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Diffstat (limited to 'arch/powerpc/kernel/crash.c')
-rw-r--r--arch/powerpc/kernel/crash.c220
1 files changed, 106 insertions, 114 deletions
diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index d879809d5c45..28be3452e67a 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -10,85 +10,85 @@
*
*/
-#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 <linux/memblock.h>
#include <asm/processor.h>
#include <asm/machdep.h>
#include <asm/kexec.h>
#include <asm/kdump.h>
#include <asm/prom.h>
-#include <asm/firmware.h>
#include <asm/smp.h>
#include <asm/system.h>
#include <asm/setjmp.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. */
+#define IPI_TIMEOUT 10000
+#define REAL_MODE_TIMEOUT 10000
+
+/* This keeps a track of which one is the crashing cpu. */
int crashing_cpu = -1;
-static cpumask_t cpus_in_crash = CPU_MASK_NONE;
-cpumask_t cpus_in_sr = CPU_MASK_NONE;
+static atomic_t cpus_in_crash;
+static int time_to_dump;
#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);
+static unsigned long crash_shutdown_buf[JMP_BUF_LEN];
+static int crash_shutdown_cpu = -1;
+
+static int handle_fault(struct pt_regs *regs)
+{
+ if (crash_shutdown_cpu == smp_processor_id())
+ longjmp(crash_shutdown_buf, 1);
+ return 0;
+}
+
#ifdef CONFIG_SMP
-static atomic_t enter_on_soft_reset = ATOMIC_INIT(0);
void crash_ipi_callback(struct pt_regs *regs)
{
+ static cpumask_t cpus_state_saved = CPU_MASK_NONE;
+
int cpu = smp_processor_id();
if (!cpu_online(cpu))
return;
hard_irq_disable();
- if (!cpumask_test_cpu(cpu, &cpus_in_crash))
+ if (!cpumask_test_cpu(cpu, &cpus_state_saved)) {
crash_save_cpu(regs, cpu);
- cpumask_set_cpu(cpu, &cpus_in_crash);
-
- /*
- * Entered via soft-reset - could be the kdump
- * process is invoked using soft-reset or user activated
- * it if some CPU did not respond to an IPI.
- * For soft-reset, the secondary CPU can enter this func
- * twice. 1 - using IPI, and 2. soft-reset.
- * Tell the kexec CPU that entered via soft-reset and ready
- * to go down.
- */
- if (cpumask_test_cpu(cpu, &cpus_in_sr)) {
- cpumask_clear_cpu(cpu, &cpus_in_sr);
- atomic_inc(&enter_on_soft_reset);
+ cpumask_set_cpu(cpu, &cpus_state_saved);
}
+ atomic_inc(&cpus_in_crash);
+ smp_mb__after_atomic_inc();
+
/*
* Starting the kdump boot.
* This barrier is needed to make sure that all CPUs are stopped.
- * If not, soft-reset will be invoked to bring other CPUs.
*/
- while (!cpumask_test_cpu(crashing_cpu, &cpus_in_crash))
+ while (!time_to_dump)
cpu_relax();
if (ppc_md.kexec_cpu_down)
@@ -103,106 +103,99 @@ void crash_ipi_callback(struct pt_regs *regs)
/* NOTREACHED */
}
-/*
- * Wait until all CPUs are entered via soft-reset.
- */
-static void crash_soft_reset_check(int cpu)
-{
- unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
-
- cpumask_clear_cpu(cpu, &cpus_in_sr);
- while (atomic_read(&enter_on_soft_reset) != ncpus)
- cpu_relax();
-}
-
-
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);
+
+ 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 CPUs reliably,
* the crash CPU will send an IPI and wait for other CPUs to
* respond.
- * Delay of at least 10 seconds.
*/
- printk(KERN_EMERG "Sending IPI to other cpus...\n");
- msecs = 10000;
- while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) {
- cpu_relax();
+ 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.
- * Soft-reset will be used until better mechanism is implemented.
