From c728252c7a072628bd3932ff87943d1e12423359 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Fri, 6 Jan 2006 00:12:03 -0800 Subject: [PATCH] x86/x86_64: mark rodata section read only: generic x86-64 bugfix Bug fix required for the .rodata work on x86-64: when change_page_attr() and friends need to break up a 2Mb page into 4Kb pages, it always set the NX bit on the PMD, which causes the cpu to consider the entire 2Mb region to be NX regardless of the actual PTE perms. This is fine in general, with one big exception: the 2Mb page that covers the last part of the kernel .text! The fix is to not invent a new permission for the new PMD entry, but to just inherit the existing one minus the PSE bit. Signed-off-by: Arjan van de Ven Signed-off-by: Ingo Molnar Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-x86_64/pgtable.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/asm-x86_64/pgtable.h') diff --git a/include/asm-x86_64/pgtable.h b/include/asm-x86_64/pgtable.h index ecf58c7c165..02888d7a496 100644 --- a/include/asm-x86_64/pgtable.h +++ b/include/asm-x86_64/pgtable.h @@ -122,6 +122,8 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, unsigned long #define pte_same(a, b) ((a).pte == (b).pte) +#define pte_pgprot(a) (__pgprot((a).pte & ~PHYSICAL_PAGE_MASK)) + #define PMD_SIZE (1UL << PMD_SHIFT) #define PMD_MASK (~(PMD_SIZE-1)) #define PUD_SIZE (1UL << PUD_SHIFT) -- cgit v1.2.3-70-g09d2