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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/mips/include/asm/fpu.h | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | arch/mips/include/asm/fpu.h | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/arch/mips/include/asm/fpu.h b/arch/mips/include/asm/fpu.h new file mode 100644 index 000000000..86310d6e1 --- /dev/null +++ b/arch/mips/include/asm/fpu.h @@ -0,0 +1,328 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2002 MontaVista Software Inc. + * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net + */ +#ifndef _ASM_FPU_H +#define _ASM_FPU_H + +#include <linux/sched.h> +#include <linux/sched/task_stack.h> +#include <linux/ptrace.h> +#include <linux/thread_info.h> +#include <linux/bitops.h> + +#include <asm/mipsregs.h> +#include <asm/cpu.h> +#include <asm/cpu-features.h> +#include <asm/fpu_emulator.h> +#include <asm/hazards.h> +#include <asm/ptrace.h> +#include <asm/processor.h> +#include <asm/current.h> +#include <asm/msa.h> + +#ifdef CONFIG_MIPS_MT_FPAFF +#include <asm/mips_mt.h> +#endif + +/* + * This enum specifies a mode in which we want the FPU to operate, for cores + * which implement the Status.FR bit. Note that the bottom bit of the value + * purposefully matches the desired value of the Status.FR bit. + */ +enum fpu_mode { + FPU_32BIT = 0, /* FR = 0 */ + FPU_64BIT, /* FR = 1, FRE = 0 */ + FPU_AS_IS, + FPU_HYBRID, /* FR = 1, FRE = 1 */ + +#define FPU_FR_MASK 0x1 +}; + +#ifdef CONFIG_MIPS_FP_SUPPORT + +extern void _save_fp(struct task_struct *); +extern void _restore_fp(struct task_struct *); + +#define __disable_fpu() \ +do { \ + clear_c0_status(ST0_CU1); \ + disable_fpu_hazard(); \ +} while (0) + +static inline int __enable_fpu(enum fpu_mode mode) +{ + int fr; + + switch (mode) { + case FPU_AS_IS: + /* just enable the FPU in its current mode */ + set_c0_status(ST0_CU1); + enable_fpu_hazard(); + return 0; + + case FPU_HYBRID: + if (!cpu_has_fre) + return SIGFPE; + + /* set FRE */ + set_c0_config5(MIPS_CONF5_FRE); + goto fr_common; + + case FPU_64BIT: +#if !(defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR5) || \ + defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_64BIT)) + /* we only have a 32-bit FPU */ + return SIGFPE; +#endif + /* fallthrough */ + case FPU_32BIT: + if (cpu_has_fre) { + /* clear FRE */ + clear_c0_config5(MIPS_CONF5_FRE); + } +fr_common: + /* set CU1 & change FR appropriately */ + fr = (int)mode & FPU_FR_MASK; + change_c0_status(ST0_CU1 | ST0_FR, ST0_CU1 | (fr ? ST0_FR : 0)); + enable_fpu_hazard(); + + /* check FR has the desired value */ + if (!!(read_c0_status() & ST0_FR) == !!fr) + return 0; + + /* unsupported FR value */ + __disable_fpu(); + return SIGFPE; + + default: + BUG(); + } + + return SIGFPE; +} + +#define clear_fpu_owner() clear_thread_flag(TIF_USEDFPU) + +static inline int __is_fpu_owner(void) +{ + return test_thread_flag(TIF_USEDFPU); +} + +static inline int is_fpu_owner(void) +{ + return cpu_has_fpu && __is_fpu_owner(); +} + +static inline int __own_fpu(void) +{ + enum fpu_mode mode; + int ret; + + if (test_thread_flag(TIF_HYBRID_FPREGS)) + mode = FPU_HYBRID; + else + mode = !test_thread_flag(TIF_32BIT_FPREGS); + + ret = __enable_fpu(mode); + if (ret) + return ret; + + KSTK_STATUS(current) |= ST0_CU1; + if (mode == FPU_64BIT || mode == FPU_HYBRID) + KSTK_STATUS(current) |= ST0_FR; + else /* mode == FPU_32BIT */ + KSTK_STATUS(current) &= ~ST0_FR; + + set_thread_flag(TIF_USEDFPU); + return 0; +} + +static inline int own_fpu_inatomic(int restore) +{ + int ret = 0; + + if (cpu_has_fpu && !