From 7d7eb1b7722acbd8277e929fe1c837b1e467dbf6 Mon Sep 17 00:00:00 2001 From: Alok Kataria Date: Mon, 11 Oct 2010 14:37:08 -0700 Subject: x86, kexec: Make sure to stop all CPUs before exiting the kernel commit 76fac077db6b34e2c6383a7b4f3f4f7b7d06d8ce upstream. x86 smp_ops now has a new op, stop_other_cpus which takes a parameter "wait" this allows the caller to specify if it wants to stop until all the cpus have processed the stop IPI. This is required specifically for the kexec case where we should wait for all the cpus to be stopped before starting the new kernel. We now wait for the cpus to stop in all cases except for panic/kdump where we expect things to be broken and we are doing our best to make things work anyway. This patch fixes a legitimate regression, which was introduced during 2.6.30, by commit id 4ef702c10b5df18ab04921fc252c26421d4d6c75. Signed-off-by: Alok N Kataria LKML-Reference: <1286833028.1372.20.camel@ank32.eng.vmware.com> Cc: Eric W. Biederman Cc: Jeremy Fitzhardinge Signed-off-by: H. Peter Anvin Signed-off-by: Paul Gortmaker --- arch/x86/include/asm/smp.h | 9 +++++++-- arch/x86/kernel/reboot.c | 2 +- arch/x86/kernel/smp.c | 15 +++++++++------ arch/x86/xen/enlighten.c | 2 +- arch/x86/xen/smp.c | 6 +++--- 5 files changed, 21 insertions(+), 13 deletions(-) diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h index 4cfc9082406..4c2f63c7fc1 100644 --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -50,7 +50,7 @@ struct smp_ops { void (*smp_prepare_cpus)(unsigned max_cpus); void (*smp_cpus_done)(unsigned max_cpus); - void (*smp_send_stop)(void); + void (*stop_other_cpus)(int wait); void (*smp_send_reschedule)(int cpu); int (*cpu_up)(unsigned cpu); @@ -73,7 +73,12 @@ extern struct smp_ops smp_ops; static inline void smp_send_stop(void) { - smp_ops.smp_send_stop(); + smp_ops.stop_other_cpus(0); +} + +static inline void stop_other_cpus(void) +{ + smp_ops.stop_other_cpus(1); } static inline void smp_prepare_boot_cpu(void) diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 8e1aac86b50..ff8cc40276e 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -633,7 +633,7 @@ void native_machine_shutdown(void) /* O.K Now that I'm on the appropriate processor, * stop all of the others. */ - smp_send_stop(); + stop_other_cpus(); #endif lapic_shutdown(); diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index d801210945d..513deac7228 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -159,10 +159,10 @@ asmlinkage void smp_reboot_interrupt(void) irq_exit(); } -static void native_smp_send_stop(void) +static void native_stop_other_cpus(int wait) { unsigned long flags; - unsigned long wait; + unsigned long timeout; if (reboot_force) return; @@ -179,9 +179,12 @@ static void native_smp_send_stop(void) if (num_online_cpus() > 1) { apic->send_IPI_allbutself(REBOOT_VECTOR); - /* Don't wait longer than a second */ - wait = USEC_PER_SEC; - while (num_online_cpus() > 1 && wait--) + /* + * Don't wait longer than a second if the caller + * didn't ask us to wait. + */ + timeout = USEC_PER_SEC; + while (num_online_cpus() > 1 && (wait || timeout--)) udelay(1); } @@ -227,7 +230,7 @@ struct smp_ops smp_ops = { .smp_prepare_cpus = native_smp_prepare_cpus, .smp_cpus_done = native_smp_cpus_done, - .smp_send_stop = native_smp_send_stop, + .stop_other_cpus = native_stop_other_cpus, .smp_send_reschedule = native_smp_send_reschedule, .cpu_up = native_cpu_up, diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 27dff06d979..4d32089d093 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1001,7 +1001,7 @@ static void xen_reboot(int reason) struct sched_shutdown r = { .reason = reason }; #ifdef CONFIG_SMP - smp_send_stop(); + stop_other_cpus(); #endif if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index a29693fd313..d2dfbf500fc 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -398,9 +398,9 @@ static void stop_self(void *v) BUG(); } -static void xen_smp_send_stop(void) +static void xen_stop_other_cpus(int wait) { - smp_call_function(stop_self, NULL, 0); + smp_call_function(stop_self, NULL, wait); } static void xen_smp_send_reschedule(int cpu) @@ -468,7 +468,7 @@ static const struct smp_ops xen_smp_ops __initdata = { .cpu_disable = xen_cpu_disable, .play_dead = xen_play_dead, - .smp_send_stop = xen_smp_send_stop, + .stop_other_cpus = xen_stop_other_cpus, .smp_send_reschedule = xen_smp_send_reschedule, .send_call_func_ipi = xen_smp_send_call_function_ipi, -- cgit v1.2.3-18-g5258