From 90b44199e83ec780d6def11a602d825dc68438e3 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sat, 18 Dec 2010 10:59:49 +0000 Subject: ARM: VFP: re-initialize VFP coprocessor access enables on CPU hotplug We can not guarantee that VFP will be enabled when CPU hotplug brings a CPU back online from a reset state. Add a hotplug CPU notifier to ensure that the VFP coprocessor access is enabled whenever a CPU comes back online. Signed-off-by: Russell King --- arch/arm/vfp/vfpmodule.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) (limited to 'arch/arm/vfp') diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c index 8063a322c790..0797cb528b46 100644 --- a/arch/arm/vfp/vfpmodule.c +++ b/arch/arm/vfp/vfpmodule.c @@ -10,9 +10,12 @@ */ #include #include +#include #include +#include #include #include +#include #include #include @@ -484,7 +487,24 @@ void vfp_flush_hwstate(struct thread_info *thread) put_cpu(); } -#include +/* + * VFP hardware can lose all context when a CPU goes offline. + * Safely clear our held state when a CPU has been killed, and + * re-enable access to VFP when the CPU comes back online. + * + * Both CPU_DYING and CPU_STARTING are called on the CPU which + * is being offlined/onlined. + */ +static int vfp_hotplug(struct notifier_block *b, unsigned long action, + void *hcpu) +{ + if (action == CPU_DYING || action == CPU_DYING_FROZEN) { + unsigned int cpu = (long)hcpu; + last_VFP_context[cpu] = NULL; + } else if (action == CPU_STARTING || action == CPU_STARTING_FROZEN) + vfp_enable(NULL); + return NOTIFY_OK; +} /* * VFP support code initialisation. @@ -514,6 +534,8 @@ static int __init vfp_init(void) else if (vfpsid & FPSID_NODOUBLE) { printk("no double precision support\n"); } else { + hotcpu_notifier(vfp_hotplug, 0); + smp_call_function(vfp_enable, NULL, 1); VFP_arch = (vfpsid & FPSID_ARCH_MASK) >> FPSID_ARCH_BIT; /* Extract the architecture version */ -- cgit v1.2.3