* 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/hardirq.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;
send_sig_info(SIGFPE, &info, current);
}
-static void vfp_panic(char *reason)
+static void vfp_panic(char *reason, u32 inst)
{
int i;
printk(KERN_ERR "VFP: Error: %s\n", reason);
printk(KERN_ERR "VFP: EXC 0x%08x SCR 0x%08x INST 0x%08x\n",
- fmrx(FPEXC), fmrx(FPSCR), fmrx(FPINST));
+ fmrx(FPEXC), fmrx(FPSCR), inst);
for (i = 0; i < 32; i += 2)
printk(KERN_ERR "VFP: s%2u: 0x%08x s%2u: 0x%08x\n",
i, vfp_get_float(i), i+1, vfp_get_float(i+1));
pr_debug("VFP: raising exceptions %08x\n", exceptions);
if (exceptions == VFP_EXCEPTION_ERROR) {
- vfp_panic("unhandled bounce");
+ vfp_panic("unhandled bounce", inst);
vfp_raise_sigfpe(0, regs);
return;
}
/*
* Package up a bounce condition.
*/
-void VFP9_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs)
+void VFP_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs)
{
- u32 fpscr, orig_fpscr, exceptions, inst;
+ u32 fpscr, orig_fpscr, fpsid, exceptions;
pr_debug("VFP: bounce: trigger %08x fpexc %08x\n", trigger, fpexc);
/*
- * Enable access to the VFP so we can handle the bounce.
+ * At this point, FPEXC can have the following configuration:
+ *
+ * EX DEX IXE
+ * 0 1 x - synchronous exception
+ * 1 x 0 - asynchronous exception
+ * 1 x 1 - sychronous on VFP subarch 1 and asynchronous on later
+ * 0 0 1 - synchronous on VFP9 (non-standard subarch 1
+ * implementation), undefined otherwise
+ *
+ * Clear various bits and enable access to the VFP so we can
+ * handle the bounce.
*/
- fmxr(FPEXC, fpexc & ~(FPEXC_EX|FPEXC_INV|FPEXC_UFC|FPEXC_IOC));
+ fmxr(FPEXC, fpexc & ~(FPEXC_EX|FPEXC_DEX|FPEXC_FP2V|FPEXC_VV|FPEXC_TRAP_MASK));
+ fpsid = fmrx(FPSID);
orig_fpscr = fpscr = fmrx(FPSCR);
/*
- * If we are running with inexact exceptions enabled, we need to
- * emulate the trigger instruction. Note that as we're emulating
- * the trigger instruction, we need to increment PC.
+ * Check for the special VFP subarch 1 and FPSCR.IXE bit case
*/
- if (fpscr & FPSCR_IXE) {
- regs->ARM_pc += 4;
+ if ((fpsid & FPSID_ARCH_MASK) == (1 << FPSID_ARCH_BIT)
+ && (fpscr & FPSCR_IXE)) {
+ /*
+ * Synchronous exception, emulate the trigger instruction
+ */
goto emulate;
}
- barrier();
+ 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
+ * unallocated VFP instruction but with FPSCR.IXE set and not
+ * on VFP subarch 1.
+ */
+ vfp_raise_exceptions(VFP_EXCEPTION_ERROR, trigger, fpscr, regs);
+ goto exit;
+ }
/*
- * Modify fpscr to indicate the number of iterations remaining
+ * Modify fpscr to indicate the number of iterations remaining.
+ * If FPEXC.EX is 0, FPEXC.DEX is 1 and the FPEXC.VV bit indicates
+ * whether FPEXC.VECITR or FPSCR.LEN is used.
*/
- if (fpexc & FPEXC_EX) {
+ if (fpexc & (FPEXC_EX | FPEXC_VV)) {
u32 len;
len = fpexc + (1 << FPEXC_LENGTH_BIT);
* FPEXC bounce reason, but this appears to be unreliable.
* Emulate the bounced instruction instead.
*/
- inst = fmrx(FPINST);
- exceptions = vfp_emulate_instruction(inst, fpscr, regs);
+ exceptions = vfp_emulate_instruction(trigger, fpscr, regs);
if (exceptions)
- vfp_raise_exceptions(exceptions, inst, orig_fpscr, regs);
+ vfp_raise_exceptions(exceptions, trigger, orig_fpscr, regs);
/*
- * If there isn't a second FP instruction, exit now.
