From mboxrd@z Thu Jan 1 00:00:00 1970 From: ashwin.chaugule@linaro.org (Ashwin Chaugule) Date: Thu, 17 Apr 2014 15:15:46 -0400 Subject: [PATCH v6 3/3] ARM: Check if a CPU has gone offline In-Reply-To: <1397762146-8337-1-git-send-email-ashwin.chaugule@linaro.org> References: <1397762146-8337-1-git-send-email-ashwin.chaugule@linaro.org> Message-ID: <1397762146-8337-4-git-send-email-ashwin.chaugule@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 Reviewed-by: Rob Herring --- arch/arm/kernel/psci_smp.c | 21 +++++++++++++++++++++ include/uapi/linux/psci.h | 5 +++++ 2 files changed, 26 insertions(+) diff --git a/arch/arm/kernel/psci_smp.c b/arch/arm/kernel/psci_smp.c index 570a48c..c6f1420 100644 --- a/arch/arm/kernel/psci_smp.c +++ b/arch/arm/kernel/psci_smp.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include @@ -66,6 +67,25 @@ 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; + + if (!psci_ops.affinity_info) + return 1; + + err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); + + if (err != PSCI_AFFINITY_INFO_RET_OFF) { + 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 +98,6 @@ 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 */ -- 1.8.3.2