From nobody Thu Sep 24 17:02:32 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5A1B84BF939 for ; Tue, 22 Sep 2026 06:16:48 +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=1790057810; cv=none; b=bSyAWJMgsMeQsN5l4GvxvHlsz8duE8LIohTeujFBXY2ckSa8ymqDrJDGA5HP0PbWbKCBJ/WYamLHr+BRtGovl6sW8ISInhC9YNdZ2VRsXtpb5BVfFG0uWids9Rn9A1kftPcuPISPXu9cRXh1WXu2YgkqD1iU3hCGDJFiEfqyb14= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790057810; c=relaxed/simple; bh=pKNC4pJssJUy9F//HluyrY+c9OqIldQrDfXH15RXtSE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VtUxvRXi0rvg0161nTTjj11ONVgxylanTNJEYsd6BLP4Br8DgjxS0dwlZbhBkgT+pRi6WMOQ0baOfstot9ihhz3O8KeJmitEg32RDkdjWgeJCAorpC5vWlmEfSXfbyzvPux7NNwsUu7KdSE2a1ZC9YeIkvwYQTiqCKDFvN0Fx6A= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=ZimIwZ5G; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="ZimIwZ5G" 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 418041595; Mon, 21 Sep 2026 23:16:44 -0700 (PDT) Received: from localhost (a085714.arm.com [10.164.19.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0F9353F632; Mon, 21 Sep 2026 23:16:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790057807; bh=pKNC4pJssJUy9F//HluyrY+c9OqIldQrDfXH15RXtSE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZimIwZ5GXmjKnSTq+el2RiaDXGsmQviBAqWAjRnxJ9q788vA7UgWgY6+04Vlmqsjx GNUqPDTPVkXJx9fxvEYYZVnFyT6WCL8UOSq6eKNwJ8hgKciIH8N+m+/1cM3q9Wj3On LZu1MZXGRpUkmAaNqTnmVJDjwi2CjdWiIdYSA8fY= 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, Mark Rtland , linx-arm-kernel@lists.infradead.org, linx-kernel@vger.kernel.org, kasan-dev@googlegrops.com Subject: [PATCH V2 1/4] arm64/mm: Use pmdp_get() for PMD accesses Date: Tue, 22 Sep 2026 11:46:35 +0530 Message-ID: <20260922061638.3967467-2-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260922061638.3967467-1-anshuman.khandual@arm.com> References: <20260922061638.3967467-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" Replace READ_ONCE() with pmdp_get() for PMD accesses in preparation for supporting both D64 and D128 translation table formats. READ_ONCE() cannot currently be used for 128-bit page table entries on arm64 because it does not provide the required 128-bit single-copy atomicity, causing builds to fail for accesses wider than 64 bits. Although LDP/STP provide the required atomicity when FEAT_LSE is available (as required by FEAT_D128), extending READ_ONCE() to support 128-bit accesses is undesirable. READ_ONCE() is a general-purpose API, so doing so could encourage other 128-bit users that would either fail to build in configurations without D128 support or, if D128 becomes a runtime option, silently permit tearing on systems without the required hardware support. Instead, standardize PMD accesses on the existing page-table helpers. These can be overridden on arm64 to provide 128-bit single-copy atomicity when required. No functional change intended. Cc: Catalin Marinas Cc: Will Deacon Cc: Ryan Roberts Cc: Mark Rtland Cc: linx-arm-kernel@lists.infradead.org Cc: linx-kernel@vger.kernel.org Cc: kasan-dev@googlegrops.com Reviewed-by: Ryan Roberts Signed-off-by: Anshuman Khandual --- arch/arm64/include/asm/pgtable.h | 3 ++- arch/arm64/mm/fault.c | 2 +- arch/arm64/mm/fixmap.c | 2 +- arch/arm64/mm/hugetlbpage.c | 2 +- arch/arm64/mm/kasan_init.c | 4 ++-- arch/arm64/mm/mmu.c | 22 +++++++++++----------- arch/arm64/mm/pageattr.c | 2 +- arch/arm64/mm/trans_pgd.c | 2 +- 8 files changed, 20 insertions(+), 19 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgta= ble.h index 763c5a411d64..b953ea0ba3ed 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -811,7 +811,8 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) } =20 /* Find an entry in the third-level page table. */ -#define pte_offset_phys(dir,addr) (pmd_page_paddr(READ_ONCE(*(dir))) + pte= _index(addr) * sizeof(pte_t)) +#define pte_offset_phys(dir, addr) (pmd_page_paddr(pmdp_get(dir)) + \ + pte_index(addr) * sizeof(pte_t)) =20 #define pte_set_fixmap(addr) ((pte_t *)set_fixmap_offset(FIX_PTE, addr)) #define