[PATCH RFC 08/13] mm/arm64: Merge pXd_huge() and pXd_leaf() definitions

peterx
2024-03-06T10:43:12Z

Unlike most archs, aarch64 defines pXd_huge() and pXd_leaf() slightly
differently. Redefine the pXd_huge() with pXd_leaf().

There used to be two traps for old aarch64 definitions over these APIs that
I found when reading the code around, they're:

(1) 4797ec2dc83a ("arm64: fix pud_huge() for 2-level pagetables")
(2) 23bc8f69f0ec ("arm64: mm: fix p?d_leaf()")

Define pXd_huge() with the current pXd_leaf() will make sure (2) isn't a
problem (on PROT_NONE checks). To make sure it also works for (1), we move
over the __PAGETABLE_PMD_FOLDED check to pud_leaf(), allowing it to
constantly returning "false" for 2-level pgtables, which looks even safer
to cover both now.

Cc: Muchun Song <muchun.song@linux.dev>
Cc: Mark Salter <msalter@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Peter Xu <peterx@redhat.com>
---
arch/arm64/include/asm/pgtable.h | 4 ++++
arch/arm64/mm/hugetlbpage.c | 8 ++------
2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 401087e8a43d..14d24c357c7a 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -704,7 +704,11 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
#define pud_none(pud) (!pud_val(pud))
#define pud_bad(pud) (!pud_table(pud))
#define pud_present(pud) pte_present(pud_pte(pud))
+#ifndef __PAGETABLE_PMD_FOLDED
#define pud_leaf(pud) (pud_present(pud) && !pud_table(pud))
+#else
+#define pud_leaf(pud) false
+#endif
#define pud_valid(pud) pte_valid(pud_pte(pud))
#define pud_user(pud) pte_user(pud_pte(pud))
#define pud_user_exec(pud) pte_user_exec(pud_pte(pud))
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 0f0e10bb0a95..1234bbaef5bf 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -81,16 +81,12 @@ bool arch_hugetlb_migration_supported(struct hstate *h)

int pmd_huge(pmd_t pmd)
{
- return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);
+ return pmd_leaf(pmd);
}

int pud_huge(pud_t pud)
{
-#ifndef __PAGETABLE_PMD_FOLDED
- return pud_val(pud) && !(pud_val(pud) & PUD_TABLE_BIT);
-#else
- return 0;
-#endif
+ return pud_leaf(pud);
}

static int find_num_contig(struct mm_struct *mm, unsigned long addr,
--
2.44.0