From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3100B3CAA3E; Tue, 16 Jun 2026 04:52:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781585555; cv=none; b=ShTzu4XXrhHQLEOp7eMQpVFJ0sTcUC4hDP6UXrTtCZiy50mIwZGQmuxtBx0irTh7E6iii10jr1NlvBLtDvszkxYnxutTaDInGeJlHsQMz92jny6re//djo2Yd2VId/RCq4x1Fj3zHTaYjmp/RxByeXyr/NEkXyybEQcKv/BXrZA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781585555; c=relaxed/simple; bh=S94842HdpKEkH7GccAAAAfsJr+zABP1dzIFQEEDrQn8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=T6jgfbc93jlQDxgcokowRUd/vSUeyQSiAmZd7xG/kbMQ0AkSENK/b6B2dYV+a3Z0j0BPRgbGe+ldGNXI3T3CAeXHF9FMp3mZmTXSIQBkYSYYs6RS7KkfgsuR8su0zGAXEPrVo2S1Ifmhmy00ANBXPDrVvnOONDUaQkIMvmPvCSE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=ZRY/rMkG; arc=none smtp.client-ip=192.198.163.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="ZRY/rMkG" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1781585554; x=1813121554; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=S94842HdpKEkH7GccAAAAfsJr+zABP1dzIFQEEDrQn8=; b=ZRY/rMkGfiz46lAjSMva4MFopw5hoaskLReoWYVDa6o5RA4tSEvjDjJM 41rs5TcnaddtpKHz0AavBnul+mrOPkyyv1Q9TCPvm2o/1zP63SNIDuA54 bLUsxrir9TGuIf3VeAGLCqyabadH1NuDSrfRLgFMaewr5Q3xJeUsWTFi7 E030280QZLTQxMheLAFJC9jT1UUD2dwoSWiW3aSLeZKavm4BUpYsbTpP5 Y/77lfB8FlrYx+N+7XSFBSYGmW93LLCC9H3Ye7SpYoi9d16/IFRBNmBtM IAzOcD+qcu3AowGxxbf0/HQ73Cyum0+ohj1plZ7SkKWENg/Wi3VItrOt7 A==; X-CSE-ConnectionGUID: OGa9GFkVRfWNwYciuwMg2w== X-CSE-MsgGUID: jJzYd/Y/S+aRFD7eRaLP9w== X-IronPort-AV: E=McAfee;i="6800,10657,11818"; a="82445381" X-IronPort-AV: E=Sophos;i="6.24,207,1774335600"; d="scan'208";a="82445381" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2026 21:52:34 -0700 X-CSE-ConnectionGUID: a0/aFbh9SkiLjHkQ0swnGQ== X-CSE-MsgGUID: DpTOfb7gTEmE6Vm47k1hqQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,207,1774335600"; d="scan'208";a="271726255" Received: from spr.sh.intel.com ([10.112.230.239]) by fmviesa001.fm.intel.com with ESMTP; 15 Jun 2026 21:52:29 -0700 From: Dapeng Mi To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Ian Rogers , Adrian Hunter , Alexander Shishkin , Andi Kleen , Eranian Stephane Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Dapeng Mi , Zide Chen , Falcon Thomas , Xudong Hao , Dapeng Mi Subject: [Patch v4 2/8] perf/x86/intel: Keep cap_user_rdpmc in sync with RDPMC user-disable state Date: Tue, 16 Jun 2026 12:46:48 +0800 Message-Id: <20260616044654.3468742-3-dapeng1.mi@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260616044654.3468742-1-dapeng1.mi@linux.intel.com> References: <20260616044654.3468742-1-dapeng1.mi@linux.intel.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit After introducing the RDPMC user disable feature, user-space RDPMC may return 0 instead of the actual event count. This creates an inconsistency with cap_user_rdpmc, where cap_user_rdpmc is set, but user-space RDPMC only returns 0. To accurately represent the user-space RDPMC capability, update cap_user_rdpmc (depending on PERF_EVENT_FLAG_USER_READ_CNT) according to the RDPMC user disable state. If RDPMC user disable is enabled, cap_user_rdpmc is updated to false eventually, allowing user-space programs to fall back to the read() syscall to obtain the real event count. Because PERF_EVENT_FLAG_USER_READ_CNT is evaluated in x86_pmu_event_init(), move intel_pmu_update_rdpmc_user_disable() earlier into intel_pmu_hw_config(). This ensures that the user-disable state is updated before updating PERF_EVENT_FLAG_USER_READ_CNT. Note that since event->ctx is not yet assigned at this stage, use the PERF_ATTACH_TASK flag to detect whether the event is task-attached. While at it, fix the indentation of x86_pmu_has_rdpmc_user_disable() to adhere to the kernel coding style. Fixes: 59af95e028d4 ("perf/x86/intel: Add support for rdpmc user disable feature") Signed-off-by: Dapeng Mi --- arch/x86/events/core.c | 3 ++- arch/x86/events/intel/core.c | 6 +++--- arch/x86/events/perf_event.h | 2 +- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 4b9e105309c6..a76a2afae2fb 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2539,7 +2539,8 @@ static int x86_pmu_event_init(struct perf_event *event) } if (READ_ONCE(x86_pmu.attr_rdpmc) && - !(event->hw.flags & PERF_X86_EVENT_LARGE_PEBS)) + !(event->hw.flags & PERF_X86_EVENT_LARGE_PEBS) && + !(event->hw.config & ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE)) event->hw.flags |= PERF_EVENT_FLAG_USER_READ_CNT; return err; diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index ea3ab3050a3b..db52e7e53a6c 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3532,7 +3532,7 @@ static void intel_pmu_update_rdpmc_user_disable(struct perf_event *event) */ if (x86_pmu.attr_rdpmc == X86_USER_RDPMC_ALWAYS_ENABLE || (x86_pmu.attr_rdpmc == X86_USER_RDPMC_CONDITIONAL_ENABLE && - event->ctx->task)) + (event->attach_state & PERF_ATTACH_TASK))) event->hw.config &= ~ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE; else event->hw.config |= ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE; @@ -3546,8 +3546,6 @@ static void intel_pmu_enable_event(struct perf_event *event) struct hw_perf_event *hwc = &event->hw; int idx = hwc->idx; - intel_pmu_update_rdpmc_user_disable(event); - if (unlikely(event->attr.precise_ip)) static_call(x86_pmu_pebs_enable)(event); @@ -5146,6 +5144,8 @@ static int intel_pmu_hw_config(struct perf_event *event) leader->hw.flags |= PERF_X86_EVENT_ACR; } + intel_pmu_update_rdpmc_user_disable(event); + if ((event->attr.type == PERF_TYPE_HARDWARE) || (event->attr.type == PERF_TYPE_HW_CACHE)) return 0; diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index 5902a297daa1..a8afea8d38f0 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -1344,7 +1344,7 @@ static inline u64 x86_pmu_get_event_config(struct perf_event *event) static inline bool x86_pmu_has_rdpmc_user_disable(struct pmu *pmu) { return !!(hybrid(pmu, config_mask) & - ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE); + ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE); } extern struct event_constraint emptyconstraint; -- 2.34.1