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Commit 54c721b8 authored by Hidehiro Kawai's avatar Hidehiro Kawai Committed by Linus Torvalds
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mips/panic: replace smp_send_stop() with kdump friendly version in panic path 

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: f06e5153 (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: default avatarHidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Reported-by: default avatarDaniel 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0ee59413

arch/mips/cavium-octeon/setup.c

+14 −0
Original line number Original line Diff line number Diff line
@@ -267,6 +267,17 @@ static void octeon_crash_shutdown(struct pt_regs *regs) 
	default_machine_crash_shutdown(regs);

	default_machine_crash_shutdown(regs);

}

}





#ifdef CONFIG_SMP

void octeon_crash_smp_send_stop(void)

{

	int cpu;



	/* disable watchdogs */

	for_each_online_cpu(cpu)

		cvmx_write_csr(CVMX_CIU_WDOGX(cpu_logical_map(cpu)), 0);

}

#endif



#endif /* CONFIG_KEXEC */

#endif /* CONFIG_KEXEC */





#ifdef CONFIG_CAVIUM_RESERVE32

#ifdef CONFIG_CAVIUM_RESERVE32
@@ -911,6 +922,9 @@ void __init prom_init(void) 
	_machine_kexec_shutdown = octeon_shutdown;

	_machine_kexec_shutdown = octeon_shutdown;

	_machine_crash_shutdown = octeon_crash_shutdown;

	_machine_crash_shutdown = octeon_crash_shutdown;

	_machine_kexec_prepare = octeon_kexec_prepare;

	_machine_kexec_prepare = octeon_kexec_prepare;

#ifdef CONFIG_SMP

	_crash_smp_send_stop = octeon_crash_smp_send_stop;

#endif

#endif

#endif





	octeon_user_io_init();

	octeon_user_io_init();

arch/mips/include/asm/kexec.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -45,6 +45,7 @@ extern const unsigned char kexec_smp_wait[]; 
extern unsigned long secondary_kexec_args[4];

extern unsigned long secondary_kexec_args[4];

extern void (*relocated_kexec_smp_wait) (void *);

extern void (*relocated_kexec_smp_wait) (void *);

extern atomic_t kexec_ready_to_reboot;

extern atomic_t kexec_ready_to_reboot;

extern void (*_crash_smp_send_stop)(void);

#endif

#endif

#endif

#endif

arch/mips/kernel/crash.c

+17 −1
Original line number Original line Diff line number Diff line
@@ -47,9 +47,14 @@ static void crash_shutdown_secondary(void *passed_regs) 




static void crash_kexec_prepare_cpus(void)

static void crash_kexec_prepare_cpus(void)

{

{

	static int cpus_stopped;

	unsigned int msecs;

	unsigned int msecs;

	unsigned int ncpus;





	unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */

	if (cpus_stopped)

		return;



	ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */





	dump_send_ipi(crash_shutdown_secondary);

	dump_send_ipi(crash_shutdown_secondary);

	smp_wmb();

	smp_wmb();
@@ -64,6 +69,17 @@ static void crash_kexec_prepare_cpus(void) 
		cpu_relax();

		cpu_relax();

		mdelay(1);

		mdelay(1);

	}

	}



	cpus_stopped = 1;

}



/* Override the weak function in kernel/panic.c */

void crash_smp_send_stop(void)

{

	if (_crash_smp_send_stop)

		_crash_smp_send_stop();



	crash_kexec_prepare_cpus();

}

}





#else /* !defined(CONFIG_SMP)  */

#else /* !defined(CONFIG_SMP)  */

arch/mips/kernel/machine_kexec.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -25,6 +25,7 @@ void (*_machine_crash_shutdown)(struct pt_regs *regs) = NULL; 
#ifdef CONFIG_SMP

#ifdef CONFIG_SMP

void (*relocated_kexec_smp_wait) (void *);

void (*relocated_kexec_smp_wait) (void *);

atomic_t kexec_ready_to_reboot = ATOMIC_INIT(0);

atomic_t kexec_ready_to_reboot = ATOMIC_INIT(0);

void (*_crash_smp_send_stop)(void) = NULL;

#endif

#endif





int

int