From nobody Thu Apr 9 12:08:35 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 BFFBA38757D; Wed, 8 Apr 2026 11:20:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775647212; cv=none; b=TSuYGxEgr6uIX0SI7jIGsv2k1KrYXFUGaSY+w25qOzwAC/0Lut8xkIsv7FF38hxNC20/rOzOpTN44RV06SAtYmsTQDi2dEzQacyZHJwjLjPIMkMmnP6BBY7VAK8hJjSgnnYrZNMsiM0agqkVdQW4kEUkUomzIwzwMqoIhR9QGgQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775647212; c=relaxed/simple; bh=ztXvtYWho15xBB7Yflj4gBp+xP6zJdxAQajec9XabzI=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=C7Age6eIf6NZhV1yCi/bzOAMqGm+7YNbKxLBuL/Pyq5pu/cBTetPYPtRdemPOjr4qHGGzW/555refDtAnejH8u22elT3yGduxpajsN9OcNhkrlhZaIE64MEJ1HL7FusRFYzln9Cx/bGP4RiDuY+CwX4b7CxkS3vKFDFv12uVdJo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=cni5Jogq; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=VOnb9J7a; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="cni5Jogq"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="VOnb9J7a" Date: Wed, 08 Apr 2026 11:20:03 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1775647204; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4v66cpIxPPI219ep4odrrp7jEcmRGFL406bsycDZWfY=; b=cni5JogqvqO6nN7S7Y1BUDDuXoHdAcTPy3hxnmQovEtbVJb5pzWVgguSbgBKrYKZcQ5EgA hjvcpqnTez9yQrF4DpYfe6y9iXOf2VzS+8pQdL1ynzXdlG+3KDow8FE/sWH/Ld1B+qwY+r gv8h4Ci46RjyX4mXXsYZy3UYH70PHgi91MrvJ5LXVEQv4xW/EFzD9a13ClKLYPaYkP2VSP iDTmMmzcz/8RVBj2VbI+YRhKeorWl3YSNSJ5YaicBzKS9jzOKlFkGi8vgVeCk0IBK0MTIU 5wn09mOKlG68lsLVTVxsNYBEKG1HrXfoH0T/LdpuoCSj90DfidQBWsO5bV9zNA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1775647204; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4v66cpIxPPI219ep4odrrp7jEcmRGFL406bsycDZWfY=; b=VOnb9J7aaLEGAEAZ09Edw3bnTPCwnMluQ4H3dhXLCraogtvtbq3kxaxo3PI2S/ijlN6h1Q iHK3KPe6UzMSM2BA== From: "tip-bot2 for Anshuman Khandual" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: perf/core] perf/events: Replace READ_ONCE() with standard pgtable accessors Cc: Anshuman Khandual , "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20260227062744.2215491-1-anshuman.khandual@arm.com> References: <20260227062744.2215491-1-anshuman.khandual@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <177564720349.801717.13934182369286903768.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the perf/core branch of tip: Commit-ID: 5a84b600050c5f16b8bba25dd0e7aea845880407 Gitweb: https://git.kernel.org/tip/5a84b600050c5f16b8bba25dd0e7aea84= 5880407 Author: Anshuman Khandual AuthorDate: Fri, 27 Feb 2026 06:27:44=20 Committer: Peter Zijlstra CommitterDate: Wed, 08 Apr 2026 13:11:46 +02:00 perf/events: Replace READ_ONCE() with standard pgtable accessors Replace raw READ_ONCE() dereferences of pgtable entries with corresponding standard page table accessors pxdp_get() in perf_get_pgtable_size(). These accessors default to READ_ONCE() on platforms that don't override them. So there is no functional change on such platforms. However arm64 platform is being extended to support 128 bit page tables via a new architecture feature i.e FEAT_D128 in which case READ_ONCE() will not provide required single copy atomic access for 128 bit page table entries. Although pxdp_get() accessors can later be overridden on arm64 platform to extend required single copy atomicity support on 128 bit entries. Signed-off-by: Anshuman Khandual Signed-off-by: Peter Zijlstra (Intel) Acked-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260227062744.2215491-1-anshuman.khandual@a= rm.com --- kernel/events/core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 5eeae86..95d7a3e 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8421,7 +8421,7 @@ static u64 perf_get_pgtable_size(struct mm_struct *mm= , unsigned long addr) pte_t *ptep, pte; =20 pgdp =3D pgd_offset(mm, addr); - pgd =3D READ_ONCE(*pgdp); + pgd =3D pgdp_get(pgdp); if (pgd_none(pgd)) return 0; =20 @@ -8429,7 +8429,7 @@ static u64 perf_get_pgtable_size(struct mm_struct *mm= , unsigned long addr) return pgd_leaf_size(pgd); =20 p4dp =3D p4d_offset_lockless(pgdp, pgd, addr); - p4d =3D READ_ONCE(*p4dp); + p4d =3D p4dp_get(p4dp); if (!p4d_present(p4d)) return 0; =20 @@ -8437,7 +8437,7 @@ static u64 perf_get_pgtable_size(struct mm_struct *mm= , unsigned long addr) return p4d_leaf_size(p4d); =20 pudp =3D pud_offset_lockless(p4dp, p4d, addr); - pud =3D READ_ONCE(*pudp); + pud =3D pudp_get(pudp); if (!pud_present(pud)) return 0; =20