__is_fpu_owner()) { + ret = __own_fpu(); + if (restore && !ret) + _restore_fp(current); + } + return ret; +} + +static inline int own_fpu(int restore) +{ + int ret; + + preempt_disable(); + ret = own_fpu_inatomic(restore); + preempt_enable(); + return ret; +} + +static inline void lose_fpu_inatomic(int save, struct task_struct *tsk) +{ + if (is_msa_enabled()) { + if (save) { + save_msa(tsk); + tsk->thread.fpu.fcr31 = + read_32bit_cp1_register(CP1_STATUS); + } + disable_msa(); + clear_tsk_thread_flag(tsk, TIF_USEDMSA); + __disable_fpu(); + } else if (is_fpu_owner()) { + if (save) + _save_fp(tsk); + __disable_fpu(); + } else { + /* FPU should not have been left enabled with no owner */ + WARN(read_c0_status() & ST0_CU1, + "Orphaned FPU left enabled"); + } + KSTK_STATUS(tsk) &= ~ST0_CU1; + clear_tsk_thread_flag(tsk, TIF_USEDFPU); +} + +static inline void lose_fpu(int save) +{ + preempt_disable(); + lose_fpu_inatomic(save, current); + preempt_enable(); +} + +/** + * init_fp_ctx() - Initialize task FP context + * @target: The task whose FP context should be initialized. + * + * Initializes the FP context of the target task to sane default values if that + * target task does not already have valid FP context. Once the context has + * been initialized, the task will be marked as having used FP & thus having + * valid FP context. + * + * Returns: true if context is initialized, else false. + */ +static inline bool init_fp_ctx(struct task_struct *target) +{ + /* If FP has been used then the target already has context */ + if (tsk_used_math(target)) + return false; + + /* Begin with data registers set to all 1s... */ + memset(&target->thread.fpu.fpr, ~0, sizeof(target->thread.fpu.fpr)); + + /* FCSR has been preset by `mips_set_personality_nan'. */ + + /* + * Record that the target has "used" math, such that the context + * just initialised, and any modifications made by the caller, + * aren't discarded. + */ + set_stopped_child_used_math(target); + + return true; +} + +static inline void save_fp(struct task_struct *tsk) +{ + if (cpu_has_fpu) + _save_fp(tsk); +} + +static inline void restore_fp(struct task_struct *tsk) +{ + if (cpu_has_fpu) + _restore_fp(tsk); +} + +static inline union fpureg *get_fpu_regs(struct task_struct *tsk) +{ + if (tsk == current) { + preempt_disable(); + if (is_fpu_owner()) + _save_fp(current); + preempt_enable(); + } + + return tsk->thread.fpu.fpr; +} + +#else /* !CONFIG_MIPS_FP_SUPPORT */ + +/* + * When FP support is disabled we provide only a minimal set of stub functions + * to avoid callers needing to care too much about CONFIG_MIPS_FP_SUPPORT. + */ + +static inline int __enable_fpu(enum fpu_mode mode) +{ + return SIGILL; +} + +static inline void __disable_fpu(void) +{ + /* no-op */ +} + + +static inline int is_fpu_owner(void) +{ + return 0; +} + +static inline void clear_fpu_owner(void) +{ + /* no-op */ +} + +static inline int own_fpu_inatomic(int restore) +{ + return SIGILL; +} + +static inline int own_fpu(int restore) +{ + return SIGILL; +} + +static inline void lose_fpu_inatomic(int save, struct task_struct *tsk) +{ + /* no-op */ +} + +static inline void lose_fpu(int save) +{ + /* no-op */ +} + +static inline bool init_fp_ctx(struct task_struct *target) +{ + return false; +} + +/* + * The following functions should only be called in paths where we know that FP + * support is enabled, typically a path where own_fpu() or __enable_fpu() have + * returned successfully. When CONFIG_MIPS_FP_SUPPORT=n it is known at compile + * time that this should never happen, so calls to these functions should be + * optimized away & never actually be emitted. + */ + +extern void save_fp(struct task_struct *tsk) + __compiletime_error("save_fp() should not be called when CONFIG_MIPS_FP_SUPPORT=n"); + +extern void _save_fp(struct task_struct *) + __compiletime_error("_save_fp() should not be called when CONFIG_MIPS_FP_SUPPORT=n"); + +extern void restore_fp(struct task_struct *tsk) + __compiletime_error("restore_fp() should not be called when CONFIG_MIPS_FP_SUPPORT=n"); + +extern void _restore_fp(struct task_struct *) + __compiletime_error("_restore_fp() should not be called when CONFIG_MIPS_FP_SUPPORT=n"); + +extern union fpureg *get_fpu_regs(struct task_struct *tsk) + __compiletime_error("get_fpu_regs() should not be called when CONFIG_MIPS_FP_SUPPORT=n"); + +#endif /* !CONFIG_MIPS_FP_SUPPORT */ +#endif /* _ASM_FPU_H */ |