The patch below does not apply to the 3.3-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 6fa99b7f80b4a7ed2cf616eae393bb6d9d51ba8f Mon Sep 17 00:00:00 2001 From: Will Deacon <[email protected]> Date: Fri, 27 Apr 2012 12:51:43 +0100 Subject: [PATCH] ARM: 7405/1: kexec: call platform_cpu_kill on the killer rather than the victim When performing a kexec on an SMP system, the secondary cores are stopped by calling machine_shutdown(), which in turn issues IPIs to offline the other CPUs. Unfortunately, this isn't enough to reboot the cores into a new kernel (since they are just executing a cpu_relax loop somewhere in memory) so we make use of platform_cpu_kill, part of the CPU hotplug implementation, to place the cores somewhere safe. This function expects to be called on the killing CPU for each core that it takes out. This patch moves the platform_cpu_kill callback out of the IPI handler and into smp_send_stop, therefore ensuring that it executes on the killing CPU rather than on the victim, matching what the hotplug code requires. Cc: [email protected] Reported-by: Russell King <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Russell King <[email protected]> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index addbbe8..f6a4d32 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -510,10 +510,6 @@ static void ipi_cpu_stop(unsigned int cpu) local_fiq_disable(); local_irq_disable(); -#ifdef CONFIG_HOTPLUG_CPU - platform_cpu_kill(cpu); -#endif - while (1) cpu_relax(); } @@ -576,17 +572,25 @@ void smp_send_reschedule(int cpu) smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); } +#ifdef CONFIG_HOTPLUG_CPU +static void smp_kill_cpus(cpumask_t *mask) +{ + unsigned int cpu; + for_each_cpu(cpu, mask) + platform_cpu_kill(cpu); +} +#else +static void smp_kill_cpus(cpumask_t *mask) { } +#endif + void smp_send_stop(void) { unsigned long timeout; + struct cpumask mask; - if (num_online_cpus() > 1) { - struct cpumask mask; - cpumask_copy(&mask, cpu_online_mask); - cpumask_clear_cpu(smp_processor_id(), &mask); - - smp_cross_call(&mask, IPI_CPU_STOP); - } + cpumask_copy(&mask, cpu_online_mask); + cpumask_clear_cpu(smp_processor_id(), &mask); + smp_cross_call(&mask, IPI_CPU_STOP); /* Wait up to one second for other CPUs to stop */ timeout = USEC_PER_SEC; @@ -595,6 +599,8 @@ void smp_send_stop(void) if (num_online_cpus() > 1) pr_warning("SMP: failed to stop secondary CPUs\n"); + + smp_kill_cpus(&mask); } /* -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
