!user_mode(regs)) { - if (current->mm) - regs = task_pt_regs(current); - else - regs = NULL; - } - - if (regs) { - regs_user->abi = perf_reg_abi(current); + if (user_mode(regs)) { + regs_user->abi = perf_reg_abi(current); regs_user->regs = regs; + } else if (current->mm) { + perf_get_regs_user(regs_user, regs, regs_user_copy); } else { regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; regs_user->regs = NULL; @@ -4951,7 +4947,8 @@ void perf_prepare_sample(struct perf_event_header *header, } if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER)) - perf_sample_regs_user(&data->regs_user, regs); + perf_sample_regs_user(&data->regs_user, regs, + &data->regs_user_copy); if (sample_type & PERF_SAMPLE_REGS_USER) { /* regs dump ABI info */ -- 2.1.0