From patchwork Mon May 8 21:19:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 13235144 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5FF29C7EE26 for ; Mon, 8 May 2023 21:37:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234419AbjEHVhI (ORCPT ); Mon, 8 May 2023 17:37:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234248AbjEHVgt (ORCPT ); Mon, 8 May 2023 17:36:49 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0906746A1; Mon, 8 May 2023 14:36:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=YB2UOIFIw2gwCNTVh1j30XHP2RZzZzmzkIRobxbOGl0=; b=M2iOJBjKCa79Kv9g3tjWPVJtfy KhgiZrTa14XHFuWNlEPcmixkV04+wlzqZJejkStuJj9v7/L8doRfz+dSC1Hh4X+EV63Q7yEPMtx3l VvKERwRhkB0Pue0edXHPZLIi7dBrgCMV5plSt4V61wT3O4pNq41WMoOdff8iW+QCXNa4J6i4gdDkH 3Op4X0qcSAppyJHS8/G/TRWwuJCq8ntWBm8EmEJdXZH5sXXGJTSYslQP651uTLAomLG6te6RB3kEf fQGbSryGVWIyKlWQBoAiJhJ7ytQTG0orrgOpToKdgeO4JFZc/HJEIrEESutvAqjUogdgXVL1c75a3 ZUxEaSrA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1pw8UZ-005J1E-1B; Mon, 08 May 2023 21:34:15 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id A98C630613F; Mon, 8 May 2023 23:33:48 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 3EBFA24829429; Mon, 8 May 2023 23:33:48 +0200 (CEST) Message-ID: <20230508213147.718633831@infradead.org> User-Agent: quilt/0.66 Date: Mon, 08 May 2023 23:19:56 +0200 From: Peter Zijlstra To: bigeasy@linutronix.de Cc: mark.rutland@arm.com, maz@kernel.org, catalin.marinas@arm.com, will@kernel.org, chenhuacai@kernel.org, kernel@xen0n.name, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, pbonzini@redhat.com, wanpengli@tencent.com, vkuznets@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, jgross@suse.com, boris.ostrovsky@oracle.com, daniel.lezcano@linaro.org, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, rafael@kernel.org, peterz@infradead.org, longman@redhat.com, boqun.feng@gmail.com, pmladek@suse.com, senozhatsky@chromium.org, rostedt@goodmis.org, john.ogness@linutronix.de, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, jstultz@google.com, sboyd@kernel.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-s390@vger.kernel.org, kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-pm@vger.kernel.org Subject: [RFC][PATCH 5/9] loongarch: Provide noinstr sched_clock_read() References: <20230508211951.901961964@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org With the intent to provide local_clock_noinstr(), a variant of local_clock() that's safe to be called from noinstr code (with the assumption that any such code will already be non-preemptible), prepare for things by providing a noinstr sched_clock_read() function. Specifically, preempt_enable_*() calls out to schedule(), which upsets noinstr validation efforts. Signed-off-by: Peter Zijlstra (Intel) --- arch/loongarch/include/asm/loongarch.h | 2 +- arch/loongarch/kernel/time.c | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-) --- a/arch/loongarch/include/asm/loongarch.h +++ b/arch/loongarch/include/asm/loongarch.h @@ -1167,7 +1167,7 @@ static __always_inline void iocsr_write6 #ifndef __ASSEMBLY__ -static inline u64 drdtime(void) +static __always_inline u64 drdtime(void) { int rID = 0; u64 val = 0; --- a/arch/loongarch/kernel/time.c +++ b/arch/loongarch/kernel/time.c @@ -190,9 +190,9 @@ static u64 read_const_counter(struct clo return drdtime(); } -static u64 native_sched_clock(void) +static noinstr u64 sched_clock_read(void) { - return read_const_counter(NULL); + return drdtime(); } static struct clocksource clocksource_const = { @@ -211,7 +211,7 @@ int __init constant_clocksource_init(voi res = clocksource_register_hz(&clocksource_const, freq); - sched_clock_register(native_sched_clock, 64, freq); + sched_clock_register(sched_clock_read, 64, freq); pr_info("Constant clock source device register\n");