aboutsummaryrefslogtreecommitdiff
path: root/arch/x86/kernel/crash_32.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kernel/crash_32.c')
-rw-r--r--arch/x86/kernel/crash_32.c137
1 files changed, 137 insertions, 0 deletions
diff --git a/arch/x86/kernel/crash_32.c b/arch/x86/kernel/crash_32.c
new file mode 100644
index 00000000000..53589d1b1a0
--- /dev/null
+++ b/arch/x86/kernel/crash_32.c
@@ -0,0 +1,137 @@
+/*
+ * Architecture specific (i386) functions for kexec based crash dumps.
+ *
+ * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
+ *
+ * Copyright (C) IBM Corporation, 2004. All rights reserved.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/smp.h>
+#include <linux/reboot.h>
+#include <linux/kexec.h>
+#include <linux/delay.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+
+#include <asm/processor.h>
+#include <asm/hardirq.h>
+#include <asm/nmi.h>
+#include <asm/hw_irq.h>
+#include <asm/apic.h>
+#include <linux/kdebug.h>
+#include <asm/smp.h>
+
+#include <mach_ipi.h>
+
+
+/* This keeps a track of which one is crashing cpu. */
+static int crashing_cpu;
+
+#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
+static atomic_t waiting_for_crash_ipi;
+
+static int crash_nmi_callback(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct pt_regs *regs;
+ struct pt_regs fixed_regs;
+ int cpu;
+
+ if (val != DIE_NMI_IPI)
+ return NOTIFY_OK;
+
+ regs = ((struct die_args *)data)->regs;
+ cpu = raw_smp_processor_id();
+
+ /* Don't do anything if this handler is invoked on crashing cpu.
+ * Otherwise, system will completely hang. Crashing cpu can get
+ * an NMI if system was initially booted with nmi_watchdog parameter.
+ */
+ if (cpu == crashing_cpu)
+ return NOTIFY_STOP;
+ local_irq_disable();
+
+ if (!user_mode_vm(regs)) {
+ crash_fixup_ss_esp(&fixed_regs, regs);
+ regs = &fixed_regs;
+ }
+ crash_save_cpu(regs, cpu);
+ disable_local_APIC();
+ atomic_dec(&waiting_for_crash_ipi);
+ /* Assume hlt works */
+ halt();
+ for (;;)
+ cpu_relax();
+
+ return 1;
+}
+
+static void smp_send_nmi_allbutself(void)
+{
+ cpumask_t mask = cpu_online_map;
+ cpu_clear(safe_smp_processor_id(), mask);
+ if (!cpus_empty(mask))
+ send_IPI_mask(mask, NMI_VECTOR);
+}
+
+static struct notifier_block crash_nmi_nb = {
+ .notifier_call = crash_nmi_callback,
+};
+
+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? */
+ if (register_die_notifier(&crash_nmi_nb))
+ return; /* return what? */
+ /* 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 */
+ disable_local_APIC();
+}
+#else
+static void nmi_shootdown_cpus(void)
+{
+ /* There are no cpus to shootdown */
+}
+#endif
+
+void machine_crash_shutdown(struct pt_regs *regs)
+{
+ /* This function is only called after the system
+ * has panicked or is otherwise in a critical state.
+ * The minimum amount of code to allow a kexec'd kernel
+ * to run successfully needs to happen here.
+ *
+ * In practice this means shooting down the other cpus in
+ * an SMP system.
+ */
+ /* The kernel is broken so disable interrupts */
+ local_irq_disable();
+
+ /* Make a note of crashing cpu. Will be used in NMI callback.*/
+ crashing_cpu = safe_smp_processor_id();
+ nmi_shootdown_cpus();
+ lapic_shutdown();
+#if defined(CONFIG_X86_IO_APIC)
+ disable_IO_APIC();
+#endif
+ crash_save_cpu(regs, safe_smp_processor_id());
+}