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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66D09E95A8E for ; Mon, 9 Oct 2023 13:12:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376949AbjJINMZ (ORCPT ); Mon, 9 Oct 2023 09:12:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376965AbjJINMJ (ORCPT ); Mon, 9 Oct 2023 09:12:09 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0BA741BD4 for ; Mon, 9 Oct 2023 06:11:04 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFC5DC433C9; Mon, 9 Oct 2023 13:11:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696857063; bh=uOxJcdMeUeNOg3LmZF35HJWluaPMk4xEj1EPjazLqoI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mQK5VzQTVk+8QoaWoCaVfD3Jx/E5VzlyviofIdehGeqHvIUbG5g+D3+yUGZ/Q8jOD 5e1uJe7bz0JiY6mO6JKM+ZdAGvHE7WRCI/HfDKwNys1rG310oMzgXJh3LlHPqtWK9b KsCXnl61pCbuo7jyvxWrQPFn0flYxcpXisXT2CgU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sandipan Das , Ingo Molnar , Sasha Levin Subject: [PATCH 6.5 083/163] perf/x86/amd/core: Fix overflow reset on hotplug Date: Mon, 9 Oct 2023 15:00:47 +0200 Message-ID: <20231009130126.338340227@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130124.021290599@linuxfoundation.org> References: <20231009130124.021290599@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sandipan Das [ Upstream commit 23d2626b841c2adccdeb477665313c02dff02dc3 ] Kernels older than v5.19 do not support PerfMonV2 and the PMI handler does not clear the overflow bits of the PerfCntrGlobalStatus register. Because of this, loading a recent kernel using kexec from an older kernel can result in inconsistent register states on Zen 4 systems. The PMI handler of the new kernel gets confused and shows a warning when an overflow occurs because some of the overflow bits are set even if the corresponding counters are inactive. These are remnants from overflows that were handled by the older kernel. During CPU hotplug, the PerfCntrGlobalCtl and PerfCntrGlobalStatus registers should always be cleared for PerfMonV2-capable processors. However, a condition used for NB event constaints applicable only to older processors currently prevents this from happening. Move the reset sequence to an appropriate place and also clear the LBR Freeze bit. Fixes: 21d59e3e2c40 ("perf/x86/amd/core: Detect PerfMonV2 support") Signed-off-by: Sandipan Das Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/882a87511af40792ba69bb0e9026f19a2e71e8a3.1694696888.git.sandipan.das@amd.com Signed-off-by: Sasha Levin --- arch/x86/events/amd/core.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c index abadd5f234254..ed626bfa1eedb 100644 --- a/arch/x86/events/amd/core.c +++ b/arch/x86/events/amd/core.c @@ -534,8 +534,12 @@ static void amd_pmu_cpu_reset(int cpu) /* Clear enable bits i.e. PerfCntrGlobalCtl.PerfCntrEn */ wrmsrl(MSR_AMD64_PERF_CNTR_GLOBAL_CTL, 0); - /* Clear overflow bits i.e. PerfCntrGLobalStatus.PerfCntrOvfl */ - wrmsrl(MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR, amd_pmu_global_cntr_mask); + /* + * Clear freeze and overflow bits i.e. PerfCntrGLobalStatus.LbrFreeze + * and PerfCntrGLobalStatus.PerfCntrOvfl + */ + wrmsrl(MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR, + GLOBAL_STATUS_LBRS_FROZEN | amd_pmu_global_cntr_mask); } static int amd_pmu_cpu_prepare(int cpu) @@ -570,6 +574,7 @@ static void amd_pmu_cpu_starting(int cpu) int i, nb_id; cpuc->perf_ctr_virt_mask = AMD64_EVENTSEL_HOSTONLY; + amd_pmu_cpu_reset(cpu); if (!x86_pmu.amd_nb_constraints) return; @@ -591,8 +596,6 @@ static void amd_pmu_cpu_starting(int cpu) cpuc->amd_nb->nb_id = nb_id; cpuc->amd_nb->refcnt++; - - amd_pmu_cpu_reset(cpu); } static void amd_pmu_cpu_dead(int cpu) @@ -601,6 +604,7 @@ static void amd_pmu_cpu_dead(int cpu) kfree(cpuhw->lbr_sel); cpuhw->lbr_sel = NULL; + amd_pmu_cpu_reset(cpu); if (!x86_pmu.amd_nb_constraints) return; @@ -613,8 +617,6 @@ static void amd_pmu_cpu_dead(int cpu) cpuhw->amd_nb = NULL; } - - amd_pmu_cpu_reset(cpu); } static inline void amd_pmu_set_global_ctl(u64 ctl) -- 2.40.1