From e5b61bafe70477e05e1dce0d6ca4ec181e23cb2a Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 13 Jul 2016 17:16:35 +0000 Subject: [PATCH] arm: Convert VFP hotplug notifiers to state machine Straight forward conversion plus commentary why code which is executed in hotplug callbacks needs to be invoked before installing them. Signed-off-by: Thomas Gleixner Signed-off-by: Anna-Maria Gleixner Reviewed-by: Sebastian Andrzej Siewior Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Russell King Cc: linux-arm-kernel@lists.infradead.org Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153335.713612993@linutronix.de Signed-off-by: Ingo Molnar --- arch/arm/vfp/vfpmodule.c | 28 +++++++++++++++++----------- include/linux/cpuhotplug.h | 1 + 2 files changed, 18 insertions(+), 11 deletions(-) diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c index 73085d3482ed..da0b33deba6d 100644 --- a/arch/arm/vfp/vfpmodule.c +++ b/arch/arm/vfp/vfpmodule.c @@ -643,19 +643,19 @@ int vfp_restore_user_hwstate(struct user_vfp __user *ufp, * hardware state at every thread switch. We clear our held state when * a CPU has been killed, indicating that the VFP hardware doesn't contain * a threads VFP state. When a CPU starts up, we re-enable access to the - * VFP hardware. - * - * Both CPU_DYING and CPU_STARTING are called on the CPU which + * VFP hardware. The callbacks below are called on the CPU which * is being offlined/onlined. */ -static int vfp_hotplug(struct notifier_block *b, unsigned long action, - void *hcpu) +static int vfp_dying_cpu(unsigned int cpu) { - if (action == CPU_DYING || action == CPU_DYING_FROZEN) - vfp_current_hw_state[(long)hcpu] = NULL; - else if (action == CPU_STARTING || action == CPU_STARTING_FROZEN) - vfp_enable(NULL); - return NOTIFY_OK; + vfp_force_reload(cpu, current_thread_info()); + return 0; +} + +static int vfp_starting_cpu(unsigned int unused) +{ + vfp_enable(NULL); + return 0; } void vfp_kmode_exception(void) @@ -732,6 +732,10 @@ static int __init vfp_init(void) unsigned int vfpsid; unsigned int cpu_arch = cpu_architecture(); + /* + * Enable the access to the VFP on all online CPUs so the + * following test on FPSID will succeed. + */ if (cpu_arch >= CPU_ARCH_ARMv6) on_each_cpu(vfp_enable, NULL, 1); @@ -794,7 +798,9 @@ static int __init vfp_init(void) VFP_arch = (vfpsid & FPSID_ARCH_MASK) >> FPSID_ARCH_BIT; } - hotcpu_notifier(vfp_hotplug, 0); + cpuhp_setup_state_nocalls(CPUHP_AP_ARM_VFP_STARTING, + "AP_ARM_VFP_STARTING", vfp_starting_cpu, + vfp_dying_cpu); vfp_vector = vfp_support_entry; diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 3e719ba44fbe..4c63cb30aee6 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -34,6 +34,7 @@ enum cpuhp_state { CPUHP_AP_PERF_X86_CQM_STARTING, CPUHP_AP_PERF_X86_CSTATE_STARTING, CPUHP_AP_PERF_XTENSA_STARTING, + CPUHP_AP_ARM_VFP_STARTING, CPUHP_AP_NOTIFY_STARTING, CPUHP_AP_ONLINE, CPUHP_TEARDOWN_CPU, -- 2.20.1