pte_set_fixmap_offset(pmd, addr) pte_set_fixmap(pte_offset_phys(pm= d, addr)) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 2cecf6ba6df7..2757ee0c4300 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -188,7 +188,7 @@ static void show_pte(unsigned long addr) break; =20 pmdp =3D pmd_offset_lockless(pudp, pud, addr); - pmd =3D READ_ONCE(*pmdp); + pmd =3D pmdp_get(pmdp); ptval_to_str(pxd_str, pmd_val(pmd)); pr_cont(", pmd=3D%s", pxd_str); if (pmd_none(pmd) || pmd_bad(pmd)) diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c index f66a0016dd02..3cdac8021d4f 100644 --- a/arch/arm64/mm/fixmap.c +++ b/arch/arm64/mm/fixmap.c @@ -42,7 +42,7 @@ static inline pte_t *fixmap_pte(unsigned long addr) =20 static void __init early_fixmap_init_pte(pmd_t *pmdp, unsigned long addr) { - pmd_t pmd =3D READ_ONCE(*pmdp); + pmd_t pmd =3D pmdp_get(pmdp); pte_t *ptep; =20 if (pmd_none(pmd)) { diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 8e799c1fe0aa..cdaa4500faf9 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -304,7 +304,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, addr &=3D CONT_PMD_MASK; =20 pmdp =3D pmd_offset(pudp, addr); - pmd =3D READ_ONCE(*pmdp); + pmd =3D pmdp_get(pmdp); if (!(sz =3D=3D PMD_SIZE || sz =3D=3D CONT_PMD_SIZE) && pmd_none(pmd)) return NULL; diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c index 45fbdce684c8..7ca833c5de5e 100644 --- a/arch/arm64/mm/kasan_init.c +++ b/arch/arm64/mm/kasan_init.c @@ -62,7 +62,7 @@ static phys_addr_t __init kasan_alloc_raw_page(int node) static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int= node, bool early) { - if (pmd_none(READ_ONCE(*pmdp))) { + if (pmd_none(pmdp_get(pmdp))) { phys_addr_t pte_phys =3D early ? __pa_symbol(kasan_early_shadow_pte) : kasan_alloc_zeroed_page(node); @@ -138,7 +138,7 @@ static void __init kasan_pmd_populate(pud_t *pudp, unsi= gned long addr, do { next =3D pmd_addr_end(addr, end); kasan_pte_populate(pmdp, addr, next, node, early); - } while (pmdp++, addr =3D next, addr !=3D end && pmd_none(READ_ONCE(*pmdp= ))); + } while (pmdp++, addr =3D next, addr !=3D end && pmd_none(pmdp_get(pmdp))= ); } =20 static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr, diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index e589fb00d1e3..95621913679e 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -200,7 +200,7 @@ static int alloc_init_cont_pte(pmd_t *pmdp, unsigned lo= ng addr, int flags) { unsigned long next; - pmd_t pmd =3D READ_ONCE(*pmdp); + pmd_t pmd =3D pmdp_get(pmdp); pte_t *ptep; =20 BUG_ON(pmd_leaf(pmd)); @@ -257,7 +257,7 @@ static int init_pmd(pmd_t *pmdp, unsigned long addr, un= signed long end, unsigned long next; =20 do { - pmd_t old_pmd =3D READ_ONCE(*pmdp); + pmd_t old_pmd =3D pmdp_get(pmdp); =20 next =3D pmd_addr_end(addr, end); =20 @@ -272,7 +272,7 @@ static int init_pmd(pmd_t *pmdp, unsigned long addr, un= signed long end, * only allow updates to the permission attributes. */ BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), - READ_ONCE(pmd_val(*pmdp)))); + pmd_val(pmdp_get(pmdp)))); } else { int ret; =20 @@ -282,7 +282,7 @@ static int init_pmd(pmd_t *pmdp, unsigned long addr, un= signed long end, return ret; =20 VM_WARN_ON_ONCE(pmd_val(old_pmd) !=3D 0 && - pmd_val(old_pmd) !=3D READ_ONCE(pmd_val(*pmdp))); + pmd_val(old_pmd) !=3D pmd_val(pmdp_get(pmdp))); } phys +=3D next - addr; } while (pmdp++, addr =3D next, addr !=3D end); @@ -293,7 +293,7 @@ static int init_pmd(pmd_t *pmdp, unsigned long addr, un= signed long end, static bool pmd_range_has_valid_noncont(pmd_t *pmdp) { for (int i =3D 0; i < CONT_PMDS; i++) { - pte_t pte =3D pmd_pte(READ_ONCE(pmdp[i])); + pte_t pte =3D pmd_pte(pmdp_get(pmdp + i)); =20 if (pte_valid(pte) && !pte_cont(pte)) return true; @@ -1553,7 +1553,7 @@ static void unmap_hotplug_pmd_range(pud_t *pudp, unsi= gned long addr, do { next =3D pmd_addr_end(addr, end); pmdp =3D pmd_offset(pudp, addr); - pmd =3D READ_ONCE(*pmdp); + pmd =3D pmdp_get(pmdp); if (pmd_none(pmd)) continue; =20 @@ -1708,7 +1708,7 @@ static void free_empty_pmd_table(pud_t *pudp, unsigne= d long addr, do { next =3D pmd_addr_end(addr, end); pmdp =3D pmd_offset(pudp, addr); - pmd =3D READ_ONCE(*pmdp); + pmd =3D pmdp_get(pmdp); if (pmd_none(pmd)) continue; =20 @@ -1729,7 +1729,7 @@ static void free_empty_pmd_table(pud_t *pudp, unsigne= d long addr, */ pmdp =3D pmd_offset(pudp, 0UL); for (i =3D 0; i < PTRS_PER_PMD; i++) { - if (!pmd_none(READ_ONCE(pmdp[i]))) + if (!pmd_none(pmdp_get(pmdp + i))) return; } =20 @@ -1881,7 +1881,7 @@ int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgpro= t_t prot) pmd_t new_pmd =3D pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); =20 /* Only allow permission changes for now */ - if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), + if (!pgattr_change_is_safe(pmd_val(pmdp_get(pmdp)), pmd_val(new_pmd))) return 0; =20 @@ -1906,7 +1906,7 @@ int pud_clear_huge(pud_t *pudp) =20 int pmd_clear_huge(pmd_t *pmdp) { - if (!pmd_leaf(READ_ONCE(*pmdp))) + if (!pmd_leaf(pmdp_get(pmdp))) return 0; pmd_clear(pmdp); return 1; @@ -1917,7 +1917,7 @@ int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) pte_t *table; pmd_t pmd; =20 - pmd =3D READ_ONCE(*pmdp); + pmd =3D pmdp_get(pmdp); =20 if (!pmd_table(pmd)) { VM_WARN_ON(1); diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index bbe98ac9ad8c..0ca07bd5ded9 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -414,7 +414,7 @@ bool kernel_page_present(struct page *page) return pud_valid(pud); =20 pmdp =3D pmd_offset(pudp, addr); - pmd =3D READ_ONCE(*pmdp); + pmd =3D pmdp_get(pmdp); if (pmd_none(pmd)) return false; if (pmd_leaf(pmd)) diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c index cca9706a875c..b27b2d2c20c3 100644 --- a/arch/arm64/mm/trans_pgd.c +++ b/arch/arm64/mm/trans_pgd.c @@ -74,7 +74,7 @@ static int copy_pmd(struct trans_pgd_info *info, pud_t *d= st_pudp, =20 src_pmdp =3D pmd_offset(src_pudp, start); 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charset="utf-8" Replace READ_ONCE() with pudp_get() for PUD accesses in preparation for supporting both D64 and D128 translation table formats. READ_ONCE() cannot currently be used for 128-bit page table entries on arm64 because it does not provide the required 128-bit single-copy atomicity, causing builds to fail for accesses wider than 64 bits. Although LDP/STP provide the required atomicity when FEAT_LSE is available (as required by FEAT_D128), extending READ_ONCE() to support 128-bit accesses is undesirable. READ_ONCE() is a general-purpose API, so doing so could encourage other 128-bit users that would either fail to build in configurations without D128 support or, if D128 becomes a runtime option, silently permit tearing on systems without the required hardware support. Instead, standardize PUD accesses on the existing page-table helpers. These can be overridden on arm64 to provide 128-bit single-copy atomicity when required. No functional change intended. 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 | 3 ++- arch/arm64/mm/fault.c | 2 +- arch/arm64/mm/fixmap.c | 2 +- arch/arm64/mm/hugetlbpage.c | 4 ++-- arch/arm64/mm/kasan_init.c | 4 ++-- arch/arm64/mm/mmu.c | 20 ++++++++++---------- arch/arm64/mm/pageattr.c | 2 +- arch/arm64/mm/trans_pgd.c | 4 ++-- 8 files changed, 21 insertions(+), 20 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgta= ble.h index b953ea0ba3ed..ae41946c54f2 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -873,7 +873,8 @@ static inline pmd_t *pud_pgtable(pud_t pud) } =20 /* Find an entry in the second-level page table. */ -#define pmd_offset_phys(dir, addr) (pud_page_paddr(READ_ONCE(*(dir))) + pm= d_index(addr) * sizeof(pmd_t)) +#define pmd_offset_phys(dir, addr) (pud_page_paddr(pudp_get(dir)) + \ + pmd_index(addr) * sizeof(pmd_t)) =20 #define pmd_set_fixmap(addr) ((pmd_t *)set_fixmap_offset(FIX_PMD, addr)) #define pmd_set_fixmap_offset(pud, addr) pmd_set_fixmap(pmd_offset_phys(pu= d, addr)) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 2757ee0c4300..435e2e14c070 