PM / x86: Save/restore MISC_ENABLE register

Save/restore MISC_ENABLE register on suspend/resume.
This fixes OOPS (invalid opcode) on resume from STR on Asus P4P800-VM,
which wakes up with MWAIT disabled.

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=15385

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Tested-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

3 files changed, 8 insertions, 0 deletions

diff --git a/arch/x86/include/asm/suspend_32.h b/arch/x86/include/asm/suspend_32.h
index 48dcfa62ea07..fd921c3a6841 100644
--- a/arch/x86/include/asm/suspend_32.h
+++ b/arch/x86/include/asm/suspend_32.h
@@ -15,6 +15,8 @@ static inline int arch_prepare_suspend(void) { return 0; }
 struct saved_context {
         u16 es, fs, gs, ss;
         unsigned long cr0, cr2, cr3, cr4;
+        u64 misc_enable;
+        bool misc_enable_saved;
         struct desc_ptr gdt;
         struct desc_ptr idt;
         u16 ldt;
diff --git a/arch/x86/include/asm/suspend_64.h b/arch/x86/include/asm/suspend_64.h
index 06284f42b759..8d942afae681 100644
--- a/arch/x86/include/asm/suspend_64.h
+++ b/arch/x86/include/asm/suspend_64.h
@@ -27,6 +27,8 @@ struct saved_context {
         u16 ds, es, fs, gs, ss;
         unsigned long gs_base, gs_kernel_base, fs_base;
         unsigned long cr0, cr2, cr3, cr4, cr8;
+        u64 misc_enable;
+        bool misc_enable_saved;
         unsigned long efer;
         u16 gdt_pad;
         u16 gdt_limit;
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 0a979f3e5b8a..1290ba54b350 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -105,6 +105,8 @@ static void __save_processor_state(struct saved_context *ctxt)
         ctxt->cr4 = read_cr4();
         ctxt->cr8 = read_cr8();
 #endif
+        ctxt->misc_enable_saved = !rdmsrl_safe(MSR_IA32_MISC_ENABLE,
+                                               &ctxt->misc_enable);
 }
 
 /* Needed by apm.c */
@@ -152,6 +154,8 @@ static void fix_processor_context(void)
  */
 static void __restore_processor_state(struct saved_context *ctxt)
 {
+        if (ctxt->misc_enable_saved)
+                wrmsrl(MSR_IA32_MISC_ENABLE, ctxt->misc_enable);
         /*
          * control registers
          */