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Diffstat (limited to 'arch/powerpc/kernel/crash.c')
-rw-r--r--arch/powerpc/kernel/crash.c376
1 files changed, 273 insertions, 103 deletions
diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index 8c21d378f5d..51dbace3269 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -10,171 +10,303 @@
*
*/
-#undef DEBUG
-
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/reboot.h>
#include <linux/kexec.h>
-#include <linux/bootmem.h>
+#include <linux/export.h>
#include <linux/crash_dump.h>
#include <linux/delay.h>
-#include <linux/elf.h>
-#include <linux/elfcore.h>
-#include <linux/init.h>
+#include <linux/irq.h>
#include <linux/types.h>
#include <asm/processor.h>
#include <asm/machdep.h>
+#include <asm/kexec.h>
#include <asm/kdump.h>
-#include <asm/lmb.h>
-#include <asm/firmware.h>
+#include <asm/prom.h>
#include <asm/smp.h>
+#include <asm/setjmp.h>
+#include <asm/debug.h>
-#ifdef DEBUG
-#include <asm/udbg.h>
-#define DBG(fmt...) udbg_printf(fmt)
-#else
-#define DBG(fmt...)
-#endif
+/*
+ * The primary CPU waits a while for all secondary CPUs to enter. This is to
+ * avoid sending an IPI if the secondary CPUs are entering
+ * crash_kexec_secondary on their own (eg via a system reset).
+ *
+ * The secondary timeout has to be longer than the primary. Both timeouts are
+ * in milliseconds.
+ */
+#define PRIMARY_TIMEOUT 500
+#define SECONDARY_TIMEOUT 1000
-/* This keeps a track of which one is crashing cpu. */
-int crashing_cpu = -1;
+#define IPI_TIMEOUT 10000
+#define REAL_MODE_TIMEOUT 10000
-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;
-}
+/* This keeps a track of which one is the crashing cpu. */
+int crashing_cpu = -1;
+static int time_to_dump;
-static void final_note(u32 *buf)
-{
- struct elf_note note;
+#define CRASH_HANDLER_MAX 3
+/* NULL terminated list of shutdown handles */
+static crash_shutdown_t crash_shutdown_handles[CRASH_HANDLER_MAX+1];
+static DEFINE_SPINLOCK(crash_handlers_lock);
- note.n_namesz = 0;
- note.n_descsz = 0;
- note.n_type = 0;
- memcpy(buf, &note, sizeof(note));
-}
+static unsigned long crash_shutdown_buf[JMP_BUF_LEN];
+static int crash_shutdown_cpu = -1;
-static void crash_save_this_cpu(struct pt_regs *regs, int cpu)
+static int handle_fault(struct pt_regs *regs)
{
- 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);
+ if (crash_shutdown_cpu == smp_processor_id())
+ longjmp(crash_shutdown_buf, 1);
+ return 0;
}
#ifdef CONFIG_SMP
-static atomic_t waiting_for_crash_ipi;
+static atomic_t cpus_in_crash;
void crash_ipi_callback(struct pt_regs *regs)
{
- int cpu = smp_processor_id();
+ static cpumask_t cpus_state_saved = CPU_MASK_NONE;
- if (cpu == crashing_cpu)
- return;
+ int cpu = smp_processor_id();
if (!cpu_online(cpu))
return;
+ hard_irq_disable();
+ if (!cpumask_test_cpu(cpu, &cpus_state_saved)) {
+ crash_save_cpu(regs, cpu);
+ cpumask_set_cpu(cpu, &cpus_state_saved);
+ }
+
+ atomic_inc(&cpus_in_crash);
+ smp_mb__after_atomic();
+
+ /*
+ * Starting the kdump boot.
+ * This barrier is needed to make sure that all CPUs are stopped.
