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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1771909987; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RxiVFUuLeDkSxqT3ivdHS3XEaH5+5qZe/ROqDJWk8+A=; b=EQAQMnXCkOhqolABpnOy8k/STFLO7lMvE3QrEE1hnRZf8AK3t2FhNUux41/PogwyQSLcDc navuB0Z4hBsm6EdNT3ZJXW79rp4XEHZX3dXNV4IJfpUxRnUy9zGQ6P+ozDhX9pJ45fi2az 67LJIzAu9dLdTtHbQp2rK+GYH8e566E= 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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 49790A000A X-Stat-Signature: 4ripj9pnuuh415fkqifxjtxjgpyk44qu X-HE-Tag: 1771909987-229250 X-HE-Meta: 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 uRLsWS7w oTZ+cinXeJo0mAPdlawtRzlNJ4v7qpubWkT45N0oYnLp/3NtwlNXeZsyKtLma1EAJVZ04ANvQKkdJh39XCgUSlwMJPnAG9zYUuuVnW//bZgTglJUWurxMi+4G1yZCeLmQH4lvE9r6cc1gpdaC/uA5shzrCTW5bZtd7OaDagzo1VquphsqCoD1LlTrivQ1C7RB301Ypzczi52G0ZTe+YUSKxhJ3qbcHir+crTg8dKyLy4eeFEmUWOO7vHihsY59fgF1+uErei9HmYgh/gMMoitn0+Ury+LDNlYtH/tzo/FKWwa8A7tChdKqDUJAQqqvZvLQQ+htWxjfaIXX54KDiPhOaChVQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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