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x86: fix compat-vdso 

Jeff Chua reported that this patch:

> -#define PTE_IDENT_ATTR  0x007          /* PRESENT+RW+USER */
> -#define PDE_IDENT_ATTR  0x067          /* PRESENT+RW+USER+DIRTY+ACCESSED */
> +#define PTE_IDENT_ATTR  0x003          /* PRESENT+RW */
> +#define PDE_IDENT_ATTR  0x063          /* PRESENT+RW+DIRTY+ACCESSED */

broke kernels with CONFIG_COMPAT_VDSO set with this init segfault:

init[1]: segfault at ffffe01c up b7f0dc28 sp bfc26628 error 5 in ld-2.7.90.so[b7f0b000+1c000]

Include USER bit in the PDE_IDENT_ATTR only, as the protection bits
are combined from the PDE and PTE entries. This will allow the high
mapped VDSO page in the case of CONFIG_COMPAT_VDSO to be user
readable.

Reported-by: Jeff Chua <jeff.chua.linux@gmail.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Jeff Chua <jeff.chua.linux@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
hifive-unleashed-5.1
Suresh Siddha 2008-10-15 07:46:27 -07:00 committed by Ingo Molnar
parent 3a1dfe6eef
commit f61f1b5717
1 changed files with 6 additions and 1 deletions
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7
include/asm-x86/pgtable.h
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@ -138,8 +138,13 @@
#ifdef CONFIG_X86_64
#define __PAGE_KERNEL_IDENT_LARGE_EXEC __PAGE_KERNEL_LARGE_EXEC
#else
/*
* For PDE_IDENT_ATTR include USER bit. As the PDE and PTE protection
* bits are combined, this will alow user to access the high address mapped
* VDSO in the presence of CONFIG_COMPAT_VDSO
*/
#define PTE_IDENT_ATTR 0x003 /* PRESENT+RW */
#define PDE_IDENT_ATTR 0x063 /* PRESENT+RW+DIRTY+ACCESSED */
#define PDE_IDENT_ATTR 0x067 /* PRESENT+RW+USER+DIRTY+ACCESSED */
#define PGD_IDENT_ATTR 0x001 /* PRESENT (no other attributes) */
#endif