| Message ID | 1398446835-5532-4-git-send-email-ashwin.chaugule@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Fri, Apr 25, 2014 at 12:27 PM, Ashwin Chaugule <ashwin.chaugule@linaro.org> wrote: > PSCIv0.2 adds a new function called AFFINITY_INFO, which > can be used to query if a specified CPU has actually gone > offline. Calling this function via cpu_kill ensures that > a CPU has quiesced after a call to cpu_die. > > Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> > Reviewed-by: Rob Herring <robh@kernel.org> > --- > arch/arm/kernel/psci_smp.c | 32 ++++++++++++++++++++++++++++++++ > include/uapi/linux/psci.h | 5 +++++ > 2 files changed, 37 insertions(+) [...] > +retry_once: > + err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); > + > + if (err != PSCI_AFFINITY_INFO_RET_OFF) { > + if (!retry++) { > + msleep(100); It would be better to sleep 10ms 10 times rather than a single 100ms sleep. And please do this with a loop rather than a goto. Rob
On 25 April 2014 14:01, Rob Herring <robherring2@gmail.com> wrote: > On Fri, Apr 25, 2014 at 12:27 PM, Ashwin Chaugule > <ashwin.chaugule@linaro.org> wrote: >> PSCIv0.2 adds a new function called AFFINITY_INFO, which >> can be used to query if a specified CPU has actually gone >> offline. Calling this function via cpu_kill ensures that >> a CPU has quiesced after a call to cpu_die. >> >> Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> >> Reviewed-by: Rob Herring <robh@kernel.org> >> --- >> arch/arm/kernel/psci_smp.c | 32 ++++++++++++++++++++++++++++++++ >> include/uapi/linux/psci.h | 5 +++++ >> 2 files changed, 37 insertions(+) > > [...] > >> +retry_once: >> + err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); >> + >> + if (err != PSCI_AFFINITY_INFO_RET_OFF) { >> + if (!retry++) { >> + msleep(100); > > It would be better to sleep 10ms 10 times rather than a single 100ms > sleep. And please do this with a loop rather than a goto. > Fixed in v8. Cheers, Ashwin
diff --git a/arch/arm/kernel/psci_smp.c b/arch/arm/kernel/psci_smp.c index 570a48c..0b1882b 100644 --- a/arch/arm/kernel/psci_smp.c +++ b/arch/arm/kernel/psci_smp.c @@ -16,6 +16,8 @@ #include <linux/init.h> #include <linux/smp.h> #include <linux/of.h> +#include <linux/delay.h> +#include <uapi/linux/psci.h> #include <asm/psci.h> #include <asm/smp_plat.h> @@ -66,6 +68,35 @@ void __ref psci_cpu_die(unsigned int cpu) /* We should never return */ panic("psci: cpu %d failed to shutdown\n", cpu); } + +int __ref psci_cpu_kill(unsigned int cpu) +{ + int err, retry = 0; + + if (!psci_ops.affinity_info) + return 1; + /* + * cpu_kill could race with cpu_die and we can + * potentially end up declaring this cpu undead + * while it is dying. So, try once more if it fails. + */ +retry_once: + err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); + + if (err != PSCI_AFFINITY_INFO_RET_OFF) { + if (!retry++) { + msleep(100); + pr_info("Retrying once more to check for CPU kill\n"); + goto retry_once; + } + pr_err("psci: Cannot kill CPU:%d, psci ret val: %d\n", + cpu, err); + /* Make platform_cpu_kill() fail. */ + return 0; + } + return 1; +} + #endif bool __init psci_smp_available(void) @@ -78,5 +109,6 @@ struct smp_operations __initdata psci_smp_ops = { .smp_boot_secondary = psci_boot_secondary, #ifdef CONFIG_HOTPLUG_CPU .cpu_die = psci_cpu_die, + .cpu_kill = psci_cpu_kill, #endif }; diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h index a4136c3..857209b 100644 --- a/include/uapi/linux/psci.h +++ b/include/uapi/linux/psci.h @@ -74,4 +74,9 @@ #define PSCI_RET_NOT_PRESENT -7 #define PSCI_RET_DISABLED -8 +/* Return values from the PSCI_ID_AFFINITY_INFO Function. */ +#define PSCI_AFFINITY_INFO_RET_ON 0 +#define PSCI_AFFINITY_INFO_RET_OFF 1 +#define PSCI_AFFINITY_INFO_RET_ON_PENDING 2 + #endif /* _UAPI_LINUX_PSCI_H */