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@@ -10,85 +10,85 @@
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*
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*/
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-#undef DEBUG
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-
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#include <linux/kernel.h>
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#include <linux/smp.h>
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#include <linux/reboot.h>
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#include <linux/kexec.h>
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-#include <linux/bootmem.h>
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#include <linux/export.h>
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#include <linux/crash_dump.h>
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#include <linux/delay.h>
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-#include <linux/elf.h>
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-#include <linux/elfcore.h>
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#include <linux/init.h>
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#include <linux/irq.h>
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#include <linux/types.h>
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-#include <linux/memblock.h>
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#include <asm/processor.h>
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#include <asm/machdep.h>
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#include <asm/kexec.h>
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#include <asm/kdump.h>
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#include <asm/prom.h>
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-#include <asm/firmware.h>
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#include <asm/smp.h>
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#include <asm/system.h>
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#include <asm/setjmp.h>
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-#ifdef DEBUG
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-#include <asm/udbg.h>
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-#define DBG(fmt...) udbg_printf(fmt)
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-#else
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-#define DBG(fmt...)
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-#endif
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+/*
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+ * The primary CPU waits a while for all secondary CPUs to enter. This is to
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+ * avoid sending an IPI if the secondary CPUs are entering
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+ * crash_kexec_secondary on their own (eg via a system reset).
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+ *
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+ * The secondary timeout has to be longer than the primary. Both timeouts are
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+ * in milliseconds.
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+ */
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+#define PRIMARY_TIMEOUT 500
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+#define SECONDARY_TIMEOUT 1000
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-/* This keeps a track of which one is crashing cpu. */
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+#define IPI_TIMEOUT 10000
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+#define REAL_MODE_TIMEOUT 10000
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+
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+/* This keeps a track of which one is the crashing cpu. */
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int crashing_cpu = -1;
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-static cpumask_t cpus_in_crash = CPU_MASK_NONE;
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-cpumask_t cpus_in_sr = CPU_MASK_NONE;
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+static atomic_t cpus_in_crash;
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+static int time_to_dump;
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#define CRASH_HANDLER_MAX 3
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/* NULL terminated list of shutdown handles */
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static crash_shutdown_t crash_shutdown_handles[CRASH_HANDLER_MAX+1];
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static DEFINE_SPINLOCK(crash_handlers_lock);
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+static unsigned long crash_shutdown_buf[JMP_BUF_LEN];
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+static int crash_shutdown_cpu = -1;
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+
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+static int handle_fault(struct pt_regs *regs)
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+{
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+ if (crash_shutdown_cpu == smp_processor_id())
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+ longjmp(crash_shutdown_buf, 1);
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+ return 0;
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+}
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+
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#ifdef CONFIG_SMP
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-static atomic_t enter_on_soft_reset = ATOMIC_INIT(0);
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void crash_ipi_callback(struct pt_regs *regs)
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{
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+ static cpumask_t cpus_state_saved = CPU_MASK_NONE;
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+
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int cpu = smp_processor_id();
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if (!cpu_online(cpu))
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return;
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hard_irq_disable();
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- if (!cpumask_test_cpu(cpu, &cpus_in_crash))
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+ if (!cpumask_test_cpu(cpu, &cpus_state_saved)) {
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crash_save_cpu(regs, cpu);
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- cpumask_set_cpu(cpu, &cpus_in_crash);
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-
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- /*
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- * Entered via soft-reset - could be the kdump
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- * process is invoked using soft-reset or user activated
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- * it if some CPU did not respond to an IPI.
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- * For soft-reset, the secondary CPU can enter this func
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- * twice. 1 - using IPI, and 2. soft-reset.
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- * Tell the kexec CPU that entered via soft-reset and ready
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- * to go down.
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- */
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- if (cpumask_test_cpu(cpu, &cpus_in_sr)) {
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- cpumask_clear_cpu(cpu, &cpus_in_sr);
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- atomic_inc(&enter_on_soft_reset);
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+ cpumask_set_cpu(cpu, &cpus_state_saved);
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}
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+ atomic_inc(&cpus_in_crash);
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+ smp_mb__after_atomic_inc();
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+
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/*
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* Starting the kdump boot.
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* This barrier is needed to make sure that all CPUs are stopped.
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- * If not, soft-reset will be invoked to bring other CPUs.
