diff options
Diffstat (limited to 'arch/arm/vfp/vfpmodule.c')
| -rw-r--r-- | arch/arm/vfp/vfpmodule.c | 576 |
1 files changed, 451 insertions, 125 deletions
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c index 5dfbb0b8e7f4..e559ad3cd148 100644 --- a/arch/arm/vfp/vfpmodule.c +++ b/arch/arm/vfp/vfpmodule.c @@ -1,12 +1,9 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * 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/types.h> #include <linux/cpu.h> @@ -15,36 +12,37 @@ #include <linux/kernel.h> #include <linux/notifier.h> #include <linux/signal.h> -#include <linux/sched.h> +#include <linux/sched/signal.h> #include <linux/smp.h> #include <linux/init.h> #include <linux/uaccess.h> #include <linux/user.h> +#include <linux/export.h> +#include <linux/perf_event.h> #include <asm/cp15.h> #include <asm/cputype.h> #include <asm/system_info.h> #include <asm/thread_notify.h> +#include <asm/traps.h> #include <asm/vfp.h> +#include <asm/neon.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; +static bool have_vfp __ro_after_init; /* * Dual-use variable. * Used in startup: set to non-zero if VFP checks fail * After startup, holds VFP architecture */ -unsigned int VFP_arch; +static unsigned int VFP_arch; + +#ifdef CONFIG_CPU_FEROCEON +extern unsigned int VFP_arch_feroceon __alias(VFP_arch); +#endif /* * The pointer to the vfpstate structure of the thread which currently @@ -58,6 +56,34 @@ unsigned int VFP_arch; union vfp_state *vfp_current_hw_state[NR_CPUS]; /* + * Claim ownership of the VFP unit. + * + * The caller may change VFP registers until vfp_state_release() is called. + * + * local_bh_disable() is used to disable preemption and to disable VFP + * processing in softirq context. On PREEMPT_RT kernels local_bh_disable() is + * not sufficient because it only serializes soft interrupt related sections + * via a local lock, but stays preemptible. Disabling preemption is the right + * choice here as bottom half processing is always in thread context on RT + * kernels so it implicitly prevents bottom half processing as well. + */ +static void vfp_state_hold(void) +{ + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_bh_disable(); + else + preempt_disable(); +} + +static void vfp_state_release(void) +{ + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_bh_enable(); + else + preempt_enable(); +} + +/* * Is 'thread's most up to date state stored in this CPUs hardware? * Must be called from non-preemptible context. */ @@ -142,7 +168,7 @@ static void vfp_thread_copy(struct thread_info *thread) /* * When this function is called with the following 'cmd's, the following * is true while this function is being run: - * THREAD_NOFTIFY_SWTICH: + * THREAD_NOTIFY_SWITCH: * - 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 @@ -155,10 +181,6 @@ static void vfp_thread_copy(struct thread_info *thread) * - 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. */ @@ -219,14 +241,6 @@ static struct notifier_block vfp_notifier_block = { */ 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 @@ -234,7 +248,9 @@ static void vfp_raise_sigfpe(unsigned int sicode, struct pt_regs *regs) current->thread.error_code = 0; current->thread.trap_no = 6; - send_sig_info(SIGFPE, &info, current); + send_sig_fault(SIGFPE, sicode, + (void __user *)(instruction_pointer(regs) - 4), + current); } static void vfp_panic(char *reason, u32 inst) @@ -252,7 +268,7 @@ static void vfp_panic(char *reason, u32 inst) /* * Process bitmask of exception conditions. */ -static void vfp_raise_exceptions(u32 exceptions, u32 inst, u32 fpscr, struct pt_regs *regs) +static int vfp_raise_exceptions(u32 exceptions, u32 inst, u32 fpscr) { int si_code = 0; @@ -260,8 +276,7 @@ static void vfp_raise_exceptions(u32 exceptions, u32 inst, u32 fpscr, struct pt_ if (exceptions == VFP_EXCEPTION_ERROR) { vfp_panic("unhandled bounce", inst); - vfp_raise_sigfpe(0, regs); - return; + return FPE_FLTINV; } /* @@ -289,8 +304,7 @@ static void vfp_raise_exceptions(u32 exceptions, u32 inst, u32 fpscr, struct pt_ RAISE(FPSCR_OFC, FPSCR_OFE, FPE_FLTOVF); RAISE(FPSCR_IOC, FPSCR_IOE, FPE_FLTINV); - if (si_code) - vfp_raise_sigfpe(si_code, regs); + return si_code; } /* @@ -326,15 +340,18 @@ static u32 vfp_emulate_instruction(u32 inst, u32 fpscr, struct pt_regs *regs) * emulate it. */ } + perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->ARM_pc); return exceptions & ~VFP_NAN_FLAG; } /* * Package up a bounce condition. */ -void VFP_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs) +static void VFP_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs) { u32 fpscr, orig_fpscr, fpsid, exceptions; + int si_code2 = 0; + int si_code = 0; pr_debug("VFP: bounce: trigger %08x fpexc %08x\n", trigger, fpexc); @@ -368,21 +385,19 @@ void VFP_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs) } 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); + si_code = vfp_raise_exceptions(VFP_EXCEPTION_ERROR, trigger, fpscr); goto exit; } @@ -407,7 +422,7 @@ void VFP_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs) */ exceptions = vfp_emulate_instruction(trigger, fpscr, regs); if (exceptions) - vfp_raise_exceptions(exceptions, trigger, orig_fpscr, regs); + si_code2 = vfp_raise_exceptions(exceptions, trigger, orig_fpscr); /* * If there isn't a second FP instruction, exit now. Note that @@ -426,9 +441,13 @@ void VFP_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs) emulate: exceptions = vfp_emulate_instruction(trigger, orig_fpscr, regs); if (exceptions) - vfp_raise_exceptions(exceptions, trigger, orig_fpscr, regs); - exit: - preempt_enable(); + si_code = vfp_raise_exceptions(exceptions, trigger, orig_fpscr); +exit: + vfp_state_release(); + if (si_code2) + vfp_raise_sigfpe(si_code2, regs); + if (si_code) + vfp_raise_sigfpe(si_code, regs); } static void vfp_enable(void *unused) @@ -444,6 +463,19 @@ static void vfp_enable(void *unused) set_copro_access(access | CPACC_FULL(10) | CPACC_FULL(11)); } +/* Called by platforms on which we want to disable VFP because it may not be + * present on all CPUs within a SMP complex. Needs to be called prior to + * vfp_init(). + */ +void __init vfp_disable(void) +{ + if (VFP_arch) { + pr_debug("%s: should be called prior to vfp_init\n", __func__); + return; + } + VFP_arch = 1; +} + #ifdef CONFIG_CPU_PM static int vfp_pm_suspend(void) { @@ -514,9 +546,9 @@ static inline void vfp_pm_init(void) { } */ void vfp_sync_hwstate(struct thread_info *thread) { - unsigned int cpu = get_cpu(); + vfp_state_hold(); - if (vfp_state_in_hw(cpu, thread)) { + if (vfp_state_in_hw(raw_smp_processor_id(), thread)) { u32 fpexc = fmrx(FPEXC); /* @@ -527,7 +559,7 @@ void vfp_sync_hwstate(struct thread_info *thread) fmxr(FPEXC, fpexc); } - put_cpu(); + vfp_state_release(); } /* Ensure