From mboxrd@z Thu Jan 1 00:00:00 1970 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32326C433F5 for ; Wed, 17 Nov 2021 14:08:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 162A361B54 for ; Wed, 17 Nov 2021 14:08:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238200AbhKQOLA (ORCPT ); Wed, 17 Nov 2021 09:11:00 -0500 Received: from foss.arm.com ([217.140.110.172]:57214 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238179AbhKQOK6 (ORCPT ); Wed, 17 Nov 2021 09:10:58 -0500 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 DEF2F11B3; Wed, 17 Nov 2021 06:07:59 -0800 (PST) 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 538DB3F70D; Wed, 17 Nov 2021 06:07:57 -0800 (PST) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: aou@eecs.berkeley.edu, borntraeger@de.ibm.com, bp@alien8.de, broonie@kernel.org, catalin.marinas@arm.com, dave.hansen@linux.intel.com, gor@linux.ibm.com, hca@linux.ibm.com, linux-kernel@vger.kernel.org, madvenka@linux.microsoft.com, mark.rutland@arm.com, mhiramat@kernel.org, mingo@redhat.com, mpe@ellerman.id.au, palmer@dabbelt.com, paul.walmsley@sifive.com, peterz@infradead.org, rostedt@goodmis.org, tglx@linutronix.de, will@kernel.org Subject: [PATCH 3/9] arm64: Mark __switch_to() as __sched Date: Wed, 17 Nov 2021 14:07:31 +0000 Message-Id: <20211117140737.44420-4-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20211117140737.44420-1-mark.rutland@arm.com> References: <20211117140737.44420-1-mark.rutland@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Unlike most architectures (and only in keeping with powerpc), arm64 has a non __sched() function on the path to our cpu_switch_to() assembly function. It is expected that for a blocked task, in_sched_functions() can be used to skip all functions between the raw context switch assembly and the scheduler functions that call into __switch_to(). This is the behaviour expected by stack_trace_consume_entry_nosched(), and the behaviour we'd like to have such that we an simplify arm64's __get_wchan() implementation to use arch_stack_walk(). This patch mark's arm64's __switch_to as __sched. This *will not* change the behaviour of arm64's current __get_wchan() implementation, which always performs an initial unwind step which skips __switch_to(). This *will* change the behaviour of stack_trace_consume_entry_nosched() and stack_trace_save_tsk() to match their expected behaviour on blocked tasks, skipping all scheduler-internal functions including __switch_to(). Other than the above, there should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Madhavan T. Venkataraman Cc: Peter Zijlstra Cc: Will Deacon --- arch/arm64/kernel/process.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index aacf2f5559a8..980cad7292af 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -490,7 +490,8 @@ void update_sctlr_el1(u64 sctlr) /* * Thread switching. */ -__notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, +__notrace_funcgraph __sched +struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next) { struct task_struct *last; -- 2.11.0