From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 46BC4400E07; Thu, 30 Jul 2026 10:25:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785407149; cv=none; b=ThmOSZw182/b1NBqQiA/aMxbN6f7wCjfHmVcYCU8TVdsnrqfynf9G2cFcu0n40l6HgcUStPz+G1FSoPJQBoo4tB9A7DdRRvhkWlhz4/scqt3zvNJemOTSAeJ9IA+VeQoOCJ4JzECiCBF6jsM4l0sTMCUJ0KcfwILR7+3Hyrdp7w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785407149; c=relaxed/simple; bh=pKljVHRgusb/ulPWnBHsXu5Iu8Mxu1QY03lTCnZWP2M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RaFQrxdrZza+j54CnFzGhvsqhUyRcMbGQCF9wlwwjWyou48SPJM5dWSD5PSRxSt9F6dFMZJguctUtEak/MvxI8vw46xtb3U5+fAuHWWiTSV2HrHXdRJAjAl1sipwwnCzdPR8m7JshPHFZbeJpHx8DfHBwQM7uXCVHREdtrzf6Yw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=cbuZuTGv; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="cbuZuTGv" Received: from pps.filterd (m0356516.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 66UAHfTr2636729; Thu, 30 Jul 2026 10:24:22 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=pp1; bh=xw9bl0UjL8IGxj4aZhOi4y5k8I/VjG wH4N8Nftf3ETs=; b=cbuZuTGvqINoexIK4WJN7w/SOfmPaw53VjLgWWtS0g1TV6 AApSlNPtfukyEGV6EI1+baii13lUpd2RVrnTO88JAS1uB01nwD67S3BhwpoT2ftm pF1aM1FG6wpbsP/2T2h/31TWb6MAMdVqk0Y0U7xObox64yGys3hlQjDIfr8/OyTT ZLk2ISyswnawz/KZ/3QxEn7Cz3+cgM9B0jXe3LlYa7dkclFQ8s+v8pXMLDuK64eU xSEo265wzDTK23P4NZS7d3IgP6C+Az950pfBRGVg8zEGHpSLAluj7s56G0jmRmD0 INGHxNZjyqwgHLW/B1Qyfn+8b6UhtSsWVxw1bs8A== Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4fmuyjeb2g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 30 Jul 2026 10:24:22 +0000 (GMT) Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 66UACIwl016888; Thu, 30 Jul 2026 10:24:21 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4fn8yhjrst-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 30 Jul 2026 10:24:21 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (smtpav01.fra02v.mail.ibm.com [10.20.54.100]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 66UAOJda30736806 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 30 Jul 2026 10:24:19 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4770120040; Thu, 30 Jul 2026 10:24:19 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 832C320043; Thu, 30 Jul 2026 10:24:18 +0000 (GMT) Received: from li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com (unknown [9.224.92.206]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTPS; Thu, 30 Jul 2026 10:24:18 +0000 (GMT) Date: Thu, 30 Jul 2026 12:24:17 +0200 From: Alexander Gordeev To: Muhammad Usama Anjum Cc: Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , David Airlie , Simona Vetter , Dimitri Sivanich , Arnd Bergmann , Greg Kroah-Hartman , "James E.J. Bottomley" , Helge Deller , Juergen Gross , Stefano Stabellini , Muchun Song , Oscar Salvador , Andrew Morton , "Liam R. Howlett" , Lorenzo Stoakes , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Peter Zijlstra , Andrey Ryabinin , David Hildenbrand , Pasha Tatashin , Chris Li , Kairui Song , Uladzislau Rezki , Steven Rostedt , Masami Hiramatsu , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , SJ Park , "Matthew Wilcox (Oracle)" , Jan Kara , Jason Gunthorpe , Leon Romanovsky , Miaohe Lin , Dennis Zhou , Tejun Heo , Christoph Lameter , Mike Rapoport , Johannes Weiner , ziy@nvidia.com, pfalcato@suse.de, ryan.roberts@arm.com, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-parisc@vger.kernel.org, xen-devel@lists.xenproject.