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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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62cac480f3
The existing implementation lets machine_kexec() CPU jump to reboot code buffer, whereas other CPUs to relocated_kexec_smp_wait. The natural way to bring up an SMP new kernel would be to let CPU0 do it while others being halted. For those failing to do so, fall back to the jumping method. Signed-off-by: Dengcheng Zhu <dzhu@wavecomp.com> [paul.burton@mips.com: Guard kexec_nonboot_cpu_jump with CONFIG_SMP] Signed-off-by: Paul Burton <paul.burton@mips.com> Patchwork: https://patchwork.linux-mips.org/patch/20570/ Cc: pburton@wavecomp.com Cc: ralf@linux-mips.org Cc: linux-mips@linux-mips.org Cc: rachel.mozes@intel.com
104 lines
2.4 KiB
C
104 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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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/crash_dump.h>
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#include <linux/delay.h>
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#include <linux/irq.h>
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/sched/task_stack.h>
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/* This keeps a track of which one is crashing cpu. */
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static int crashing_cpu = -1;
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static cpumask_t cpus_in_crash = CPU_MASK_NONE;
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#ifdef CONFIG_SMP
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static void crash_shutdown_secondary(void *passed_regs)
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{
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struct pt_regs *regs = passed_regs;
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int cpu = smp_processor_id();
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/*
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* If we are passed registers, use those. Otherwise get the
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* regs from the last interrupt, which should be correct, as
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* we are in an interrupt. But if the regs are not there,
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* pull them from the top of the stack. They are probably
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* wrong, but we need something to keep from crashing again.
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*/
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if (!regs)
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regs = get_irq_regs();
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if (!regs)
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regs = task_pt_regs(current);
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if (!cpu_online(cpu))
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return;
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/* We won't be sent IPIs any more. */
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set_cpu_online(cpu, false);
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local_irq_disable();
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if (!cpumask_test_cpu(cpu, &cpus_in_crash))
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crash_save_cpu(regs, cpu);
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cpumask_set_cpu(cpu, &cpus_in_crash);
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while (!atomic_read(&kexec_ready_to_reboot))
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cpu_relax();
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kexec_reboot();
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/* NOTREACHED */
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}
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static void crash_kexec_prepare_cpus(void)
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{
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static int cpus_stopped;
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unsigned int msecs;
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unsigned int ncpus;
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if (cpus_stopped)
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return;
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ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
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smp_call_function(crash_shutdown_secondary, NULL, 0);
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smp_wmb();
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/*
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* The crash CPU sends an IPI and wait for other CPUs to
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* respond. Delay of at least 10 seconds.
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*/
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pr_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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mdelay(1);
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}
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cpus_stopped = 1;
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}
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/* Override the weak function in kernel/panic.c */
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void crash_smp_send_stop(void)
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{
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if (_crash_smp_send_stop)
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_crash_smp_send_stop();
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crash_kexec_prepare_cpus();
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}
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#else /* !defined(CONFIG_SMP) */
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static void crash_kexec_prepare_cpus(void) {}
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#endif /* !defined(CONFIG_SMP) */
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void default_machine_crash_shutdown(struct pt_regs *regs)
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{
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local_irq_disable();
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crashing_cpu = smp_processor_id();
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crash_save_cpu(regs, crashing_cpu);
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crash_kexec_prepare_cpus();
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cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
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}
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