[PATCH v2 01/14] smp: Create a new function to shutdown nonboot cpus

Qais Yousef
2019-11-25T11:28:09Z

This function will be used later in machine_shutdown() for some archs.

Signed-off-by: Qais Yousef <qais.yousef@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Josh Poimboeuf <jpoimboe@redhat.com>
CC: "Peter Zijlstra (Intel)" <peterz@infradead.org>
CC: Jiri Kosina <jkosina@suse.cz>
CC: Nicholas Piggin <npiggin@gmail.com>
CC: Daniel Lezcano <daniel.lezcano@linaro.org>
CC: Ingo Molnar <mingo@kernel.org>
CC: Eiichi Tsukata <devel@etsukata.com>
CC: Zhenzhong Duan <zhenzhong.duan@oracle.com>
CC: Nadav Amit <namit@vmware.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
CC: Tony Luck <tony.luck@intel.com>
CC: Fenghua Yu <fenghua.yu@intel.com>
CC: Russell King <linux@armlinux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will@kernel.org>
CC: linux-arm-kernel@lists.infradead.org
CC: linux-ia64@vger.kernel.org
CC: linux-kernel@vger.kernel.org
---
include/linux/cpu.h | 2 ++
kernel/cpu.c | 17 +++++++++++++++++
2 files changed, 19 insertions(+)

diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index bc6c879bd110..8229932fb053 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -118,6 +118,7 @@ extern void cpu_hotplug_disable(void);
extern void cpu_hotplug_enable(void);
void clear_tasks_mm_cpumask(int cpu);
int cpu_down(unsigned int cpu);
+extern void smp_shutdown_nonboot_cpus(unsigned int primary_cpu);

#else /* CONFIG_HOTPLUG_CPU */

@@ -129,6 +130,7 @@ static inline int cpus_read_trylock(void) { return true; }
static inline void lockdep_assert_cpus_held(void) { }
static inline void cpu_hotplug_disable(void) { }
static inline void cpu_hotplug_enable(void) { }
+static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }
#endif /* !CONFIG_HOTPLUG_CPU */

/* Wrappers which go away once all code is converted */
diff --git a/kernel/cpu.c b/kernel/cpu.c
index e2cad3ee2ead..94055a0d989e 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1058,6 +1058,23 @@ int cpu_down(unsigned int cpu)
}
EXPORT_SYMBOL(cpu_down);

+void smp_shutdown_nonboot_cpus(unsigned int primary_cpu)
+{
+ unsigned int cpu;
+
+ if (!cpu_online(primary_cpu)) {
+ pr_info("Attempting to shutdodwn nonboot cpus while boot cpu is offline!\n");
+ cpu_online(primary_cpu);
+ }
+
+ for_each_present_cpu(cpu) {
+ if (cpu == primary_cpu)
+ continue;
+ if (cpu_online(cpu))
+ cpu_down(cpu);
+ }
+}
+
#else
#define takedown_cpu NULL
#endif /*CONFIG_HOTPLUG_CPU*/
--
2.17.1