ARM: 6522/1: kexec: Add call to non-crashing cores through IPI

When kexec is used to start a crash kernel the other cores
are notified. These non-crashing cores will save their state
in the crash notes and then do nothing.

Signed-off-by: Per Fransson <per.xx.fransson@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 30 insertions, 0 deletions

diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 3a8fd5140d7a..30ead135ff5f 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -23,6 +23,8 @@ extern unsigned long kexec_indirection_page;
 extern unsigned long kexec_mach_type;
 extern unsigned long kexec_boot_atags;
 
+static atomic_t waiting_for_crash_ipi;
+
 /*
  * Provide a dummy crash_notes definition while crash dump arrives to arm.
  * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
@@ -37,9 +39,37 @@ void machine_kexec_cleanup(struct kimage *image)
 {
 }
 
+void machine_crash_nonpanic_core(void *unused)
+{
+        struct pt_regs regs;
+
+        crash_setup_regs(&regs, NULL);
+        printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
+               smp_processor_id());
+        crash_save_cpu(&regs, smp_processor_id());
+        flush_cache_all();
+
+        atomic_dec(&waiting_for_crash_ipi);
+        while (1)
+                cpu_relax();
+}
+
 void machine_crash_shutdown(struct pt_regs *regs)
 {
+        unsigned long msecs;
+
         local_irq_disable();
+
+        atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
+        smp_call_function(machine_crash_nonpanic_core, NULL, false);
+        msecs = 1000; /* Wait at most a second for the other cpus to stop */
+        while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
+                mdelay(1);
+                msecs--;
+        }
+        if (atomic_read(&waiting_for_crash_ipi) > 0)
+                printk(KERN_WARNING "Non-crashing CPUs did not react to IPI\n");
+
         crash_save_cpu(regs, smp_processor_id());
 
         printk(KERN_INFO "Loading crashdump kernel...\n");