+ */
+ while (!time_to_dump)
+ cpu_relax();
+
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);
+#ifdef CONFIG_PPC64
kexec_smp_wait();
+#else
+ for (;;); /* FIXME */
+#endif
+
/* NOTREACHED */
}
-static void crash_kexec_prepare_cpus(void)
+static void crash_kexec_prepare_cpus(int cpu)
{
unsigned int msecs;
+ unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
+ int tries = 0;
+ int (*old_handler)(struct pt_regs *regs);
- atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
+ printk(KERN_EMERG "Sending IPI to other CPUs\n");
crash_send_ipi(crash_ipi_callback);
smp_wmb();
+again:
/*
- * FIXME: Until we will have the way to stop other CPUSs reliabally,
+ * FIXME: Until we will have the way to stop other CPUs reliably,
* 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.
+ * respond.
*/
- msecs = 1000000;
- while ((atomic_read(&waiting_for_crash_ipi) > 0) && (--msecs > 0)) {
- barrier();
+ msecs = IPI_TIMEOUT;
+ while ((atomic_read(&cpus_in_crash) < ncpus) && (--msecs > 0))
mdelay(1);
- }
/* Would it be better to replace the trap vector here? */
+ if (atomic_read(&cpus_in_crash) >= ncpus) {
+ printk(KERN_EMERG "IPI complete\n");
+ return;
+ }
+
+ printk(KERN_EMERG "ERROR: %d cpu(s) not responding\n",
+ ncpus - atomic_read(&cpus_in_crash));
+
/*
- * 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 we have a panic timeout set then we can't wait indefinitely
+ * for someone to activate system reset. We also give up on the
+ * second time through if system reset fail to work.
*/
- 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 */
+ if ((panic_timeout > 0) || (tries > 0))
+ return;
+
+ /*
+ * A system reset will cause all CPUs to take an 0x100 exception.
+ * The primary CPU returns here via setjmp, and the secondary
+ * CPUs reexecute the crash_kexec_secondary path.
+ */
+ old_handler = __debugger;
+ __debugger = handle_fault;
+ crash_shutdown_cpu = smp_processor_id();
+
+ if (setjmp(crash_shutdown_buf) == 0) {
+ printk(KERN_EMERG "Activate system reset (dumprestart) "
+ "to stop other cpu(s)\n");
+
+ /*
+ * A system reset will force all CPUs to execute the
+ * crash code again. We need to reset cpus_in_crash so we
+ * wait for everyone to do this.
+ */
+ atomic_set(&cpus_in_crash, 0);
+ smp_mb();
+
+ while (atomic_read(&cpus_in_crash) < ncpus)
+ cpu_relax();
+ }
+
+ crash_shutdown_cpu = -1;
+ __debugger = old_handler;
+
+ tries++;
+ goto again;
}
-#else
-static void crash_kexec_prepare_cpus(void)
+
+/*
+ * This function will be called by secondary cpus.
+ */
+void crash_kexec_secondary(struct pt_regs *regs)
+{
+ unsigned long flags;
+ int msecs = SECONDARY_TIMEOUT;
+
+ local_irq_save(flags);
+
+ /* Wait for the primary crash CPU to signal its progress */
+ while (crashing_cpu < 0) {
+ if (--msecs < 0) {
+ /* No response, kdump image may not have been loaded */
+ local_irq_restore(flags);
+ return;
+ }
+
+ mdelay(1);
+ }
+
+ crash_ipi_callback(regs);
+}
+
+#else /* ! CONFIG_SMP */
+
+static void crash_kexec_prepare_cpus(int cpu)
{
/*
- * move the secondarys to us so that we can copy
+ * move the secondaries to us so that we can copy
* the new kernel 0-0x100 safely
*
* do this if kexec in setup.c ?
*/
+#ifdef CONFIG_PPC64
smp_release_cpus();
+#else
+ /* FIXME */
+#endif
}
-#endif
+void crash_kexec_secondary(struct pt_regs *regs)
+{
+}
+#endif /* CONFIG_SMP */
+
+/* wait for all the CPUs to hit real mode but timeout if they don't come in */
+#if defined(CONFIG_SMP) && defined(CONFIG_PPC_STD_MMU_64)
+static void crash_kexec_wait_realmode(int cpu)
+{
+ unsigned int msecs;
+ int i;
+
+ msecs = REAL_MODE_TIMEOUT;
+ for (i=0; i < nr_cpu_ids && msecs > 0; i++) {
+ if (i == cpu)
+ continue;
+
+ while (paca[i].kexec_state < KEXEC_STATE_REAL_MODE) {
+ barrier();
+ if (!cpu_possible(i) || !cpu_online(i) || (msecs <= 0))
+ break;
+ msecs--;
+ mdelay(1);
+ }
+ }
+ mb();
+}
+#else
+static inline void crash_kexec_wait_realmode(int cpu) {}
+#endif /* CONFIG_SMP && CONFIG_PPC_STD_MMU_64 */
+
+/*
+ * Register a function to be called on shutdown. Only use this if you
+ * can't reset your device in the second kernel.
