[patch 26/37] riscv: Switch to hotplug core state synchronization

[Thomas Gleixner <tglx@xxxxxxxxxxxxx>]

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

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
---
 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
@@ -116,6 +116,7 @@ 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 MODULES_USE_ELF_RELA if MODULES
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -64,7 +64,7 @@ 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>
@@ -48,17 +49,15 @@ 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*/
@@ -75,9 +74,10 @@ void 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