x86, suspend: Correct the restore of CR4, EFER; skip computing EFLAGS.ID

The patch:

    73201dbe x86, suspend: On wakeup always initialize cr4 and EFER

... was incorrectly committed in an intermediate (unfinished) form.

- We need to test CF, not ZF, for a bit test with btl.
- We don't actually need to compute the existence of EFLAGS.ID,
  since we set a flag at suspend time if CR4 should be restored.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Link: http://lkml.kernel.org/r/1348529239-17943-1-git-send-email-hpa@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 3 insertions, 12 deletions

diff --git a/arch/x86/realmode/rm/wakeup_asm.S b/arch/x86/realmode/rm/wakeup_asm.S
index e56479e5805..9e7e14797a7 100644
--- a/arch/x86/realmode/rm/wakeup_asm.S
+++ b/arch/x86/realmode/rm/wakeup_asm.S
@@ -74,18 +74,9 @@ ENTRY(wakeup_start)
 
         lidtl   wakeup_idt
 
-        /* Clear the EFLAGS but remember if we have EFLAGS.ID */
-        movl $X86_EFLAGS_ID, %ecx
-        pushl %ecx
-        popfl
-        pushfl
-        popl %edi
+        /* Clear the EFLAGS */
         pushl $0
         popfl
-        pushfl
-        popl %edx
-        xorl %edx, %edi
-        andl %ecx, %edi         /* %edi is zero iff CPUID & %cr4 are missing */
 
         /* Check header signature... */
         movl    signature, %eax
@@ -120,12 +111,12 @@ ENTRY(wakeup_start)
         movl    %eax, %cr3
 
         btl     $WAKEUP_BEHAVIOR_RESTORE_CR4, %edi
-        jz      1f
+        jnc     1f
         movl    pmode_cr4, %eax
         movl    %eax, %cr4
 1:
         btl     $WAKEUP_BEHAVIOR_RESTORE_EFER, %edi
-        jz      1f
+        jnc     1f
         movl    pmode_efer, %eax
         movl    pmode_efer + 4, %edx
         movl    $MSR_EFER, %ecx