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xen: don't use sysret for sysexit32

PATCH Applied Jeremy Fitzhardinge 2 participants 2 messages Jul 21, 2008 – Jul 24, 2008

Subsystems (2)
x86 Xen hypervisor x86
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Jeremy Fitzhardinge

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PATCH 2/2 xen: don't use sysret for sysexit32

When implementing sysexit32, don't let Xen use sysret to return to userspace. That results in usermode register state being trashed.

Signed-off-by Jeremy Fitzhardinge <[email protected]>

---
arch/x86/xen/xen-asm_64.S | 2 +-

1 file changed, 1 insertion(+), 1 deletion(-)

===================================================================

arch/x86/xen/xen-asm_64.S +0 -0
@@ -173,7 +173,7 @@

	pushq $__USER32_CS
	pushq %rdx

- pushq $VGCF_in_syscall
+ pushq $0
1: jmp hypercall_iret
ENDPATCH(xen_sysexit)
RELOC(xen_sysexit, 1b+1)

Applied
#1 lore raw
Quoted 2 lines · Jeremy Fitzhardinge

When implementing sysexit32, don't let Xen use sysret to return to userspace. That results in usermode register state being trashed.

applied to tip/x86/urgent, thanks Jeremy.

Ingo