[patch v3 26/36] riscv: Switch to hotplug core state synchronization

Thomas Gleixner
2023-05-08T19:47:10Z

From: Thomas Gleixner <tglx@linutronix.de>

Switch to the CPU hotplug core state tracking and synchronization
mechanim. No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>

---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/smp.h | 2 +-
arch/riscv/kernel/cpu-hotplug.c | 14 +++++++-------
3 files changed, 9 insertions(+), 8 deletions(-)
---

--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -122,6 +122,7 @@ config RISCV
select HAVE_RSEQ
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
+ select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
select IRQ_DOMAIN
select IRQ_FORCED_THREADING
select KASAN_VMALLOC if KASAN
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -70,7 +70,7 @@ asmlinkage void smp_callin(void);

#if defined CONFIG_HOTPLUG_CPU
int __cpu_disable(void);
-void __cpu_die(unsigned int cpu);
+static inline void __cpu_die(unsigned int cpu) { }
#endif /* CONFIG_HOTPLUG_CPU */

#else
--- a/arch/riscv/kernel/cpu-hotplug.c
+++ b/arch/riscv/kernel/cpu-hotplug.c
@@ -8,6 +8,7 @@
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/irq.h>
+#include <linux/cpuhotplug.h>
#include <linux/cpu.h>
#include <linux/sched/hotplug.h>
#include <asm/irq.h>
@@ -49,17 +50,15 @@ int __cpu_disable(void)
return ret;
}

+#ifdef CONFIG_HOTPLUG_CPU
/*
- * Called on the thread which is asking for a CPU to be shutdown.
+ * Called on the thread which is asking for a CPU to be shutdown, if the
+ * CPU reported dead to the hotplug core.
*/
-void __cpu_die(unsigned int cpu)
+void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu)
{
int ret = 0;

- if (!cpu_wait_death(cpu, 5)) {
- pr_err("CPU %u: didn't die\n", cpu);
- return;
- }
pr_notice("CPU%u: off\n", cpu);

/* Verify from the firmware if the cpu is really stopped*/
@@ -76,9 +75,10 @@ void __noreturn arch_cpu_idle_dead(void)
{
idle_task_exit();

- (void)cpu_report_death();
+ cpuhp_ap_report_dead();

cpu_ops[smp_processor_id()]->cpu_stop();
/* It should never reach here */
BUG();
}
+#endif