* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
-#include <linux/module.h>
#include <linux/types.h>
+#include <linux/cpu.h>
+#include <linux/cpu_pm.h>
#include <linux/kernel.h>
+#include <linux/notifier.h>
#include <linux/signal.h>
#include <linux/sched.h>
+#include <linux/smp.h>
#include <linux/init.h>
+#include <linux/uaccess.h>
+#include <linux/user.h>
+#include <asm/cp15.h>
+#include <asm/cputype.h>
+#include <asm/system_info.h>
#include <asm/thread_notify.h>
#include <asm/vfp.h>
void vfp_null_entry(void);
void (*vfp_vector)(void) = vfp_null_entry;
-union vfp_state *last_VFP_context[NR_CPUS];
/*
* Dual-use variable.
*/
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];
+
+/*
+ * Is 'thread's most up to date state stored in this CPUs hardware?
+ * Must be called from non-preemptible context.
+ */
+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 vfp_current_hw_state. 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.
+ */
+static void vfp_thread_flush(struct thread_info *thread)
+{
+ union vfp_state *vfp = &thread->vfpstate;
+ unsigned int cpu;
+
+ /*
+ * 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.
+ *
+ * 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)
+{
+ /* release case: Per-thread VFP cleanup. */
+ union vfp_state *vfp = &thread->vfpstate;
+ unsigned int cpu = get_cpu();
+
+ if (vfp_current_hw_state[cpu] == vfp)
+ vfp_current_hw_state[cpu] = NULL;
+ put_cpu();
+}
+
+static void vfp_thread_copy(struct thread_info *thread)
+{
+ struct thread_info *parent = current_thread_info();
+
+ vfp_sync_hwstate(parent);
+ thread->vfpstate = parent->vfpstate;
+#ifdef CONFIG_SMP
+ thread->vfpstate.hard.cpu = NR_CPUS;
+#endif
+}
+
+/*
+ * When this function is called with the following 'cmd's, the following
+ * is true while this function is being run:
+ * THREAD_NOFTIFY_SWTICH:
+ * - the previously running thread will not be scheduled onto another CPU.
+ * - the next thread to be run (v) will not be running on another CPU.
+ * - thread->cpu is the local CPU number
+ * - not preemptible as we're called in the middle of a thread switch
+ * THREAD_NOTIFY_FLUSH:
+ * - the thread (v) will be running on the local CPU, so
+ * v === current_thread_info()
+ * - thread->cpu is the local CPU number at the time it is accessed,
+ * but may change at any time.
+ * - we could be preempted if tree preempt rcu is enabled, so
+ * it is unsafe to use thread->cpu.
+ * THREAD_NOTIFY_EXIT
+ * - the thread (v) will be running on the local CPU, so
+ * v === current_thread_info()
+ * - thread->cpu is the local CPU number at the time it is accessed,
+ * but may change at any time.
+ * - we could be preempted if tree preempt rcu is enabled, so
+ * it is unsafe to use thread->cpu.
+ */
static int vfp_notifier(struct notifier_block *self, unsigned long cmd, void *v)
{
struct thread_info *thread = v;
- union vfp_state *vfp;
- __u32 cpu = thread->cpu;
+ u32 fpexc;
+#ifdef CONFIG_SMP
+ unsigned int cpu;
+#endif
- if (likely(cmd == THREAD_NOTIFY_SWITCH)) {
- u32 fpexc = fmrx(FPEXC);
+ switch (cmd) {
+ case THREAD_NOTIFY_SWITCH:
+ fpexc = fmrx(FPEXC);
#ifdef CONFIG_SMP
+ cpu = thread->cpu;
+
/*
* On SMP, if VFP is enabled, save the old state in
* case the thread migrates to a different CPU. The
* restoring is done lazily.
*/
- if ((fpexc & FPEXC_EN) && last_VFP_context[cpu]) {
- vfp_save_state(last_VFP_context[cpu], fpexc);
- last_VFP_context[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)
- last_VFP_context[cpu] = NULL;
+ if ((fpexc & FPEXC_EN) && vfp_current_hw_state[cpu])
+ vfp_save_state(vfp_current_hw_state[cpu], fpexc);
#endif
/*
* old state.