that the thread reloads the hardware VFP state on the next use. */ @@ -544,12 +576,11 @@ void vfp_flush_hwstate(struct thread_info *thread) * 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) +int vfp_preserve_user_clear_hwstate(struct user_vfp *ufp, + struct user_vfp_exc *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); @@ -558,22 +589,19 @@ int vfp_preserve_user_clear_hwstate(struct user_vfp __user *ufp, * 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)); + memcpy(&ufp->fpregs, &hwstate->fpregs, sizeof(hwstate->fpregs)); + /* * Copy the status and control register. */ - __put_user_error(hwstate->fpscr, &ufp->fpscr, err); + ufp->fpscr = hwstate->fpscr; /* * 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; + ufp_exc->fpexc = hwstate->fpexc; + ufp_exc->fpinst = hwstate->fpinst; + ufp_exc->fpinst2 = hwstate->fpinst2; /* Ensure that VFP is disabled. */ vfp_flush_hwstate(thread); @@ -587,13 +615,11 @@ int vfp_preserve_user_clear_hwstate(struct user_vfp __user *ufp, } /* 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) +int vfp_restore_user_hwstate(struct user_vfp *ufp, struct user_vfp_exc *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); @@ -602,17 +628,16 @@ int vfp_restore_user_hwstate(struct user_vfp __user *ufp, * 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)); + memcpy(&hwstate->fpregs, &ufp->fpregs, sizeof(hwstate->fpregs)); /* * Copy the status and control register. */ - __get_user_error(hwstate->fpscr, &ufp->fpscr, err); + hwstate->fpscr = ufp->fpscr; /* * Sanitise and restore the exception registers. */ - __get_user_error(fpexc, &ufp_exc->fpexc, err); + fpexc = ufp_exc->fpexc; /* Ensure the VFP is enabled. */ fpexc |= FPEXC_EN; @@ -621,10 +646,10 @@ int vfp_restore_user_hwstate(struct user_vfp __user *ufp, 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); + hwstate->fpinst = ufp_exc->fpinst; + hwstate->fpinst2 = ufp_exc->fpinst2; - return err ? -EFAULT : 0; + return 0; } /* @@ -633,29 +658,283 @@ int vfp_restore_user_hwstate(struct user_vfp __user *ufp, * 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 + * VFP hardware. The callbacks below are called on the CPU which * is being offlined/onlined. */ -static int vfp_hotplug(struct notifier_block *b, unsigned long action, - void *hcpu) +static int vfp_dying_cpu(unsigned int cpu) { - 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_current_hw_state[cpu] = NULL; + return 0; +} + +static int vfp_starting_cpu(unsigned int unused) +{ + vfp_enable(NULL); + return 0; +} + +static int vfp_kmode_exception(struct pt_regs *regs, unsigned int instr) +{ + /* + * If we reach this point, a floating point exception has been raised + * while running in kernel mode. If the NEON/VFP unit was enabled at the + * time, it means a VFP instruction has been issued that requires + * software assistance to complete, something which is not currently + * supported in kernel mode. + * If the NEON/VFP unit was disabled, and the location pointed to below + * is properly preceded by a call to kernel_neon_begin(), something has + * caused the task to be scheduled out and back in again. In this case, + * rebuilding and running with CONFIG_DEBUG_ATOMIC_SLEEP enabled should + * be helpful in localizing the problem. + */ + if (fmrx(FPEXC) & FPEXC_EN) + pr_crit("BUG: unsupported FP