From patchwork Thu Oct 17 09:25:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 13839717 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 CEB32D2126E for ; Thu, 17 Oct 2024 09:46:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=b9TSuIi5lXTJLC3mm+HFFHF6e72sr6VnlrolsFYua2M=; b=pPo08MPrwyhJna4uYPNuLO/K08 UlOF0ZC/BHt2VDHbUNxw74CiEhINf3PvdPJKGN3jZB7wNVXZIaKNRn07UZM7yoI0CeOEWXJXwUN8R 0bZZcqLHNPi6gBWl58AM1XmXXjnozXRndzU6pH42Os5X+d9JibPahUq1I8UZPCWMLNXhI7+1X1ES4 mqXSbjmTtAAedbfmvy6MIpPniUlnsdNI6R+5ZNM+QaQweElipzK/9po4QO1cgdNV41ihEdsFrpooc HfHydvtgFf33ITrwNdKHKid/zuzh8ylZ54+qJjcWegu/1Fddw80GUxjiggDr1oDRai086qjLGl9VX L4JMka2w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t1N59-0000000EORU-1fYC; Thu, 17 Oct 2024 09:46:11 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t1Mlm-0000000EKju-3S9n for linux-arm-kernel@lists.infradead.org; Thu, 17 Oct 2024 09:26:12 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 067801477; Thu, 17 Oct 2024 02:26:40 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 558C13F528; Thu, 17 Oct 2024 02:26:08 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: ardb@kernel.org, broonie@kernel.org, catalin.marinas@arm.com, jpoimboe@kernel.org, kaleshsingh@google.com, madvenka@linux.microsoft.com, mark.rutland@arm.com, maz@kernel.org, mbenes@suse.cz, puranjay12@gmail.com, will@kernel.org Subject: [PATCH v2 09/10] arm64: stacktrace: split unwind_consume_stack() Date: Thu, 17 Oct 2024 10:25:37 +0100 Message-Id: <20241017092538.1859841-10-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20241017092538.1859841-1-mark.rutland@arm.com> References: <20241017092538.1859841-1-mark.rutland@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241017_022610_992223_117B402C X-CRM114-Status: GOOD ( 22.19 ) 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 When unwinding stacks, we use unwind_consume_stack() to both find whether an object (e.g. a frame record) is on an accessible stack *and* to update the stack boundaries. This works fine today since we only care about one type of object which does not overlap other objects. In subsequent patches we'll want to check whether an object (e.g a frame record) is on the stack and follow this up by accessing a larger object containing the first (e.g. a pt_regs with an embedded frame record). To make that pattern easier to implement, this patch reworks unwind_find_next_stack() and unwind_consume_stack() so that the former can be used to check if an object is on any accessible stack, and the latter is purely used to update the stack boundaries. As unwind_find_next_stack() is modified to also check the stack currently being unwound, it is renamed to unwind_find_stack(). There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Reviewed-by: Mark Brown Reviewed-by: Miroslav Benes Reviewed-by: Puranjay Mohan Cc: Ard Biesheuvel Cc: Josh Poimboeuf Cc: Kalesh Singh Cc: Madhavan T. Venkataraman Cc: Marc Zyngier Cc: Will Deacon --- arch/arm64/include/asm/stacktrace/common.h | 68 +++++++++++++--------- 1 file changed, 39 insertions(+), 29 deletions(-) diff --git a/arch/arm64/include/asm/stacktrace/common.h b/arch/arm64/include/asm/stacktrace/common.h index 7fab6876e4970..821a8fdd31af4 100644 --- a/arch/arm64/include/asm/stacktrace/common.h +++ b/arch/arm64/include/asm/stacktrace/common.h @@ -60,13 +60,27 @@ static inline void unwind_init_common(struct unwind_state *state) state->stack = stackinfo_get_unknown(); } -static struct stack_info *unwind_find_next_stack(const struct unwind_state *state, - unsigned long sp, - unsigned long size) +/** + * unwind_find_stack() - Find the accessible stack which entirely contains an + * object. + * + * @state: the current unwind state. + * @sp: the base address of the object. + * @size: the size of the object. + * + * Return: a pointer to the relevant stack_info if found; NULL otherwise. + */ +static struct stack_info *unwind_find_stack(struct unwind_state *state, + unsigned long sp, + unsigned long size) { - for (int i = 0; i < state->nr_stacks; i++) { - struct stack_info *info = &state->stacks[i]; + struct stack_info *info = &state->stack; + if (stackinfo_on_stack(info, sp, size)) + return info; + + for (int i = 0; i < state->nr_stacks; i++) { + info = &state->stacks[i]; if (stackinfo_on_stack(info, sp, size)) return info; } @@ -75,36 +89,31 @@ static struct stack_info *unwind_find_next_stack(const struct unwind_state *stat } /** - * unwind_consume_stack() - Check if an object is on an accessible stack, - * updating stack boundaries so that future unwind steps cannot consume this - * object again. + * unwind_consume_stack() - Update stack boundaries so that future unwind steps + * cannot consume this object again. * * @state: the current unwind state. + * @info: the stack_info of the stack containing the object. * @sp: the base address of the object. * @size: the size of the object. * * Return: 0 upon success, an error code otherwise. */ -static inline int unwind_consume_stack(struct unwind_state *state, - unsigned long sp, - unsigned long size) +static inline void unwind_consume_stack(struct unwind_state *state, + struct stack_info *info, + unsigned long sp, + unsigned long size) { - struct stack_info *next; - - if (stackinfo_on_stack(&state->stack, sp, size)) - goto found; - - next = unwind_find_next_stack(state, sp, size); - if (!next) - return -EINVAL; + struct stack_info tmp; /* * Stack transitions are strictly one-way, and once we've * transitioned from one stack to another, it's never valid to * unwind back to the old stack. * - * Remove the current stack from the list of stacks so that it cannot - * be found on a subsequent transition. + * Destroy the old stack info so that it cannot be found upon a + * subsequent transition. If the stack has not changed, we'll + * immediately restore the current stack info. * * Note that stacks can nest in several valid orders, e.g. * @@ -115,16 +124,15 @@ static inline int unwind_consume_stack(struct unwind_state *state, * ... so we do not check the specific order of stack * transitions. */ - state->stack = *next; - *next = stackinfo_get_unknown(); + tmp = *info; + *info = stackinfo_get_unknown(); + state->stack = tmp; -found: /* * Future unwind steps can only consume stack above this frame record. * Update the current stack to start immediately above it. */ state->stack.low = sp + size; - return 0; } /** @@ -137,16 +145,18 @@ static inline int unwind_consume_stack(struct unwind_state *state, static inline int unwind_next_frame_record(struct unwind_state *state) { + struct stack_info *info; struct frame_record *record; unsigned long fp = state->fp; - int err; if (fp & 0x7) return -EINVAL; - err = unwind_consume_stack(state, fp, sizeof(*record)); - if (err) - return err; + info = unwind_find_stack(state, fp, sizeof(*record)); + if (!info) + return -EINVAL; + + unwind_consume_stack(state, info, fp, sizeof(*record)); /* * Record this frame record's values.