[PATCH] x86: Remove nx_enabled from fault.c

[PATCH] x86: Remove nx_enabled from fault.c

[Harvey Harrison]

On !PAE 32-bit, _PAGE_NX will be 0, making is_prefetch always
return early.  The test is sufficient on PAE as __supported_pte_mask
is updated in the same places as nx_enabled in init_32.c which also
takes disable_nx into account.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
 arch/x86/mm/fault.c |   13 ++++---------
 1 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index bdf0282..32755eb 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -92,18 +92,13 @@ static int is_prefetch(struct pt_regs *regs, unsigned long addr,
 	unsigned char *max_instr;
 
 #ifdef CONFIG_X86_32
-# ifdef CONFIG_X86_PAE
-	/* If it was a exec fault on NX page, ignore */
-	if (nx_enabled && (error_code & PF_INSTR))
+	if (!(__supported_pte_mask & _PAGE_NX))
 		return 0;
-# else
-	return 0;
-# endif
-#else /* CONFIG_X86_64 */
+#endif
+
 	/* If it was a exec fault on NX page, ignore */
 	if (error_code & PF_INSTR)
 		return 0;
-#endif
 
 	instr = (unsigned char *)convert_ip_to_linear(current, regs);
 	max_instr = instr + 15;
@@ -468,7 +463,7 @@ static int vmalloc_fault(unsigned long address)
 	pmd_t *pmd, *pmd_ref;
 	pte_t *pte, *pte_ref;
 
-	if (address >= VMALLOC_START && address < VMALLOC_END)
+	if (!(address >= VMALLOC_START && address < VMALLOC_END))
 		return -1;
 
 	/* Copy kernel mappings over when needed. This can also
-- 
1.5.4.rc4.1142.gf5a97

Re: [PATCH] x86: Remove nx_enabled from fault.c

[Ingo Molnar]

* Harvey Harrison <harvey.harrison@gmail.com> wrote:

> On !PAE 32-bit, _PAGE_NX will be 0, making is_prefetch always return 
> early.  The test is sufficient on PAE as __supported_pte_mask is 
> updated in the same places as nx_enabled in init_32.c which also takes 
> disable_nx into account.

> @@ -92,18 +92,13 @@ static int is_prefetch(struct pt_regs *regs, unsigned long addr,
>  	unsigned char *max_instr;
>  
>  #ifdef CONFIG_X86_32
> -# ifdef CONFIG_X86_PAE
> -	/* If it was a exec fault on NX page, ignore */
> -	if (nx_enabled && (error_code & PF_INSTR))
> +	if (!(__supported_pte_mask & _PAGE_NX))
>  		return 0;
> -# else
> -	return 0;
> -# endif
> -#else /* CONFIG_X86_64 */
> +#endif
> +

thanks, applied this portion of the patch.

> @@ -468,7 +463,7 @@ static int vmalloc_fault(unsigned long address)
>  	pmd_t *pmd, *pmd_ref;
>  	pte_t *pte, *pte_ref;
>  
> -	if (address >= VMALLOC_START && address < VMALLOC_END)
> +	if (!(address >= VMALLOC_START && address < VMALLOC_END))
>  		return -1;

hm, what's this?

	Ingo