Sorry this took so long, but I have finally tested this, it seems to work fine: Tested-by: Corey Minyard <cminyard at mvista.com> Reviewed-by: Corey Minyard <cminyard at mvista.com> On 08/10/2016 03:09 AM, Hidehiro Kawai wrote: > 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. > > Reported-by: Daniel Walker <dwalker at fifo99.com> > Fixes: f06e5153f4ae (kernel/panic.c: add "crash_kexec_post_notifiers" option) > Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez at hitachi.com> > Cc: Ralf Baechle <ralf at linux-mips.org> > Cc: David Daney <david.daney at cavium.com> > Cc: Aaro Koskinen <aaro.koskinen at iki.fi> > Cc: "Steven J. Hill" <steven.hill at cavium.com> > Cc: Corey Minyard <cminyard at mvista.com> > > --- > I'm not familiar with MIPS, and I don't have a test environment and > just did build tests only. Please don't apply this patch until > someone does enough tests, otherwise simply drop this patch. > --- > arch/mips/cavium-octeon/setup.c | 14 ++++++++++++++ > arch/mips/include/asm/kexec.h | 1 + > arch/mips/kernel/crash.c | 18 +++++++++++++++++- > arch/mips/kernel/machine_kexec.c | 1 + > 4 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/arch/mips/cavium-octeon/setup.c b/arch/mips/cavium-octeon/setup.c > index cb16fcc..5537f95 100644 > --- a/arch/mips/cavium-octeon/setup.c > +++ b/arch/mips/cavium-octeon/setup.c > @@ -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(); > diff --git a/arch/mips/include/asm/kexec.h b/arch/mips/include/asm/kexec.h > index ee25ebb..493a3cc 100644 > --- a/arch/mips/include/asm/kexec.h > +++ b/arch/mips/include/asm/kexec.h > @@ -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 > > diff --git a/arch/mips/kernel/crash.c b/arch/mips/kernel/crash.c > index 610f0f3..1723b17 100644 > --- a/arch/mips/kernel/crash.c > +++ b/arch/mips/kernel/crash.c > @@ -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) */ > diff --git a/arch/mips/kernel/machine_kexec.c b/arch/mips/kernel/machine_kexec.c > index 50980bf3..5972520 100644 > --- a/arch/mips/kernel/machine_kexec.c > +++ b/arch/mips/kernel/machine_kexec.c > @@ -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 > >