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, kasan-dev@googlegroups.com, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, damon@lists.linux.dev Subject: Re: [PATCH RFC 05/11] mm: convert PTE table entries in ptep_get() Message-ID: <9ac3f058-2a22-4801-8633-65635053c8ea-agordeev@linux.ibm.com> References: <20260727164715.2866609-1-usama.anjum@arm.com> <20260727164715.2866609-6-usama.anjum@arm.com> <34eed5fd-c569-49d8-bc4d-a3d4b1207fbd-agordeev@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYwNzMwMDA3NyBTYWx0ZWRfX4Ckb6VFvsR9K iulXf5F6J1kbO3S70H2cESI4ld0w043xIGqpEZSAio/jR2ldVb59L2x/b1Cpx4Kz3J+55BAkaM9 AupsGP2HnWvt72AfxwuZCRHnnZzHlFA= X-Proofpoint-GUID: lqUngdZpiUvWS2H94qSv0rrypUIzUueB X-Proofpoint-ORIG-GUID: lqUngdZpiUvWS2H94qSv0rrypUIzUueB X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzMwMDA3NyBTYWx0ZWRfX06YvqUElSumU CX2i3BnWz3n82hQOJuDP+Eanqg4avWjidLhYvcVNnamNO07ZloFlgeCgnjzpU+K/axVetiCls6t fKTSRdUkAcS0rVX5DnmB5M3W+uSpPU1IR/K4E27Sif4nh0pOXRleMzORssdR6V6MA7b5OjvGCGl tmvL0lRGkg/9y7/aNGQHm7zP9EpllmztMk0bjuCc6uOo5iaioj63uiUyglAwfqaYT/no/5x3iQn vH4Y1m9mc+79iOqDEv4VRNaHyLb/P8hiMxjG+nu/SRMxZsyV5wIoBoehG5Qe599Oqn8bsFRSCM3 nyuj5Wj5auh3/+ccZhKHFFSfFIyH9mArzZF7DQ5gDzyTNL3gEudzEqBeGvpOI/h3/KDV8L04T7O OCFoQvBOxFLH/rPHH9zdO6BPTMqXuYhm4NtAFZGuJ1Oen3ihETQeEK2CjltziDECdSbdSoTjDB5 7szof3AH3iJlA7l4pXg== X-Authority-Analysis: v=2.4 cv=X5Vi7mTe c=1 sm=1 tr=0 ts=6a6b2656 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=kj9zAlcOel0A:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=7CQSdrXTAAAA:8 a=7fzHlb7OYtr7bZKlnRAA:9 a=CjuIK1q_8ugA:10 a=a-qgeE7W1pNrGK8U0ZQC:22 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-30_03,2026-07-29_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 impostorscore=0 lowpriorityscore=0 phishscore=0 priorityscore=1501 malwarescore=0 spamscore=0 suspectscore=0 bulkscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607300077 On Thu, Jul 30, 2026 at 11:11:35AM +0100, Muhammad Usama Anjum wrote: > On 30/07/2026 11:08 am, Alexander Gordeev wrote: > > On Mon, Jul 27, 2026 at 05:46:56PM +0100, Muhammad Usama Anjum wrote: > >> ptep_get() now accepts a pointer to hw_pte_t storage but must continue to > >> return a logical pte_t value. Add __pte_from_hw() as the conversion hook > >> and apply it in the generic ptep_get() implementation. > >> > >> Signed-off-by: Muhammad Usama Anjum > >> --- > >> include/linux/pgtable.h | 2 +- > >> include/linux/pgtable_types.h | 1 + > >> 2 files changed, 2 insertions(+), 1 deletion(-) > >> > >> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h > >> index dad80d264aac2..3003ac9cd81fe 100644 > >> --- a/include/linux/pgtable.h > >> +++ b/include/linux/pgtable.h > >> @@ -493,7 +493,7 @@ static inline int pudp_set_access_flags(struct vm_area_struct *vma, > >> #ifndef ptep_get > >> static inline pte_t ptep_get(hw_pte_t *ptep) > >> { > >> - return READ_ONCE(*ptep); > >> + return READ_ONCE(__pte_from_hw(*ptep)); > > > > Should it be something like? > > > > return __pte_from_hw(READ_ONCE(*ptep)); > I'd thought about it. My thinking is that we should get the pte_t first before > before calling READ_ONCE(). Please correct me what makes more sense? I have a problem with "get the pte_t first" part ;) I think what we want is atomically read the hw_pte_t from the HW table and then convert the result to pte_t. > > > >> } > >> #endif > >> > >> diff --git a/include/linux/pgtable_types.h b/include/linux/pgtable_types.h > >> index ed5dba42a4f8c..61afe27307ec2 100644 > >> --- a/include/linux/pgtable_types.h > >> +++ b/include/linux/pgtable_types.h > >> @@ -6,6 +6,7 @@ > >> > >> #ifndef __HAVE_ARCH_HW_PTE_T > >> #define hw_pte_t pte_t > >> +#define __pte_from_hw(pte) (pte) > >> #endif > >> > >> #endif /* _LINUX_PGTABLE_TYPES_H */ > >> -- > >> 2.47.3 > >> > > -- > Thanks, > Usama >