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -181,7 +181,7 @@ static void show_pte(unsigned long addr) break; =20 pudp =3D pud_offset_lockless(p4dp, p4d, addr); - pud =3D READ_ONCE(*pudp); + pud =3D pudp_get(pudp); ptval_to_str(pxd_str, pud_val(pud)); pr_cont(", pud=3D%s", pxd_str); if (pud_none(pud) || pud_bad(pud)) diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c index 3cdac8021d4f..d9a870836faf 100644 --- a/arch/arm64/mm/fixmap.c +++ b/arch/arm64/mm/fixmap.c @@ -56,7 +56,7 @@ static void __init early_fixmap_init_pmd(pud_t *pudp, uns= igned long addr, unsigned long end) { unsigned long next; - pud_t pud =3D READ_ONCE(*pudp); + pud_t pud =3D pudp_get(pudp); pmd_t *pmdp; =20 if (pud_none(pud)) diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index cdaa4500faf9..c9ad5e75b073 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -262,7 +262,7 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_a= rea_struct *vma, WARN_ON(addr & (sz - 1)); ptep =3D pte_alloc_huge(mm, pmdp, addr); } else if (sz =3D=3D PMD_SIZE) { - if (want_pmd_share(vma, addr) && pud_none(READ_ONCE(*pudp))) + if (want_pmd_share(vma, addr) && pud_none(pudp_get(pudp))) ptep =3D huge_pmd_share(mm, vma, addr, pudp); else ptep =3D (pte_t *)pmd_alloc(mm, pudp, addr); @@ -292,7 +292,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, return NULL; =20 pudp =3D pud_offset(p4dp, addr); - pud =3D READ_ONCE(*pudp); + pud =3D pudp_get(pudp); if (sz !=3D PUD_SIZE && pud_none(pud)) return NULL; /* hugepage or swap? */ diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c index 7ca833c5de5e..aad29bcc7622 100644 --- a/arch/arm64/mm/kasan_init.c +++ b/arch/arm64/mm/kasan_init.c @@ -76,7 +76,7 @@ static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsign= ed long addr, int node, static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int= node, bool early) { - if (pud_none(READ_ONCE(*pudp))) { + if (pud_none(pudp_get(pudp))) { phys_addr_t pmd_phys =3D early ? __pa_symbol(kasan_early_shadow_pmd) : kasan_alloc_zeroed_page(node); @@ -150,7 +150,7 @@ static void __init kasan_pud_populate(p4d_t *p4dp, unsi= gned long addr, do { next =3D pud_addr_end(addr, end); kasan_pmd_populate(pudp, addr, next, node, early); - } while (pudp++, addr =3D next, addr !=3D end && pud_none(READ_ONCE(*pudp= ))); + } while (pudp++, addr =3D next, addr !=3D end && pud_none(pudp_get(pudp))= ); } =20 static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr, diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 95621913679e..22efaee79293 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -309,7 +309,7 @@ static int alloc_init_cont_pmd(pud_t *pudp, unsigned lo= ng addr, { int ret; unsigned long next; - pud_t pud =3D READ_ONCE(*pudp); + pud_t pud =3D pudp_get(pudp); pmd_t *pmdp; =20 /* @@ -390,7 +390,7 @@ static int alloc_init_pud(p4d_t *p4dp, unsigned long ad= dr, unsigned long end, } =20 do { - pud_t old_pud =3D READ_ONCE(*pudp); + pud_t old_pud =3D pudp_get(pudp); =20 next =3D pud_addr_end(addr, end); =20 @@ -408,7 +408,7 @@ static int alloc_init_pud(p4d_t *p4dp, unsigned long ad= dr, unsigned long end, * only allow updates to the permission attributes. */ BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), - READ_ONCE(pud_val(*pudp)))); + pud_val(pudp_get(pudp)))); } else { ret =3D alloc_init_cont_pmd(pudp, addr, next, phys, prot, pgtable_alloc, flags); @@ -416,7 +416,7 @@ static int alloc_init_pud(p4d_t *p4dp, unsigned long ad= dr, unsigned long end, goto out; =20 VM_WARN_ON_ONCE(pud_val(old_pud) !=3D 0 && - pud_val(old_pud) !=3D READ_ONCE(pud_val(*pudp))); + pud_val(old_pud) !=3D pud_val(pudp_get(pudp))); } phys +=3D next - addr; } while (pudp++, addr =3D next, addr !