instruction in kernel mode\n"); + else + pr_crit("BUG: FP instruction issued in kernel mode with FP unit disabled\n"); + pr_crit("FPEXC == 0x%08x\n", fmrx(FPEXC)); + return 1; } /* + * vfp_support_entry - Handle VFP exception + * + * @regs: pt_regs structure holding the register state at exception entry + * @trigger: The opcode of the instruction that triggered the exception + * + * Returns 0 if the exception was handled, or an error code otherwise. + */ +static int vfp_support_entry(struct pt_regs *regs, u32 trigger) +{ + struct thread_info *ti = current_thread_info(); + u32 fpexc; + + if (unlikely(!have_vfp)) + return -ENODEV; + + if (!user_mode(regs)) + return vfp_kmode_exception(regs, trigger); + + vfp_state_hold(); + fpexc = fmrx(FPEXC); + + /* + * If the VFP unit was not enabled yet, we have to check whether the + * VFP state in the CPU's registers is the most recent VFP state + * associated with the process. On UP systems, we don't save the VFP + * state eagerly on a context switch, so we may need to save the + * VFP state to memory first, as it may belong to another process. + */ + if (!(fpexc & FPEXC_EN)) { + /* + * Enable the VFP unit but mask the FP exception flag for the + * time being, so we can access all the registers. + */ + fpexc |= FPEXC_EN; + fmxr(FPEXC, fpexc & ~FPEXC_EX); + + /* + * Check whether or not the VFP state in the CPU's registers is + * the most recent VFP state associated with this task. On SMP, + * migration may result in multiple CPUs holding VFP states + * that belong to the same task, but only the most recent one + * is valid. + */ + if (!vfp_state_in_hw(ti->cpu, ti)) { + if (!IS_ENABLED(CONFIG_SMP) && + vfp_current_hw_state[ti->cpu] != NULL) { + /* + * This CPU is currently holding the most + * recent VFP state associated with another + * task, and we must save that to memory first. + */ + vfp_save_state(vfp_current_hw_state[ti->cpu], + fpexc); + } + + /* + * We can now proceed with loading the task's VFP state + * from memory into the CPU registers. + */ + fpexc = vfp_load_state(&ti->vfpstate); + vfp_current_hw_state[ti->cpu] = &ti->vfpstate; +#ifdef CONFIG_SMP + /* + * Record that this CPU is now the one holding the most + * recent VFP state of the task. + */ + ti->vfpstate.hard.cpu = ti->cpu; +#endif + } + + if (fpexc & FPEXC_EX) + /* + * Might as well handle the pending exception before + * retrying branch out before setting an FPEXC that + * stops us reading stuff. + */ + goto bounce; + + /* + * No FP exception is pending: just enable the VFP and + * replay the instruction that trapped. + */ + fmxr(FPEXC, fpexc); + vfp_state_release(); + } else { + /* Check for synchronous or asynchronous exceptions */ + if (!(fpexc & (FPEXC_EX | FPEXC_DEX))) { + u32 fpscr = fmrx(FPSCR); + + /* + * On some implementations of the VFP subarch 1, + * setting FPSCR.IXE causes all the CDP instructions to + * be bounced synchronously without setting the + * FPEXC.EX bit + */ + if (!(fpscr & FPSCR_IXE)) { + if (!