[PATCH] powerpc: Add arch dependent basic infrastructure for Kdump.

Implementing the machine_crash_shutdown which will be called by
crash_kexec (called in case of a panic, sysrq etc.). Disable the
interrupts, shootdown cpus using debugger IPI and collect regs
for all CPUs.

elfcorehdr= specifies the location of elf core header stored by
the crashed kernel. This command line option will be passed by
the kexec-tools to capture kernel.

savemaxmem= specifies the actual memory size that the first kernel
has and this value will be used for dumping in the capture kernel.
This command line option will be passed by the kexec-tools to
capture kernel.

Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 20 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index a90df6bf0940..8e3ca674d359 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -75,6 +75,8 @@ void smp_call_function_interrupt(void);
 
 int smt_enabled_at_boot = 1;
 
+static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
+
 #ifdef CONFIG_MPIC
 int __init smp_mpic_probe(void)
 {
@@ -123,11 +125,16 @@ void smp_message_recv(int msg, struct pt_regs *regs)
                 /* XXX Do we have to do this? */
                 set_need_resched();
                 break;
-#ifdef CONFIG_DEBUGGER
         case PPC_MSG_DEBUGGER_BREAK:
+                if (crash_ipi_function_ptr) {
+                        crash_ipi_function_ptr(regs);
+                        break;
+                }
+#ifdef CONFIG_DEBUGGER
                 debugger_ipi(regs);
                 break;
-#endif
+#endif /* CONFIG_DEBUGGER */
+                /* FALLTHROUGH */
         default:
                 printk("SMP %d: smp_message_recv(): unknown msg %d\n",
                        smp_processor_id(), msg);
@@ -147,6 +154,17 @@ void smp_send_debugger_break(int cpu)
 }
 #endif
 
+#ifdef CONFIG_KEXEC
+void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
+{
+        crash_ipi_function_ptr = crash_ipi_callback;
+        if (crash_ipi_callback) {
+                mb();
+                smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
+        }
+}
+#endif
+
 static void stop_this_cpu(void *dummy)
 {
         local_irq_disable();