[PATCH v4 3/3] ARM: Check if a CPU has gone offline
From: Ashwin Chaugule <hidden>
Date: 2014-03-31 15:02:59
Subsystem:
arm port, power state coordination interface (psci), the rest · Maintainers:
Russell King, Mark Rutland, Lorenzo Pieralisi, Linus Torvalds
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 <redacted> Reviewed-by: Rob Herring <robh@kernel.org> --- 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 <linux/init.h> #include <linux/smp.h> #include <linux/of.h> +#include <uapi/linux/psci.h> #include <asm/psci.h> #include <asm/smp_plat.h>
@@ -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 0354bb1..65b4878 100644
--- a/include/uapi/linux/psci.h
+++ b/include/uapi/linux/psci.h@@ -58,4 +58,9 @@ ((ver & PSCI_VER_MAJOR_MASK) >> PSCI_VER_MAJOR_SHIFT) #define PSCI_VER_MINOR(ver) (ver & PSCI_VER_MINOR_MASK) +/* 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