=3D end); @@ -1591,7 +1591,7 @@ static void unmap_hotplug_pud_range(p4d_t *p4dp, unsi= gned long addr, do { next =3D pud_addr_end(addr, end); pudp =3D pud_offset(p4dp, addr); - pud =3D READ_ONCE(*pudp); + pud =3D pudp_get(pudp); if (pud_none(pud)) continue; =20 @@ -1748,7 +1748,7 @@ static void free_empty_pud_table(p4d_t *p4dp, unsigne= d long addr, do { next =3D pud_addr_end(addr, end); pudp =3D pud_offset(p4dp, addr); - pud =3D READ_ONCE(*pudp); + pud =3D pudp_get(pudp); if (pud_none(pud)) continue; =20 @@ -1769,7 +1769,7 @@ static void free_empty_pud_table(p4d_t *p4dp, unsigne= d long addr, */ pudp =3D pud_offset(p4dp, 0UL); for (i =3D 0; i < PTRS_PER_PUD; i++) { - if (!pud_none(READ_ONCE(pudp[i]))) + if (!pud_none(pudp_get(pudp + i))) return; } =20 @@ -1867,7 +1867,7 @@ int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgpro= t_t prot) pud_t new_pud =3D pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); =20 /* Only allow permission changes for now */ - if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), + if (!pgattr_change_is_safe(pud_val(pudp_get(pudp)), pud_val(new_pud))) return 0; =20 @@ -1898,7 +1898,7 @@ void p4d_clear_huge(p4d_t *p4dp) =20 int pud_clear_huge(pud_t *pudp) { - if (!pud_leaf(READ_ONCE(*pudp))) + if (!pud_leaf(pudp_get(pudp))) return 0; pud_clear(pudp); return 1; @@ -1938,7 +1938,7 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr) pud_t pud; unsigned long next, end; =20 - pud =3D READ_ONCE(*pudp); + pud =3D pudp_get(pudp); =20 if (!pud_table(pud)) { VM_WARN_ON(1); diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index 0ca07bd5ded9..07b2fa4de57f 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -407,7 +407,7 @@ bool kernel_page_present(struct page *page) return false; =20 pudp =3D pud_offset(p4dp, addr); - pud =3D READ_ONCE(*pudp); + pud =3D pudp_get(pudp); if (pud_none(pud)) return false; if (pud_leaf(pud)) diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c index b27b2d2c20c3..d119119455f1 100644 --- a/arch/arm64/mm/trans_pgd.c +++ b/arch/arm64/mm/trans_pgd.c @@ -64,7 +64,7 @@ static int copy_pmd(struct trans_pgd_info *info, pud_t *d= st_pudp, unsigned long next; unsigned long addr =3D start; =20 - if (pud_none(READ_ONCE(*dst_pudp))) { + if (pud_none(pudp_get(dst_pudp))) { dst_pmdp =3D trans_alloc(info); if (!dst_pmdp) return -ENOMEM; @@ -109,7 +109,7 @@ static int copy_pud(struct trans_pgd_info *info, p4d_t = *dst_p4dp, =20 src_pudp =3D pud_offset(src_p4dp, start); do { - pud_t pud =3D READ_ONCE(*src_pudp); + pud_t pud =3D pudp_get(src_pudp); =20 next =3D pud_addr_end(addr, end); if (pud_none(pud)) --=20 2.43.0 From nobody Thu Sep 24 17:02:32 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 046544BF939 for ; 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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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="bf29M5Gv" 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 D1DB4152B; Mon, 21 Sep 2026 23:16:51 -0700 (PDT) Received: from localhost (a085714.arm.com [10.164.19.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9F81E3F632; Mon, 21 Sep 2026 23:16:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790057815; bh=MpnntGHJ8hu3lzncZnuAewJpmhM2iJ+Ei03Xl4MTGF8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bf29M5GvjhPa+GXFpLah+FqNO9adCknuWuj7gh6DWF3CdMKtV6K6W7uzCfTThPuyf o8sfPSxEtlIUezX0Zi0+ZvqwPDUwIhIYiYhXYNOS7X2oieTub00Jofeg0p+zeEEaoc uZv4pSO9QRu+iMo3Y54vBM4l+fxijgjrkQZ9cD2I= 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: [PATCH V2 3/4] arm64/mm: Use p4dp_get() for P4D accesses Date: Tue, 22 Sep 2026 11:46:37 +0530 Message-ID: <20260922061638.3967467-4-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260922061638.3967467-1-anshuman.khandual@arm.com> References: <20260922061638.3967467-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" Replace READ_ONCE() with p4dp_get() for P4D accesses in preparation for supporting both D64 and D128 translation table formats. READ_ONCE() cannot currently be used for 128-bit page table entries on arm64 because it does not provide the required 128-bit single-copy atomicity, causing builds to fail for accesses wider than 64 bits. Although LDP/STP provide the required atomicity when FEAT_LSE is available (as required by FEAT_D128), extending READ_ONCE() to support 128-bit accesses is undesirable. READ_ONCE() is a general-purpose API, so doing so could encourage other 128-bit users that would either fail to build in configurations without D128 support or, if D128 becomes a runtime option, silently permit tearing on systems without the required hardware support. Instead, standardize P4D accesses on the existing page-table helpers. These can be overridden on arm64 to provide 128-bit single-copy atomicity when required. No functional change intended. 