diff options
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 11 | ||||
| -rw-r--r-- | include/linux/sched/smt.h | 2 | ||||
| -rw-r--r-- | kernel/cpu.c | 10 |
3 files changed, 16 insertions, 7 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index ef98bf0b269c..3ae095584577 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -13,6 +13,7 @@ #include <linux/module.h> #include <linux/nospec.h> #include <linux/prctl.h> +#include <linux/sched/smt.h> #include <asm/spec-ctrl.h> #include <asm/cmdline.h> @@ -340,16 +341,14 @@ void arch_smt_update(void) return; mutex_lock(&spec_ctrl_mutex); - mask = x86_spec_ctrl_base; - if (IS_ENABLED(CONFIG_SMP)) + + mask = x86_spec_ctrl_base & ~SPEC_CTRL_STIBP; + if (sched_smt_active()) mask |= SPEC_CTRL_STIBP; - else - mask &= ~SPEC_CTRL_STIBP; if (mask != x86_spec_ctrl_base) { pr_info("Spectre v2 cross-process SMT mitigation: %s STIBP\n", - IS_ENABLED(CONFIG_SMP) ? - "Enabling" : "Disabling"); + mask & SPEC_CTRL_STIBP ? "Enabling" : "Disabling"); x86_spec_ctrl_base = mask; on_each_cpu(update_stibp_msr, NULL, 1); } diff --git a/include/linux/sched/smt.h b/include/linux/sched/smt.h index 5209c268c6fd..559ac4590593 100644 --- a/include/linux/sched/smt.h +++ b/include/linux/sched/smt.h @@ -15,4 +15,6 @@ static __always_inline bool sched_smt_active(void) static inline bool sched_smt_active(void) { return false; } #endif +void arch_smt_update(void); + #endif diff --git a/kernel/cpu.c b/kernel/cpu.c index 42ce0b0ae5c5..c2bfeed74be3 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -8,6 +8,7 @@ #include <linux/init.h> #include <linux/notifier.h> #include <linux/sched.h> +#include <linux/sched/smt.h> #include <linux/unistd.h> #include <linux/cpu.h> #include <linux/oom.h> @@ -199,6 +200,12 @@ void cpu_hotplug_enable(void) EXPORT_SYMBOL_GPL(cpu_hotplug_enable); #endif /* CONFIG_HOTPLUG_CPU */ +/* + * Architectures that need SMT-specific errata handling during SMT hotplug + * should override this. + */ +void __weak arch_smt_update(void) { } + /* Need to know about CPUs going up/down? */ int register_cpu_notifier(struct notifier_block *nb) { @@ -434,6 +441,7 @@ out_release: cpu_hotplug_done(); if (!err) cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu); + arch_smt_update(); return err; } @@ -537,7 +545,7 @@ out_notify: __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL); out: cpu_hotplug_done(); - + arch_smt_update(); return ret; } |