diff options
Diffstat (limited to 'arch/x86/kernel/smp.c')
| -rw-r--r-- | arch/x86/kernel/smp.c | 85 |
1 files changed, 44 insertions, 41 deletions
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index 7eb18ca7bd45..b014e6d229f9 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -131,11 +131,11 @@ static int smp_stop_nmi_callback(unsigned int val, struct pt_regs *regs) } /* - * Disable virtualization, APIC etc. and park the CPU in a HLT loop + * this function calls the 'stop' function on all other CPUs in the system. */ DEFINE_IDTENTRY_SYSVEC(sysvec_reboot) { - ack_APIC_irq(); + apic_eoi(); cpu_emergency_disable_virtualization(); stop_this_cpu(NULL); } @@ -148,14 +148,16 @@ static int register_stop_handler(void) static void native_stop_other_cpus(int wait) { - unsigned int cpu = smp_processor_id(); + unsigned int old_cpu, this_cpu; unsigned long flags, timeout; if (reboot_force) return; /* Only proceed if this is the first CPU to reach this code */ - if (atomic_cmpxchg(&stopping_cpu, -1, cpu) != -1) + old_cpu = -1; + this_cpu = smp_processor_id(); + if (!atomic_try_cmpxchg(&stopping_cpu, &old_cpu, this_cpu)) return; /* For kexec, ensure that offline CPUs are out of MWAIT and in HLT */ @@ -172,17 +174,13 @@ static void native_stop_other_cpus(int wait) * 2) Wait for all other CPUs to report that they reached the * HLT loop in stop_this_cpu() * - * 3) If the system uses INIT/STARTUP for CPU bringup, then - * send all present CPUs an INIT vector, which brings them - * completely out of the way. + * 3) If #2 timed out send an NMI to the CPUs which did not + * yet report * - * 4) If #3 is not possible and #2 timed out send an NMI to the - * CPUs which did not yet report - * - * 5) Wait for all other CPUs to report that they reached the + * 4) Wait for all other CPUs to report that they reached the * HLT loop in stop_this_cpu() * - * #4 can obviously race against a CPU reaching the HLT loop late. + * #3 can obviously race against a CPU reaching the HLT loop late. * That CPU will have reported already and the "have all CPUs * reached HLT" condition will be true despite the fact that the * other CPU is still handling the NMI. Again, there is no @@ -190,7 +188,7 @@ static void native_stop_other_cpus(int wait) * NMIs. */ cpumask_copy(&cpus_stop_mask, cpu_online_mask); - cpumask_clear_cpu(cpu, &cpus_stop_mask); + cpumask_clear_cpu(this_cpu, &cpus_stop_mask); if (!cpumask_empty(&cpus_stop_mask)) { apic_send_IPI_allbutself(REBOOT_VECTOR); @@ -198,7 +196,7 @@ static void native_stop_other_cpus(int wait) /* * Don't wait longer than a second for IPI completion. The * wait request is not checked here because that would - * prevent an NMI/INIT shutdown in case that not all + * prevent an NMI shutdown attempt in case that not all * CPUs reach shutdown state. */ timeout = USEC_PER_SEC; @@ -206,27 +204,7 @@ static void native_stop_other_cpus(int wait) udelay(1); } - /* - * Park all other CPUs in INIT including "offline" CPUs, if - * possible. That's a safe place where they can't resume execution - * of HLT and then execute the HLT loop from overwritten text or - * page tables. - * - * The only downside is a broadcast MCE, but up to the point where - * the kexec() kernel brought all APs online again an MCE will just - * make HLT resume and handle the MCE. The machine crashes and burns - * due to overwritten text, page tables and data. So there is a - * choice between fire and frying pan. The result is pretty much - * the same. Chose frying pan until x86 provides a sane mechanism - * to park a CPU. - */ - if (smp_park_other_cpus_in_init()) - goto done; - - /* - * If park with INIT was not possible and the REBOOT_VECTOR didn't - * take all secondary CPUs offline, try with the NMI. - */ + /* if the REBOOT_VECTOR didn't work, try with the NMI */ if (!cpumask_empty(&cpus_stop_mask)) { /* * If NMI IPI is enabled, try to register the stop handler @@ -234,10 +212,12 @@ static void native_stop_other_cpus(int wait) * CPUs to stop. */ if (!smp_no_nmi_ipi && !register_stop_handler()) { + unsigned int cpu; + pr_emerg("Shutting down cpus with NMI\n"); for_each_cpu(cpu, &cpus_stop_mask) - apic->send_IPI(cpu, NMI_VECTOR); + __apic_send_IPI(cpu, NMI_VECTOR); } /* * Don't wait longer than 10 ms if the caller didn't @@ -249,7 +229,6 @@ static void native_stop_other_cpus(int wait) udelay(1); } -done: local_irq_save(flags); disable_local_APIC(); mcheck_cpu_clear(this_cpu_ptr(&cpu_info)); @@ -268,7 +247,7 @@ done: */ DEFINE_IDTENTRY_SYSVEC_SIMPLE(sysvec_reschedule_ipi) { - ack_APIC_irq(); + apic_eoi(); trace_reschedule_entry(RESCHEDULE_VECTOR); inc_irq_stat(irq_resched_count); scheduler_ipi(); @@ -277,7 +256,7 @@ DEFINE_IDTENTRY_SYSVEC_SIMPLE(sysvec_reschedule_ipi) DEFINE_IDTENTRY_SYSVEC(sysvec_call_function) { - ack_APIC_irq(); + apic_eoi(); trace_call_function_entry(CALL_FUNCTION_VECTOR); inc_irq_stat(irq_call_count); generic_smp_call_function_interrupt(); @@ -286,7 +265,7 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_call_function) DEFINE_IDTENTRY_SYSVEC(sysvec_call_function_single) { - ack_APIC_irq(); + apic_eoi(); trace_call_function_single_entry(CALL_FUNCTION_SINGLE_VECTOR); inc_irq_stat(irq_call_count); generic_smp_call_function_single_interrupt(); @@ -307,7 +286,7 @@ struct smp_ops smp_ops = { .smp_cpus_done = native_smp_cpus_done, .stop_other_cpus = native_stop_other_cpus, -#if defined(CONFIG_KEXEC_CORE) +#if defined(CONFIG_CRASH_DUMP) .crash_stop_other_cpus = kdump_nmi_shootdown_cpus, #endif .smp_send_reschedule = native_smp_send_reschedule, @@ -320,3 +299,27 @@ struct smp_ops smp_ops = { .send_call_func_single_ipi = native_send_call_func_single_ipi, }; EXPORT_SYMBOL_GPL(smp_ops); + +int arch_cpu_rescan_dead_smt_siblings(void) +{ + enum cpuhp_smt_control old = cpu_smt_control; + int ret; + + /* + * If SMT has been disabled and SMT siblings are in HLT, bring them back + * online and offline them again so that they end up in MWAIT proper. + * + * Called with hotplug enabled. + */ + if (old != CPU_SMT_DISABLED && old != CPU_SMT_FORCE_DISABLED) + return 0; + + ret = cpuhp_smt_enable(); + if (ret) + return ret; + + ret = cpuhp_smt_disable(old); + + return ret; +} +EXPORT_SYMBOL_GPL(arch_cpu_rescan_dead_smt_siblings); |