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/mm/fault.c | 2 +- arch/arm64/mm/fixmap.c | 2 +- arch/arm64/mm/hugetlbpage.c | 2 +- arch/arm64/mm/kasan_init.c | 4 ++-- arch/arm64/mm/mmu.c | 12 ++++++------ arch/arm64/mm/pageattr.c | 2 +- arch/arm64/mm/trans_pgd.c | 4 ++-- 7 files changed, 14 insertions(+), 14 deletions(-) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 435e2e14c070..a6afd8929a10 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -174,7 +174,7 @@ static void show_pte(unsigned long addr) break; =20 p4dp =3D p4d_offset_lockless(pgdp, pgd, addr); - p4d =3D READ_ONCE(*p4dp); + p4d =3D p4dp_get(p4dp); ptval_to_str(pxd_str, p4d_val(p4d)); pr_cont(", p4d=3D%s", pxd_str); if (p4d_none(p4d) || p4d_bad(p4d)) diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c index d9a870836faf..2a0fe0b0f771 100644 --- a/arch/arm64/mm/fixmap.c +++ b/arch/arm64/mm/fixmap.c @@ -74,7 +74,7 @@ static void __init early_fixmap_init_pmd(pud_t *pudp, uns= igned long addr, static void __init early_fixmap_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end) { - p4d_t p4d =3D READ_ONCE(*p4dp); + p4d_t p4d =3D p4dp_get(p4dp); pud_t *pudp; =20 if (CONFIG_PGTABLE_LEVELS > 3 && !p4d_none(p4d) && diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index c9ad5e75b073..5771bf49e1fe 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -288,7 +288,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, return NULL; =20 p4dp =3D p4d_offset(pgdp, addr); - if (!p4d_present(READ_ONCE(*p4dp))) + if (!p4d_present(p4dp_get(p4dp))) return NULL; =20 pudp =3D pud_offset(p4dp, addr); diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c index aad29bcc7622..4dd8c1186471 100644 --- a/arch/arm64/mm/kasan_init.c +++ b/arch/arm64/mm/kasan_init.c @@ -89,7 +89,7 @@ static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsign= ed long addr, int node, static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int= node, bool early) { - if (p4d_none(READ_ONCE(*p4dp))) { + if (p4d_none(p4dp_get(p4dp))) { phys_addr_t pud_phys =3D early ? __pa_symbol(kasan_early_shadow_pud) : kasan_alloc_zeroed_page(node); @@ -162,7 +162,7 @@ static void __init kasan_p4d_populate(pgd_t *pgdp, unsi= gned long addr, do { next =3D p4d_addr_end(addr, end); kasan_pud_populate(p4dp, addr, next, node, early); - } while (p4dp++, addr =3D next, addr !=3D end && p4d_none(READ_ONCE(*p4dp= ))); + } while (p4dp++, addr =3D next, addr !=3D end && p4d_none(p4dp_get(p4dp))= ); } =20 static void __init kasan_pgd_populate(unsigned long addr, unsigned long en= d, diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 22efaee79293..83709d987e7c 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -367,7 +367,7 @@ static int alloc_init_pud(p4d_t *p4dp, unsigned long ad= dr, unsigned long end, { int ret =3D 0; unsigned long next; - p4d_t p4d =3D READ_ONCE(*p4dp); + p4d_t p4d =3D p4dp_get(p4dp); pud_t *pudp; =20 if (p4d_none(p4d)) { @@ -457,7 +457,7 @@ static int alloc_init_p4d(pgd_t *pgdp, unsigned long ad= dr, unsigned long end, } =20 do { - p4d_t old_p4d =3D READ_ONCE(*p4dp); + p4d_t old_p4d =3D p4dp_get(p4dp); =20 next =3D p4d_addr_end(addr, end); =20 @@ -467,7 +467,7 @@ static int alloc_init_p4d(pgd_t *pgdp, unsigned long ad= dr, unsigned long end, goto out; =20 VM_WARN_ON_ONCE(p4d_val(old_p4d) !=3D 0 && - p4d_val(old_p4d) !=3D READ_ONCE(p4d_val(*p4dp))); + p4d_val(old_p4d) !=3D (p4d_val(p4dp_get(p4dp)))); =20 phys +=3D next - addr; } while (p4dp++, addr =3D next, addr !