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>
diff --git a/include/asm-x86/irqflags.h b/include/asm-x86/irqflags.h
index c242527..99ee525 100644
--- a/include/asm-x86/irqflags.h
+++ b/include/asm-x86/irqflags.h
@@ -112,13 +112,13 @@
#ifdef CONFIG_X86_64
#define INTERRUPT_RETURN iretq
-#define ENABLE_INTERRUPTS_SYSCALL_RET \
+#define USERSP_SYSRET \
movq %gs:pda_oldrsp, %rsp; \
swapgs; \
sysretq;
#else
#define INTERRUPT_RETURN iret
-#define ENABLE_INTERRUPTS_SYSCALL_RET sti; sysexit
+#define ENABLE_INTERRUPTS_SYSEXIT sti; sysexit
#define GET_CR0_INTO_EAX movl %cr0, %eax
#endif