diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 3582f30b60b7..9ca7148b5881 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -565,6 +565,35 @@ void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) } #endif +#ifdef CONFIG_NMI_IPI +static void nmi_stop_this_cpu(struct pt_regs *regs) +{ + /* + * This is a special case because it never returns, so the NMI IPI + * handling would never mark it as done, which makes any later + * smp_send_nmi_ipi() call spin forever. Mark it done now. + * + * IRQs are already hard disabled by the smp_handle_nmi_ipi. + */ + nmi_ipi_lock(); + nmi_ipi_busy_count--; + nmi_ipi_unlock(); + + /* Remove this CPU */ + set_cpu_online(smp_processor_id(), false); + + spin_begin(); + while (1) + spin_cpu_relax(); +} + +void smp_send_stop(void) +{ + smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, nmi_stop_this_cpu, 1000000); +} + +#else /* CONFIG_NMI_IPI */ + static void stop_this_cpu(void *dummy) { /* Remove this CPU */ @@ -576,30 +605,24 @@ static void stop_this_cpu(void *dummy) spin_cpu_relax(); } -#ifdef CONFIG_NMI_IPI -static void nmi_stop_this_cpu(struct pt_regs *regs) -{ - /* - * This is a special case because it never returns, so the NMI IPI - * handling would never mark it as done, which makes any later - * smp_send_nmi_ipi() call spin forever. Mark it done now. - */ - nmi_ipi_lock(); - nmi_ipi_busy_count--; - nmi_ipi_unlock(); - - stop_this_cpu(NULL); -} -#endif - void smp_send_stop(void) { -#ifdef CONFIG_NMI_IPI - smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, nmi_stop_this_cpu, 1000000); -#else + static bool stopped = false; + + /* + * Prevent waiting on csd lock from a previous smp_send_stop. + * This is racy, but in general callers try to do the right + * thing and only fire off one smp_send_stop (e.g., see + * kernel/panic.c) + */ + if (stopped) + return; + + stopped = true; + smp_call_function(stop_this_cpu, NULL, 0); -#endif } +#endif /* CONFIG_NMI_IPI */ struct thread_info *current_set[NR_CPUS];