| Message ID | de2fda64cc5eebcf96d9d845b185c6382c900ac3.1410302383.git.geoff@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Geoff, On Tue, Sep 09, 2014 at 11:49:05PM +0100, Geoff Levand wrote: > Commit 90f51a09ef83 ("arm64: Fix machine_shutdown() definition") changed the > implementation of machine_shutdown() from calling smp_send_stop() to > calling disable_nonboot_cpus(). Revert that part of the commit so that > machine_shutdown() once again calls smp_send_stop(). I don't think this is the right way to go. I think we should be using the hotplug infrastructure (i.e. disable_nonboot_cpus()) rather than rolling our own, and we should be paying attention to the return value. So as far as I can tell, disable_nonboot_cpus is the right thing to call, but machine_shutdown is the wrong place to call it (due to not returning an error code). We need to call it when we can still abort the kexec. Mark. > With the application of another patch in this series, (arm64: Use cpu_ops for > smp_stop), smp_send_stop() will do the correct thing for a kexec reboot. This > change also corrects the source code comment for the machine_shutdown() routine. > > Signed-off-by: Geoff Levand <geoff@infradead.org> > --- > arch/arm64/kernel/process.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 0a3414b..cd0ae9d 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -101,15 +101,12 @@ void arch_cpu_idle_dead(void) > /* > * Called by kexec, immediately prior to machine_kexec(). > * > - * This must completely disable all secondary CPUs; simply causing those CPUs > - * to execute e.g. a RAM-based pin loop is not sufficient. This allows the > - * kexec'd kernel to use any and all RAM as it sees fit, without having to > - * avoid any code or data used by any SW CPU pin loop. The CPU hotplug > - * functionality embodied in disable_nonboot_cpus() to achieve this. > + * This must shutdown all secondary CPUs. The functionality > + * embodied in smp_send_stop() will achieve this. > */ > void machine_shutdown(void) > { > - disable_nonboot_cpus(); > + smp_send_stop(); > } > > /* > -- > 1.9.1 > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 0a3414b..cd0ae9d 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -101,15 +101,12 @@ void arch_cpu_idle_dead(void) /* * Called by kexec, immediately prior to machine_kexec(). * - * This must completely disable all secondary CPUs; simply causing those CPUs - * to execute e.g. a RAM-based pin loop is not sufficient. This allows the - * kexec'd kernel to use any and all RAM as it sees fit, without having to - * avoid any code or data used by any SW CPU pin loop. The CPU hotplug - * functionality embodied in disable_nonboot_cpus() to achieve this. + * This must shutdown all secondary CPUs. The functionality + * embodied in smp_send_stop() will achieve this. */ void machine_shutdown(void) { - disable_nonboot_cpus(); + smp_send_stop(); } /*
Commit 90f51a09ef83 ("arm64: Fix machine_shutdown() definition") changed the implementation of machine_shutdown() from calling smp_send_stop() to calling disable_nonboot_cpus(). Revert that part of the commit so that machine_shutdown() once again calls smp_send_stop(). With the application of another patch in this series, (arm64: Use cpu_ops for smp_stop), smp_send_stop() will do the correct thing for a kexec reboot. This change also corrects the source code comment for the machine_shutdown() routine. Signed-off-by: Geoff Levand <geoff@infradead.org> --- arch/arm64/kernel/process.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)