From 2f3edfd7e27ad4206acbc2ae99c9df5f46353024 Mon Sep 17 00:00:00 2001 From: Shawn Guo Date: Tue, 26 Mar 2013 16:46:07 +0800 Subject: ARM: imx: fix sync issue between imx_cpu_die and imx_cpu_kill There is a sync issue with hotplug operation. It's possible that when imx_cpu_kill gets running on primary core, the imx_cpu_die execution on the core which is to be killed hasn't been finished yet. The problem will very likely be hit when running suspend without no_console_suspend setting on kernel cmdline. It uses cpu jumping argument register to sync imx_cpu_die and imx_cpu_kill. The register will be set in imx_cpu_die and imx_cpu_kill will wait for the register being cleared to actually kill the cpu. Signed-off-by: Shawn Guo Cc: --- arch/arm/mach-imx/hotplug.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'arch/arm/mach-imx/hotplug.c') diff --git a/arch/arm/mach-imx/hotplug.c b/arch/arm/mach-imx/hotplug.c index 7bc5fe15dda2..361a253e2b63 100644 --- a/arch/arm/mach-imx/hotplug.c +++ b/arch/arm/mach-imx/hotplug.c @@ -46,11 +46,23 @@ static inline void cpu_enter_lowpower(void) void imx_cpu_die(unsigned int cpu) { cpu_enter_lowpower(); + /* + * We use the cpu jumping argument register to sync with + * imx_cpu_kill() which is running on cpu0 and waiting for + * the register being cleared to kill the cpu. + */ + imx_set_cpu_arg(cpu, ~0); cpu_do_idle(); } int imx_cpu_kill(unsigned int cpu) { + unsigned long timeout = jiffies + msecs_to_jiffies(50); + + while (imx_get_cpu_arg(cpu) == 0) + if (time_after(jiffies, timeout)) + return 0; imx_enable_cpu(cpu, false); + imx_set_cpu_arg(cpu, 0); return 1; } -- cgit v1.2.3