>From 1396adc3c2bdc556d4cdd1cf107aa0b6d59fbb1e Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Mon, 1 Oct 2012 14:34:42 -0700 Subject: [PATCH] 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 Cc: Rafael J. Wysocki Link: http://lkml.kernel.org/r/1348529239-17943-1-git-send-email-hpa@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/realmode/rm/wakeup_asm.S | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) diff --git a/arch/x86/realmode/rm/wakeup_asm.S b/arch/x86/realmode/rm/wakeup_asm.S index e56479e..9e7e147 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 -- 1.7.11.7