2022-04-22 19:25:16

by Muchun Song

[permalink] [raw]
Subject: [PATCH v3] arm64: mm: fix p?d_leaf()

The pmd_leaf() is used to test a leaf mapped PMD, however, it misses
the PROT_NONE mapped PMD on arm64. Fix it. A real world issue [1]
caused by this was reported by Qian Cai. Also fix pud_leaf().

Link: https://patchwork.kernel.org/comment/24798260/ [1]
Fixes: 8aa82df3c123 ("arm64: mm: add p?d_leaf() definitions")
Reported-by: Qian Cai <[email protected]>
Signed-off-by: Muchun Song <[email protected]>
---
v3:
- Fix pud_leaf() as well.
- Rework pmd_leaf() as present && !table.

arch/arm64/include/asm/pgtable.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 930077f7b572..9aae3773b6c4 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -551,7 +551,7 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
PMD_TYPE_TABLE)
#define pmd_sect(pmd) ((pmd_val(pmd) & PMD_TYPE_MASK) == \
PMD_TYPE_SECT)
-#define pmd_leaf(pmd) pmd_sect(pmd)
+#define pmd_leaf(pmd) (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)
@@ -641,7 +641,7 @@ 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))
-#define pud_leaf(pud) pud_sect(pud)
+#define pud_leaf(pud) (pud_present(pud) && !pud_table(pud))
#define pud_valid(pud) pte_valid(pud_pte(pud))

static inline void set_pud(pud_t *pudp, pud_t pud)
--
2.11.0