Make x86 use the generic SMP-stop logic provided by common code unified smp_send_stop() function.
Introduce needed arch_smp_stop_call()/arch_smp_cpus_stop_complete() helpers that implement the backend architectures specific functionalities previously provided by native_stop_other_cpus(): common logic is now delegated to common SMP stop code. Remove arch-specific smp_send_stop(), and redefine original function native_stop_other_cpus() to rely instead on the unified common code version of smp_send_stop(): native_stop_other_cpus() is anyway kept since it is wired to smp_ops.stop_other_cpus() which get called at reboot time with particular waiting settings. Signed-off-by: Cristian Marussi <[email protected]> --- Note that in this patch we kept in use the original x86 local handling of 'stopping_cpu' variable: atomic_cmpxchg(&stopping_cpu, -1, safe_smp_processor_id()); Instead, common SMP stop code could have been easily extended to keep and expose to architectures backends such value using some additional helper like smp_stop_get_stopping_cpu_id(). This has not been addressed in this series. --- arch/x86/Kconfig | 1 + arch/x86/include/asm/smp.h | 5 -- arch/x86/kernel/smp.c | 95 ++++++++++++++++---------------------- 3 files changed, 41 insertions(+), 60 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 222855cc0158..0fcee2f03a5b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -92,6 +92,7 @@ config X86 select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_QUEUED_RWLOCKS select ARCH_USE_QUEUED_SPINLOCKS + select ARCH_USE_COMMON_SMP_STOP select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH select ARCH_WANTS_DYNAMIC_TASK_STRUCT select ARCH_WANT_HUGE_PMD_SHARE diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h index e1356a3b8223..5cf590259d68 100644 --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -67,11 +67,6 @@ extern void set_cpu_sibling_map(int cpu); #ifdef CONFIG_SMP extern struct smp_ops smp_ops; -static inline void smp_send_stop(void) -{ - smp_ops.stop_other_cpus(0); -} - static inline void stop_other_cpus(void) { smp_ops.stop_other_cpus(1); diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index 96421f97e75c..0942cae46fee 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -179,78 +179,63 @@ asmlinkage __visible void smp_reboot_interrupt(void) irq_exit(); } -static void native_stop_other_cpus(int wait) +void arch_smp_stop_call(cpumask_t *cpus, unsigned int attempt_num) { - unsigned long flags; - unsigned long timeout; - if (reboot_force) return; - /* - * Use an own vector here because smp_call_function - * does lots of things not suitable in a panic situation. - */ - - /* - * We start by using the REBOOT_VECTOR irq. - * The irq is treated as a sync point to allow critical - * regions of code on other cpus to release their spin locks - * and re-enable irqs. Jumping straight to an NMI might - * accidentally cause deadlocks with further shutdown/panic - * code. By syncing, we give the cpus up to one second to - * finish their work before we force them off with the NMI. - */ - if (num_online_cpus() > 1) { - /* did someone beat us here? */ - if (atomic_cmpxchg(&stopping_cpu, -1, safe_smp_processor_id()) != -1) - return; - - /* sync above data before sending IRQ */ - wmb(); - - apic->send_IPI_allbutself(REBOOT_VECTOR); - + if (attempt_num == 1) { /* - * Don't wait longer than a second if the caller - * didn't ask us to wait. + * We start by using the REBOOT_VECTOR irq. + * The irq is treated as a sync point to allow critical + * regions of code on other cpus to release their spin locks + * and re-enable irqs. Jumping straight to an NMI might + * accidentally cause deadlocks with further shutdown/panic + * code. By syncing, we give the cpus up to one second to + * finish their work before we force them off with the NMI. */ - timeout = USEC_PER_SEC; - while (num_online_cpus() > 1 && (wait || timeout--)) - udelay(1); - } - - /* if the REBOOT_VECTOR didn't work, try with the NMI */ - if ((num_online_cpus() > 1) && (!smp_no_nmi_ipi)) { - if (register_nmi_handler(NMI_LOCAL, smp_stop_nmi_callback, - NMI_FLAG_FIRST, "smp_stop")) - /* Note: we ignore failures here */ - /* Hope the REBOOT_IRQ is good enough */ - goto finish; + + /* Used by NMI handler callback to skip the stopping_cpu. */ + atomic_cmpxchg(&stopping_cpu, -1, safe_smp_processor_id()); /* sync above data before sending IRQ */ wmb(); - - pr_emerg("Shutting down cpus with NMI\n"); - - apic->send_IPI_allbutself(NMI_VECTOR); - - /* - * Don't wait longer than a 10 ms if the caller - * didn't ask us to wait. - */ - timeout = USEC_PER_MSEC * 10; - while (num_online_cpus() > 1 && (wait || timeout--)) - udelay(1); + apic->send_IPI_mask(cpus, REBOOT_VECTOR); + } else if (attempt_num > 1 && !smp_no_nmi_ipi) { + /* if the REBOOT_VECTOR didn't work, try with the NMI */ + + /* Don't wait longer than 10 ms when not asked to wait */ + smp_stop_set_wait_timeout_us(USEC_PER_MSEC * 10); + + /* Note: we ignore failures here */ + /* Hope the REBOOT_IRQ was good enough */ + if (!register_nmi_handler(NMI_LOCAL, smp_stop_nmi_callback, + NMI_FLAG_FIRST, "smp_stop")) { + /* sync above data before sending IRQ */ + wmb(); + pr_emerg("Shutting down cpus with NMI\n"); + apic->send_IPI_mask(cpus, NMI_VECTOR); + } } +} + +void arch_smp_cpus_stop_complete(void) +{ + unsigned long flags; -finish: local_irq_save(flags); disable_local_APIC(); mcheck_cpu_clear(this_cpu_ptr(&cpu_info)); local_irq_restore(flags); } +static void native_stop_other_cpus(int wait) +{ + smp_stop_set_wait_forever(wait); + /* use common SMP stop code */ + smp_send_stop(); +} + /* * Reschedule call back. KVM uses this interrupt to force a cpu out of * guest mode -- 2.17.1
