[PATCH v2 3/3] arm64: mm: Remove pmd_sect() and pud_sect()

Ryan Roberts
2026-03-30T16:17:22Z

The semantics of pXd_leaf() are very similar to pXd_sect(). The only
difference is that pXd_sect() only considers it a section if PTE_VALID
is set, whereas pXd_leaf() permits both "valid" and "present-invalid"
types.

Using pXd_sect() has caused issues now that large leaf entries can be
present-invalid since commit a166563e7ec37 ("arm64: mm: support large
block mapping when rodata=full"), so let's just remove the API and
standardize on pXd_leaf().

There are a few callsites of the form pXd_leaf(READ_ONCE(*pXdp)). This
was previously fine for the pXd_sect() macro because it only evaluated
its argument once. But pXd_leaf() evaluates its argument multiple times.
So let's avoid unintended side effects by reimplementing pXd_leaf() as
an inline function.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
arch/arm64/include/asm/pgtable.h | 19 ++++++++++++-------
arch/arm64/mm/mmu.c | 18 +++++++++---------
2 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index dd062179b9b66..5bc42b85acfc0 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -784,9 +784,13 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,

#define pmd_table(pmd) ((pmd_val(pmd) & PMD_TYPE_MASK) == \
PMD_TYPE_TABLE)
-#define pmd_sect(pmd) ((pmd_val(pmd) & PMD_TYPE_MASK) == \
- PMD_TYPE_SECT)
-#define pmd_leaf(pmd) (pmd_present(pmd) && !pmd_table(pmd))
+
+#define pmd_leaf pmd_leaf
+static inline bool pmd_leaf(pmd_t pmd)
+{
+ return pmd_present(pmd) && !pmd_table(pmd);
+}
+
#define pmd_bad(pmd) (!pmd_table(pmd))

#define pmd_leaf_size(pmd) (pmd_cont(pmd) ? CONT_PMD_SIZE : PMD_SIZE)
@@ -804,11 +808,8 @@ static inline int pmd_trans_huge(pmd_t pmd)
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

#if defined(CONFIG_ARM64_64K_PAGES) || CONFIG_PGTABLE_LEVELS < 3
-static inline bool pud_sect(pud_t pud) { return false; }
static inline bool pud_table(pud_t pud) { return true; }
#else
-#define pud_sect(pud) ((pud_val(pud) & PUD_TYPE_MASK) == \
- PUD_TYPE_SECT)
#define pud_table(pud) ((pud_val(pud) & PUD_TYPE_MASK) == \
PUD_TYPE_TABLE)
#endif
@@ -878,7 +879,11 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
PUD_TYPE_TABLE)
#define pud_present(pud) pte_present(pud_pte(pud))
#ifndef __PAGETABLE_PMD_FOLDED
-#define pud_leaf(pud) (pud_present(pud) && !pud_table(pud))
+#define pud_leaf pud_leaf
+static inline bool pud_leaf(pud_t pud)
+{
+ return pud_present(pud) && !pud_table(pud);
+}
#else
#define pud_leaf(pud) false
#endif
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 1575680675d8d..dcee56bb622ad 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -204,7 +204,7 @@ static int alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr,
pmd_t pmd = READ_ONCE(*pmdp);
pte_t *ptep;

- BUG_ON(pmd_sect(pmd));
+ BUG_ON(pmd_leaf(pmd));
if (pmd_none(pmd)) {
pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN | PMD_TABLE_AF;
phys_addr_t pte_phys;
@@ -303,7 +303,7 @@ static int alloc_init_cont_pmd(pud_t *pudp, unsigned long addr,
/*
* Check for initial section mappings in the pgd/pud.
*/
- BUG_ON(pud_sect(pud));
+ BUG_ON(pud_leaf(pud));
if (pud_none(pud)) {
pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN | PUD_TABLE_AF;
phys_addr_t pmd_phys;
@@ -1503,7 +1503,7 @@ static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr,
continue;

WARN_ON(!pmd_present(pmd));
- if (pmd_sect(pmd)) {
+ if (pmd_leaf(pmd)) {
pmd_clear(pmdp);

/*
@@ -1536,7 +1536,7 @@ static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr,
continue;

WARN_ON(!pud_present(pud));
- if (pud_sect(pud)) {
+ if (pud_leaf(pud)) {
pud_clear(pudp);

/*
@@ -1650,7 +1650,7 @@ static void free_empty_pmd_table(pud_t *pudp, unsigned long addr,
if (pmd_none(pmd))
continue;

- WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd));
+ WARN_ON(!pmd_present(pmd) || !pmd_table(pmd));
free_empty_pte_table(pmdp, addr, next, floor, ceiling);
} while (addr = next, addr < end);

@@ -1690,7 +1690,7 @@ static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr,
if (pud_none(pud))
continue;

- WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud));
+ WARN_ON(!pud_present(pud) || !pud_table(pud));
free_empty_pmd_table(pudp, addr, next, floor, ceiling);
} while (addr = next, addr < end);

@@ -1786,7 +1786,7 @@ int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node,
{
vmemmap_verify((pte_t *)pmdp, node, addr, next);

- return pmd_sect(READ_ONCE(*pmdp));
+ return pmd_leaf(READ_ONCE(*pmdp));
}

int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
@@ -1850,7 +1850,7 @@ void p4d_clear_huge(p4d_t *p4dp)

int pud_clear_huge(pud_t *pudp)
{
- if (!pud_sect(READ_ONCE(*pudp)))
+ if (!pud_leaf(READ_ONCE(*pudp)))
return 0;
pud_clear(pudp);
return 1;
@@ -1858,7 +1858,7 @@ int pud_clear_huge(pud_t *pudp)

int pmd_clear_huge(pmd_t *pmdp)
{
- if (!pmd_sect(READ_ONCE(*pmdp)))
+ if (!pmd_leaf(READ_ONCE(*pmdp)))
return 0;
pmd_clear(pmdp);
return 1;
--
2.43.0