The current implementation of ipi_cpu_stop() is just a tight infinite loop around cpu_relax(). This infinite loop implementation is OK if the machine will soon do a poweroff, but it doesn't have any mechanism to allow a CPU to be brought back on-line, nor is it compatible with kexec re-boot. Add a check for a valid cpu_die method of the appropriate cpu_ops structure, and if a valid method is found, transfer control to that method. It is expected that the cpu_die method puts the CPU into a state such that they can be brought back on-line or progress through a kexec re-boot. Signed-off-by: Geoff Levand <geoff at infradead.org> --- arch/arm64/kernel/smp.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 4743397..002aa8a 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -555,6 +555,15 @@ static void ipi_cpu_stop(unsigned int cpu) local_irq_disable(); + /* If we have the cpu ops use them. */ + + if (cpu_ops[cpu]->cpu_disable && + cpu_ops[cpu]->cpu_die && + !cpu_ops[cpu]->cpu_disable(cpu)) + cpu_ops[cpu]->cpu_die(cpu); + + /* Otherwise spin here. */ + while (1) cpu_relax(); } -- 1.9.1
