[PATCH] crashdump: x86: add NMI handler to capture other CPUs

[linux-2.6-omap-h63xx.git] / arch / i386 / kernel / crash.c

diff --git a/arch/i386/kernel/crash.c b/arch/i386/kernel/crash.c
index fa27a6c2abb6468d056aba199b0c43fabd682eec..882779c07874fd17b97144cfaa680f5038c701aa 100644 (file)
--- a/arch/i386/kernel/crash.c
+++ b/arch/i386/kernel/crash.c
@@ -23,12 +23,65 @@
 #include <asm/hardirq.h>
 #include <asm/nmi.h>
 #include <asm/hw_irq.h>
+#include <mach_ipi.h>
 
 #define MAX_NOTE_BYTES 1024
 typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
 
 note_buf_t crash_notes[NR_CPUS];
 
+#ifdef CONFIG_SMP
+static atomic_t waiting_for_crash_ipi;
+
+static int crash_nmi_callback(struct pt_regs *regs, int cpu)
+{
+       local_irq_disable();
+       atomic_dec(&waiting_for_crash_ipi);
+       /* Assume hlt works */
+       __asm__("hlt");
+       for(;;);
+       return 1;
+}
+
+/*
+ * By using the NMI code instead of a vector we just sneak thru the
+ * word generator coming out with just what we want.  AND it does
+ * not matter if clustered_apic_mode is set or not.
+ */
+static void smp_send_nmi_allbutself(void)
+{
+       send_IPI_allbutself(APIC_DM_NMI);
+}
+
+static void nmi_shootdown_cpus(void)
+{
+       unsigned long msecs;
+       atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
+
+       /* Would it be better to replace the trap vector here? */
+       set_nmi_callback(crash_nmi_callback);
+       /* Ensure the new callback function is set before sending
+        * out the NMI
+        */
+       wmb();
+
+       smp_send_nmi_allbutself();
+
+       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--;
+       }
+
+       /* Leave the nmi callback set */
+}
+#else
+static void nmi_shootdown_cpus(void)
+{
+       /* There are no cpus to shootdown */
+}
+#endif
+
 void machine_crash_shutdown(void)
 {
        /* This function is only called after the system
@@ -39,4 +92,7 @@ void machine_crash_shutdown(void)
         * In practice this means shooting down the other cpus in
         * an SMP system.
         */
+       /* The kernel is broken so disable interrupts */
+       local_irq_disable();
+       nmi_shootdown_cpus();
 }