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x86, mm: fault.c, factor out the vm86 fault check 

Impact: cleanup

Instead of an ugly, open-coded, #ifdef-ed vm86 related legacy check
in do_page_fault(), put it into the check_v8086_mode() helper
function and merge it with an existing #ifdef.

Also, simplify the code flow a tiny bit in the helper.

No code changed:

arch/x86/mm/fault.o:

   text	   data	    bss	    dec	    hex	filename
   2711	     12	     12	   2735	    aaf	fault.o.before
   2711	     12	     12	   2735	    aaf	fault.o.after

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2009-02-20 22:12:18 +01:00
parent 107a03678c
commit 8c938f9fae
1 changed files with 31 additions and 12 deletions
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43
arch/x86/mm/fault.c
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@ -328,14 +328,41 @@ static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
return pmd_k;
}
#endif
#ifdef CONFIG_X86_64
/*
* Did it hit the DOS screen memory VA from vm86 mode?
*/
static inline void
check_v8086_mode(struct pt_regs *regs, unsigned long address,
struct task_struct *tsk)
{
unsigned long bit;
if (!v8086_mode(regs))
return;
bit = (address - 0xA0000) >> PAGE_SHIFT;
if (bit < 32)
tsk->thread.screen_bitmap |= 1 << bit;
}
#else /* CONFIG_X86_64: */
static const char errata93_warning[] =
KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n"
KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n"
KERN_ERR "******* Please consider a BIOS update.\n"
KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n";
/*
* No vm86 mode in 64-bit mode:
*/
static inline void
check_v8086_mode(struct pt_regs *regs, unsigned long address,
struct task_struct *tsk)
{
}
#endif
/*
@ -1091,16 +1118,8 @@ good_area:
else
tsk->min_flt++;
#ifdef CONFIG_X86_32
/*
* Did it hit the DOS screen memory VA from vm86 mode?
*/
if (v8086_mode(regs)) {
unsigned long bit = (address - 0xA0000) >> PAGE_SHIFT;
if (bit < 32)
tsk->thread.screen_bitmap |= 1 << bit;
}
#endif
check_v8086_mode(regs, address, tsk);
up_read(&mm->mmap_sem);
}