mips/panic: replace smp_send_stop() with kdump friendly version in panic path (54c721b8) · Commits · 戴 / test

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: (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>

arch/mips/cavium-octeon/setup.c

+14 −0

Original line number	Diff line number	Diff line
		@@ -267,6 +267,17 @@ static void octeon_crash_shutdown(struct pt_regs *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 */

		#ifdef CONFIG_CAVIUM_RESERVE32
		@@ -911,6 +922,9 @@ void __init prom_init(void)
		_machine_kexec_shutdown = octeon_shutdown;
		_machine_crash_shutdown = octeon_crash_shutdown;
		_machine_kexec_prepare = octeon_kexec_prepare;
		#ifdef CONFIG_SMP
		_crash_smp_send_stop = octeon_crash_smp_send_stop;
		#endif
		#endif

		octeon_user_io_init();

arch/mips/include/asm/kexec.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -45,6 +45,7 @@ extern const unsigned char kexec_smp_wait[];
		extern unsigned long secondary_kexec_args[4];
		extern void (relocated_kexec_smp_wait) (void );
		extern atomic_t kexec_ready_to_reboot;
		extern void (*_crash_smp_send_stop)(void);
		#endif
		#endif

arch/mips/kernel/crash.c

+17 −1

Original line number	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 int cpus_stopped;
		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);
		smp_wmb();
		@@ -64,6 +69,17 @@ static void crash_kexec_prepare_cpus(void)
		cpu_relax();
		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) */

arch/mips/kernel/machine_kexec.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -25,6 +25,7 @@ void (_machine_crash_shutdown)(struct pt_regs regs) = NULL;
		#ifdef CONFIG_SMP
		void (relocated_kexec_smp_wait) (void );
		atomic_t kexec_ready_to_reboot = ATOMIC_INIT(0);
		void (*_crash_smp_send_stop)(void) = NULL;
		#endif

		int

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