Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc-merge

1 files changed, 264 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
new file mode 100644
index 000000000000..4681155121ef
--- /dev/null
+++ b/arch/powerpc/kernel/crash.c
@@ -0,0 +1,264 @@
+/*
+ * Architecture specific (PPC64) functions for kexec based crash dumps.
+ *
+ * Copyright (C) 2005, IBM Corp.
+ *
+ * Created by: Haren Myneni
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ *
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/smp.h>
+#include <linux/reboot.h>
+#include <linux/kexec.h>
+#include <linux/bootmem.h>
+#include <linux/crash_dump.h>
+#include <linux/irq.h>
+#include <linux/delay.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/init.h>
+#include <linux/types.h>
+
+#include <asm/processor.h>
+#include <asm/machdep.h>
+#include <asm/kdump.h>
+#include <asm/lmb.h>
+#include <asm/firmware.h>
+
+#ifdef DEBUG
+#include <asm/udbg.h>
+#define DBG(fmt...) udbg_printf(fmt)
+#else
+#define DBG(fmt...)
+#endif
+
+/* This keeps a track of which one is crashing cpu. */
+int crashing_cpu = -1;
+
+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 = &crash_notes[cpu][0];
+	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);
+}
+
+/* FIXME Merge this with xmon_save_regs ?? */
+static inline void crash_get_current_regs(struct pt_regs *regs)
+{
+	unsigned long tmp1, tmp2;
+
+	__asm__ __volatile__ (
+		"std    0,0(%2)\n"
+		"std    1,8(%2)\n"
+		"std    2,16(%2)\n"
+		"std    3,24(%2)\n"
+		"std    4,32(%2)\n"
+		"std    5,40(%2)\n"
+		"std    6,48(%2)\n"
+		"std    7,56(%2)\n"
+		"std    8,64(%2)\n"
+		"std    9,72(%2)\n"
+		"std    10,80(%2)\n"
+		"std    11,88(%2)\n"
+		"std    12,96(%2)\n"
+		"std    13,104(%2)\n"
+		"std    14,112(%2)\n"
+		"std    15,120(%2)\n"
+		"std    16,128(%2)\n"
+		"std    17,136(%2)\n"
+		"std    18,144(%2)\n"
+		"std    19,152(%2)\n"
+		"std    20,160(%2)\n"
+		"std    21,168(%2)\n"
+		"std    22,176(%2)\n"
+		"std    23,184(%2)\n"
+		"std    24,192(%2)\n"
+		"std    25,200(%2)\n"
+		"std    26,208(%2)\n"
+		"std    27,216(%2)\n"
+		"std    28,224(%2)\n"
+		"std    29,232(%2)\n"
+		"std    30,240(%2)\n"
+		"std    31,248(%2)\n"
+		"mfmsr  %0\n"
+		"std    %0, 264(%2)\n"
+		"mfctr  %0\n"
+		"std    %0, 280(%2)\n"
+		"mflr   %0\n"
+		"std    %0, 288(%2)\n"
+		"bl     1f\n"
+	"1:      mflr   %1\n"
+		"std    %1, 256(%2)\n"
+		"mtlr   %0\n"
+		"mfxer  %0\n"
+		"std    %0, 296(%2)\n"
+		: "=&r" (tmp1), "=&r" (tmp2)
+		: "b" (regs));
+}
+
+/* We may have saved_regs from where the error came from
+ * or it is NULL if via a direct panic().
+ */
+static void crash_save_self(struct pt_regs *saved_regs)
+{
+	struct pt_regs regs;
+	int cpu;
+
+	cpu = smp_processor_id();
+	if (saved_regs)
+		memcpy(&regs, saved_regs, sizeof(regs));
+	else
+		crash_get_current_regs(&regs);
+	crash_save_this_cpu(&regs, cpu);
+}
+
+#ifdef CONFIG_SMP
+static atomic_t waiting_for_crash_ipi;
+
+void crash_ipi_callback(struct pt_regs *regs)
+{
+	int cpu = smp_processor_id();
+
+	if (cpu == crashing_cpu)
+		return;
+
+	if (!cpu_online(cpu))
+		return;
+
+	if (ppc_md.kexec_cpu_down)
+		ppc_md.kexec_cpu_down(1, 1);
+
+	local_irq_disable();
+
+	crash_save_this_cpu(regs, cpu);
+	atomic_dec(&waiting_for_crash_ipi);
+	kexec_smp_wait();
+	/* NOTREACHED */
+}
+
+static void crash_kexec_prepare_cpus(void)
+{
+	unsigned int msecs;
+
+	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
+
+	crash_send_ipi(crash_ipi_callback);
+	smp_wmb();
+
+	/*
+	 * FIXME: Until we will have the way to stop other CPUSs reliabally,
+	 * the crash CPU will send an IPI and wait for other CPUs to
+	 * respond. If not, proceed the kexec boot even though we failed to
+	 * capture other CPU states.
+	 */
+	msecs = 1000000;
+	while ((atomic_read(&waiting_for_crash_ipi) > 0) && (--msecs > 0)) {
+		barrier();
+		mdelay(1);
+	}
+
+	/* Would it be better to replace the trap vector here? */
+
+	/*
+	 * FIXME: In case if we do not get all CPUs, one possibility: ask the
+	 * user to do soft reset such that we get all.
+	 * IPI handler is already set by the panic cpu initially. Therefore,
+	 * all cpus could invoke this handler from die() and the panic CPU
+	 * will call machine_kexec() directly from this handler to do
+	 * kexec boot.
+	 */
+	if (atomic_read(&waiting_for_crash_ipi))
+		printk(KERN_ALERT "done waiting: %d cpus not responding\n",
+			atomic_read(&waiting_for_crash_ipi));
+	/* Leave the IPI callback set */
+}
+#else
+static void crash_kexec_prepare_cpus(void)
+{
+	/*
+	 * move the secondarys to us so that we can copy
+	 * the new kernel 0-0x100 safely
+	 *
+	 * do this if kexec in setup.c ?
+	 */
+	smp_release_cpus();
+}
+
+#endif
+
+void default_machine_crash_shutdown(struct pt_regs *regs)
+{
+	/*
+	 * 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.
+	 *
+	 * In practice this means stopping other cpus in
+	 * an SMP system.
+	 * The kernel is broken so disable interrupts.
+	 */
+	local_irq_disable();
+
+	if (ppc_md.kexec_cpu_down)
+		ppc_md.kexec_cpu_down(1, 0);
+
+	/*
+	 * Make a note of crashing cpu. Will be used in machine_kexec
+	 * such that another IPI will not be sent.
+	 */
+	crashing_cpu = smp_processor_id();
+	crash_kexec_prepare_cpus();
+	crash_save_self(regs);
+}