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-rw-r--r--arch/arm/include/asm/smp_plat.h3
-rw-r--r--arch/arm/kernel/machine_kexec.c20
-rw-r--r--arch/arm/kernel/smp.c10
3 files changed, 29 insertions, 4 deletions
diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h
index 6462a72..a252c0b 100644
--- a/arch/arm/include/asm/smp_plat.h
+++ b/arch/arm/include/asm/smp_plat.h
@@ -88,4 +88,7 @@ static inline u32 mpidr_hash_size(void)
{
return 1 << mpidr_hash.bits;
}
+
+extern int platform_can_cpu_hotplug(void);
+
#endif
diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 4fb074c..d7c82df 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -15,6 +15,7 @@
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>
#include <asm/mach-types.h>
+#include <asm/smp_plat.h>
#include <asm/system_misc.h>
extern const unsigned char relocate_new_kernel[];
@@ -39,6 +40,14 @@ int machine_kexec_prepare(struct kimage *image)
int i, err;
/*
+ * Validate that if the current HW supports SMP, then the SW supports
+ * and implements CPU hotplug for the current HW. If not, we won't be
+ * able to kexec reliably, so fail the prepare operation.
+ */
+ if (num_possible_cpus() > 1 && !platform_can_cpu_hotplug())
+ return -EINVAL;
+
+ /*
* No segment at default ATAGs address. try to locate
* a dtb using magic.
*/
@@ -134,10 +143,13 @@ void machine_kexec(struct kimage *image)
unsigned long reboot_code_buffer_phys;
void *reboot_code_buffer;
- if (num_online_cpus() > 1) {
- pr_err("kexec: error: multiple CPUs still online\n");
- return;
- }
+ /*
+ * This can only happen if machine_shutdown() failed to disable some
+ * CPU, and that can only happen if the checks in
+ * machine_kexec_prepare() were not correct. If this fails, we can't
+ * reliably kexec anyway, so BUG_ON is appropriate.
+ */
+ BUG_ON(num_online_cpus() > 1);
page_list = image->head & PAGE_MASK;
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index c2b4f8f..2dc19349e 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -145,6 +145,16 @@ int boot_secondary(unsigned int cpu, struct task_struct *idle)
return -ENOSYS;
}
+int platform_can_cpu_hotplug(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+ if (smp_ops.cpu_kill)
+ return 1;
+#endif
+
+ return 0;
+}
+
#ifdef CONFIG_HOTPLUG_CPU
static void percpu_timer_stop(void);
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