[PATCH AUTOSEL 6.1 13/15] LoongArch: Let pmd_present() return true when splitting pmd

Sasha Levin
2023-08-29T13:34:49Z

From: Hongchen Zhang <zhanghongchen@loongson.cn>

[ Upstream commit ddc1729b07cc84bb29f577698b8d2e74a4004a6e ]

When we split a pmd into ptes, pmd_present() and pmd_trans_huge() should
return true, otherwise it would be treated as a swap pmd.

This is the same as arm64 does in commit b65399f6111b ("arm64/mm: Change
THP helpers to comply with generic MM semantics"), we also add a new bit
named _PAGE_PRESENT_INVALID for LoongArch.

Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/loongarch/include/asm/pgtable-bits.h | 2 ++
arch/loongarch/include/asm/pgtable.h | 3 ++-
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/loongarch/include/asm/pgtable-bits.h b/arch/loongarch/include/asm/pgtable-bits.h
index 3d1e0a69975a5..5f2ebcea509cd 100644
--- a/arch/loongarch/include/asm/pgtable-bits.h
+++ b/arch/loongarch/include/asm/pgtable-bits.h
@@ -21,12 +21,14 @@
#define _PAGE_HGLOBAL_SHIFT 12 /* HGlobal is a PMD bit */
#define _PAGE_PFN_SHIFT 12
#define _PAGE_PFN_END_SHIFT 48
+#define _PAGE_PRESENT_INVALID_SHIFT 60
#define _PAGE_NO_READ_SHIFT 61
#define _PAGE_NO_EXEC_SHIFT 62
#define _PAGE_RPLV_SHIFT 63

/* Used by software */
#define _PAGE_PRESENT (_ULCAST_(1) << _PAGE_PRESENT_SHIFT)
+#define _PAGE_PRESENT_INVALID (_ULCAST_(1) << _PAGE_PRESENT_INVALID_SHIFT)
#define _PAGE_WRITE (_ULCAST_(1) << _PAGE_WRITE_SHIFT)
#define _PAGE_ACCESSED (_ULCAST_(1) << _PAGE_ACCESSED_SHIFT)
#define _PAGE_MODIFIED (_ULCAST_(1) << _PAGE_MODIFIED_SHIFT)
diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index 79d5bfd913e0f..e748fad82f13e 100644
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h
@@ -208,7 +208,7 @@ static inline int pmd_bad(pmd_t pmd)
static inline int pmd_present(pmd_t pmd)
{
if (unlikely(pmd_val(pmd) & _PAGE_HUGE))
- return !!(pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROTNONE));
+ return !!(pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROTNONE | _PAGE_PRESENT_INVALID));

return pmd_val(pmd) != (unsigned long)invalid_pte_table;
}
@@ -525,6 +525,7 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)

static inline pmd_t pmd_mkinvalid(pmd_t pmd)
{
+ pmd_val(pmd) |= _PAGE_PRESENT_INVALID;
pmd_val(pmd) &= ~(_PAGE_PRESENT | _PAGE_VALID | _PAGE_DIRTY | _PAGE_PROTNONE);

return pmd;
--
2.40.1