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Commit f12d3d04 authored by Matthieu CASTET's avatar Matthieu CASTET Committed by H. Peter Anvin
Browse files

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 64edc8ed.  There is
absolutely no reason to force these pages RW after they have already
been marked RO.

Signed-off-by: default avatarMatthieu CASTET <castet.matthieu@free.fr>
Tested-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent afe8a887

arch/x86/mm/pageattr.c

+0 −8
Original line number Diff line number Diff line
@@ -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;

}