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[5/7] mm/x86: Make pud_leaf() only cares about PSE bit

Message ID 20240621142504.1940209-6-peterx@redhat.com (mailing list archive)
State Handled Elsewhere, archived
Headers show
Series mm/mprotect: Fix dax puds | expand

Commit Message

Peter Xu June 21, 2024, 2:25 p.m. UTC 
An entry should be reported as PUD leaf even if it's PROT_NONE, in which
case PRESENT bit isn't there. I hit bad pud without this when testing dax
1G on zapping a PROT_NONE PUD.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 arch/x86/include/asm/pgtable.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Comments

Dave Hansen June 21, 2024, 2:32 p.m. UTC | #1 
On 6/21/24 07:25, Peter Xu wrote:
> An entry should be reported as PUD leaf even if it's PROT_NONE, in which
> case PRESENT bit isn't there. I hit bad pud without this when testing dax
> 1G on zapping a PROT_NONE PUD.

Yeah, looks like pmd_leaf() got fixed up because of its involvement in
THP, but PUDs got missed.  This patch also realigns pmd_leaf() and
pud_leaf() behavior, which is important.

Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
diff mbox series

Patch

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 65b8e5bb902c..25fc6d809572 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1073,8 +1073,7 @@  static inline pmd_t *pud_pgtable(pud_t pud)
 #define pud_leaf pud_leaf
 static inline bool pud_leaf(pud_t pud)
 {
-	return (pud_val(pud) & (_PAGE_PSE | _PAGE_PRESENT)) ==
-		(_PAGE_PSE | _PAGE_PRESENT);
+	return pud_val(pud) & _PAGE_PSE;
 }
 
 static inline int pud_bad(pud_t pud)