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-rw-r--r--arch/arm/vfp/vfpmodule.c613
1 files changed, 613 insertions, 0 deletions
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
new file mode 100644
index 00000000..2bd4980b
--- /dev/null
+++ b/arch/arm/vfp/vfpmodule.c
@@ -0,0 +1,613 @@
+/*
+ * linux/arch/arm/vfp/vfpmodule.c
+ *
+ * Copyright (C) 2004 ARM Limited.
+ * Written by Deep Blue Solutions Limited.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * 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/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 <asm/cputype.h>
+#include <asm/thread_notify.h>
+#include <asm/vfp.h>
+
+#include "vfpinstr.h"
+#include "vfp.h"
+
+/*
+ * Our undef handlers (in entry.S)
+ */
+void vfp_testing_entry(void);
+void vfp_support_entry(void);
+void vfp_null_entry(void);
+
+void (*vfp_vector)(void) = vfp_null_entry;
+
+/*
+ * 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.
+ */
+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
+ */
+unsigned int VFP_arch;
+
+/*
+ * Per-thread VFP initialization.
+ */
+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.
+ */
+ cpu = get_cpu();
+ if (vfp_current_hw_state[cpu] == vfp)
+ vfp_current_hw_state[cpu] = NULL;
+ fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
+ put_cpu();
+}
+
+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;
+}
+
+/*
+ * 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;
+ u32 fpexc;
+#ifdef CONFIG_SMP
+ unsigned int cpu;
+#endif
+
+ 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) && 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
+
+ /*
+ * Always disable VFP so we can lazily save/restore the
+ * old state.
+ */
+ fmxr(FPEXC, fpexc & ~FPEXC_EN);
+ break;
+
+ case THREAD_NOTIFY_FLUSH:
+ vfp_thread_flush(thread);
+ break;
+
+ case THREAD_NOTIFY_EXIT:
+ vfp_thread_exit(thread);
+ break;
+
+ case THREAD_NOTIFY_COPY:
+ vfp_thread_copy(thread);
+ break;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block vfp_notifier_block = {
+ .notifier_call = vfp_notifier,
+};
+
+/*
+ * Raise a SIGFPE for the current process.
+ * sicode describes the signal being raised.
+ */
+static void vfp_raise_sigfpe(unsigned int sicode, struct pt_regs *regs)
+{
+ siginfo_t info;
+
+ memset(&info, 0, sizeof(info));
+
+ info.si_signo = SIGFPE;
+ info.si_code = sicode;
+ info.si_addr = (void __user *)(instruction_pointer(regs) - 4);
+
+ /*
+ * This is the same as NWFPE, because it's not clear what
+ * this is used for
+ */
+ current->thread.error_code = 0;
+ current->thread.trap_no = 6;
+
+ send_sig_info(SIGFPE, &info, current);
+}
+
+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), 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));
+}
+
+/*
+ * Process bitmask of exception conditions.
+ */
+static void vfp_raise_exceptions(u32 exceptions, u32 inst, u32 fpscr, struct pt_regs *regs)
+{
+ int si_code = 0;
+
+ pr_debug("VFP: raising exceptions %08x\n", exceptions);
+
+ if (exceptions == VFP_EXCEPTION_ERROR) {
+ vfp_panic("unhandled bounce", inst);
+ vfp_raise_sigfpe(0, regs);
+ return;
+ }
+
+ /*
+ * 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);
+
+#define RAISE(stat,en,sig) \
+ if (exceptions & stat && fpscr & en) \
+ si_code = sig;
+
+ /*
+ * These are arranged in priority order, least to highest.
+ */
+ RAISE(FPSCR_DZC, FPSCR_DZE, FPE_FLTDIV);
+ RAISE(FPSCR_IXC, FPSCR_IXE, FPE_FLTRES);
+ RAISE(FPSCR_UFC, FPSCR_UFE, FPE_FLTUND);
+ RAISE(FPSCR_OFC, FPSCR_OFE, FPE_FLTOVF);
+ RAISE(FPSCR_IOC, FPSCR_IOE, FPE_FLTINV);
+
+ if (si_code)
+ vfp_raise_sigfpe(si_code, regs);
+}
+
+/*
+ * Emulate a VFP instruction.
+ */
+static u32 vfp_emulate_instruction(u32 inst, u32 fpscr, struct pt_regs *regs)
+{
+ u32 exceptions = VFP_EXCEPTION_ERROR;
+
+ pr_debug("VFP: emulate: INST=0x%08x SCR=0x%08x\n", inst, fpscr);
+
+ if (INST_CPRTDO(inst)) {
+ if (!INST_CPRT(inst)) {
+ /*
+ * CPDO
+ */
+ if (vfp_single(inst)) {
+ exceptions = vfp_single_cpdo(inst, fpscr);
+ } else {
+ exceptions = vfp_double_cpdo(inst, fpscr);
+ }
+ } else {
+ /*
+ * A CPRT instruction can not appear in FPINST2, nor
+ * can it cause an exception. Therefore, we do not
+ * have to emulate it.
