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>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/asm-x86/irqflags.h b/include/asm-x86/irqflags.h
index c242527f970e..99ee5256a7e3 100644
--- a/include/asm-x86/irqflags.h
+++ b/include/asm-x86/irqflags.h
@@ -112,13 +112,13 @@ static inline unsigned long __raw_local_irq_save(void)
 
 #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