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54c721b857
Daniel Walker reported problems which happens when
crash_kexec_post_notifiers kernel option is enabled
(https://lkml.org/lkml/2015/6/24/44).
In that case, smp_send_stop() is called before entering kdump routines
which assume other CPUs are still online. As the result, kdump
routines fail to save other CPUs' registers. Additionally for MIPS
OCTEON, it misses to stop the watchdog timer.
To fix this problem, call a new kdump friendly function,
crash_smp_send_stop(), instead of the smp_send_stop() when
crash_kexec_post_notifiers is enabled. crash_smp_send_stop() is a
weak function, and it just call smp_send_stop(). Architecture
codes should override it so that kdump can work appropriately.
This patch provides MIPS version.
Fixes: f06e5153f4 (kernel/panic.c: add "crash_kexec_post_notifiers" option)
Link: http://lkml.kernel.org/r/20160810080950.11028.28000.stgit@sysi4-13.yrl.intra.hitachi.co.jp
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Reported-by: Daniel Walker <dwalker@fifo99.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Daniel Walker <dwalker@fifo99.com>
Cc: Xunlei Pang <xpang@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: "Steven J. Hill" <steven.hill@cavium.com>
Cc: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
97 lines
2.2 KiB
C
97 lines
2.2 KiB
C
#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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/* 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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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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relocated_kexec_smp_wait(NULL);
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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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dump_send_ipi(crash_shutdown_secondary);
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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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