From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Commit c4bc34d20273db698c51951a1951dba0a722e162 upstream.
Adds a routine which can be used to park CPUs (spinning in kernel)
when they can't be killed.
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
arch/arm64/include/asm/smp.h | 8 ++++++++
arch/arm64/kernel/cpufeature.c | 5 +----
2 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h
index d9c3d6a6100a..53b53a9b3e5a 100644
--- a/arch/arm64/include/asm/smp.h
+++ b/arch/arm64/include/asm/smp.h
@@ -69,4 +69,12 @@ extern int __cpu_disable(void);
extern void __cpu_die(unsigned int cpu);
extern void cpu_die(void);
+static inline void cpu_park_loop(void)
+{
+ for (;;) {
+ wfe();
+ wfi();
+ }
+}
+
#endif /* ifndef __ASM_SMP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index b7f01bf47988..4adf18307568 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -868,10 +868,7 @@ void cpu_die_early(void)
/* Check if we can park ourselves */
if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_die)
cpu_ops[cpu]->cpu_die(cpu);
- asm(
- "1: wfe\n"
- " wfi\n"
- " b 1b");
+ cpu_park_loop();
}
/*
--
2.21.0.rc0.269.g1a574e7a288b
