[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, 16 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 1511454c4690..76b579ca5230 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -31,6 +31,7 @@
 #include <linux/prctl.h>
 #include <linux/delay.h>
 #include <linux/kprobes.h>
+#include <linux/kexec.h>
 
 #include <asm/kdebug.h>
 #include <asm/pgtable.h>
@@ -95,7 +96,7 @@ static DEFINE_SPINLOCK(die_lock);
 
 int die(const char *str, struct pt_regs *regs, long err)
 {
-        static int die_counter;
+        static int die_counter, crash_dump_start = 0;
         int nl = 0;
 
         if (debugger(regs))
@@ -156,7 +157,21 @@ int die(const char *str, struct pt_regs *regs, long err)
         print_modules();
         show_regs(regs);
         bust_spinlocks(0);
+
+        if (!crash_dump_start && kexec_should_crash(current)) {
+                crash_dump_start = 1;
+                spin_unlock_irq(&die_lock);
+                crash_kexec(regs);
+                /* NOTREACHED */
+        }
         spin_unlock_irq(&die_lock);
+        if (crash_dump_start)
+                /*
+                 * Only for soft-reset: Other CPUs will be responded to an IPI
+                 * sent by first kexec CPU.
+                 */
+                for(;;)
+                        ;
 
         if (in_interrupt())
                 panic("Fatal exception in interrupt");