(fpscr & FPSCR_LENGTH_MASK)) { + pr_debug("not VFP\n"); + vfp_state_release(); + return -ENOEXEC; + } + fpexc |= FPEXC_DEX; + } + } +bounce: regs->ARM_pc += 4; + /* VFP_bounce() will invoke vfp_state_release() */ + VFP_bounce(trigger, fpexc, regs); + } + + return 0; +} + +static struct undef_hook neon_support_hook[] = {{ + .instr_mask = 0xfe000000, + .instr_val = 0xf2000000, + .cpsr_mask = PSR_T_BIT, + .cpsr_val = 0, + .fn = vfp_support_entry, +}, { + .instr_mask = 0xff100000, + .instr_val = 0xf4000000, + .cpsr_mask = PSR_T_BIT, + .cpsr_val = 0, + .fn = vfp_support_entry, +}, { + .instr_mask = 0xef000000, + .instr_val = 0xef000000, + .cpsr_mask = PSR_T_BIT, + .cpsr_val = PSR_T_BIT, + .fn = vfp_support_entry, +}, { + .instr_mask = 0xff100000, + .instr_val = 0xf9000000, + .cpsr_mask = PSR_T_BIT, + .cpsr_val = PSR_T_BIT, + .fn = vfp_support_entry, +}, { + .instr_mask = 0xff000800, + .instr_val = 0xfc000800, + .cpsr_mask = 0, + .cpsr_val = 0, + .fn = vfp_support_entry, +}, { + .instr_mask = 0xff000800, + .instr_val = 0xfd000800, + .cpsr_mask = 0, + .cpsr_val = 0, + .fn = vfp_support_entry, +}, { + .instr_mask = 0xff000800, + .instr_val = 0xfe000800, + .cpsr_mask = 0, + .cpsr_val = 0, + .fn = vfp_support_entry, +}}; + +static struct undef_hook vfp_support_hook = { + .instr_mask = 0x0c000e00, + .instr_val = 0x0c000a00, + .fn = vfp_support_entry, +}; + +#ifdef CONFIG_KERNEL_MODE_NEON + +/* + * Kernel-side NEON support functions + */ +void kernel_neon_begin(void) +{ + struct thread_info *thread = current_thread_info(); + unsigned int cpu; + u32 fpexc; + + vfp_state_hold(); + + /* + * Kernel mode NEON is only allowed outside of hardirq context with + * preemption and softirq processing disabled. This will make sure that + * the kernel mode NEON register contents never need to be preserved. + */ + BUG_ON(in_hardirq()); + BUG_ON(irqs_disabled()); + cpu = __smp_processor_id(); + + fpexc = fmrx(FPEXC) | FPEXC_EN; + fmxr(FPEXC, fpexc); + + /* + * Save the userland NEON/VFP state. Under UP, + * the owner could be a task other than 'current' + */ + if (vfp_state_in_hw(cpu, thread)) + vfp_save_state(&thread->vfpstate, fpexc); +#ifndef CONFIG_SMP + else if (vfp_current_hw_state[cpu] != NULL) + vfp_save_state(vfp_current_hw_state[cpu], fpexc); +#endif + vfp_current_hw_state[cpu] = NULL; +} +EXPORT_SYMBOL(kernel_neon_begin); + +void kernel_neon_end(void) +{ + /* Disable the NEON/VFP unit. */ + fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN); + vfp_state_release(); +} +EXPORT_SYMBOL(kernel_neon_end); + +#endif /* CONFIG_KERNEL_MODE_NEON */ + +static int __init vfp_detect(struct pt_regs *regs, unsigned int instr) +{ + VFP_arch = UINT_MAX; /* mark as not present */ + regs->ARM_pc += 4; + return 0; +} + +static struct undef_hook vfp_detect_hook __initdata = { + .instr_mask = 0x0c000e00, + .instr_val = 0x0c000a00, + .cpsr_mask = MODE_MASK, + .cpsr_val = SVC_MODE, + .fn = vfp_detect, +}; + +/* * VFP support code initialisation. */ static int __init vfp_init(void) { unsigned int vfpsid; unsigned int cpu_arch = cpu_architecture(); + unsigned int isar6; + /* + * Enable the access to the VFP on all online CPUs so the + * following test on FPSID will succeed. + */ if (cpu_arch >= CPU_ARCH_ARMv6) on_each_cpu(vfp_enable, NULL, 1); @@ -664,71 +943,118 @@ static int __init vfp_init(void) * The handler is already setup to just log calls, so * we just need to read the VFPSID register. */ - vfp_vector = vfp_testing_entry; + register_undef_hook(&vfp_detect_hook); barrier(); vfpsid = fmrx(FPSID); barrier(); - vfp_vector = vfp_null_entry; + unregister_undef_hook(&vfp_detect_hook); pr_info("VFP support v0.3: "); - if (VFP_arch) + if (VFP_arch) { pr_cont("not present\n"); - else if (vfpsid & FPSID_NODOUBLE) { - pr_cont("no double precision support\n"); - } else { - hotcpu_notifier(vfp_hotplug, 0); - - VFP_arch = (vfpsid & FPSID_ARCH_MASK) >> FPSID_ARCH_BIT; /* Extract the architecture version */ - pr_cont("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 and VFPv4 D16. CPUs in - * this configuration only have 16 x 64bit - * registers. - */ - if (((fmrx(MVFR0) & MVFR0_A_SIMD_MASK)) == 1) - elf_hwcap |= HWCAP_VFPv3D16; /* also v4-D16 */ - else - elf_hwcap |= HWCAP_VFPD32; - } -#endif + return 0; + /* Extract the architecture on CPUID scheme */ + } else if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) { + VFP_arch = vfpsid & FPSID_CPUID_ARCH_MASK; + VFP_arch >>= FPSID_ARCH_BIT; /* * 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 -#ifdef CONFIG_VFPv3 + if (IS_ENABLED(CONFIG_NEON) && + (fmrx(MVFR1) & 0x000fff00) == 0x00011100) { + elf_hwcap |= HWCAP_NEON; + for (int i = 0; i < ARRAY_SIZE(neon_support_hook); i++) + register_undef_hook(&neon_support_hook[i]); + } + + if (IS_ENABLED(CONFIG_VFPv3)) { + u32 mvfr0 = fmrx(MVFR0); + if (((mvfr0 & MVFR0_DP_MASK) >> MVFR0_DP_BIT) == 0x2 || + ((mvfr0 & MVFR0_SP_MASK) >> MVFR0_SP_BIT) == 0x2) { + elf_hwcap |= HWCAP_VFPv3; + /* + * Check for VFPv3 D16 and VFPv4 D16. CPUs in + * this configuration only have 16 x 64bit + * registers. + */ + if ((mvfr0 & MVFR0_A_SIMD_MASK) == 1) + /* also v4-D16 */ + elf_hwcap |= HWCAP_VFPv3D16; + else + elf_hwcap |= HWCAP_VFPD32; + } + if ((fmrx(MVFR1) & 0xf0000000) == 0x10000000) elf_hwcap |= HWCAP_VFPv4; -#endif + if (((fmrx(MVFR1) & MVFR1_ASIMDHP_MASK) >> MVFR1_ASIMDHP_BIT) == 0x2) + elf_hwcap |= HWCAP_ASIMDHP; + if (((fmrx(MVFR1) & MVFR1_FPHP_MASK) >> MVFR1_FPHP_BIT) == 0x3) + elf_hwcap |= HWCAP_FPHP; } + + /* + * Check for the presence of Advanced SIMD Dot Product + * instructions. + */ + isar6 = read_cpuid_ext(CPUID_EXT_ISAR6); + if (cpuid_feature_extract_field(isar6, 4) == 0x1) + elf_hwcap |= HWCAP_ASIMDDP; + /* + * Check for the presence of Advanced SIMD Floating point + * half-precision multiplication instructions. + */ + if (cpuid_feature_extract_field(isar6, 8) == 0x1) + elf_hwcap |= HWCAP_ASIMDFHM; + /* + * Check for the presence of Advanced SIMD Bfloat16 + * floating point instructions. + */ + if (cpuid_feature_extract_field(isar6, 20) == 0x1) + elf_hwcap |= HWCAP_ASIMDBF16; + /* + * Check for the presence of Advanced SIMD and floating point + * Int8 matrix multiplication instructions instructions. + */ + if (cpuid_feature_extract_field(isar6, 24) == 0x1) + elf_hwcap |= HWCAP_I8MM; + + /* Extract the architecture version on pre-cpuid scheme */ + } else { + if (vfpsid & FPSID_NODOUBLE) { + pr_cont("no double precision support\n"); + return 0; + } + + VFP_arch = (vfpsid & FPSID_ARCH_MASK) >> FPSID_ARCH_BIT; } + + cpuhp_setup_state_nocalls(CPUHP_AP_ARM_VFP_STARTING, + "arm/vfp:starting", vfp_starting_cpu, + vfp_dying_cpu); + + have_vfp = true; + + register_undef_hook(&vfp_support_hook); + 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; + + pr_cont("implementor %02x architecture %d part %02x variant %x rev %x\n", + (vfpsid & FPSID_IMPLEMENTER_MASK) >> FPSID_IMPLEMENTER_BIT, + VFP_arch, + (vfpsid & FPSID_PART_MASK) >> FPSID_PART_BIT, + (vfpsid & FPSID_VARIANT_MASK) >> FPSID_VARIANT_BIT, + (vfpsid & FPSID_REV_MASK) >> FPSID_REV_BIT); + return 0; } -late_initcall(vfp_init); +core_initcall(vfp_init); |