ARM: stop: execute platform callback from cpu_stop code (02b73e2e) · Commits · 戴 / test

Sending IPI_CPU_STOP to a CPU causes it to execute a busy cpu_relax loop forever. This makes it impossible to kexec successfully on an SMP system since the secondary CPUs do not reset. This patch adds a callback to platform_cpu_kill, defined when CONFIG_HOTPLUG_CPU=y, from the ipi_cpu_stop handling code. This function currently just returns 1 on all platforms that define it but allows them to do something more sophisticated in the future. Signed-off-by:

Will Deacon <will.deacon@arm.com>

arch/arm/Kconfig

+1 −1

Original line number	Diff line number	Diff line
		@@ -2001,7 +2001,7 @@ config XIP_PHYS_ADDR

		config KEXEC
		bool "Kexec system call (EXPERIMENTAL)"
		depends on EXPERIMENTAL
		depends on EXPERIMENTAL && (!SMP \|\| HOTPLUG_CPU)
		help
		kexec is a system call that implements the ability to shutdown your
		current kernel, and to start another kernel. It is like a reboot

arch/arm/kernel/smp.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -522,6 +522,10 @@ static void ipi_cpu_stop(unsigned int cpu)
		local_fiq_disable();
		local_irq_disable();

		#ifdef CONFIG_HOTPLUG_CPU
		platform_cpu_kill(cpu);
		#endif

		while (1)
		cpu_relax();
		}

Admin message