+ * 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 (cpumask_weight(&cpus_in_crash) < ncpus) {
- printk(KERN_EMERG "done waiting: %d cpu(s) not responding\n",
- ncpus - cpumask_weight(&cpus_in_crash));
- printk(KERN_EMERG "Activate soft-reset to stop other cpu(s)\n");
- cpumask_clear(&cpus_in_sr);
- atomic_set(&enter_on_soft_reset, 0);
- while (cpumask_weight(&cpus_in_crash) < ncpus)
- cpu_relax();
- }
+ if ((panic_timeout > 0) || (tries > 0))
+ return;
+
/*
- * Make sure all CPUs are entered via soft-reset if the kdump is
- * invoked using soft-reset.
+ * 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.
*/
- if (cpumask_test_cpu(cpu, &cpus_in_sr))
- crash_soft_reset_check(cpu);
- /* Leave the IPI callback set */
+ 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;
}
/*
- * This function will be called by secondary cpus or by kexec cpu
- * if soft-reset is activated to stop some CPUs.
+ * This function will be called by secondary cpus.
*/
void crash_kexec_secondary(struct pt_regs *regs)
{
- int cpu = smp_processor_id();
unsigned long flags;
- int msecs = 5;
+ int msecs = SECONDARY_TIMEOUT;
local_irq_save(flags);
- /* Wait 5ms if the kexec CPU is not entered yet. */
+
+ /* Wait for the primary crash CPU to signal its progress */
while (crashing_cpu < 0) {
if (--msecs < 0) {
- /*
- * Either kdump image is not loaded or
- * kdump process is not started - Probably xmon
- * exited using 'x'(exit and recover) or
- * kexec_should_crash() failed for all running tasks.
- */
- cpumask_clear_cpu(cpu, &cpus_in_sr);
+ /* No response, kdump image may not have been loaded */
local_irq_restore(flags);
return;
}
+
mdelay(1);
- cpu_relax();
- }
- if (cpu == crashing_cpu) {
- /*
- * Panic CPU will enter this func only via soft-reset.
- * Wait until all secondary CPUs entered and
- * then start kexec boot.
- */
- crash_soft_reset_check(cpu);
- cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
- if (ppc_md.kexec_cpu_down)
- ppc_md.kexec_cpu_down(1, 0);
- machine_kexec(kexec_crash_image);
- /* NOTREACHED */
}
+
crash_ipi_callback(regs);
}
@@ -211,7 +204,7 @@ void crash_kexec_secondary(struct pt_regs *regs)
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 ?
@@ -225,7 +218,6 @@ static void crash_kexec_prepare_cpus(int cpu)
void crash_kexec_secondary(struct pt_regs *regs)
{
- cpumask_clear(&cpus_in_sr);
}
#endif /* CONFIG_SMP */
@@ -236,7 +228,7 @@ static void crash_kexec_wait_realmode(int cpu)
unsigned int msecs;
int i;
- msecs = 10000;
+ msecs = REAL_MODE_TIMEOUT;
for (i=0; i < nr_cpu_ids && msecs > 0; i++) {
if (i == cpu)
continue;
@@ -308,22 +300,11 @@ int crash_shutdown_unregister(crash_shutdown_t handler)
}
EXPORT_SYMBOL(crash_shutdown_unregister);
-static unsigned long crash_shutdown_buf[JMP_BUF_LEN];
-static int crash_shutdown_cpu = -1;
-
-static int handle_fault(struct pt_regs *regs)
-{
- if (crash_shutdown_cpu == smp_processor_id())
- longjmp(crash_shutdown_buf, 1);
- return 0;
-}
-
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 panicked or is otherwise in a critical state.
@@ -341,15 +322,26 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
* such that another IPI will not be sent.
*/
crashing_cpu = smp_processor_id();
- crash_save_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);
- cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
+
+ crash_save_cpu(regs, crashing_cpu);
+
+ time_to_dump = 1;
+
crash_kexec_wait_realmode(crashing_cpu);
machine_kexec_mask_interrupts();
/*
- * Call registered shutdown routines savely. Swap out
+ * Call registered shutdown routines safely. Swap out
* __debugger_fault_handler, and replace on exit.
*/
old_handler = __debugger_fault_handler;