Merge with /home/shaggy/git/linus-clean/

1 files changed, 154 insertions, 2 deletions

diff --git a/arch/x86_64/kernel/crash.c b/arch/x86_64/kernel/crash.c
index 535e0446607..4e6c3b729e3 100644
--- a/arch/x86_64/kernel/crash.c
+++ b/arch/x86_64/kernel/crash.c
@@ -11,19 +11,156 @@
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/smp.h>
+#include <linux/irq.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/mach_apic.h>
 
-note_buf_t crash_notes[NR_CPUS];
+/* This keeps a track of which one is crashing cpu. */
+static int crashing_cpu;
+
+static u32 *append_elf_note(u32 *buf, char *name, unsigned type,
+						void *data, size_t data_len)
+{
+	struct elf_note note;
+
+	note.n_namesz = strlen(name) + 1;
+	note.n_descsz = data_len;
+	note.n_type   = type;
+	memcpy(buf, &note, sizeof(note));
+	buf += (sizeof(note) +3)/4;
+	memcpy(buf, name, note.n_namesz);
+	buf += (note.n_namesz + 3)/4;
+	memcpy(buf, data, note.n_descsz);
+	buf += (note.n_descsz + 3)/4;
+
+	return buf;
+}
+
+static void final_note(u32 *buf)
+{
+	struct elf_note note;
+
+	note.n_namesz = 0;
+	note.n_descsz = 0;
+	note.n_type   = 0;
+	memcpy(buf, &note, sizeof(note));
+}
+
+static void crash_save_this_cpu(struct pt_regs *regs, int cpu)
+{
+	struct elf_prstatus prstatus;
+	u32 *buf;
+
+	if ((cpu < 0) || (cpu >= NR_CPUS))
+		return;
+
+	/* Using ELF notes here is opportunistic.
+	 * I need a well defined structure format
+	 * for the data I pass, and I need tags
+	 * on the data to indicate what information I have
+	 * squirrelled away.  ELF notes happen to provide
+	 * all of that that no need to invent something new.
+	 */
+
+	buf = (u32*)per_cpu_ptr(crash_notes, cpu);
+
+	if (!buf)
+		return;
+
+	memset(&prstatus, 0, sizeof(prstatus));
+	prstatus.pr_pid = current->pid;
+	elf_core_copy_regs(&prstatus.pr_reg, regs);
+	buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus,
+					sizeof(prstatus));
+	final_note(buf);
+}
+
+static void crash_save_self(struct pt_regs *regs)
+{
+	int cpu;
+
+	cpu = smp_processor_id();
+	crash_save_this_cpu(regs, cpu);
+}
+
+#ifdef CONFIG_SMP
+static atomic_t waiting_for_crash_ipi;
+
+static int crash_nmi_callback(struct pt_regs *regs, int cpu)
+{
+	/*
+	 * 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 1;
+	local_irq_disable();
+
+	crash_save_this_cpu(regs, cpu);
+	disable_local_APIC();
+	atomic_dec(&waiting_for_crash_ipi);
+	/* Assume hlt works */
+	for(;;)
+		asm("hlt");
+
+	return 1;
+}
+
+static void smp_send_nmi_allbutself(void)
+{
+	send_IPI_allbutself(APIC_DM_NMI);
+}
+
+/*
+ * This code is a best effort heuristic to get the
+ * other cpus to stop executing. So races with
+ * cpu hotplug shouldn't matter.
+ */
+
+static void nmi_shootdown_cpus(void)
+{
+	unsigned long msecs;
+
+	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
+	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 */
+	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
+	/*
+	 * This function is only called after the system
 	 * has paniced 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.
@@ -31,4 +168,19 @@ void machine_crash_shutdown(struct pt_regs *regs)
 	 * 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 = smp_processor_id();
+	nmi_shootdown_cpus();
+
+	if(cpu_has_apic)
+		 disable_local_APIC();
+
+#if defined(CONFIG_X86_IO_APIC)
+	disable_IO_APIC();
+#endif
+
+	crash_save_self(regs);
 }