| /* |
| * 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/kernel.h> |
| #include <linux/signal.h> |
| #include <linux/sched.h> |
| #include <linux/init.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_vector)(void) = vfp_testing_entry; |
| union vfp_state *last_VFP_context; |
| |
| /* |
| * Dual-use variable. |
| * Used in startup: set to non-zero if VFP checks fail |
| * After startup, holds VFP architecture |
| */ |
| unsigned int VFP_arch; |
| |
| static int vfp_notifier(struct notifier_block *self, unsigned long cmd, void *v) |
| { |
| struct thread_info *thread = v; |
| union vfp_state *vfp; |
| |
| if (likely(cmd == THREAD_NOTIFY_SWITCH)) { |
| /* |
| * Always disable VFP so we can lazily save/restore the |
| * old state. |
| */ |
| fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_ENABLE); |
| return NOTIFY_DONE; |
| } |
| |
| vfp = &thread->vfpstate; |
| if (cmd == THREAD_NOTIFY_FLUSH) { |
| /* |
| * Per-thread VFP initialisation. |
| */ |
| memset(vfp, 0, sizeof(union vfp_state)); |
| |
| vfp->hard.fpexc = FPEXC_ENABLE; |
| vfp->hard.fpscr = FPSCR_ROUND_NEAREST; |
| |
| /* |
| * Disable VFP to ensure we initialise it first. |
| */ |
| fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_ENABLE); |
| } |
| |
| /* flush and release case: Per-thread VFP cleanup. */ |
| if (last_VFP_context == vfp) |
| last_VFP_context = NULL; |
| |
| 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. |
| */ |
| 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) |
| { |
| 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)); |
| 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"); |
| 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 VFP9_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs) |
| { |
| u32 fpscr, orig_fpscr, exceptions, inst; |
| |
| pr_debug("VFP: bounce: trigger %08x fpexc %08x\n", trigger, fpexc); |
| |
| /* |
| * Enable access to the VFP so we can handle the bounce. |
| */ |
| fmxr(FPEXC, fpexc & ~(FPEXC_EXCEPTION|FPEXC_INV|FPEXC_UFC|FPEXC_IOC)); |
| |
| 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. |
| */ |
| if (fpscr & FPSCR_IXE) { |
| regs->ARM_pc += 4; |
| goto emulate; |
| } |
| |
| barrier(); |
| |
| /* |
| * Modify fpscr to indicate the number of iterations remaining |
| */ |
| if (fpexc & FPEXC_EXCEPTION) { |
| 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. |
| */ |
| inst = fmrx(FPINST); |
| exceptions = vfp_emulate_instruction(inst, fpscr, regs); |
| if (exceptions) |
| vfp_raise_exceptions(exceptions, inst, orig_fpscr, regs); |
| |
| /* |
| * If there isn't a second FP instruction, exit now. |
| */ |
| if (!(fpexc & FPEXC_FPV2)) |
| return; |
| |
| /* |
| * The barrier() here prevents fpinst2 being read |
| * before the condition above. |
| */ |
| barrier(); |
| trigger = fmrx(FPINST2); |
| orig_fpscr = fpscr = fmrx(FPSCR); |
| |
| emulate: |
| exceptions = vfp_emulate_instruction(trigger, fpscr, regs); |
| if (exceptions) |
| vfp_raise_exceptions(exceptions, trigger, orig_fpscr, regs); |
| } |
| |
| static void vfp_enable(void *unused) |
| { |
| u32 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> |
| |
| /* |
| * VFP support code initialisation. |
| */ |
| static int __init vfp_init(void) |
| { |
| unsigned int vfpsid; |
| unsigned int cpu_arch = cpu_architecture(); |
| u32 access = 0; |
| |
| if (cpu_arch >= CPU_ARCH_ARMv6) { |
| access = get_copro_access(); |
| |
| /* |
| * Enable full access to VFP (cp10 and cp11) |
| */ |
| set_copro_access(access | CPACC_FULL(10) | CPACC_FULL(11)); |
| } |
| |
| /* |
| * 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. |
| */ |
| vfpsid = fmrx(FPSID); |
| barrier(); |
| |
| printk(KERN_INFO "VFP support v0.3: "); |
| 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) { |
| printk("no double precision support\n"); |
| } else { |
| smp_call_function(vfp_enable, NULL, 1, 1); |
| |
| 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); |
| |
| /* |
| * We detected VFP, and the support code is |
| * in place; report VFP support to userspace. |
| */ |
| elf_hwcap |= HWCAP_VFP; |
| } |
| return 0; |
| } |
| |
| late_initcall(vfp_init); |