From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793618592; b=Gi+5cMjYA/UaGIqV4jB6Ib5kPulGnSEvgUJJU0mOoLgZiWbQGHFTdI43ay3Kr6/8DsX5 jngLmxC0Hxv8bv/2dnorpAg3HnnwqbNGUrw1HPIyB1412z/WbwIP7gPSXZb0ffhD4JazF 6Hv9v+j8OTCbiPc0qJNaydnmaoMHDJsncfzSknDInvsO6RhDvteJFFncO8uLxyawLmhQJ e9w5qLoVmiTccGWyx6JxZuXa0lSj4Dw8kkhAgRORcsh9tnUanhgC9BYNyhuBMIutVlojh mTaFwxgtObPsLogfXvYMyGbuw+pj70JLgWH8XT351GGd5Nn2vCZS1o3nXYPWbnMIMEg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793618592; h=DMARC-Filter:Received:Received:DKIM-Signature:From:Date:Subject: MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id: References:In-Reply-To:To:Cc:X-Mailer:X-Developer-Signature: X-Developer-Key; bh=vD0t3P4YZyVqhT6ml/GIwYbaOKBZr/6svGx4h3XrrSs=; b=zE0hkRDOOB3mhNiVerS7OIBrzof9uDmpcf+/DwhG0AwI1sCnEL+E+UqckSzQiHKmk07x 94KKbQb70Kcx0+zhEQmUjyQqwvJBIbMLQ+rcDZm/TW7RUNYCCiwGwbtWizacBMKTkDvwq avonJAWAWYhWEeWFXFN81znf8ORN+wIB1xFj6Ym4VYnYv8BNpfsjJGq2SgBeQNIffyW37 VOg0Ft8aIo+0fKmLmDMdCgk4Fb2FxyUkAR6AW0pfyhPN7LhQ0h1IwTvILb7/SxZS/XzUD oeZJ6zeDE849NmjbKx2xqegp7jgK3cTpMQFkts1ZpmPSxNUJ4iB6orQmlZ9VTEhRh2Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=s3VQGmGS; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1EB9760A260E; Mon, 2 Nov 2026 11:23:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 1EB9760A260E Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=s3VQGmGS Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 967762972; Mon, 2 Nov 2026 03:23:08 -0800 (PST) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8A9393F632; Mon, 2 Nov 2026 03:23:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1793618591; bh=ObU14gVurwRSCSStZTYINkZuQOqrowSMvXaNGghdZu0=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=s3VQGmGSFtCFwjtay8s4nbDojFMYzMaLVbCeQdcpPV1HNgNaORCKmDpIS0w9cWEt5 k2nsjLkC4akHLis92DY08iQdz/CbZUP9bBXBOpvuSHsIe8nqoGpoezGyEgPlE6yr2d HS7E0Rq1Nd3osETVyGojSrQmm+VyuCL111GZ6D38= From: Yeoreum Yun Date: Mon, 02 Nov 2026 11:21:28 +0000 Subject: [PATCH RESEND v2 15/21] x86: mm: carve out the generic compile-time folded pgtable case in effective_prot() X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261102-dummy_ptxp3-v2-15-78840b2ec73c@arm.com> References: <20261102-dummy_ptxp3-v2-0-78840b2ec73c@arm.com> In-Reply-To: <20261102-dummy_ptxp3-v2-0-78840b2ec73c@arm.com> To: Russell King , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Catalin Marinas , Will Deacon , Arnd Bergmann , Andrew Morton , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Johannes Weiner , David Hildenbrand , Michal Hocko , Lorenzo Stoakes , Tianrui Zhao , Bibo Mao , Anup Patel , Atish Patra , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonas Bonn , Stefan Kristiansson , Stafford Horne Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-openrisc@vger.kernel.org, Yeoreum Yun X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4850; i=yeoreum.yun@arm.com; h=from:subject:message-id; bh=ObU14gVurwRSCSStZTYINkZuQOqrowSMvXaNGghdZu0=; b=owEB7QES/pANAwAKAW3Vw9FaxTEzAcsmYgBq6HI21a3e3zjd8W2uW8CRkndVxlUB/t8qZHEA4 Wo+rp9btw+JAbMEAAEKAB0WIQQtg+CS3QUzuFh1pJ1t1cPRWsUxMwUCauhyNgAKCRBt1cPRWsUx M3c2DADaK9APAB6iyN04UeG0okpA48pg0nK7q2fvyOWzmvboP05U+SvnXs+PPyp4dxqxM2WdGEg u6LTFtD3xNtAExQLnDq4ijA5aWcQ7yQAFiY2f2VeRcJqSGjDqkXDCtMKnY2RIOI5fYE69n5eAzv 3aCrKENELb5xtq2Y7NJLuYjHHSiy8iIraa49yK6So1R0xmnYNBvkOxwaLUjYIUFOStv9J191xgg mfDHR5QylIGmtyDOtmCQZV7pJY/+tF0VPlFmuGUGQFu1095XMIHCwFQyzeqp3HI8L/WM3uT/CLj hFcZ3U7P8Q0dxKwC6ztmWUMfGjeTe1bezOmIRIwMjY+AR2mMiVRiQlIDtiCI1s/hDlJOYWwS+mJ vVTfqk62NMFi9m4mee9kz7qrvY3B5OJO4to7ow8YsyyWThvx+23PaxMNoYczZ3NmYDJ3H/eU7MB 8EmN3el/Or1kGz8YIcK9MtfiZ9DhbXql0+uRTRI0NsEPtSjsoGaUc2WNCZEzlAbHalD0s= X-Developer-Key: i=yeoreum.yun@arm.com; a=openpgp; fpr=2D83E092DD0533B85875A49D6DD5C3D15AC53133 The behaviour of pXdp_get() will change with generic compile-time folded page tables. To prepare for that, rework effective_prot() to ignore any folded page tables entries, as it will unconditionally get called by ptdump core with pXd_val(pXdp_get()), and the value for folded entries really should be ignored. For this, introduce mm_first_pgtable_level() to identify the first real page-table level, move mm_pXd_folded() in !