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Diffstat (limited to 'arch/nds32/include/asm/fpu.h')
| -rw-r--r-- | arch/nds32/include/asm/fpu.h | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/arch/nds32/include/asm/fpu.h b/arch/nds32/include/asm/fpu.h new file mode 100644 index 000000000000..019f1bcfc5ee --- /dev/null +++ b/arch/nds32/include/asm/fpu.h @@ -0,0 +1,126 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2005-2018 Andes Technology Corporation */ + +#ifndef __ASM_NDS32_FPU_H +#define __ASM_NDS32_FPU_H + +#if IS_ENABLED(CONFIG_FPU) +#ifndef __ASSEMBLY__ +#include <linux/sched/task_stack.h> +#include <linux/preempt.h> +#include <asm/ptrace.h> + +extern bool has_fpu; + +extern void save_fpu(struct task_struct *__tsk); +extern void load_fpu(const struct fpu_struct *fpregs); +extern bool do_fpu_exception(unsigned int subtype, struct pt_regs *regs); +extern int do_fpuemu(struct pt_regs *regs, struct fpu_struct *fpu); + +#define test_tsk_fpu(regs) (regs->fucop_ctl & FUCOP_CTL_mskCP0EN) + +/* + * Initially load the FPU with signalling NANS. This bit pattern + * has the property that no matter whether considered as single or as + * double precision, it still represents a signalling NAN. + */ + +#define sNAN64 0xFFFFFFFFFFFFFFFFULL +#define sNAN32 0xFFFFFFFFUL + +#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC) +/* + * Denormalized number is unsupported by nds32 FPU. Hence the operation + * is treated as underflow cases when the final result is a denormalized + * number. To enhance precision, underflow exception trap should be + * enabled by default and kerenl will re-execute it by fpu emulator + * when getting underflow exception. + */ +#define FPCSR_INIT FPCSR_mskUDFE +#else +#define FPCSR_INIT 0x0UL +#endif + +extern const struct fpu_struct init_fpuregs; + +static inline void disable_ptreg_fpu(struct pt_regs *regs) +{ + regs->fucop_ctl &= ~FUCOP_CTL_mskCP0EN; +} + +static inline void enable_ptreg_fpu(struct pt_regs *regs) +{ + regs->fucop_ctl |= FUCOP_CTL_mskCP0EN; +} + +static inline void enable_fpu(void) +{ + unsigned long fucop_ctl; + + fucop_ctl = __nds32__mfsr(NDS32_SR_FUCOP_CTL) | FUCOP_CTL_mskCP0EN; + __nds32__mtsr(fucop_ctl, NDS32_SR_FUCOP_CTL); + __nds32__isb(); +} + +static inline void disable_fpu(void) +{ + unsigned long fucop_ctl; + + fucop_ctl = __nds32__mfsr(NDS32_SR_FUCOP_CTL) & ~FUCOP_CTL_mskCP0EN; + __nds32__mtsr(fucop_ctl, NDS32_SR_FUCOP_CTL); + __nds32__isb(); +} + +static inline void lose_fpu(void) +{ + preempt_disable(); +#if IS_ENABLED(CONFIG_LAZY_FPU) + if (last_task_used_math == current) { + last_task_used_math = NULL; +#else + if (test_tsk_fpu(task_pt_regs(current))) { +#endif + save_fpu(current); + } + disable_ptreg_fpu(task_pt_regs(current)); + preempt_enable(); +} + +static inline void own_fpu(void) +{ + preempt_disable(); +#if IS_ENABLED(CONFIG_LAZY_FPU) + if (last_task_used_math != current) { + if (last_task_used_math != NULL) + save_fpu(last_task_used_math); + load_fpu(¤t->thread.fpu); + last_task_used_math = current; + } +#else + if (!test_tsk_fpu(task_pt_regs(current))) { + load_fpu(¤t->thread.fpu); + } +#endif + enable_ptreg_fpu(task_pt_regs(current)); + preempt_enable(); +} + +#if !IS_ENABLED(CONFIG_LAZY_FPU) +static inline void unlazy_fpu(struct task_struct *tsk) +{ + preempt_disable(); + if (test_tsk_fpu(task_pt_regs(tsk))) + save_fpu(tsk); + preempt_enable(); +} +#endif /* !CONFIG_LAZY_FPU */ +static inline void clear_fpu(struct pt_regs *regs) +{ + preempt_disable(); + if (test_tsk_fpu(regs)) + disable_ptreg_fpu(regs); + preempt_enable(); +} +#endif /* CONFIG_FPU */ +#endif /* __ASSEMBLY__ */ +#endif /* __ASM_NDS32_FPU_H */ |