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[PATCH] i386: fix get_segment_eip() with vm86 segments

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We need to check for vm86 mode first before looking at selector privilege
bits.

Segment limit is always base + 64k and only the low 16 bits of EIP are
significant in vm86 mode.

Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Rohit Seth <rohitseth@google.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Chuck Ebbert 2006-06-23 02:04:29 -07:00 committed by Linus Torvalds
parent 110cb1d2e3
commit 19964fecf2
1 changed files with 7 additions and 4 deletions
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11
arch/i386/mm/fault.c
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@ -77,12 +77,15 @@ static inline unsigned long get_segment_eip(struct pt_regs *regs,
unsigned seg = regs->xcs & 0xffff;
u32 seg_ar, seg_limit, base, *desc;
/* Unlikely, but must come before segment checks. */
if (unlikely(regs->eflags & VM_MASK)) {
base = seg << 4;
*eip_limit = base + 0xffff;
return base + (eip & 0xffff);
}
/* The standard kernel/user address space limit. */
*eip_limit = (seg & 3) ? USER_DS.seg : KERNEL_DS.seg;
/* Unlikely, but must come before segment checks. */
if (unlikely((regs->eflags & VM_MASK) != 0))
return eip + (seg << 4);
/* By far the most common cases. */
if (likely(seg == __USER_CS || seg == __KERNEL_CS))