=3D end); @@ -1622,7 +1622,7 @@ static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsi= gned long addr, do { next =3D p4d_addr_end(addr, end); p4dp =3D p4d_offset(pgdp, addr); - p4d =3D READ_ONCE(*p4dp); + p4d =3D p4dp_get(p4dp); if (p4d_none(p4d)) continue; =20 @@ -1788,7 +1788,7 @@ static void free_empty_p4d_table(pgd_t *pgdp, unsigne= d long addr, do { next =3D p4d_addr_end(addr, end); p4dp =3D p4d_offset(pgdp, addr); - p4d =3D READ_ONCE(*p4dp); + p4d =3D p4dp_get(p4dp); if (p4d_none(p4d)) continue; =20 @@ -1809,7 +1809,7 @@ static void free_empty_p4d_table(pgd_t *pgdp, unsigne= d long addr, */ p4dp =3D p4d_offset(pgdp, 0UL); for (i =3D 0; i < PTRS_PER_P4D; i++) { - if (!p4d_none(READ_ONCE(p4dp[i]))) + if (!p4d_none(p4dp_get(p4dp + i))) return; } =20 diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index 07b2fa4de57f..826856ef64a8 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -403,7 +403,7 @@ bool kernel_page_present(struct page *page) return false; =20 p4dp =3D p4d_offset(pgdp, addr); - if (p4d_none(READ_ONCE(*p4dp))) + if (p4d_none(p4dp_get(p4dp))) return false; =20 pudp =3D pud_offset(p4dp, addr); diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c index d119119455f1..7afe2beca4ba 100644 --- a/arch/arm64/mm/trans_pgd.c +++ b/arch/arm64/mm/trans_pgd.c @@ -99,7 +99,7 @@ static int copy_pud(struct trans_pgd_info *info, p4d_t *d= st_p4dp, unsigned long next; unsigned long addr =3D start; =20 - if (p4d_none(READ_ONCE(*dst_p4dp))) { + if (p4d_none(p4dp_get(dst_p4dp))) { dst_pudp =3D trans_alloc(info); if (!dst_pudp) return -ENOMEM; @@ -145,7 +145,7 @@ static int copy_p4d(struct trans_pgd_info *info, pgd_t = *dst_pgdp, src_p4dp =3D p4d_offset(src_pgdp, start); do { next =3D p4d_addr_end(addr, end); - if (p4d_none(READ_ONCE(*src_p4dp))) + if (p4d_none(p4dp_get(src_p4dp))) continue; if (copy_pud(info, dst_p4dp, src_p4dp, addr, next)) return -ENOMEM; --=20 2.43.0 From nobody Thu Sep 24 17:02:32 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2BAB24BEE5D for ; Tue, 22 Sep 2026 06:16:59 +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=1790057822; cv=none; b=E3GNZDh8tNL0W9727OI8HtXAPzUAMm05H2forWCfWJniZG/WK0R9bipCdtA+m/IMVkhEDhDlHdjkKee0MwQE1EtyqkFcDL2hTBjM0zghUDrkqzxPb+4t7Mmk+7L0OYJ5R5OYk/XfzzN3h2a1DfPZjJmTbZxDprco72OslcN72Hg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790057822; c=relaxed/simple; bh=YPhwXo+wZb0LPzJLyEuEwvluXfQVUw7xmrdIkATrj74=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; 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Mon, 21 Sep 2026 23:16:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790057819; bh=YPhwXo+wZb0LPzJLyEuEwvluXfQVUw7xmrdIkATrj74=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cg8BnpDI/5IKSPk/5ru5ySdweqI1LGvk1Pa2oXZsbp3x36QOPFvgMuaia0rW5PPLp dhvJ7I7EH2FSskGukOJLnUcHlRc6HS7ihY1PRZ+toTOH90AQVnzXd62YuoU6TOJP+A 12/IDLzudXUaqgX2a99CidvFZ2M8FlWRhdaFPevo= 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: [PATCH V2 4/4] arm64/mm: Use pgdp_get() for PGD accesses Date: Tue, 22 Sep 2026 11:46:38 +0530 Message-ID: <20260922061638.3967467-5-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260922061638.3967467-1-anshuman.khandual@arm.com> References: <20260922061638.3967467-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" Replace READ_ONCE() with pgdp_get() for PGD accesses in preparation for supporting both D64 and D128 translation table formats. READ_ONCE() cannot currently be used for 128-bit page table entries on arm64 because it does not provide the required 128-bit single-copy atomicity, causing builds to fail for accesses wider than 64 bits. Although LDP/STP provide the required atomicity when FEAT_LSE is available (as required by FEAT_D128), extending READ_ONCE() to support 128-bit accesses is undesirable. READ_ONCE() is a general-purpose API, so doing so could encourage other 128-bit users that would either fail to build in configurations without D128 support or, if D128 becomes a runtime option, silently permit tearing on systems without the required hardware support. Instead, standardize PGD accesses on the existing page-table helpers. These can be overridden on arm64 to provide 128-bit single-copy atomicity when required. No functional change intended. 