Commit-ID: f12d3d04e8f6223276abb068c5d72852174b8c31
Gitweb: http://git.kernel.org/tip/f12d3d04e8f6223276abb068c5d72852174b8c31
Author: Matthieu CASTET <castet.matthieu@xxxxxxx>
AuthorDate: Thu, 20 Jan 2011 21:11:45 +0100
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Wed, 2 Feb 2011 16:02:36 -0800
x86, nx: Don't force pages RW when setting NX bits
Xen want page table pages read only.
But the initial page table (from head_*.S) live in .data or .bss.
That was broken by 64edc8ed5ffae999d8d413ba006850e9e34166cb. There is
absolutely no reason to force these pages RW after they have already
been marked RO.
Signed-off-by: Matthieu CASTET <castet.matthieu@xxxxxxx>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
arch/x86/mm/pageattr.c | 8 --------
1 files changed, 0 insertions(+), 8 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 8b830ca..d343b3c 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -256,7 +256,6 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
unsigned long pfn)
{
pgprot_t forbidden = __pgprot(0);
- pgprot_t required = __pgprot(0);
/*
* The BIOS area between 640k and 1Mb needs to be executable for
@@ -282,12 +281,6 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
if (within(pfn, __pa((unsigned long)__start_rodata) >> PAGE_SHIFT,
__pa((unsigned long)__end_rodata) >> PAGE_SHIFT))
pgprot_val(forbidden) |= _PAGE_RW;
- /*
- * .data and .bss should always be writable.
- */
- if (within(address, (unsigned long)_sdata, (unsigned long)_edata) ||
- within(address, (unsigned long)__bss_start, (unsigned long)__bss_stop))
- pgprot_val(required) |= _PAGE_RW;
#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
/*
@@ -327,7 +320,6 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
#endif
prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden));
- prot = __pgprot(pgprot_val(prot) | pgprot_val(required));
return prot;
}
--
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