__ASSEMBLER__ and update effective_prot with higher_prot only when the current entry is not folded nor the first level. There should be no functional change. Reviewed-by: David Hildenbrand (Arm) Acked-by: Dave Hansen Signed-off-by: Yeoreum Yun --- arch/x86/mm/dump_pagetables.c | 6 +++-- include/linux/pgtable.h | 61 ++++++++++++++++++++++++++++++++----------- 2 files changed, 50 insertions(+), 17 deletions(-) diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index a18a61e732c3d..2acbe41eb58f2 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -38,6 +38,7 @@ struct pg_state { bool check_wx; unsigned long wx_pages; struct seq_file *seq; + struct mm_struct *mm; }; struct addr_marker { @@ -254,7 +255,7 @@ static void effective_prot(struct ptdump_state *pt_st, enum pgtable_level level, pgprotval_t prot = val & PTE_FLAGS_MASK; pgprotval_t effective; - if (level > PGTABLE_LEVEL_PGD) { + if (level > mm_first_pgtable_level(st->mm)) { pgprotval_t higher_prot = st->prot_levels[level - 1]; effective = (higher_prot & prot & (_PAGE_USER | _PAGE_RW)) | @@ -452,7 +453,8 @@ bool ptdump_walk_pgd_level_core(struct seq_file *m, .level = -1, .to_dmesg = dmesg, .check_wx = checkwx, - .seq = m + .seq = m, + .mm = mm, }; ptdump_walk_pgd(&st.ptdump, mm, pgd); diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index a032f95943357..b0d0e32ad6aef 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -392,6 +392,22 @@ static inline void lazy_mmu_mode_pause(void) {} static inline void lazy_mmu_mode_resume(void) {} #endif +/* + * On some architectures it depends on the mm if the p4d/pud or pmd + * layer of the page table hierarchy is folded or not. + */ +#ifndef mm_p4d_folded +#define mm_p4d_folded(mm) __is_defined(__PAGETABLE_P4D_FOLDED) +#endif + +#ifndef mm_pud_folded +#define mm_pud_folded(mm) __is_defined(__PAGETABLE_PUD_FOLDED) +#endif + +#ifndef mm_pmd_folded +#define mm_pmd_folded(mm) __is_defined(__PAGETABLE_PMD_FOLDED) +#endif + #ifndef pte_batch_hint /** * pte_batch_hint - Number of pages that can be added to batch without scanning. @@ -2313,6 +2329,36 @@ static inline const char *pgtable_level_to_str(enum pgtable_level level) } } +#ifdef CONFIG_MMU +/** + * mm_first_pgtable_level - return the first non-folded page-table level + * @mm: The mm structure. + * + * With runtime- or compile-time folded page tables, page-table walkers + * effectively skip the folded top-level page tables, treating them as + * always-present entries pointing to the next lower-level page table. + * + * Return the first page-table level in @mm that is not folded. + * + * Return: the first non-folded page-table level. + */ +static inline enum pgtable_level mm_first_pgtable_level(struct mm_struct *mm) +{ + /* + * "PMD folded" actually means "PMD is folded into PUD", and + * pud_present() etc. are hard-coded to look like present page table + * levels, whereby pmd_present() etc. contain real logic. + */ + if (mm_pmd_folded(mm)) + return PGTABLE_LEVEL_PMD; + if (mm_pud_folded(mm)) + return PGTABLE_LEVEL_PUD; + if (mm_p4d_folded(mm)) + return PGTABLE_LEVEL_P4D; + return PGTABLE_LEVEL_PGD; +} +#endif /* CONFIG_MMU */ + void ptval_bytes_to_hex_str(char *buf, size_t buf_size, const void *entry, size_t entry_size); #define ptval_to_str(buf, val) \ @@ -2349,21 +2395,6 @@ void ptval_bytes_to_hex_str(char *buf, size_t buf_size, const void *entry, size_ #ifndef has_transparent_pud_hugepage #define has_transparent_pud_hugepage() IS_BUILTIN(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) #endif -/* - * On some architectures it depends on the mm if the p4d/pud or pmd - * layer of the page table hierarchy is folded or not. - */ -#ifndef mm_p4d_folded -#define mm_p4d_folded(mm) __is_defined(__PAGETABLE_P4D_FOLDED) -#endif - -#ifndef mm_pud_folded -#define mm_pud_folded(mm) __is_defined(__PAGETABLE_PUD_FOLDED) -#endif - -#ifndef mm_pmd_folded -#define mm_pmd_folded(mm) __is_defined(__PAGETABLE_PMD_FOLDED) -#endif #ifndef p4d_offset_lockless #define p4d_offset_lockless(pgdp, pgd, address) p4d_offset(&(pgd), address) -- 2.43.0