3.16.62-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Borislav Petkov <bp@xxxxxxx> commit 4167709bbf826512a52ebd6aafda2be104adaec9 upstream. Since on Intel we're required to do CPUID(1) first, before reading the microcode revision MSR, let's add a special helper which does the required steps so that we don't forget to do them next time, when we want to read the microcode revision. Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: http://lkml.kernel.org/r/20170109114147.5082-4-bp@xxxxxxxxx Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> [bwh: Backported to 3.16: - Don't touch prev_rev variable in apply_microcode() - Keep using sync_core(), which will alway includes the necessary CPUID - Adjust filename, context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- --- a/arch/x86/include/asm/microcode_intel.h +++ b/arch/x86/include/asm/microcode_intel.h @@ -63,6 +63,21 @@ extern int get_matching_sig(unsigned int extern int update_match_revision(struct microcode_header_intel *mc_header, int rev); +static inline u32 intel_get_microcode_revision(void) +{ + u32 rev, dummy; + + native_wrmsrl(MSR_IA32_UCODE_REV, 0); + + /* As documented in the SDM: Do a CPUID 1 here */ + sync_core(); + + /* get the current revision from MSR 0x8B */ + native_rdmsr(MSR_IA32_UCODE_REV, dummy, rev); + + return rev; +} + #ifdef CONFIG_MICROCODE_INTEL_EARLY extern void __init load_ucode_intel_bsp(void); extern void load_ucode_intel_ap(void); --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -14,6 +14,7 @@ #include <asm/bugs.h> #include <asm/cpu.h> #include <asm/intel-family.h> +#include <asm/microcode_intel.h> #ifdef CONFIG_X86_64 #include <linux/topology.h> @@ -103,14 +104,8 @@ static void early_init_intel(struct cpui (c->x86 == 0x6 && c->x86_model >= 0x0e)) set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC); - if (c->x86 >= 6 && !cpu_has(c, X86_FEATURE_IA64)) { - unsigned lower_word; - - wrmsr(MSR_IA32_UCODE_REV, 0, 0); - /* Required by the SDM */ - sync_core(); - rdmsr(MSR_IA32_UCODE_REV, lower_word, c->microcode); - } + if (c->x86 >= 6 && !cpu_has(c, X86_FEATURE_IA64)) + c->microcode = intel_get_microcode_revision(); /* Now if any of them are set, check the blacklist and clear the lot */ if ((cpu_has(c, X86_FEATURE_SPEC_CTRL) || --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -134,9 +134,9 @@ int apply_microcode(int cpu) { struct microcode_intel *mc_intel; struct ucode_cpu_info *uci; - unsigned int val[2]; int cpu_num = raw_smp_processor_id(); struct cpuinfo_x86 *c = &cpu_data(cpu_num); + u32 rev; uci = ucode_cpu_info + cpu; mc_intel = uci->mc; @@ -159,27 +159,22 @@ int apply_microcode(int cpu) wrmsr(MSR_IA32_UCODE_WRITE, (unsigned long) mc_intel->bits, (unsigned long) mc_intel->bits >> 16 >> 16); - wrmsr(MSR_IA32_UCODE_REV, 0, 0); - /* As documented in the SDM: Do a CPUID 1 here */ - sync_core(); + rev = intel_get_microcode_revision(); - /* get the current revision from MSR 0x8B */ - rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]); - - if (val[1] != mc_intel->hdr.rev) { + if (rev != mc_intel->hdr.rev) { pr_err("CPU%d update to revision 0x%x failed\n", cpu_num, mc_intel->hdr.rev); return -1; } pr_info("CPU%d updated to revision 0x%x, date = %04x-%02x-%02x\n", - cpu_num, val[1], + cpu_num, rev, mc_intel->hdr.date & 0xffff, mc_intel->hdr.date >> 24, (mc_intel->hdr.date >> 16) & 0xff); - uci->cpu_sig.rev = val[1]; - c->microcode = val[1]; + uci->cpu_sig.rev = rev; + c->microcode = rev; return 0; } --- a/arch/x86/kernel/cpu/microcode/intel_early.c +++ b/arch/x86/kernel/cpu/microcode/intel_early.c @@ -391,15 +391,8 @@ static int collect_cpu_info_early(struct native_rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]); csig.pf = 1 << ((val[1] >> 18) & 7); } - native_wrmsr(MSR_IA32_UCODE_REV, 0, 0); - /* As documented in the SDM: Do a CPUID 1 here */ - sync_core(); - - /* get the current revision from MSR 0x8B */ - native_rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]); - - csig.rev = val[1]; + csig.rev = intel_get_microcode_revision(); uci->cpu_sig = csig; uci->valid = 1; @@ -654,7 +647,7 @@ static int apply_microcode_early(struct struct ucode_cpu_info *uci) { struct microcode_intel *mc_intel; - unsigned int val[2]; + u32 rev; mc_intel = uci->mc; if (mc_intel == NULL) @@ -664,21 +657,16 @@ static int apply_microcode_early(struct native_wrmsr(MSR_IA32_UCODE_WRITE, (unsigned long) mc_intel->bits, (unsigned long) mc_intel->bits >> 16 >> 16); - native_wrmsr(MSR_IA32_UCODE_REV, 0, 0); - - /* As documented in the SDM: Do a CPUID 1 here */ - sync_core(); - /* get the current revision from MSR 0x8B */ - native_rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]); - if (val[1] != mc_intel->hdr.rev) + rev = intel_get_microcode_revision(); + if (rev != mc_intel->hdr.rev) return -1; #ifdef CONFIG_X86_64 /* Flush global tlb. This is precaution. */ flush_tlb_early(); #endif - uci->cpu_sig.rev = val[1]; + uci->cpu_sig.rev = rev; print_ucode(uci);
