diff options
Diffstat (limited to 'arch/arm/vfp/vfpmodule.c')
| -rw-r--r-- | arch/arm/vfp/vfpmodule.c | 227 |
1 files changed, 169 insertions, 58 deletions
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c index 0e46a47..2541b9b 100644 --- a/arch/arm/vfp/vfpmodule.c +++ b/arch/arm/vfp/vfpmodule.c @@ -11,6 +11,7 @@ #include <linux/module.h> #include <linux/types.h> #include <linux/cpu.h> +#include <linux/cpu_pm.h> #include <linux/hardirq.h> #include <linux/kernel.h> #include <linux/notifier.h> @@ -18,6 +19,8 @@ #include <linux/sched.h> #include <linux/smp.h> #include <linux/init.h> +#include <linux/uaccess.h> +#include <linux/user.h> #include <asm/cputype.h> #include <asm/thread_notify.h> @@ -36,18 +39,51 @@ void vfp_null_entry(void); void (*vfp_vector)(void) = vfp_null_entry; /* + * Dual-use variable. + * Used in startup: set to non-zero if VFP checks fail + * After startup, holds VFP architecture + */ +unsigned int VFP_arch; + +/* * The pointer to the vfpstate structure of the thread which currently * owns the context held in the VFP hardware, or NULL if the hardware * context is invalid. + * + * For UP, this is sufficient to tell which thread owns the VFP context. + * However, for SMP, we also need to check the CPU number stored in the + * saved state too to catch migrations. */ union vfp_state *vfp_current_hw_state[NR_CPUS]; /* - * Dual-use variable. - * Used in startup: set to non-zero if VFP checks fail - * After startup, holds VFP architecture + * Is 'thread's most up to date state stored in this CPUs hardware? + * Must be called from non-preemptible context. */ -unsigned int VFP_arch; +static bool vfp_state_in_hw(unsigned int cpu, struct thread_info *thread) +{ +#ifdef CONFIG_SMP + if (thread->vfpstate.hard.cpu != cpu) + return false; +#endif + return vfp_current_hw_state[cpu] == &thread->vfpstate; +} + +/* + * Force a reload of the VFP context from the thread structure. We do + * this by ensuring that access to the VFP hardware is disabled, and + * clear last_VFP_context. Must be called from non-preemptible context. + */ +static void vfp_force_reload(unsigned int cpu, struct thread_info *thread) +{ + if (vfp_state_in_hw(cpu, thread)) { + fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN); + vfp_current_hw_state[cpu] = NULL; + } +#ifdef CONFIG_SMP + thread->vfpstate.hard.cpu = NR_CPUS; +#endif +} /* * Per-thread VFP initialization. @@ -57,21 +93,27 @@ static void vfp_thread_flush(struct thread_info *thread) union vfp_state *vfp = &thread->vfpstate; unsigned int cpu; - memset(vfp, 0, sizeof(union vfp_state)); - - vfp->hard.fpexc = FPEXC_EN; - vfp->hard.fpscr = FPSCR_ROUND_NEAREST; - /* * Disable VFP to ensure we initialize it first. We must ensure - * that the modification of vfp_current_hw_state[] and hardware disable - * are done for the same CPU and without preemption. + * that the modification of vfp_current_hw_state[] and hardware + * disable are done for the same CPU and without preemption. + * + * Do this first to ensure that preemption won't overwrite our + * state saving should access to the VFP be enabled at this point. */ cpu = get_cpu(); if (vfp_current_hw_state[cpu] == vfp) vfp_current_hw_state[cpu] = NULL; fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN); put_cpu(); + + memset(vfp, 0, sizeof(union vfp_state)); + + vfp->hard.fpexc = FPEXC_EN; + vfp->hard.fpscr = FPSCR_ROUND_NEAREST; +#ifdef CONFIG_SMP + vfp->hard.cpu = NR_CPUS; +#endif } static void vfp_thread_exit(struct thread_info *thread) @@ -91,6 +133,9 @@ static void vfp_thread_copy(struct thread_info *thread) vfp_sync_hwstate(parent); thread->vfpstate = parent->vfpstate; +#ifdef CONFIG_SMP + thread->vfpstate.hard.cpu = NR_CPUS; +#endif } /* @@ -136,17 +181,8 @@ static int vfp_notifier(struct notifier_block *self, unsigned long cmd, void *v) * case the thread migrates to a different CPU. The * restoring is done lazily. */ - if ((fpexc & FPEXC_EN) && vfp_current_hw_state[cpu]) { + if ((fpexc & FPEXC_EN) && vfp_current_hw_state[cpu]) vfp_save_state(vfp_current_hw_state[cpu], fpexc); - vfp_current_hw_state[cpu]->hard.cpu = cpu; - } - /* - * Thread migration, just force the reloading of the - * state on the new CPU in case the VFP registers - * contain stale data. - */ - if (thread->vfpstate.hard.cpu != cpu) - vfp_current_hw_state[cpu] = NULL; #endif /* @@ -406,9 +442,7 @@ static void vfp_enable(void *unused) set_copro_access(access | CPACC_FULL(10) | CPACC_FULL(11)); } -#ifdef CONFIG_PM -#include <linux/syscore_ops.h> - +#ifdef CONFIG_CPU_PM static int vfp_pm_suspend(void) { struct thread_info *ti = current_thread_info(); @@ -444,29 +478,43 @@ static void vfp_pm_resume(void) fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN); } -static struct syscore_ops vfp_pm_syscore_ops = { - .suspend = vfp_pm_suspend, - .resume = vfp_pm_resume, +static int