diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 13d80111bc1f7da1093e80027fc07ffa3cbe7901..188a7db8501bd95019938f7106dfa8f27b773792 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3788,6 +3788,13 @@
Run specified binary instead of /init from the ramdisk,
used for early userspace startup. See initrd.
+ rdrand= [X86]
+ force - Override the decision by the kernel to hide the
+ advertisement of RDRAND support (this affects
+ certain AMD processors because of buggy BIOS
+ support, specifically around the suspend/resume
+ path).
+
rdt= [HW,X86,RDT]
Turn on/off individual RDT features. List is:
cmt, mbmtotal, mbmlocal, l3cat, l3cdp, l2cat, mba.
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 7f1c8448d595222f03d2a772869371045fb92632..fda3bf75de6c38a0b02bc56cf160a4f9c20cce2c 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -334,6 +334,7 @@
#define MSR_AMD64_PATCH_LEVEL 0x0000008b
#define MSR_AMD64_TSC_RATIO 0xc0000104
#define MSR_AMD64_NB_CFG 0xc001001f
+#define MSR_AMD64_CPUID_FN_1 0xc0011004
#define MSR_AMD64_PATCH_LOADER 0xc0010020
#define MSR_AMD64_OSVW_ID_LENGTH 0xc0010140
#define MSR_AMD64_OSVW_STATUS 0xc0010141
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index bbebcd7a781ead84ffe16ab27633e8cfac8b7118..3914f9218a6bcfc131ef34189fe1654a2a79338e 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -772,6 +772,64 @@ static void init_amd_ln(struct cpuinfo_x86 *c)
msr_set_bit(MSR_AMD64_DE_CFG, 31);
}
+static bool rdrand_force;
+
+static int __init rdrand_cmdline(char *str)
+{
+ if (!str)
+ return -EINVAL;
+
+ if (!strcmp(str, "force"))
+ rdrand_force = true;
+ else
+ return -EINVAL;
+
+ return 0;
+}
+early_param("rdrand", rdrand_cmdline);
+
+static void clear_rdrand_cpuid_bit(struct cpuinfo_x86 *c)
+{
+ /*
+ * Saving of the MSR used to hide the RDRAND support during
+ * suspend/resume is done by arch/x86/power/cpu.c, which is
+ * dependent on CONFIG_PM_SLEEP.
+ */
+ if (!IS_ENABLED(CONFIG_PM_SLEEP))
+ return;
+
+ /*
+ * The nordrand option can clear X86_FEATURE_RDRAND, so check for
+ * RDRAND support using the CPUID function directly.
+ */
+ if (!(cpuid_ecx(1) & BIT(30)) || rdrand_force)
+ return;
+
+ msr_clear_bit(MSR_AMD64_CPUID_FN_1, 62);
+
+ /*
+ * Verify that the CPUID change has occurred in case the kernel is
+ * running virtualized and the hypervisor doesn't support the MSR.
+ */
+ if (cpuid_ecx(1) & BIT(30)) {
+ pr_info_once("BIOS may not properly restore RDRAND after suspend, but hypervisor does not support hiding RDRAND via CPUID.\n");
+ return;
+ }
+
+ clear_cpu_cap(c, X86_FEATURE_RDRAND);
+ pr_info_once("BIOS may not properly restore RDRAND after suspend, hiding RDRAND via CPUID. Use rdrand=force to reenable.\n");
+}
+
+static void init_amd_jg(struct cpuinfo_x86 *c)
+{
+ /*
+ * Some BIOS implementations do not restore proper RDRAND support
+ * across suspend and resume. Check on whether to hide the RDRAND
+ * instruction support via CPUID.
+ */
+ clear_rdrand_cpuid_bit(c);
+}
+
static void init_amd_bd(struct cpuinfo_x86 *c)
{
u64 value;
@@ -786,6 +844,13 @@ static void init_amd_bd(struct cpuinfo_x86 *c)
wrmsrl_safe(MSR_F15H_IC_CFG, value);
}
}
+
+ /*
+ * Some BIOS implementations do not restore proper RDRAND support
+ * across suspend and resume. Check on whether to hide the RDRAND
+ * instruction support via CPUID.
