Commit 8c938f9f authored by Ingo Molnar's avatar Ingo Molnar
Browse files

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: default avatarIngo Molnar <mingo@elte.hu>
parent 107a0367

arch/x86/mm/fault.c

+31 −12
Original line number Diff line number Diff line
@@ -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);

}

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