4 files changed, 104 insertions, 0 deletions

diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 77d8b284e4a7..24feb3c1dc41 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -32,6 +32,16 @@ struct msr_regs_info {
         int err;
 };
 
+struct saved_msr {
+        bool valid;
+        struct msr_info info;
+};
+
+struct saved_msrs {
+        unsigned int num;
+        struct saved_msr *array;
+};
+
 static inline unsigned long long native_read_tscp(unsigned int *aux)
 {
         unsigned long low, high;
diff --git a/arch/x86/include/asm/suspend_32.h b/arch/x86/include/asm/suspend_32.h
index d1793f06854d..8e9dbe7b73a1 100644
--- a/arch/x86/include/asm/suspend_32.h
+++ b/arch/x86/include/asm/suspend_32.h
@@ -15,6 +15,7 @@ struct saved_context {
         unsigned long cr0, cr2, cr3, cr4;
         u64 misc_enable;
         bool misc_enable_saved;
+        struct saved_msrs saved_msrs;
         struct desc_ptr gdt_desc;
         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 7ebf0ebe4e68..6136a18152af 100644
--- a/arch/x86/include/asm/suspend_64.h
+++ b/arch/x86/include/asm/suspend_64.h
@@ -24,6 +24,7 @@ struct saved_context {
         unsigned long cr0, cr2, cr3, cr4, cr8;
         u64 misc_enable;
         bool misc_enable_saved;
+        struct saved_msrs saved_msrs;
         unsigned long efer;
         u16 gdt_pad; /* Unused */
         struct desc_ptr gdt_desc;
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);