+ */
+ clear_rdrand_cpuid_bit(c);
}
static void init_amd_zn(struct cpuinfo_x86 *c)
@@ -828,6 +893,7 @@ static void init_amd(struct cpuinfo_x86 *c)
case 0x10: init_amd_gh(c); break;
case 0x12: init_amd_ln(c); break;
case 0x15: init_amd_bd(c); break;
+ case 0x16: init_amd_jg(c); break;
case 0x17: init_amd_zn(c); break;
}
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 513ce09e99504368eaac0c39f6a1d1346bad1d36..3aa3149df07f9d5e596867f4afd11604ec62dcd0 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -13,6 +13,7 @@
#include <linux/smp.h>
#include <linux/perf_event.h>
#include <linux/tboot.h>
+#include <linux/dmi.h>
#include <asm/pgtable.h>
#include <asm/proto.h>
@@ -24,7 +25,7 @@
#include <asm/debugreg.h>
#include <asm/cpu.h>
#include <asm/mmu_context.h>
-#include <linux/dmi.h>
+#include <asm/cpu_device_id.h>
#ifdef CONFIG_X86_32
__visible unsigned long saved_context_ebx;
@@ -398,15 +399,14 @@ 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)
+static int msr_build_context(const u32 *msr_id, const int num)
{
- int i = 0;
+ struct saved_msrs *saved_msrs = &saved_context.saved_msrs;
struct saved_msr *msr_array;
+ int total_num;
+ int i, j;
- 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;
- }
+ total_num = saved_msrs->num + num;
msr_array = kmalloc_array(total_num, sizeof(struct saved_msr), GFP_KERNEL);
if (!msr_array) {
@@ -414,19 +414,30 @@ static int msr_init_context(const u32 *msr_id, const int total_num)
return -ENOMEM;
}
- for (i = 0; i < total_num; i++) {
- msr_array[i].info.msr_no = msr_id[i];
+ if (saved_msrs->array) {
+ /*
+ * Multiple callbacks can invoke this function, so copy any
+ * MSR save requests from previous invocations.
+ */
+ memcpy(msr_array, saved_msrs->array,
+ sizeof(struct saved_msr) * saved_msrs->num);
+
+ kfree(saved_msrs->array);
+ }
+
+ for (i = saved_msrs->num, j = 0; i < total_num; i++, j++) {
+ msr_array[i].info.msr_no = msr_id[j];
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;
+ saved_msrs->num = total_num;
+ saved_msrs->array = msr_array;
return 0;
}
/*
- * The following section is a quirk framework for problematic BIOSen:
+ * The following sections are 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
@@ -441,7 +452,7 @@ static int msr_initialize_bdw(const struct dmi_system_id *d)
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));
+ return msr_build_context(bdw_msr_id, ARRAY_SIZE(bdw_msr_id));
}
static const struct dmi_system_id msr_save_dmi_table[] = {
@@ -456,9 +467,58 @@ static const struct dmi_system_id msr_save_dmi_table[] = {
{}
};
+static int msr_save_cpuid_features(const struct x86_cpu_id *c)
+{
+ u32 cpuid_msr_id[] = {
+ MSR_AMD64_CPUID_FN_1,
+ };
+
+ pr_info("x86/pm: family %#hx cpu detected, MSR saving is needed during suspending.\n",
+ c->family);
+
+ return msr_build_context(cpuid_msr_id, ARRAY_SIZE(cpuid_msr_id));
+}
+
+static const struct x86_cpu_id msr_save_cpu_table[] = {
+ {
+ .vendor = X86_VENDOR_AMD,
+ .family = 0x15,
+ .model = X86_MODEL_ANY,
+ .feature = X86_FEATURE_ANY,
+ .driver_data = (kernel_ulong_t)msr_save_cpuid_features,
+ },
+ {
+ .vendor = X86_VENDOR_AMD,
+ .family = 0x16,
+ .model = X86_MODEL_ANY,
+ .feature = X86_FEATURE_ANY,
+ .driver_data = (kernel_ulong_t)msr_save_cpuid_features,
+ },
+ {}
+};
+
+typedef int (*pm_cpu_match_t)(const struct x86_cpu_id *);
+static int pm_cpu_check(const struct x86_cpu_id *c)
+{
+ const struct x86_cpu_id *m;
+ int ret = 0;
+
+ m = x86_match_cpu(msr_save_cpu_table);
+ if (m) {
+ pm_cpu_match_t fn;
+
+ fn = (pm_cpu_match_t)m->driver_data;
+ ret = fn(m);
+ }
+
+ return ret;
+}
+
static int pm_check_save_msr(void)
{
dmi_check_system(msr_save_dmi_table);
+ pm_cpu_check(msr_save_cpu_table);
+
return 0;
}