*/
fmxr(FPEXC, fpexc & ~FPEXC_EN);
- return NOTIFY_DONE;
- }
+ break;
- vfp = &thread->vfpstate;
- if (cmd == THREAD_NOTIFY_FLUSH) {
- /*
- * Per-thread VFP initialisation.
- */
- memset(vfp, 0, sizeof(union vfp_state));
+ case THREAD_NOTIFY_FLUSH:
+ vfp_thread_flush(thread);
+ break;
- vfp->hard.fpexc = FPEXC_EN;
- vfp->hard.fpscr = FPSCR_ROUND_NEAREST;
+ case THREAD_NOTIFY_EXIT:
+ vfp_thread_exit(thread);
+ break;
- /*
- * Disable VFP to ensure we initialise it first.
- */
- fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
+ case THREAD_NOTIFY_COPY:
+ vfp_thread_copy(thread);
+ break;
}
- /* flush and release case: Per-thread VFP cleanup. */
- if (last_VFP_context[cpu] == vfp)
- last_VFP_context[cpu] = NULL;
-
return NOTIFY_DONE;
}
* Raise a SIGFPE for the current process.
* sicode describes the signal being raised.
*/
-void vfp_raise_sigfpe(unsigned int sicode, struct pt_regs *regs)
+static void vfp_raise_sigfpe(unsigned int sicode, struct pt_regs *regs)
{
siginfo_t info;
}
/*
- * Update the FPSCR with the additional exception flags.
+ * If any of the status flags are set, update the FPSCR.
* Comparison instructions always return at least one of
* these flags set.
*/
+ if (exceptions & (FPSCR_N|FPSCR_Z|FPSCR_C|FPSCR_V))
+ fpscr &= ~(FPSCR_N|FPSCR_Z|FPSCR_C|FPSCR_V);
+
fpscr |= exceptions;
fmxr(FPSCR, fpscr);
}
if (fpexc & FPEXC_EX) {
+#ifndef CONFIG_CPU_FEROCEON
/*
* Asynchronous exception. The instruction is read from FPINST
* and the interrupted instruction has to be restarted.
*/
trigger = fmrx(FPINST);
regs->ARM_pc -= 4;
+#endif
} else if (!(fpexc & FPEXC_DEX)) {
/*
* Illegal combination of bits. It can be caused by an
* on VFP subarch 1.
*/
vfp_raise_exceptions(VFP_EXCEPTION_ERROR, trigger, fpscr, regs);
- return;
+ goto exit;
}
/*
* the FPEXC.FP2V bit is valid only if FPEXC.EX is 1.
*/
if (fpexc ^ (FPEXC_EX | FPEXC_FP2V))
- return;
+ goto exit;
/*
* The barrier() here prevents fpinst2 being read
exceptions = vfp_emulate_instruction(trigger, orig_fpscr, regs);
if (exceptions)
vfp_raise_exceptions(exceptions, trigger, orig_fpscr, regs);
+ exit:
+ preempt_enable();
}
static void vfp_enable(void *unused)
set_copro_access(access | CPACC_FULL(10) | CPACC_FULL(11));
}
-#ifdef CONFIG_PM
-#include <linux/sysdev.h>
-
-static int vfp_pm_suspend(struct sys_device *dev, pm_message_t state)
+#ifdef CONFIG_CPU_PM
+static int vfp_pm_suspend(void)
{
struct thread_info *ti = current_thread_info();
u32 fpexc = fmrx(FPEXC);
}
/* clear any information we had about last context state */
- memset(last_VFP_context, 0, sizeof(last_VFP_context));
+ memset(vfp_current_hw_state, 0, sizeof(vfp_current_hw_state));
return 0;
}
-static int vfp_pm_resume(struct sys_device *dev)
+static void vfp_pm_resume(void)
{
/* ensure we have access to the vfp */
vfp_enable(NULL);
/* and disable it to ensure the next usage restores the state */
fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
-
- return 0;
}
-static struct sysdev_class vfp_pm_sysclass = {
- .name = "vfp",
- .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 sys_device vfp_pm_sysdev = {
- .cls = &vfp_pm_sysclass,
+static struct notifier_block vfp_cpu_pm_notifier_block = {
+ .notifier_call = vfp_cpu_pm_notifier,
};
static void vfp_pm_init(void)
{
- sysdev_class_register(&vfp_pm_sysclass);
- sysdev_register(&vfp_pm_sysdev);
+ cpu_pm_register_notifier(&vfp_cpu_pm_notifier_block);
}
-
#else
static inline void vfp_pm_init(void) { }
-#endif /* CONFIG_PM */
+#endif /* CONFIG_CPU_PM */
-#include <linux/smp.h>
+/*
+ * 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 (vfp_state_in_hw(cpu, thread)) {
+ u32 fpexc = fmrx(FPEXC);
+
+ /*
+ * Save the last VFP state on this CPU.
