powerpc/kdump: Only save CPU state first time through the secondary CPU capture code
We might enter the secondary CPU capture code twice, eg if we have to unstick some CPUs with a system reset. In this case we don't want to overwrite the state on CPUs that had made it into the capture code OK, so use the cpus_state_saved cpumask for that and make it local to crash_ipi_callback. For controlling progress now use atomic_t cpus_in_crash to count how many CPUs have made it into the kdump code, and time_to_dump to tell everyone it's time to dump. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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@ -46,7 +46,8 @@
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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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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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@ -67,21 +68,27 @@ static int handle_fault(struct pt_regs *regs)
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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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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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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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* Starting the kdump boot.
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* This barrier is needed to make sure that all CPUs are stopped.
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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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@ -115,19 +122,18 @@ again:
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* respond.
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*/
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msecs = IPI_TIMEOUT;
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while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) {
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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 (cpumask_weight(&cpus_in_crash) >= ncpus) {
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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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printk(KERN_EMERG "ERROR: %d cpu(s) not responding\n",
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ncpus - cpumask_weight(&cpus_in_crash));
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ncpus - atomic_read(&cpus_in_crash));
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/*
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* If we have a panic timeout set then we can't wait indefinitely
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@ -155,10 +161,10 @@ again:
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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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cpus_in_crash = CPU_MASK_NONE;
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atomic_set(&cpus_in_crash, 0);
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smp_mb();
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while (cpumask_weight(&cpus_in_crash) < ncpus)
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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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@ -316,7 +322,6 @@ 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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* If we came in via system reset, wait a while for the secondary
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@ -326,7 +331,11 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
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mdelay(PRIMARY_TIMEOUT);
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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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crash_save_cpu(regs, crashing_cpu);
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time_to_dump = 1;
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crash_kexec_wait_realmode(crashing_cpu);
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machine_kexec_mask_interrupts();
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