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authorJeremy Fitzhardinge <jeremy@goop.org>2008-06-25 08:19:26 +0400
committerIngo Molnar <mingo@elte.hu>2008-07-08 15:13:15 +0400
commitd75cd22fdd5f7d203fb60014d426942df33dd9a6 (patch)
tree0613fca9d594eab9a0679f80510fa11b48b31571 /arch/x86/kernel/entry_32.S
parente04e0a630d8b5c621b3a8e70ff20db737d3a5728 (diff)
downloadlinux-d75cd22fdd5f7d203fb60014d426942df33dd9a6.tar.xz
x86/paravirt: split sysret and sysexit
Don't conflate sysret and sysexit; they're different instructions with different semantics, and may be in use at the same time (at least within the same kernel, depending on whether its an Intel or AMD system). sysexit - just return to userspace, does no register restoration of any kind; must explicitly atomically enable interrupts. sysret - reloads flags from r11, so no need to explicitly enable interrupts on 64-bit, responsible for restoring usermode %gs Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citirx.com> Cc: xen-devel <xen-devel@lists.xensource.com> Cc: Stephen Tweedie <sct@redhat.com> Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/entry_32.S')
-rw-r--r--arch/x86/kernel/entry_32.S8
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 159a1c76d2bd..53393c306e11 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -58,7 +58,7 @@
* for paravirtualization. The following will never clobber any registers:
* INTERRUPT_RETURN (aka. "iret")
* GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
- * ENABLE_INTERRUPTS_SYSCALL_RET (aka "sti; sysexit").
+ * ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit").
*
* For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
* specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
@@ -349,7 +349,7 @@ sysenter_past_esp:
xorl %ebp,%ebp
TRACE_IRQS_ON
1: mov PT_FS(%esp), %fs
- ENABLE_INTERRUPTS_SYSCALL_RET
+ ENABLE_INTERRUPTS_SYSEXIT
CFI_ENDPROC
.pushsection .fixup,"ax"
2: movl $0,PT_FS(%esp)
@@ -874,10 +874,10 @@ ENTRY(native_iret)
.previous
END(native_iret)
-ENTRY(native_irq_enable_syscall_ret)
+ENTRY(native_irq_enable_sysexit)
sti
sysexit
-END(native_irq_enable_syscall_ret)
+END(native_irq_enable_sysexit)
#endif
KPROBE_ENTRY(int3)