+ */
+ }
+ } else {
+ /*
+ * A CPDT instruction can not appear in FPINST2, nor can
+ * it cause an exception. Therefore, we do not have to
+ * emulate it.
+ */
+ }
+ return exceptions & ~VFP_NAN_FLAG;
+}
+
+/*
+ * Package up a bounce condition.
+ */
+void VFP_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs)
+{
+ u32 fpscr, orig_fpscr, fpsid, exceptions;
+
+ pr_debug("VFP: bounce: trigger %08x fpexc %08x\n", trigger, fpexc);
+
+ /*
+ * 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_DEX|FPEXC_FP2V|FPEXC_VV|FPEXC_TRAP_MASK));
+
+ fpsid = fmrx(FPSID);
+ orig_fpscr = fpscr = fmrx(FPSCR);
+
+ /*
+ * Check for the special VFP subarch 1 and FPSCR.IXE bit case
+ */
+ if ((fpsid & FPSID_ARCH_MASK) == (1 << FPSID_ARCH_BIT)
+ && (fpscr & FPSCR_IXE)) {
+ /*
+ * Synchronous exception, emulate the trigger instruction
+ */
+ goto emulate;
+ }
+
+ 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.
+ * 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 | FPEXC_VV)) {
+ u32 len;
+
+ len = fpexc + (1 << FPEXC_LENGTH_BIT);
+
+ fpscr &= ~FPSCR_LENGTH_MASK;
+ fpscr |= (len & FPEXC_LENGTH_MASK) << (FPSCR_LENGTH_BIT - FPEXC_LENGTH_BIT);
+ }
+
+ /*
+ * Handle the first FP instruction. We used to take note of the
+ * FPEXC bounce reason, but this appears to be unreliable.
+ * Emulate the bounced instruction instead.
+ */
+ exceptions = vfp_emulate_instruction(trigger, fpscr, regs);
+ if (exceptions)
+ vfp_raise_exceptions(exceptions, trigger, orig_fpscr, regs);
+
+ /*
+ * 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_EX | FPEXC_FP2V))
+ goto exit;
+
+ /*
+ * The barrier() here prevents fpinst2 being read
+ * before the condition above.
+ */
+ barrier();
+ trigger = fmrx(FPINST2);
+
+ emulate:
+ 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;
+
+ 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));
+}
+
+#ifdef CONFIG_PM
+#include <linux/syscore_ops.h>
+
+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);
+ } else if (vfp_current_hw_state[ti->cpu]) {
+ fmxr(FPEXC, fpexc | FPEXC_EN);
+ vfp_save_state(vfp_current_hw_state[ti->cpu], fpexc);
+ fmxr(FPEXC, fpexc);
+ }
+
+ /* 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 struct syscore_ops vfp_pm_syscore_ops = {
+ .suspend = vfp_pm_suspend,
+ .resume = vfp_pm_resume,
+};
+
+static void vfp_pm_init(void)
+{
+ register_syscore_ops(&vfp_pm_syscore_ops);
+}
+
+#else
+static inline void vfp_pm_init(void) { }
+#endif /* CONFIG_PM */
+
+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) {
+ 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();
+}
+
+void vfp_flush_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) {
+ u32 fpexc = fmrx(FPEXC);
+
+ fmxr(FPEXC, fpexc & ~FPEXC_EN);
+
+ /*
+ * Set the context to NULL to force a reload the next time
+ * the thread uses the VFP.
+ */
+ vfp_current_hw_state[cpu] = NULL;
+ }
+
+#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.
+ */
+ thread->vfpstate.hard.cpu = NR_CPUS;
+#endif
+ put_cpu();
+}
+
+/*
+ * 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) {
+ unsigned int cpu = (long)hcpu;
+ vfp_current_hw_state[cpu] = NULL;
+ } 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)
+ printk("not present\n");
+ else if (vfpsid & FPSID_NODOUBLE) {
+ printk("no double precision support\n");
+ } else {
+ 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",
+ (vfpsid & FPSID_IMPLEMENTER_MASK) >> FPSID_IMPLEMENTER_BIT,
+ (vfpsid & FPSID_ARCH_MASK) >> FPSID_ARCH_BIT,
+ (vfpsid & FPSID_PART_MASK) >> FPSID_PART_BIT,
+ (vfpsid & FPSID_VARIANT_MASK) >> FPSID_VARIANT_BIT,
+ (vfpsid & FPSID_REV_MASK) >> FPSID_REV_BIT);
+
+ 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
+#ifdef CONFIG_NEON
+ /*
+ * 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) {
+ if ((fmrx(MVFR1) & 0x000fff00) == 0x00011100)
+ elf_hwcap |= HWCAP_NEON;
+ }
+#endif
+ }
+ return 0;
+}
+
+late_initcall(vfp_init);
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-09 18:19:14 +0000