From nobody Thu Apr 2 01:51:05 2026 Received: from mail-244123.protonmail.ch (mail-244123.protonmail.ch [109.224.244.123]) (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 B10CE2EDD69 for ; Mon, 30 Mar 2026 14:34:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=109.224.244.123 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774881245; cv=none; b=Vzj3GenFiNw/9zkBDVFer/CQsMX7BCpRaVmMwzIy2AETtFk7IgFlvCZ/5Om8SyFlHpfPUnZRY5sFPV0i+ThC1Dwd1uvnG38xK+gHvhlFZFiCTIOEx6MlB4PCcdBexVIfNo6L5YFhB/BJIHHYWr4HpwUNnSZNX5c536fZOw3TszI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774881245; c=relaxed/simple; bh=IrdPXXebpwRuiG3UcmBGZipuHvApjSHn/WQXzPro91E=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=vAVj8fncpqS1et8Htx0cBdRFVyAND3QA1orbFeWQtS6OdtmFJDHRz07vfjdmA1lMTHWLyYgBy6p6Xj/GZ0qyFjCqvCNTo0vDiggLqRcdZHG3fOjl5S6+eukDdYev6KNib52J2+Flk4VG0ZLGxMOGNANyDsJD3iwNfO0oJFqbnlQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=pm.me; spf=pass smtp.mailfrom=pm.me; dkim=pass (2048-bit key) header.d=pm.me header.i=@pm.me header.b=hHWE4XfX; arc=none smtp.client-ip=109.224.244.123 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=pm.me Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pm.me Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=pm.me header.i=@pm.me header.b="hHWE4XfX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pm.me; s=protonmail3; t=1774881241; x=1775140441; bh=fLHwEkOWFBQMUpvTpaURzpC8jNFoLdOQa4MBEpchEew=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=hHWE4XfXCv7a8w9mDClxb9DYUnLhlr3ZuEFUYkbY45rHLExh0jNgs5GqAhq/89PBQ NQ04fc17shF35uPeXvVbDAr5TGQVoqQfd/P2NvFK3eNtDVlVnq4dlBEJkMaaILnTjG 0xEgzMCY+C+e86LeegsVd8WX+JQD8eHmBigN1DFK8hKalDkq7CqcAzYqETyQFVALdu RtzZ+8ehHBMXD5ZHF2DRvp6u6mYpg3oN7wJSH0mjxPO5s5ShsfECij0Qdr18PkPZAT G6kK8FrELG9YduQsAKk/UXd/++u0LXtM11wcZx/19Rf3hUsw3la3x8E8utj1hF1VxE KG5nLs9AcdxYQ== Date: Mon, 30 Mar 2026 14:33:56 +0000 To: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" From: Maciej Wieczor-Retman Cc: m.wieczorretman@pm.me, Maciej Wieczor-Retman , linux-kernel@vger.kernel.org Subject: [PATCH v12 08/15] x86/mm: Use physical address comparisons in fill_p*d/pte Message-ID: In-Reply-To: References: Feedback-ID: 164464600:user:proton X-Pm-Message-ID: 4ca4907790ed77eb3f17b37e52c05e2350ec7cee Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Maciej Wieczor-Retman Calculating page offset returns a pointer without a tag. When comparing the calculated offset to a tagged page pointer an error is raised because they are not equal. Change pointer comparisons to physical address comparisons as to avoid issues with tagged pointers that pointer arithmetic would create. Open code pte_offset_kernel(), pmd_offset(), pud_offset() and p4d_offset(). Because one parameter is always zero and the rest of the function insides are enclosed inside __va(), removing that layer lowers the complexity of final assembly. Signed-off-by: Maciej Wieczor-Retman Acked-by: Dave Hansen --- Changelog v11: - Add Dave's Acked-by. Changelog v9: - Rename patch title so it fits the tip standards. Changelog v7: - Swap ternary operator outcomes in fill_p4d since the order was incorrect. Changelog v2: - Open code *_offset() to avoid it's internal __va(). arch/x86/mm/init_64.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index df2261fa4f98..dd9f15ab8b86 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -269,7 +269,10 @@ static p4d_t *fill_p4d(pgd_t *pgd, unsigned long vaddr) if (pgd_none(*pgd)) { p4d_t *p4d =3D (p4d_t *)spp_getpage(); pgd_populate(&init_mm, pgd, p4d); - if (p4d !=3D p4d_offset(pgd, 0)) + + if (__pa(p4d) !=3D (pgtable_l5_enabled() ? + (unsigned long)pgd_val(*pgd) & PTE_PFN_MASK : + __pa(pgd))) printk(KERN_ERR "PAGETABLE BUG #00! %p <-> %p\n", p4d, p4d_offset(pgd, 0)); } @@ -281,7 +284,7 @@ static pud_t *fill_pud(p4d_t *p4d, unsigned long vaddr) if (p4d_none(*p4d)) { pud_t *pud =3D (pud_t *)spp_getpage(); p4d_populate(&init_mm, p4d, pud); - if (pud !=3D pud_offset(p4d, 0)) + if (__pa(pud) !=3D (p4d_val(*p4d) & p4d_pfn_mask(*p4d))) printk(KERN_ERR "PAGETABLE BUG #01! %p <-> %p\n", pud, pud_offset(p4d, 0)); } @@ -293,7 +296,7 @@ static pmd_t *fill_pmd(pud_t *pud, unsigned long vaddr) if (pud_none(*pud)) { pmd_t *pmd =3D (pmd_t *) spp_getpage(); pud_populate(&init_mm, pud, pmd); - if (pmd !=3D pmd_offset(pud, 0)) + if (__pa(pmd) !=3D (pud_val(*pud) & pud_pfn_mask(*pud))) printk(KERN_ERR "PAGETABLE BUG #02! %p <-> %p\n", pmd, pmd_offset(pud, 0)); } @@ -305,7 +308,7 @@ static pte_t *fill_pte(pmd_t *pmd, unsigned long vaddr) if (pmd_none(*pmd)) { pte_t *pte =3D (pte_t *) spp_getpage(); pmd_populate_kernel(&init_mm, pmd, pte); - if (pte !=3D pte_offset_kernel(pmd, 0)) + if (__pa(pte) !=3D (pmd_val(*pmd) & pmd_pfn_mask(*pmd))) printk(KERN_ERR "PAGETABLE BUG #03!\n"); } return pte_offset_kernel(pmd, vaddr); --=20 2.53.0