diff options
Diffstat (limited to 'arch/mips/include/asm/fpu.h')
-rw-r--r-- | arch/mips/include/asm/fpu.h | 145 |
1 files changed, 107 insertions, 38 deletions
diff --git a/arch/mips/include/asm/fpu.h b/arch/mips/include/asm/fpu.h index a2813fe381cf..42bc2bbbd3d7 100644 --- a/arch/mips/include/asm/fpu.h +++ b/arch/mips/include/asm/fpu.h @@ -30,13 +30,6 @@ #include <asm/mips_mt.h> #endif -struct sigcontext; -struct sigcontext32; - -extern void _init_fpu(unsigned int); -extern void _save_fp(struct task_struct *); -extern void _restore_fp(struct task_struct *); - /* * 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 @@ -51,6 +44,11 @@ enum fpu_mode { #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); \ @@ -198,42 +196,36 @@ static inline void lose_fpu(int save) preempt_enable(); } -static inline int init_fpu(void) +/** + * 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) { - unsigned int fcr31 = current->thread.fpu.fcr31; - int ret = 0; + /* If FP has been used then the target already has context */ + if (tsk_used_math(target)) + return false; - if (cpu_has_fpu) { - unsigned int config5; - - ret = __own_fpu(); - if (ret) - return ret; + /* Begin with data registers set to all 1s... */ + memset(&target->thread.fpu.fpr, ~0, sizeof(target->thread.fpu.fpr)); - if (!cpu_has_fre) { - _init_fpu(fcr31); + /* FCSR has been preset by `mips_set_personality_nan'. */ - return 0; - } - - /* - * Ensure FRE is clear whilst running _init_fpu, since - * single precision FP instructions are used. If FRE - * was set then we'll just end up initialising all 32 - * 64b registers. - */ - config5 = clear_c0_config5(MIPS_CONF5_FRE); - enable_fpu_hazard(); + /* + * 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); - _init_fpu(fcr31); - - /* Restore FRE */ - write_c0_config5(config5); - enable_fpu_hazard(); - } else - fpu_emulator_init_fpu(); - - return ret; + return true; } static inline void save_fp(struct task_struct *tsk) @@ -260,4 +252,81 @@ static inline union fpureg *get_fpu_regs(struct task_struct *tsk) 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 */ |