+ */
+ fmxr(FPEXC, fpexc | FPEXC_EN);
+ vfp_save_state(&thread->vfpstate, fpexc | FPEXC_EN);
+ fmxr(FPEXC, fpexc);
+ }
+
+ 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);
+
+ /*
+ * Copy the floating point registers. There can be unused
+ * registers see asm/hwcap.h for details.
+ */
+ 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);
+
+ /*
+ * 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);
+
+ if (err)
+ return -EFAULT;
+
+ /* Ensure that VFP is disabled. */
+ vfp_flush_hwstate(thread);
+
+ /*
+ * As per the PCS, clear the length and stride bits for function
+ * entry.
+ */
+ hwstate->fpscr &= ~(FPSCR_LENGTH_MASK | FPSCR_STRIDE_MASK);
+
+ /*
+ * Disable VFP in the hwstate so that we can detect if it gets
+ * used.
+ */
+ hwstate->fpexc &= ~FPEXC_EN;
+ 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;
+
+ /*
+ * If VFP has been used, then disable it to avoid corrupting
+ * the new thread state.
+ */
+ if (hwstate->fpexc & FPEXC_EN)
+ 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;
+}
+
+/*
+ * VFP hardware can lose all context when a CPU goes offline.
+ * As we will be running in SMP mode with CPU hotplug, we will save the
+ * 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
+ * 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) {
+ vfp_force_reload((long)hcpu, current_thread_info());
+ } else if (action == CPU_STARTING || action == CPU_STARTING_FROZEN)
+ vfp_enable(NULL);
+ return NOTIFY_OK;
+}
/*
* VFP support code initialisation.
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 */
* in place; report VFP support to userspace.
*/
elf_hwcap |= HWCAP_VFP;
-#ifdef CONFIG_NEON
+#ifdef CONFIG_VFPv3
+ if (VFP_arch >= 2) {
+ elf_hwcap |= HWCAP_VFPv3;
+
+ /*
+ * Check for VFPv3 D16. CPUs in this configuration
+ * only have 16 x 64bit registers.
+ */
+ if (((fmrx(MVFR0) & MVFR0_A_SIMD_MASK)) == 1)
+ elf_hwcap |= HWCAP_VFPv3D16;
+ }
+#endif
/*
* Check for the presence of the Advanced SIMD
* load/store instructions, integer and single
- * precision floating point operations.
+ * precision floating point operations. Only check
+ * for NEON if the hardware has the MVFR registers.
*/
- if ((fmrx(MVFR1) & 0x000fff00) == 0x00011100)
- elf_hwcap |= HWCAP_NEON;
+ if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) {
+#ifdef CONFIG_NEON
+ if ((fmrx(MVFR1) & 0x000fff00) == 0x00011100)
+ elf_hwcap |= HWCAP_NEON;
#endif
+ if ((fmrx(MVFR1) & 0xf0000000) == 0x10000000)
+ elf_hwcap |= HWCAP_VFPv4;
+ }
}
return 0;
}
projects / linux-flexiantxendom0-3.2.10.git / blobdiff