+ * If there isn't a second FP instruction, exit now. Note that
+ * the FPEXC.FP2V bit is valid only if FPEXC.EX is 1.
*/
- if (!(fpexc & FPEXC_FPV2))
- return;
+ if (fpexc ^ (FPEXC_EX | FPEXC_FP2V))
+ goto exit;
/*
* The barrier() here prevents fpinst2 being read
*/
barrier();
trigger = fmrx(FPINST2);
- orig_fpscr = fpscr = fmrx(FPSCR);
emulate:
- exceptions = vfp_emulate_instruction(trigger, fpscr, regs);
+ 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)
{
- u32 access = get_copro_access();
+ u32 access;
+
+ BUG_ON(preemptible());
+ access = get_copro_access();
/*
* Enable full access to VFP (cp10 and cp11)
set_copro_access(access | CPACC_FULL(10) | CPACC_FULL(11));
}
-#include <linux/smp.h>
+#ifdef CONFIG_CPU_PM
+static int vfp_pm_suspend(void)
+{
+ struct thread_info *ti = current_thread_info();
+ u32 fpexc = fmrx(FPEXC);
+
+ /* if vfp is on, then save state for resumption */
+ if (fpexc & FPEXC_EN) {
+ printk(KERN_DEBUG "%s: saving vfp state\n", __func__);
+ vfp_save_state(&ti->vfpstate, fpexc);
+
+ /* disable, just in case */
+ fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
+ }
+
+ /* clear any information we had about last context state */
+ memset(vfp_current_hw_state, 0, sizeof(vfp_current_hw_state));
+
+ return 0;
+}
+
+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);
+}
+
+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)
+{
+ cpu_pm_register_notifier(&vfp_cpu_pm_notifier_block);
+}
+
+#else
+static inline void vfp_pm_init(void) { }
+#endif /* CONFIG_CPU_PM */
/*
- * VFP support code initialisation.
+ * Ensure that the VFP state stored in 'thread->vfpstate' is up to date
+ * with the hardware state.
*/
-static int __init vfp_init(void)
+void vfp_sync_hwstate(struct thread_info *thread)
{
- unsigned int vfpsid;
- unsigned int cpu_arch = cpu_architecture();
- u32 access = 0;
+ unsigned int cpu = get_cpu();
- if (cpu_arch >= CPU_ARCH_ARMv6) {
- access = get_copro_access();
+ if (vfp_state_in_hw(cpu, thread)) {
+ u32 fpexc = fmrx(FPEXC);
/*
- * Enable full access to VFP (cp10 and cp11)
+ * Save the last VFP state on this CPU.
*/
- set_copro_access(access | CPACC_FULL(10) | CPACC_FULL(11));
+ 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);
+ 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;
+}
+
+/*
+ * 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.
+ */
+static int __init vfp_init(void)
+{
+ unsigned int vfpsid;
+ unsigned int cpu_arch = cpu_architecture();
+
+ if (cpu_arch >= CPU_ARCH_ARMv6)
+ on_each_cpu(vfp_enable, NULL, 1);
+
/*
* First check that there is a VFP that we can use.
* The handler is already setup to just log calls, so
* we just need to read the VFPSID register.
*/
vfp_vector = vfp_testing_entry;
+ barrier();
vfpsid = fmrx(FPSID);
barrier();
vfp_vector = vfp_null_entry;
printk(KERN_INFO "VFP support v0.3: ");
- if (VFP_arch) {
+ if (VFP_arch)
printk("not present\n");
-
- /*
- * Restore the copro access register.
- */
- if (cpu_arch >= CPU_ARCH_ARMv6)
- set_copro_access(access);
- } else if (vfpsid & FPSID_NODOUBLE) {
+ else if (vfpsid & FPSID_NODOUBLE) {
printk("no double precision support\n");
} else {
- smp_call_function(vfp_enable, NULL, 1, 1);
+ hotcpu_notifier(vfp_hotplug, 0);
VFP_arch = (vfpsid & FPSID_ARCH_MASK) >> FPSID_ARCH_BIT; /* Extract the architecture version */
printk("implementor %02x architecture %d part %02x variant %x rev %x\n",
vfp_vector = vfp_support_entry;
thread_register_notifier(&vfp_notifier_block);
+ vfp_pm_init();
/*
* We detected VFP, and the support code is
* in place; report VFP support to userspace.
*/
elf_hwcap |= HWCAP_VFP;
+#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. Only check
+ * for NEON if the hardware has the MVFR registers.
+ */
+ 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