vfp_cpu_pm_notifier(struct notifier_block *self, unsigned long cmd, + void *v) +{ + switch (cmd) { + case CPU_PM_ENTER: + vfp_pm_suspend(); + break; + case CPU_PM_ENTER_FAILED: + case CPU_PM_EXIT: + vfp_pm_resume(); + break; + } + return NOTIFY_OK; +} + +static struct notifier_block vfp_cpu_pm_notifier_block = { + .notifier_call = vfp_cpu_pm_notifier, }; static void vfp_pm_init(void) { - register_syscore_ops(&vfp_pm_syscore_ops); + cpu_pm_register_notifier(&vfp_cpu_pm_notifier_block); } #else static inline void vfp_pm_init(void) { } -#endif /* CONFIG_PM */ +#endif /* CONFIG_CPU_PM */ +/* + * Ensure that the VFP state stored in 'thread->vfpstate' is up to date + * with the hardware state. + */ void vfp_sync_hwstate(struct thread_info *thread) { unsigned int cpu = get_cpu(); - /* - * If the thread we're interested in is the current owner of the - * hardware VFP state, then we need to save its state. - */ - if (vfp_current_hw_state[cpu] == &thread->vfpstate) { + if (vfp_state_in_hw(cpu, thread)) { u32 fpexc = fmrx(FPEXC); /* @@ -480,37 +528,101 @@ void vfp_sync_hwstate(struct thread_info *thread) put_cpu(); } +/* Ensure that the thread reloads the hardware VFP state on the next use. */ void vfp_flush_hwstate(struct thread_info *thread) { unsigned int cpu = get_cpu(); + vfp_force_reload(cpu, thread); + + put_cpu(); +} + +/* + * Save the current VFP state into the provided structures and prepare + * for entry into a new function (signal handler). + */ +int vfp_preserve_user_clear_hwstate(struct user_vfp __user *ufp, + struct user_vfp_exc __user *ufp_exc) +{ + struct thread_info *thread = current_thread_info(); + struct vfp_hard_struct *hwstate = &thread->vfpstate.hard; + int err = 0; + + /* Ensure that the saved hwstate is up-to-date. */ + vfp_sync_hwstate(thread); + /* - * If the thread we're interested in is the current owner of the - * hardware VFP state, then we need to save its state. + * Copy the floating point registers. There can be unused + * registers see asm/hwcap.h for details. */ - if (vfp_current_hw_state[cpu] == &thread->vfpstate) { - u32 fpexc = fmrx(FPEXC); + err |= __copy_to_user(&ufp->fpregs, &hwstate->fpregs, + sizeof(hwstate->fpregs)); + /* + * Copy the status and control register. + */ + __put_user_error(hwstate->fpscr, &ufp->fpscr, err); - fmxr(FPEXC, fpexc & ~FPEXC_EN); + /* + * Copy the exception registers. + */ + __put_user_error(hwstate->fpexc, &ufp_exc->fpexc, err); + __put_user_error(hwstate->fpinst, &ufp_exc->fpinst, err); + __put_user_error(hwstate->fpinst2, &ufp_exc->fpinst2, err); - /* - * Set the context to NULL to force a reload the next time - * the thread uses the VFP. - */ - vfp_current_hw_state[cpu] = NULL; - } + if (err) + return -EFAULT; + + /* Ensure that VFP is disabled. */ + vfp_flush_hwstate(thread); -#ifdef CONFIG_SMP /* - * For SMP we still have to take care of the case where the thread - * migrates to another CPU and then back to the original CPU on which - * the last VFP user is still the same thread. Mark the thread VFP - * state as belonging to a non-existent CPU so that the saved one will - * be reloaded in the above case. + * As per the PCS, clear the length and stride bits for function + * entry. */ - thread->vfpstate.hard.cpu = NR_CPUS; -#endif - put_cpu(); + hwstate->fpscr &= ~(FPSCR_LENGTH_MASK | FPSCR_STRIDE_MASK); + return 0; +} + +/* Sanitise and restore the current VFP state from the provided structures. */ +int vfp_restore_user_hwstate(struct user_vfp __user *ufp, + struct user_vfp_exc __user *ufp_exc) +{ + struct thread_info *thread = current_thread_info(); + struct vfp_hard_struct *hwstate = &thread->vfpstate.hard; + unsigned long fpexc; + int err = 0; + + /* Disable VFP to avoid corrupting the new thread state. */ + vfp_flush_hwstate(thread); + + /* + * Copy the floating point registers. There can be unused + * registers see asm/hwcap.h for details. + */ + err |= __copy_from_user(&hwstate->fpregs, &ufp->fpregs, + sizeof(hwstate->fpregs)); + /* + * Copy the status and control register. + */ + __get_user_error(hwstate->fpscr, &ufp->fpscr, err); + + /* + * Sanitise and restore the exception registers. + */ + __get_user_error(fpexc, &ufp_exc->fpexc, err); + + /* Ensure the VFP is enabled. */ + fpexc |= FPEXC_EN; + + /* Ensure FPINST2 is invalid and the exception flag is cleared. */ + fpexc &= ~(FPEXC_EX | FPEXC_FP2V); + hwstate->fpexc = fpexc; + + __get_user_error(hwstate->fpinst, &ufp_exc->fpinst, err); + __get_user_error(hwstate->fpinst2, &ufp_exc->fpinst2, err); + + return err ? -EFAULT : 0; } /* @@ -527,10 +639,9 @@ void vfp_flush_hwstate(struct thread_info *thread) 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; - vfp_current_hw_state[cpu] = NULL; - } else if (action == CPU_STARTING || action == CPU_STARTING_FROZEN) + 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; } |