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*/
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- while (!cpumask_test_cpu(crashing_cpu, &cpus_in_crash))
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+ while (!time_to_dump)
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cpu_relax();
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if (ppc_md.kexec_cpu_down)
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@@ -103,106 +103,99 @@ void crash_ipi_callback(struct pt_regs *regs)
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/* NOTREACHED */
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}
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-/*
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- * Wait until all CPUs are entered via soft-reset.
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- */
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-static void crash_soft_reset_check(int cpu)
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-{
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- unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
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-
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- cpumask_clear_cpu(cpu, &cpus_in_sr);
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- while (atomic_read(&enter_on_soft_reset) != ncpus)
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- cpu_relax();
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-}
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-
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-
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static void crash_kexec_prepare_cpus(int cpu)
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{
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unsigned int msecs;
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-
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unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
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+ int tries = 0;
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+ int (*old_handler)(struct pt_regs *regs);
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+
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+ printk(KERN_EMERG "Sending IPI to other CPUs\n");
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crash_send_ipi(crash_ipi_callback);
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smp_wmb();
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+again:
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/*
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* FIXME: Until we will have the way to stop other CPUs reliably,
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* the crash CPU will send an IPI and wait for other CPUs to
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* respond.
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- * Delay of at least 10 seconds.
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*/
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- printk(KERN_EMERG "Sending IPI to other cpus...\n");
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- msecs = 10000;
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- while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) {
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- cpu_relax();
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+ msecs = IPI_TIMEOUT;
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+ while ((atomic_read(&cpus_in_crash) < ncpus) && (--msecs > 0))
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mdelay(1);
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- }
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/* Would it be better to replace the trap vector here? */
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+ if (atomic_read(&cpus_in_crash) >= ncpus) {
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+ printk(KERN_EMERG "IPI complete\n");
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+ return;
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+ }
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+
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+ printk(KERN_EMERG "ERROR: %d cpu(s) not responding\n",
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+ ncpus - atomic_read(&cpus_in_crash));
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+
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/*
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- * FIXME: In case if we do not get all CPUs, one possibility: ask the
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- * user to do soft reset such that we get all.
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- * Soft-reset will be used until better mechanism is implemented.
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+ * If we have a panic timeout set then we can't wait indefinitely
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+ * for someone to activate system reset. We also give up on the
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+ * second time through if system reset fail to work.
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*/
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- if (cpumask_weight(&cpus_in_crash) < ncpus) {
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- printk(KERN_EMERG "done waiting: %d cpu(s) not responding\n",
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- ncpus - cpumask_weight(&cpus_in_crash));
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- printk(KERN_EMERG "Activate soft-reset to stop other cpu(s)\n");
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- cpumask_clear(&cpus_in_sr);
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- atomic_set(&enter_on_soft_reset, 0);
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- while (cpumask_weight(&cpus_in_crash) < ncpus)
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- cpu_relax();
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- }
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+ if ((panic_timeout > 0) || (tries > 0))
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+ return;
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+
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/*
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- * Make sure all CPUs are entered via soft-reset if the kdump is
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- * invoked using soft-reset.
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+ * A system reset will cause all CPUs to take an 0x100 exception.
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+ * The primary CPU returns here via setjmp, and the secondary
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+ * CPUs reexecute the crash_kexec_secondary path.
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*/
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- if (cpumask_test_cpu(cpu, &cpus_in_sr))
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- crash_soft_reset_check(cpu);
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- /* Leave the IPI callback set */
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+ old_handler = __debugger;
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+ __debugger = handle_fault;
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+ crash_shutdown_cpu = smp_processor_id();
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+
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+ if (setjmp(crash_shutdown_buf) == 0) {
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+ printk(KERN_EMERG "Activate system reset (dumprestart) "
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+ "to stop other cpu(s)\n");
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+
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+ /*
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+ * A system reset will force all CPUs to execute the
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+ * crash code again. We need to reset cpus_in_crash so we
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+ * wait for everyone to do this.
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+ */
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+ atomic_set(&cpus_in_crash, 0);
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+ smp_mb();
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+
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+ while (atomic_read(&cpus_in_crash) < ncpus)
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+ cpu_relax();
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+ }
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+
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+ crash_shutdown_cpu = -1;
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+ __debugger = old_handler;
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+
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+ tries++;
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+ goto again;
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}
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/*
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- * This function will be called by secondary cpus or by kexec cpu
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- * if soft-reset is activated to stop some CPUs.
