From patchwork Tue Jul 12 02:15:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Li Huafei X-Patchwork-Id: 12914463 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D9431C433EF for ; Tue, 12 Jul 2022 02:19:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=YZPXzmgVmqXo/PdvcujhA7u4SzQZstQqLNFyTtqnMa0=; b=rqkxhI0M6Vqo91 854mQnOl8kcx46E/6IE8e2F66ZJK50Y/JAYsOjO+VIjWDQywiO4V7Oc1Y/sUNODCV1PpzZFwki/Wi SH3ethqWlCqT/3fBB36mQPNwUgiUIXiu3MPuEsbDbhbfNTo9kTzGQKWU89xmRv0gvkGimW2OYzcPh JxOF09bmdPjri3+putYx1nhMPtzNPnpeji11qIbPd82GuBHxYZvU6UwYhuXgbmza30HNIBJi4yYAr df9UVBbQAjjwYA65Itn+X1MGEr+RdDy7MjOfqnRhDzZ5hAB8AtLb9+kXB3RgLQdv4mGM39sglFezS Z8TMSW8eSddiI84pPafQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oB5U8-006guE-Ul; Tue, 12 Jul 2022 02:18:49 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oB5TX-006gdO-00 for linux-arm-kernel@lists.infradead.org; Tue, 12 Jul 2022 02:18:13 +0000 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LhkpW56YhzVfgC; Tue, 12 Jul 2022 10:14:27 +0800 (CST) Received: from kwepemm600010.china.huawei.com (7.193.23.86) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 12 Jul 2022 10:17:55 +0800 Received: from ubuntu1804.huawei.com (10.67.174.174) by kwepemm600010.china.huawei.com (7.193.23.86) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 12 Jul 2022 10:17:54 +0800 From: Li Huafei To: , , , CC: , , , , , , , , , , , , , , , , , , , , Subject: [PATCH 2/5] ARM: stacktrace: Avoid duplicate saving of exception PC value Date: Tue, 12 Jul 2022 10:15:24 +0800 Message-ID: <20220712021527.109921-3-lihuafei1@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220712021527.109921-1-lihuafei1@huawei.com> References: <20220712021527.109921-1-lihuafei1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.174.174] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemm600010.china.huawei.com (7.193.23.86) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220711_191811_438810_CB0AED7A X-CRM114-Status: GOOD ( 16.41 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Because an exception stack frame is not created in the exception entry, save_trace() does special handling for the exception PC, but this is only needed when CONFIG_FRAME_POINTER_UNWIND=y. When CONFIG_ARM_UNWIND=y, unwind annotations have been added to the exception entry and save_trace() will repeatedly save the exception PC: [0x7f000090] hrtimer_hander+0x8/0x10 [hrtimer] [0x8019ec50] __hrtimer_run_queues+0x18c/0x394 [0x8019f760] hrtimer_run_queues+0xbc/0xd0 [0x8019def0] update_process_times+0x34/0x80 [0x801ad2a4] tick_periodic+0x48/0xd0 [0x801ad3dc] tick_handle_periodic+0x1c/0x7c [0x8010f2e0] twd_handler+0x30/0x40 [0x80177620] handle_percpu_devid_irq+0xa0/0x23c [0x801718d0] generic_handle_domain_irq+0x24/0x34 [0x80502d28] gic_handle_irq+0x74/0x88 [0x8085817c] generic_handle_arch_irq+0x58/0x78 [0x80100ba8] __irq_svc+0x88/0xc8 [0x80108114] arch_cpu_idle+0x38/0x3c [0x80108114] arch_cpu_idle+0x38/0x3c <==== duplicate saved exception PC [0x80861bf8] default_idle_call+0x38/0x130 [0x8015d5cc] do_idle+0x150/0x214 [0x8015d978] cpu_startup_entry+0x18/0x1c [0x808589c0] rest_init+0xd8/0xdc [0x80c00a44] arch_post_acpi_subsys_init+0x0/0x8 We can move the special handling of the exception PC in save_trace() to the unwind_frame() of the frame pointer unwinder. Signed-off-by: Li Huafei Reviewed-by: Linus Waleij --- arch/arm/include/asm/stacktrace.h | 6 +++++ arch/arm/kernel/return_address.c | 1 + arch/arm/kernel/stacktrace.c | 38 +++++++++++++++++++------------ 3 files changed, 31 insertions(+), 14 deletions(-) diff --git a/arch/arm/include/asm/stacktrace.h b/arch/arm/include/asm/stacktrace.h index 3e78f921b8b2..25282ff645fb 100644 --- a/arch/arm/include/asm/stacktrace.h +++ b/arch/arm/include/asm/stacktrace.h @@ -21,6 +21,9 @@ struct stackframe { struct llist_node *kr_cur; struct task_struct *tsk; #endif +#ifdef CONFIG_UNWINDER_FRAME_POINTER + bool ex_frame; +#endif }; static __always_inline @@ -34,6 +37,9 @@ void arm_get_current_stackframe(struct pt_regs *regs, struct stackframe *frame) frame->kr_cur = NULL; frame->tsk = current; #endif +#ifdef CONFIG_UNWINDER_FRAME_POINTER + frame->ex_frame = in_entry_text(frame->pc) ? true : false; +#endif } extern int unwind_frame(struct stackframe *frame); diff --git a/arch/arm/kernel/return_address.c b/arch/arm/kernel/return_address.c index 8aac1e10b117..38f1ea9c724d 100644 --- a/arch/arm/kernel/return_address.c +++ b/arch/arm/kernel/return_address.c @@ -47,6 +47,7 @@ void *return_address(unsigned int level) frame.kr_cur = NULL; frame.tsk = current; #endif + frame.ex_frame = false; walk_stackframe(&frame, save_return_addr, &data); diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c index af87040b0353..3acf51ee46bb 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -82,6 +82,21 @@ int notrace unwind_frame(struct stackframe *frame) if (frame_pointer_check(frame)) return -EINVAL; + /* + * When we unwind through an exception stack, include the saved PC + * value into the stack trace. + */ + if (frame->ex_frame) { + struct pt_regs *regs = (struct pt_regs *)frame->sp; + + if ((unsigned long)®s[1] > ALIGN(frame->sp, THREAD_SIZE)) + return -EINVAL; + + frame->pc = regs->ARM_pc; + frame->ex_frame = false; + return 0; + } + /* restore the registers from the stack frame */ #ifdef CONFIG_CC_IS_CLANG frame->sp = frame->fp; @@ -98,6 +113,9 @@ int notrace unwind_frame(struct stackframe *frame) (void *)frame->fp, &frame->kr_cur); #endif + if (in_entry_text(frame->pc)) + frame->ex_frame = true; + return 0; } #endif @@ -128,7 +146,6 @@ static int save_trace(struct stackframe *frame, void *d) { struct stack_trace_data *data = d; struct stack_trace *trace = data->trace; - struct pt_regs *regs; unsigned long addr = frame->pc; if (data->no_sched_functions && in_sched_functions(addr)) @@ -139,19 +156,6 @@ static int save_trace(struct stackframe *frame, void *d) } trace->entries[trace->nr_entries++] = addr; - - if (trace->nr_entries >= trace->max_entries) - return 1; - - if (!in_entry_text(frame->pc)) - return 0; - - regs = (struct pt_regs *)frame->sp; - if ((unsigned long)®s[1] > ALIGN(frame->sp, THREAD_SIZE)) - return 0; - - trace->entries[trace->nr_entries++] = regs->ARM_pc; - return trace->nr_entries >= trace->max_entries; } @@ -193,6 +197,9 @@ static noinline void __save_stack_trace(struct task_struct *tsk, frame.kr_cur = NULL; frame.tsk = tsk; #endif +#ifdef CONFIG_UNWINDER_FRAME_POINTER + frame.ex_frame = false; +#endif walk_stackframe(&frame, save_trace, &data); } @@ -214,6 +221,9 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) frame.kr_cur = NULL; frame.tsk = current; #endif +#ifdef CONFIG_UNWINDER_FRAME_POINTER + frame.ex_frame = in_entry_text(frame.pc) ? true : false; +#endif walk_stackframe(&frame, save_trace, &data); }