diff options
author | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2009-11-25 16:15:38 -0500 |
---|---|---|
committer | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2009-12-03 14:14:54 -0500 |
commit | 6aaf5d633bb6cead81b396d861d7bae4b9a0ba7e (patch) | |
tree | 3bd503d3e7b9aa84c1ab618c53c1b1eadad87c83 /arch | |
parent | 922cc38ab71d1360978e65207e4a4f4988987127 (diff) |
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>
Diffstat (limited to 'arch')
-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 02f496a8dba..53adefda427 100644 --- a/arch/x86/xen/xen-asm_64.S +++ b/arch/x86/xen/xen-asm_64.S | |||
@@ -96,7 +96,7 @@ ENTRY(xen_sysret32) | |||
96 | pushq $__USER32_CS | 96 | pushq $__USER32_CS |
97 | pushq %rcx | 97 | pushq %rcx |
98 | 98 | ||
99 | pushq $VGCF_in_syscall | 99 | pushq $0 |
100 | 1: jmp hypercall_iret | 100 | 1: jmp hypercall_iret |
101 | ENDPATCH(xen_sysret32) | 101 | ENDPATCH(xen_sysret32) |
102 | RELOC(xen_sysret32, 1b+1) | 102 | RELOC(xen_sysret32, 1b+1) |
@@ -151,7 +151,7 @@ ENTRY(xen_syscall32_target) | |||
151 | ENTRY(xen_sysenter_target) | 151 | ENTRY(xen_sysenter_target) |
152 | lea 16(%rsp), %rsp /* strip %rcx, %r11 */ | 152 | lea 16(%rsp), %rsp /* strip %rcx, %r11 */ |
153 | mov $-ENOSYS, %rax | 153 | mov $-ENOSYS, %rax |
154 | pushq $VGCF_in_syscall | 154 | pushq $0 |
155 | jmp hypercall_iret | 155 | jmp hypercall_iret |
156 | ENDPROC(xen_syscall32_target) | 156 | ENDPROC(xen_syscall32_target) |
157 | ENDPROC(xen_sysenter_target) | 157 | ENDPROC(xen_sysenter_target) |