[RFC V1 06/16] arm64/mm: Convert READ_ONCE() as pudp_get() while accessing PUD
From: Anshuman Khandual <hidden>
Date: 2026-02-24 05:12:56
Also in:
linux-mm, lkml
Subsystem:
arm64 port (aarch64 architecture), kasan, the rest · Maintainers:
Catalin Marinas, Will Deacon, Andrey Ryabinin, Linus Torvalds
Convert all READ_ONCE() based PUD accesses as pudp_get() instead which will support both D64 and D128 translation regime going forward. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: kasan-dev@googlegroups.com Signed-off-by: Anshuman Khandual <redacted> --- 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/pgtable.h
index 4b5bc2c09bf2..93d06b5de34b 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h@@ -913,7 +913,8 @@ static inline pmd_t *pud_pgtable(pud_t pud) } /* Find an entry in the second-level page table. */ -#define pmd_offset_phys(dir, addr) (pud_page_paddr(READ_ONCE(*(dir))) + pmd_index(addr) * sizeof(pmd_t)) +#define pmd_offset_phys(dir, addr) (pud_page_paddr(pudp_get(dir)) + \ + pmd_index(addr) * sizeof(pmd_t)) #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(pud, addr))
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 1389ba26ec74..64836bc14798 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c@@ -171,7 +171,7 @@ static void show_pte(unsigned long addr) break; pudp = pud_offset(p4dp, addr); - pud = READ_ONCE(*pudp); + pud = pudp_get(pudp); pr_cont(", pud=%016llx", pud_val(pud)); if (pud_none(pud) || pud_bad(pud)) break;
diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c
index 7a4bbcb39094..dd58af6561e0 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, unsigned long addr, unsigned long end) { unsigned long next; - pud_t pud = READ_ONCE(*pudp); + pud_t pud = pudp_get(pudp); pmd_t *pmdp; if (pud_none(pud))
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 6117aca2bac7..b229c05bfbb6 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_area_struct *vma, WARN_ON(addr & (sz - 1)); ptep = pte_alloc_huge(mm, pmdp, addr); } else if (sz == 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 = huge_pmd_share(mm, vma, addr, pudp); else ptep = (pte_t *)pmd_alloc(mm, pudp, addr);
@@ -292,7 +292,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, return NULL; pudp = pud_offset(p4dp, addr); - pud = READ_ONCE(*pudp); + pud = pudp_get(pudp); if (sz != 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 709e8ad15603..19492ef5940a 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, unsigned 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 = 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, unsigned long addr, do { next = pud_addr_end(addr, end); kasan_pmd_populate(pudp, addr, next, node, early); - } while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp))); + } while (pudp++, addr = next, addr != end && pud_none(pudp_get(pudp))); } 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 dea1b595f237..a80d06db4de6 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c@@ -297,7 +297,7 @@ static int alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, { int ret; unsigned long next; - pud_t pud = READ_ONCE(*pudp); + pud_t pud = pudp_get(pudp); pmd_t *pmdp; /*
@@ -377,7 +377,7 @@ static int alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end, } do { - pud_t old_pud = READ_ONCE(*pudp); + pud_t old_pud = pudp_get(pudp); next = pud_addr_end(addr, end);
@@ -394,7 +394,7 @@ static int alloc_init_pud(p4d_t *p4dp, unsigned long addr, 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 = alloc_init_cont_pmd(pudp, addr, next, phys, prot, pgtable_alloc, flags);
@@ -402,7 +402,7 @@ static int alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end, goto out; BUG_ON(pud_val(old_pud) != 0 && - pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); + pud_val(old_pud) != pud_val(pudp_get(pudp))); } phys += next - addr; } while (pudp++, addr = next, addr != end);
@@ -1508,7 +1508,7 @@ static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, do { next = pud_addr_end(addr, end); pudp = pud_offset(p4dp, addr); - pud = READ_ONCE(*pudp); + pud = pudp_get(pudp); if (pud_none(pud)) continue;
@@ -1663,7 +1663,7 @@ static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, do { next = pud_addr_end(addr, end); pudp = pud_offset(p4dp, addr); - pud = READ_ONCE(*pudp); + pud = pudp_get(pudp); if (pud_none(pud)) continue;
@@ -1684,7 +1684,7 @@ static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, */ pudp = pud_offset(p4dp, 0UL); for (i = 0; i < PTRS_PER_PUD; i++) { - if (!pud_none(READ_ONCE(pudp[i]))) + if (!pud_none(pudp_get(pudp + i))) return; }
@@ -1796,7 +1796,7 @@ int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); /* 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;
@@ -1827,7 +1827,7 @@ void p4d_clear_huge(p4d_t *p4dp) int pud_clear_huge(pud_t *pudp) { - if (!pud_sect(READ_ONCE(*pudp))) + if (!pud_sect(pudp_get(pudp))) return 0; pud_clear(pudp); return 1;
@@ -1880,7 +1880,7 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr) pud_t pud; unsigned long next, end; - pud = READ_ONCE(*pudp); + pud = pudp_get(pudp); if (!pud_table(pud)) { VM_WARN_ON(1);
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index ed1eec4c757d..581b461d4d15 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c@@ -401,7 +401,7 @@ bool kernel_page_present(struct page *page) return false; pudp = pud_offset(p4dp, addr); - pud = READ_ONCE(*pudp); + pud = pudp_get(pudp); if (pud_none(pud)) return false; if (pud_sect(pud))
diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
index ddde0f2983b0..71f489d439ef 100644
--- a/arch/arm64/mm/trans_pgd.c
+++ b/arch/arm64/mm/trans_pgd.c@@ -90,7 +90,7 @@ static int copy_pmd(struct trans_pgd_info *info, pud_t *dst_pudp, unsigned long next; unsigned long addr = start; - if (pud_none(READ_ONCE(*dst_pudp))) { + if (pud_none(pudp_get(dst_pudp))) { dst_pmdp = trans_alloc(info); if (!dst_pmdp) return -ENOMEM;
@@ -136,7 +136,7 @@ static int copy_pud(struct trans_pgd_info *info, p4d_t *dst_p4dp, src_pudp = pud_offset(src_p4dp, start); do { - pud_t pud = READ_ONCE(*src_pudp); + pud_t pud = pudp_get(src_pudp); next = pud_addr_end(addr, end); if (pud_none(pud))
--
2.43.0