From patchwork Wed Apr 13 14:05:22 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Madhavan T. Venkataraman" X-Patchwork-Id: 12812068 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 B2BB1C433FE for ; Wed, 13 Apr 2022 14:07:04 +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:To:From:Reply-To:Cc:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=JtLfbH+83Y/Dt+irlWFYnB0GNbAa8qUMdwnYVVqOkfA=; b=1qyX7jxiXJ2V1A ymI+oVvKuBvJMwBw1TBLLAx1iUk6pf84FaBOUawxWUjsNKkki36F5cjpylWq572my9S+jJN6OTBxk MAqr/ddCS5s5rbirCuudggKki7e8kVusMtpIMd0SKk7nQN5VFn1hmfjAXwWxd35Aa/4m+OXYtyjnh 3f+jJJ+rZNfnmskfIewJuUp/Vm/Ib12EFvXJ8yJblvJcTMqqvVDrfqUIkWWWUBuRg25gO4oti0ICI d7Nq5pgtS3xInT+xkk6J7j4XDmjdML6YSsTnxBo7Q2zTmSI0HqSaSi/HfZ3daRa9TnvexGFg1Yqo6 sWkFkil4V7FWP6OuEJug==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nedd8-001Js7-Ly; Wed, 13 Apr 2022 14:05:58 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nedcw-001Jml-FK for linux-arm-kernel@lists.infradead.org; Wed, 13 Apr 2022 14:05:48 +0000 Received: from x64host.home (unknown [47.189.24.195]) by linux.microsoft.com (Postfix) with ESMTPSA id 0B0D520C34CA; Wed, 13 Apr 2022 07:05:42 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 0B0D520C34CA DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1649858743; bh=rq9hnVI/Y4H4vRXgmKmfpdtj1W5zhGVLrIDwQqVIs14=; h=From:To:Subject:Date:In-Reply-To:References:From; b=YnYthjC6iqx7LeDpXzExD1CxOuAjqVKKh4uIgRwTboHD90c5Icl2kMNXalfpKjKJ+ euHXz2aEmDqAZZ1h5hjufGIQdqXfTxdNhYhA537RlPEc3D3beHcZaqk3i0B31bkrFi O2pPULrCAKsQNHJh6Iv/dcQtJwkddF8hyr+/D/f4= From: madvenka@linux.microsoft.com To: mark.rutland@arm.com, broonie@kernel.org, jpoimboe@redhat.com, ardb@kernel.org, nobuta.keiya@fujitsu.com, sjitindarsingh@gmail.com, catalin.marinas@arm.com, will@kernel.org, jmorris@namei.org, linux-arm-kernel@lists.infradead.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, madvenka@linux.microsoft.com Subject: [PATCH v14 1/7] arm64: Split unwind_init() Date: Wed, 13 Apr 2022 09:05:22 -0500 Message-Id: <20220413140528.3815-2-madvenka@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220413140528.3815-1-madvenka@linux.microsoft.com> References: <20220413140528.3815-1-madvenka@linux.microsoft.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220413_070546_614241_C6234BB6 X-CRM114-Status: GOOD ( 16.12 ) 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 From: "Madhavan T. Venkataraman" unwind_init() is currently a single function that initializes all of the unwind state. Split it into the following functions and call them appropriately: - unwind_init_from_regs() - initialize from regs passed by caller. - unwind_init_from_caller() - initialize for the current task from the caller of arch_stack_walk(). - unwind_init_from_task() - initialize from the saved state of a task other than the current task. In this case, the other task must not be running. This is done for two reasons: - the different ways of initializing are clear - specialized code can be added to each initializer in the future. Signed-off-by: Madhavan T. Venkataraman Reviewed-by: Mark Brown --- arch/arm64/kernel/stacktrace.c | 66 ++++++++++++++++++++++++++++------ 1 file changed, 55 insertions(+), 11 deletions(-) diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 0467cb79f080..e44f93ff25f0 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -50,11 +50,8 @@ struct unwind_state { #endif }; -static notrace void unwind_init(struct unwind_state *state, unsigned long fp, - unsigned long pc) +static void unwind_init_common(struct unwind_state *state) { - state->fp = fp; - state->pc = pc; #ifdef CONFIG_KRETPROBES state->kr_cur = NULL; #endif @@ -72,7 +69,57 @@ static notrace void unwind_init(struct unwind_state *state, unsigned long fp, state->prev_fp = 0; state->prev_type = STACK_TYPE_UNKNOWN; } -NOKPROBE_SYMBOL(unwind_init); + +/* + * Start an unwind from a pt_regs. + * + * The unwind will begin at the PC within the regs. + * + * The regs must be on a stack currently owned by the calling task. + */ +static inline void unwind_init_from_regs(struct unwind_state *state, + struct pt_regs *regs) +{ + unwind_init_common(state); + + state->fp = regs->regs[29]; + state->pc = regs->pc; +} + +/* + * Start an unwind from a caller. + * + * The unwind will begin at the caller of whichever function this is inlined + * into. + * + * The function which invokes this must be noinline. + */ +static __always_inline void unwind_init_from_caller(struct unwind_state *state) +{ + unwind_init_common(state); + + state->fp = (unsigned long)__builtin_frame_address(1); + state->pc = (unsigned long)__builtin_return_address(0); +} + +/* + * Start an unwind from a blocked task. + * + * The unwind will begin at the blocked tasks saved PC (i.e. the caller of + * cpu_switch_to()). + * + * The caller should ensure the task is blocked in cpu_switch_to() for the + * duration of the unwind, or the unwind will be bogus. It is never valid to + * call this for the current task. + */ +static inline void unwind_init_from_task(struct unwind_state *state, + struct task_struct *task) +{ + unwind_init_common(state); + + state->fp = thread_saved_fp(task); + state->pc = thread_saved_pc(task); +} /* * Unwind from one frame record (A) to the next frame record (B). @@ -213,14 +260,11 @@ noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry, struct unwind_state state; if (regs) - unwind_init(&state, regs->regs[29], regs->pc); + unwind_init_from_regs(&state, regs); else if (task == current) - unwind_init(&state, - (unsigned long)__builtin_frame_address(1), - (unsigned long)__builtin_return_address(0)); + unwind_init_from_caller(&state); else - unwind_init(&state, thread_saved_fp(task), - thread_saved_pc(task)); + unwind_init_from_task(&state, task); unwind(task, &state, consume_entry, cookie); }