From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id CE31F203710 for ; Tue, 24 Feb 2026 05:13:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771909988; cv=none; b=Yg7Z/3z3bO55ZzLxtiXHxB8oPFrdWkWNzGkIoNdE5vxtafZhFw87NUuIwuA1fW1a9B/WyhjPl3xfWBByG+q3GbzkQSXP/WG1Io5zqV1xLuas53m2yVo+I1chMdX1iiRbv3/nApkLmf52PvBtTYYhxwckgojbEyFs5haQV90FxAg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771909988; c=relaxed/simple; bh=2+PbnNN/csWaUt6LGxN7k69U7Br8al4+kWgE/yRyZ5E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qB3BzHGbrHkBw//3ha+AfpGlFkC+IRaFamVCz2jLBm5muU3Imjz5uhFiJKHHFgr12+HnCFVDBlue5nDANPEQda1EQQCwRX6p7TK76ADFWSaO+hwW7XnjChhzG7ymJpRkGeCIZ8d6vcDhW7JXonEQvtQ8k/sVAqEmNyq2Tfmz0Ts= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 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 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 EDB95497; Mon, 23 Feb 2026 21:12:59 -0800 (PST) Received: from a085714.blr.arm.com (a085714.arm.com [10.164.18.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C46A93F7BD; Mon, 23 Feb 2026 21:13:01 -0800 (PST) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org Cc: Anshuman Khandual , Catalin Marinas , Will Deacon , Ryan Roberts , Mark Rutland , Lorenzo Stoakes , Andrew Morton , David Hildenbrand , Mike Rapoport , Linu Cherian , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kasan-dev@googlegroups.com Subject: [RFC V1 08/16] arm64/mm: Convert READ_ONCE() as pgdp_get() while accessing PGD Date: Tue, 24 Feb 2026 10:41:45 +0530 Message-ID: <20260224051153.3150613-9-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260224051153.3150613-1-anshuman.khandual@arm.com> References: <20260224051153.3150613-1-anshuman.khandual@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Convert all READ_ONCE() based PGD accesses as pgdp_get() instead which will support both D64 and D128 translation regime going forward. Cc: Catalin Marinas Cc: Will Deacon Cc: Ryan Roberts Cc: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: kasan-dev@googlegroups.com Signed-off-by: Anshuman Khandual --- arch/arm64/include/asm/pgtable.h | 12 ++---------- arch/arm64/mm/fault.c | 2 +- arch/arm64/mm/hugetlbpage.c | 2 +- arch/arm64/mm/kasan_init.c | 2 +- arch/arm64/mm/mmu.c | 25 ++++++++++++++++++++++--- arch/arm64/mm/pageattr.c | 2 +- arch/arm64/mm/trans_pgd.c | 4 ++-- 7 files changed, 30 insertions(+), 19 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 24ea4e04e9a1..257af1c3015d 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -1119,12 +1119,7 @@ static inline p4d_t *pgd_to_folded_p4d(pgd_t *pgdp, unsigned long addr) return (p4d_t *)PTR_ALIGN_DOWN(pgdp, PAGE_SIZE) + p4d_index(addr); } -static inline phys_addr_t p4d_offset_phys(pgd_t *pgdp, unsigned long addr) -{ - BUG_ON(!pgtable_l5_enabled()); - - return pgd_page_paddr(READ_ONCE(*pgdp)) + p4d_index(addr) * sizeof(p4d_t); -} +phys_addr_t p4d_offset_phys(pgd_t *pgdp, unsigned long addr); static inline p4d_t *p4d_offset_lockless(pgd_t *pgdp, pgd_t pgd, unsigned long addr) @@ -1135,10 +1130,7 @@ p4d_t *p4d_offset_lockless(pgd_t *pgdp, pgd_t pgd, unsigned long addr) } #define p4d_offset_lockless p4d_offset_lockless -static inline p4d_t *p4d_offset(pgd_t *pgdp, unsigned long addr) -{ - return p4d_offset_lockless(pgdp, READ_ONCE(*pgdp), addr); -} +p4d_t *p4d_offset(pgd_t *pgdp, unsigned long addr); static inline p4d_t *p4d_set_fixmap(unsigned long addr) { diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index f41f4c628d22..7bb14765a98d 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -152,7 +152,7 @@ static void show_pte(unsigned long addr) mm == &init_mm ? "swapper" : "user", PAGE_SIZE / SZ_1K, vabits_actual, mm_to_pgd_phys(mm)); pgdp = pgd_offset(mm, addr); - pgd = READ_ONCE(*pgdp); + pgd = pgdp_get(pgdp); pr_alert("[%016lx] pgd=%016llx", addr, pgd_val(pgd)); do { diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 15241307baec..ccf08ba06a48 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -284,7 +284,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, pmd_t *pmdp, pmd; pgdp = pgd_offset(mm, addr); - if (!pgd_present(READ_ONCE(*pgdp))) + if (!pgd_present(pgdp_get(pgdp))) return NULL; p4dp = p4d_offset(pgdp, addr); diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c index e50c40162bce..d05c16cfa5aa 100644 --- a/arch/arm64/mm/kasan_init.c +++ b/arch/arm64/mm/kasan_init.c @@ -102,7 +102,7 @@ static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node, static p4d_t *__init kasan_p4d_offset(pgd_t *pgdp, unsigned long addr, int node, bool early) { - if (pgd_none(READ_ONCE(*pgdp))) { + if (pgd_none(pgdp_get(pgdp))) { phys_addr_t p4d_phys = early ? __pa_symbol(kasan_early_shadow_p4d) : kasan_alloc_zeroed_page(node); diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 16ae11b29f66..bcf32d1a92de 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -420,7 +420,7 @@ static int alloc_init_p4d(pgd_t *pgdp, unsigned long addr, unsigned long end, { int ret; unsigned long next; - pgd_t pgd = READ_ONCE(*pgdp); + pgd_t pgd = pgdp_get(pgdp); p4d_t *p4dp; if (pgd_none(pgd)) { @@ -1567,7 +1567,7 @@ static void unmap_hotplug_range(unsigned long addr, unsigned long end, do { next = pgd_addr_end(addr, end); pgdp = pgd_offset_k(addr); - pgd = READ_ONCE(*pgdp); + pgd = pgdp_get(pgdp); if (pgd_none(pgd)) continue; @@ -1742,7 +1742,7 @@ static void free_empty_tables(unsigned long addr, unsigned long end, do { next = pgd_addr_end(addr, end); pgdp = pgd_offset_k(addr); - pgd = READ_ONCE(*pgdp); + pgd = pgdp_get(pgdp); if (pgd_none(pgd)) continue; @@ -2275,4 +2275,23 @@ pud_t *pud_offset(p4d_t *p4dp, unsigned long addr) return pud_offset_lockless(p4dp, p4d, addr); } #endif + +#if CONFIG_PGTABLE_LEVELS > 4 +phys_addr_t p4d_offset_phys(pgd_t *pgdp, unsigned long addr) +{ + pgd_t pgd = pgdp_get(pgdp); + + BUG_ON(!pgtable_l5_enabled()); + + return pgd_page_paddr(pgd) + p4d_index(addr) * sizeof(p4d_t); +} + +p4d_t *p4d_offset(pgd_t *pgdp, unsigned long addr) +{ + pgd_t pgd = pgdp_get(pgdp); + + return p4d_offset_lockless(pgdp, pgd, addr); +} +#endif + #endif diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index b45190507e59..0928946a9b19 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -393,7 +393,7 @@ bool kernel_page_present(struct page *page) unsigned long addr = (unsigned long)page_address(page); pgdp = pgd_offset_k(addr); - if (pgd_none(READ_ONCE(*pgdp))) + if (pgd_none(pgdp_get(pgdp))) return false; p4dp = p4d_offset(pgdp, addr); diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c index 75f0a6a5a43a..a3a48c88e05c 100644 --- a/arch/arm64/mm/trans_pgd.c +++ b/arch/arm64/mm/trans_pgd.c @@ -162,7 +162,7 @@ static int copy_p4d(struct trans_pgd_info *info, pgd_t *dst_pgdp, unsigned long next; unsigned long addr = start; - if (pgd_none(READ_ONCE(*dst_pgdp))) { + if (pgd_none(pgdp_get(dst_pgdp))) { dst_p4dp = trans_alloc(info); if (!dst_p4dp) return -ENOMEM; @@ -192,7 +192,7 @@ static int copy_page_tables(struct trans_pgd_info *info, pgd_t *dst_pgdp, dst_pgdp = pgd_offset_pgd(dst_pgdp, start); do { next = pgd_addr_end(addr, end); - if (pgd_none(READ_ONCE(*src_pgdp))) + if (pgd_none(pgdp_get(src_pgdp))) continue; if (copy_p4d(info, dst_pgdp, src_pgdp, addr, next)) return -ENOMEM; -- 2.43.0