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+ * This function will be called by secondary cpus.
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*/
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void crash_kexec_secondary(struct pt_regs *regs)
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{
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- int cpu = smp_processor_id();
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unsigned long flags;
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- int msecs = 5;
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+ int msecs = SECONDARY_TIMEOUT;
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local_irq_save(flags);
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- /* Wait 5ms if the kexec CPU is not entered yet. */
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+
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+ /* Wait for the primary crash CPU to signal its progress */
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while (crashing_cpu < 0) {
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if (--msecs < 0) {
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- /*
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- * Either kdump image is not loaded or
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- * kdump process is not started - Probably xmon
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- * exited using 'x'(exit and recover) or
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- * kexec_should_crash() failed for all running tasks.
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- */
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- cpumask_clear_cpu(cpu, &cpus_in_sr);
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+ /* No response, kdump image may not have been loaded */
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local_irq_restore(flags);
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return;
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}
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+
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mdelay(1);
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- cpu_relax();
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- }
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- if (cpu == crashing_cpu) {
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- /*
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- * Panic CPU will enter this func only via soft-reset.
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- * Wait until all secondary CPUs entered and
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- * then start kexec boot.
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- */
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- crash_soft_reset_check(cpu);
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- cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
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- if (ppc_md.kexec_cpu_down)
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- ppc_md.kexec_cpu_down(1, 0);
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- machine_kexec(kexec_crash_image);
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- /* NOTREACHED */
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}
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+
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crash_ipi_callback(regs);
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}
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@@ -211,7 +204,7 @@ void crash_kexec_secondary(struct pt_regs *regs)
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static void crash_kexec_prepare_cpus(int cpu)
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{
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/*
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- * move the secondarys to us so that we can copy
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+ * move the secondaries to us so that we can copy
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* the new kernel 0-0x100 safely
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*
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* do this if kexec in setup.c ?
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@@ -225,7 +218,6 @@ static void crash_kexec_prepare_cpus(int cpu)
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void crash_kexec_secondary(struct pt_regs *regs)
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{
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- cpumask_clear(&cpus_in_sr);
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}
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#endif /* CONFIG_SMP */
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@@ -236,7 +228,7 @@ static void crash_kexec_wait_realmode(int cpu)
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unsigned int msecs;
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int i;
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- msecs = 10000;
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+ msecs = REAL_MODE_TIMEOUT;
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for (i=0; i < nr_cpu_ids && msecs > 0; i++) {
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if (i == cpu)
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continue;
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@@ -308,22 +300,11 @@ int crash_shutdown_unregister(crash_shutdown_t handler)
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}
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EXPORT_SYMBOL(crash_shutdown_unregister);
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-static unsigned long crash_shutdown_buf[JMP_BUF_LEN];
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-static int crash_shutdown_cpu = -1;
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-
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-static int handle_fault(struct pt_regs *regs)
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-{
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- if (crash_shutdown_cpu == smp_processor_id())
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- longjmp(crash_shutdown_buf, 1);
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- return 0;
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-}
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-
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void default_machine_crash_shutdown(struct pt_regs *regs)
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{
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unsigned int i;
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int (*old_handler)(struct pt_regs *regs);
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-
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/*
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* This function is only called after the system
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* has panicked or is otherwise in a critical state.
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@@ -341,15 +322,26 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
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* such that another IPI will not be sent.
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*/
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crashing_cpu = smp_processor_id();
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- crash_save_cpu(regs, crashing_cpu);
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+
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+ /*
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+ * If we came in via system reset, wait a while for the secondary
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+ * CPUs to enter.
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+ */
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+ if (TRAP(regs) == 0x100)
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+ mdelay(PRIMARY_TIMEOUT);
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+
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crash_kexec_prepare_cpus(crashing_cpu);
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- cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
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+
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+ crash_save_cpu(regs, crashing_cpu);
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+
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+ time_to_dump = 1;
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+
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crash_kexec_wait_realmode(crashing_cpu);
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machine_kexec_mask_interrupts();
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/*
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- * Call registered shutdown routines savely. Swap out
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+ * Call registered shutdown routines safely. Swap out
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* __debugger_fault_handler, and replace on exit.
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*/
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old_handler = __debugger_fault_handler;
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Benjamin Herrenschmidt