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/mm/fault.c | 2 +- arch/arm64/mm/hugetlbpage.c | 2 +- arch/arm64/mm/kasan_init.c | 6 +++--- arch/arm64/mm/mmu.c | 6 +++--- arch/arm64/mm/pageattr.c | 2 +- arch/arm64/mm/trans_pgd.c | 4 ++-- 6 files changed, 11 insertions(+), 11 deletions(-) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index a6afd8929a10..43f25418275a 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -160,7 +160,7 @@ static void show_pte(unsigned long addr) guard(irqsave)(); =20 pgdp =3D pgd_offset(mm, addr); - pgd =3D READ_ONCE(*pgdp); + pgd =3D pgdp_get(pgdp); ptval_to_str(pxd_str, pgd_val(pgd)); pr_alert("[%016lx] pgd=3D%s", addr, pxd_str); =20 diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 5771bf49e1fe..e05e5b41ae50 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; =20 pgdp =3D pgd_offset(mm, addr); - if (!pgd_present(READ_ONCE(*pgdp))) + if (!pgd_present(pgdp_get(pgdp))) return NULL; =20 p4dp =3D p4d_offset(pgdp, addr); diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c index 4dd8c1186471..f61f5bc09467 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, unsi= gned 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 =3D early ? __pa_symbol(kasan_early_shadow_p4d) : kasan_alloc_zeroed_page(node); @@ -256,7 +256,7 @@ static int __init root_level_idx(u64 addr) static void __init clone_next_level(u64 addr, pgd_t *tmp_pg_dir, pud_t *pu= d) { int idx =3D root_level_idx(addr); - pgd_t pgd =3D READ_ONCE(swapper_pg_dir[idx]); + pgd_t pgd =3D pgdp_get(swapper_pg_dir + idx); pud_t *pudp =3D (pud_t *)__phys_to_kimg(__pgd_to_phys(pgd)); =20 memcpy(pud, pudp, PAGE_SIZE); @@ -280,7 +280,7 @@ static int __init next_level_idx(u64 addr) */ static void __init clear_next_level(int pgd_idx, int start, int end) { - pgd_t pgd =3D READ_ONCE(swapper_pg_dir[pgd_idx]); + pgd_t pgd =3D pgdp_get(swapper_pg_dir + pgd_idx); pud_t *pudp =3D (pud_t *)__phys_to_kimg(__pgd_to_phys(pgd)); =20 memset(&pudp[start], 0, (end - start) * sizeof(pud_t)); diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 83709d987e7c..76d8d320aeed 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -434,7 +434,7 @@ static int alloc_init_p4d(pgd_t *pgdp, unsigned long ad= dr, unsigned long end, { int ret; unsigned long next; - pgd_t pgd =3D READ_ONCE(*pgdp); + pgd_t pgd =3D pgdp_get(pgdp); p4d_t *p4dp; =20 if (pgd_none(pgd)) { @@ -1649,7 +1649,7 @@ static void unmap_hotplug_range(unsigned long addr, u= nsigned long end, do { next =3D pgd_addr_end(addr, end); pgdp =3D pgd_offset_k(addr); - pgd =3D READ_ONCE(*pgdp); + pgd =3D pgdp_get(pgdp); if (pgd_none(pgd)) continue; =20 @@ -1827,7 +1827,7 @@ static void free_empty_tables(unsigned long addr, uns= igned long end, do { next =3D pgd_addr_end(addr, end); pgdp =3D pgd_offset_k(addr); - pgd =3D READ_ONCE(*pgdp); + pgd =3D pgdp_get(pgdp); if (pgd_none(pgd)) continue; =20 diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index 826856ef64a8..dfa1356daac2 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -399,7 +399,7 @@ bool kernel_page_present(struct page *page) unsigned long addr =3D (unsigned long)page_address(page); =20 pgdp =3D pgd_offset_k(addr); - if (pgd_none(READ_ONCE(*pgdp))) + if (pgd_none(pgdp_get(pgdp))) return false; =20 p4dp =3D p4d_offset(pgdp, addr); diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c index 7afe2beca4ba..06470d690f9f 100644 --- a/arch/arm64/mm/trans_pgd.c +++ b/arch/arm64/mm/trans_pgd.c @@ -134,7 +134,7 @@ static int copy_p4d(struct trans_pgd_info *info, pgd_t = *dst_pgdp, unsigned long next; unsigned long addr =3D start; =20 - if (pgd_none(READ_ONCE(*dst_pgdp))) { + if (pgd_none(pgdp_get(dst_pgdp))) { dst_p4dp =3D trans_alloc(info); if (!dst_p4dp) return -ENOMEM; @@ -164,7 +164,7 @@ static int copy_page_tables(struct trans_pgd_info *info= , pgd_t *dst_pgdp, dst_pgdp =3D pgd_offset_pgd(dst_pgdp, start); do { next =3D 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; --=20 2.43.0