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| author | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2009-11-25 13:15:38 -0800 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2009-12-03 11:14:54 -0800 |
| commit | 6aaf5d633bb6cead81b396d861d7bae4b9a0ba7e (patch) | |
| tree | 3bd503d3e7b9aa84c1ab618c53c1b1eadad87c83 | |
| parent | 922cc38ab71d1360978e65207e4a4f4988987127 (diff) | |
| download | blackbird-op-linux-6aaf5d633bb6cead81b396d861d7bae4b9a0ba7e.tar.gz blackbird-op-linux-6aaf5d633bb6cead81b396d861d7bae4b9a0ba7e.zip | |
xen: use iret for return from 64b kernel to 32b usermode
If Xen wants to return to a 32b usermode with sysret it must use the
right form. When using VCGF_in_syscall to trigger this, it looks at
the code segment and does a 32b sysret if it is FLAT_USER_CS32.
However, this is different from __USER32_CS, so it fails to return
properly if we use the normal Linux segment.
So avoid the whole mess by dropping VCGF_in_syscall and simply use
plain iret to return to usermode.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Jan Beulich <jbeulich@novell.com>
Cc: Stable Kernel <stable@kernel.org>
| -rw-r--r-- | arch/x86/xen/xen-asm_64.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S index 02f496a8dbaa..53adefda4275 100644 --- a/arch/x86/xen/xen-asm_64.S +++ b/arch/x86/xen/xen-asm_64.S @@ -96,7 +96,7 @@ ENTRY(xen_sysret32) pushq $__USER32_CS pushq %rcx - pushq $VGCF_in_syscall + pushq $0 1: jmp hypercall_iret ENDPATCH(xen_sysret32) RELOC(xen_sysret32, 1b+1) @@ -151,7 +151,7 @@ ENTRY(xen_syscall32_target) ENTRY(xen_sysenter_target) lea 16(%rsp), %rsp /* strip %rcx, %r11 */ mov $-ENOSYS, %rax - pushq $VGCF_in_syscall + pushq $0 jmp hypercall_iret ENDPROC(xen_syscall32_target) ENDPROC(xen_sysenter_target) |