+ */
+int crash_shutdown_register(crash_shutdown_t handler)
+{
+ unsigned int i, rc;
+
+ spin_lock(&crash_handlers_lock);
+ for (i = 0 ; i < CRASH_HANDLER_MAX; i++)
+ if (!crash_shutdown_handles[i]) {
+ /* Insert handle at first empty entry */
+ crash_shutdown_handles[i] = handler;
+ rc = 0;
+ break;
+ }
+
+ if (i == CRASH_HANDLER_MAX) {
+ printk(KERN_ERR "Crash shutdown handles full, "
+ "not registered.\n");
+ rc = 1;
+ }
+
+ spin_unlock(&crash_handlers_lock);
+ return rc;
+}
+EXPORT_SYMBOL(crash_shutdown_register);
+
+int crash_shutdown_unregister(crash_shutdown_t handler)
+{
+ unsigned int i, rc;
+
+ spin_lock(&crash_handlers_lock);
+ for (i = 0 ; i < CRASH_HANDLER_MAX; i++)
+ if (crash_shutdown_handles[i] == handler)
+ break;
+
+ if (i == CRASH_HANDLER_MAX) {
+ printk(KERN_ERR "Crash shutdown handle not found\n");
+ rc = 1;
+ } else {
+ /* Shift handles down */
+ for (; crash_shutdown_handles[i]; i++)
+ crash_shutdown_handles[i] =
+ crash_shutdown_handles[i+1];
+ rc = 0;
+ }
+
+ spin_unlock(&crash_handlers_lock);
+ return rc;
+}
+EXPORT_SYMBOL(crash_shutdown_unregister);
void default_machine_crash_shutdown(struct pt_regs *regs)
{
+ unsigned int i;
+ int (*old_handler)(struct pt_regs *regs);
+
/*
* This function is only called after the system
- * has paniced or is otherwise in a critical state.
+ * 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.
*
@@ -182,16 +314,54 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
* 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);
+ hard_irq_disable();
/*
* 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_this_cpu(regs, crashing_cpu);
+
+ /*
+ * If we came in via system reset, wait a while for the secondary
+ * CPUs to enter.
+ */
+ if (TRAP(regs) == 0x100)
+ mdelay(PRIMARY_TIMEOUT);
+
+ crash_kexec_prepare_cpus(crashing_cpu);
+
+ crash_save_cpu(regs, crashing_cpu);
+
+ time_to_dump = 1;
+
+ crash_kexec_wait_realmode(crashing_cpu);
+
+ machine_kexec_mask_interrupts();
+
+ /*
+ * Call registered shutdown routines safely. Swap out
+ * __debugger_fault_handler, and replace on exit.
+ */
+ old_handler = __debugger_fault_handler;
+ __debugger_fault_handler = handle_fault;
+ crash_shutdown_cpu = smp_processor_id();
+ for (i = 0; crash_shutdown_handles[i]; i++) {
+ if (setjmp(crash_shutdown_buf) == 0) {
+ /*
+ * Insert syncs and delay to ensure
+ * instructions in the dangerous region don't
+ * leak away from this protected region.
+ */
+ asm volatile("sync; isync");
+ /* dangerous region */
+ crash_shutdown_handles[i]();
+ asm volatile("sync; isync");
+ }
+ }
+ crash_shutdown_cpu = -1;
+ __debugger_fault_handler = old_handler;
+
+ if (ppc_md.kexec_cpu_down)
+ ppc_md.kexec_cpu_down(1, 0);
}
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