1 files changed, 92 insertions, 0 deletions

diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 9ab52791fed5..d5f64996394a 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -23,6 +23,7 @@
 #include <asm/debugreg.h>
 #include <asm/cpu.h>
 #include <asm/mmu_context.h>
+#include <linux/dmi.h>
 
 #ifdef CONFIG_X86_32
 __visible unsigned long saved_context_ebx;
@@ -32,6 +33,29 @@ __visible unsigned long saved_context_eflags;
 #endif
 struct saved_context saved_context;
 
+static void msr_save_context(struct saved_context *ctxt)
+{
+	struct saved_msr *msr = ctxt->saved_msrs.array;
+	struct saved_msr *end = msr + ctxt->saved_msrs.num;
+
+	while (msr < end) {
+		msr->valid = !rdmsrl_safe(msr->info.msr_no, &msr->info.reg.q);
+		msr++;
+	}
+}
+
+static void msr_restore_context(struct saved_context *ctxt)
+{
+	struct saved_msr *msr = ctxt->saved_msrs.array;
+	struct saved_msr *end = msr + ctxt->saved_msrs.num;
+
+	while (msr < end) {
+		if (msr->valid)
+			wrmsrl(msr->info.msr_no, msr->info.reg.q);
+		msr++;
+	}
+}
+
 /**
  *	__save_processor_state - save CPU registers before creating a
  *		hibernation image and before restoring the memory state from it
@@ -111,6 +135,7 @@ static void __save_processor_state(struct saved_context *ctxt)
 #endif
 	ctxt->misc_enable_saved = !rdmsrl_safe(MSR_IA32_MISC_ENABLE,
 					       &ctxt->misc_enable);
+	msr_save_context(ctxt);
 }
 
 /* Needed by apm.c */
@@ -229,6 +254,7 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
 	x86_platform.restore_sched_clock_state();
 	mtrr_bp_restore();
 	perf_restore_debug_store();
+	msr_restore_context(ctxt);
 }
 
 /* Needed by apm.c */
@@ -320,3 +346,69 @@ static int __init bsp_pm_check_init(void)
 }
 
 core_initcall(bsp_pm_check_init);
+
+static int msr_init_context(const u32 *msr_id, const int total_num)
+{
+	int i = 0;
+	struct saved_msr *msr_array;
+
+	if (saved_context.saved_msrs.array || saved_context.saved_msrs.num > 0) {
+		pr_err("x86/pm: MSR quirk already applied, please check your DMI match table.\n");
+		return -EINVAL;
+	}
+
+	msr_array = kmalloc_array(total_num, sizeof(struct saved_msr), GFP_KERNEL);
+	if (!msr_array) {
+		pr_err("x86/pm: Can not allocate memory to save/restore MSRs during suspend.\n");
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < total_num; i++) {
+		msr_array[i].info.msr_no	= msr_id[i];
+		msr_array[i].valid		= false;
+		msr_array[i].info.reg.q		= 0;
+	}
+	saved_context.saved_msrs.num	= total_num;
+	saved_context.saved_msrs.array	= msr_array;
+
+	return 0;
+}
+
+/*
+ * The following section is a quirk framework for problematic BIOSen:
+ * Sometimes MSRs are modified by the BIOSen after suspended to
+ * RAM, this might cause unexpected behavior after wakeup.
+ * Thus we save/restore these specified MSRs across suspend/resume
+ * in order to work around it.
+ *
+ * For any further problematic BIOSen/platforms,
+ * please add your own function similar to msr_initialize_bdw.
+ */
+static int msr_initialize_bdw(const struct dmi_system_id *d)
+{
+	/* Add any extra MSR ids into this array. */
+	u32 bdw_msr_id[] = { MSR_IA32_THERM_CONTROL };
+
+	pr_info("x86/pm: %s detected, MSR saving is needed during suspending.\n", d->ident);
+	return msr_init_context(bdw_msr_id, ARRAY_SIZE(bdw_msr_id));
+}
+
+static struct dmi_system_id msr_save_dmi_table[] = {
+	{
+	 .callback = msr_initialize_bdw,
+	 .ident = "BROADWELL BDX_EP",
+	 .matches = {
+		DMI_MATCH(DMI_PRODUCT_NAME, "GRANTLEY"),
+		DMI_MATCH(DMI_PRODUCT_VERSION, "E63448-400"),
+		},
+	},
+	{}
+};
+
+static int pm_check_save_msr(void)
+{
+	dmi_check_system(msr_save_dmi_table);
+	return 0;
+}
+
+device_initcall(pm_check_save_msr);