diff options
| -rw-r--r-- | arch/x86/include/asm/microcode.h | 12 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/microcode/core.c | 42 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/microcode/intel.c | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/microcode/internal.h | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/nmi.c | 4 |
5 files changed, 57 insertions, 5 deletions
diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h index 78f1eb2532dc..82924828a94b 100644 --- a/arch/x86/include/asm/microcode.h +++ b/arch/x86/include/asm/microcode.h @@ -72,4 +72,16 @@ static inline u32 intel_get_microcode_revision(void) } #endif /* !CONFIG_CPU_SUP_INTEL */ +bool microcode_nmi_handler(void); + +#ifdef CONFIG_MICROCODE_LATE_LOADING +DECLARE_STATIC_KEY_FALSE(microcode_nmi_handler_enable); +static __always_inline bool microcode_nmi_handler_enabled(void) +{ + return static_branch_unlikely(µcode_nmi_handler_enable); +} +#else +static __always_inline bool microcode_nmi_handler_enabled(void) { return false; } +#endif + #endif /* _ASM_X86_MICROCODE_H */ diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 1c2710b7db6d..7b8ade552b55 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -23,6 +23,7 @@ #include <linux/miscdevice.h> #include <linux/capability.h> #include <linux/firmware.h> +#include <linux/cpumask.h> #include <linux/kernel.h> #include <linux/delay.h> #include <linux/mutex.h> @@ -31,6 +32,7 @@ #include <linux/fs.h> #include <linux/mm.h> +#include <asm/apic.h> #include <asm/cpu_device_id.h> #include <asm/perf_event.h> #include <asm/processor.h> @@ -265,8 +267,10 @@ struct microcode_ctrl { enum sibling_ctrl ctrl; enum ucode_state result; unsigned int ctrl_cpu; + bool nmi_enabled; }; +DEFINE_STATIC_KEY_FALSE(microcode_nmi_handler_enable); static DEFINE_PER_CPU(struct microcode_ctrl, ucode_ctrl); static atomic_t late_cpus_in; @@ -282,7 +286,8 @@ static bool wait_for_cpus(atomic_t *cnt) udelay(1); - if (!(timeout % USEC_PER_MSEC)) + /* If invoked directly, tickle the NMI watchdog */ + if (!microcode_ops->use_nmi && !(timeout % USEC_PER_MSEC)) touch_nmi_watchdog(); } /* Prevent the late comers from making progress and let them time out */ @@ -298,7 +303,8 @@ static bool wait_for_ctrl(void) if (this_cpu_read(ucode_ctrl.ctrl) != SCTRL_WAIT) return true; udelay(1); - if (!(timeout % 1000)) + /* If invoked directly, tickle the NMI watchdog */ + if (!microcode_ops->use_nmi && !(timeout % 1000)) touch_nmi_watchdog(); } return false; @@ -374,7 +380,7 @@ static void load_primary(unsigned int cpu) } } -static int load_cpus_stopped(void *unused) +static bool microcode_update_handler(void) { unsigned int cpu = smp_processor_id(); @@ -383,7 +389,29 @@ static int load_cpus_stopped(void *unused) else load_secondary(cpu); - /* No point to wait here. The CPUs will all wait in stop_machine(). */ + touch_nmi_watchdog(); + return true; +} + +bool microcode_nmi_handler(void) +{ + if (!this_cpu_read(ucode_ctrl.nmi_enabled)) + return false; + + this_cpu_write(ucode_ctrl.nmi_enabled, false); + return microcode_update_handler(); +} + +static int load_cpus_stopped(void *unused) +{ + if (microcode_ops->use_nmi) { + /* Enable the NMI handler and raise NMI */ + this_cpu_write(ucode_ctrl.nmi_enabled, true); + apic->send_IPI(smp_processor_id(), NMI_VECTOR); + } else { + /* Just invoke the handler directly */ + microcode_update_handler(); + } return 0; } @@ -404,8 +432,14 @@ static int load_late_stop_cpus(void) */ store_cpu_caps(&prev_info); + if (microcode_ops->use_nmi) + static_branch_enable_cpuslocked(µcode_nmi_handler_enable); + stop_machine_cpuslocked(load_cpus_stopped, NULL, cpu_online_mask); + if (microcode_ops->use_nmi) + static_branch_disable_cpuslocked(µcode_nmi_handler_enable); + /* Analyze the results */ for_each_cpu_and(cpu, cpu_present_mask, &cpus_booted_once_mask) { switch (per_cpu(ucode_ctrl.result, cpu)) { diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index e5c5ddfd6831..905ed3b557fb 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -611,6 +611,7 @@ static struct microcode_ops microcode_intel_ops = { .collect_cpu_info = collect_cpu_info, .apply_microcode = apply_microcode_late, .finalize_late_load = finalize_late_load, + .use_nmi = IS_ENABLED(CONFIG_X86_64), }; static __init void calc_llc_size_per_core(struct cpuinfo_x86 *c) diff --git a/arch/x86/kernel/cpu/microcode/internal.h b/arch/x86/kernel/cpu/microcode/internal.h index c6990431b5de..627d23809b89 100644 --- a/arch/x86/kernel/cpu/microcode/internal.h +++ b/arch/x86/kernel/cpu/microcode/internal.h @@ -31,7 +31,8 @@ struct microcode_ops { enum ucode_state (*apply_microcode)(int cpu); int (*collect_cpu_info)(int cpu, struct cpu_signature *csig); void (*finalize_late_load)(int result); - unsigned int nmi_safe : 1; + unsigned int nmi_safe : 1, + use_nmi : 1; }; extern struct ucode_cpu_info ucode_cpu_info[]; diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index a0c551846b35..a87d856a3808 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -33,6 +33,7 @@ #include <asm/reboot.h> #include <asm/cache.h> #include <asm/nospec-branch.h> +#include <asm/microcode.h> #include <asm/sev.h> #define CREATE_TRACE_POINTS @@ -343,6 +344,9 @@ static noinstr void default_do_nmi(struct pt_regs *regs) instrumentation_begin(); + if (microcode_nmi_handler_enabled() && microcode_nmi_handler()) + goto out; + handled = nmi_handle(NMI_LOCAL, regs); __this_cpu_add(nmi_stats.normal, handled); if (handled) { |