1 /* 2 * include/asm-i386/i387.h 3 * 4 * Copyright (C) 1994 Linus Torvalds 5 * 6 * Pentium III FXSR, SSE support 7 * General FPU state handling cleanups 8 * Gareth Hughes <gareth (at) valinux.com>, May 2000 9 */ 10 11 #ifndef __ASM_I386_I387_H 12 #define __ASM_I386_I387_H 13 14 #include <linux/sched.h> 15 #include <linux/init.h> 16 #include <linux/kernel_stat.h> 17 #include <asm/processor.h> 18 #include <asm/sigcontext.h> 19 #include <asm/user.h> 20 21 extern void mxcsr_feature_mask_init(void); 22 extern void init_fpu(struct task_struct *); 23 24 /* 25 * FPU lazy state save handling... 26 */ 27 28 /* 29 * The "nop" is needed to make the instructions the same 30 * length. 31 */ 32 #define restore_fpu(tsk) \ 33 alternative_input( \ 34 "nop ; frstor %1", \ 35 "fxrstor %1", \ 36 X86_FEATURE_FXSR, \ 37 "m" ((tsk)->thread.i387.fxsave)) 38 39 extern void kernel_fpu_begin(void); 40 #define kernel_fpu_end() do { stts(); preempt_enable(); } while(0) 41 42 /* We need a safe address that is cheap to find and that is already 43 in L1 during context switch. The best choices are unfortunately 44 different for UP and SMP */ 45 #ifdef CONFIG_SMP 46 #define safe_address (__per_cpu_offset[0]) 47 #else 48 #define safe_address (kstat_cpu(0).cpustat.user) 49 #endif 50 51 /* 52 * These must be called with preempt disabled 53 */ 54 static inline void __save_init_fpu( struct task_struct *tsk ) 55 { 56 /* Use more nops than strictly needed in case the compiler 57 varies code */ 58 alternative_input( 59 "fnsave %[fx] ;fwait;" GENERIC_NOP8 GENERIC_NOP4, 60 "fxsave %[fx]\n" 61 "bt $7,%[fsw] ; jnc 1f ; fnclex\n1:", 62 X86_FEATURE_FXSR, 63 [fx] "m" (tsk->thread.i387.fxsave), 64 [fsw] "m" (tsk->thread.i387.fxsave.swd) : "memory"); 65 /* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception 66 is pending. Clear the x87 state here by setting it to fixed 67 values. safe_address is a random variable that should be in L1 */ 68 alternative_input( 69 GENERIC_NOP8 GENERIC_NOP2, 70 "emms\n\t" /* clear stack tags */ 71 "fildl %[addr]", /* set F?P to defined value */ 72 X86_FEATURE_FXSAVE_LEAK, 73 [addr] "m" (safe_address)); 74 task_thread_info(tsk)->status &= ~TS_USEDFPU; 75 } 76 77 #define __unlazy_fpu( tsk ) do { \ 78 if (task_thread_info(tsk)->status & TS_USEDFPU) { \ 79 __save_init_fpu(tsk); \ 80 stts(); \ 81 } else \ 82 tsk->fpu_counter = 0; \ 83 } while (0) 84 85 #define __clear_fpu( tsk ) \ 86 do { \ 87 if (task_thread_info(tsk)->status & TS_USEDFPU) { \ 88 asm volatile("fnclex ; fwait"); \ 89 task_thread_info(tsk)->status &= ~TS_USEDFPU; \ 90 stts(); \ 91 } \ 92 } while (0) 93 94 95 /* 96 * These disable preemption on their own and are safe 97 */ 98 static inline void save_init_fpu( struct task_struct *tsk ) 99 { 100 preempt_disable(); 101 __save_init_fpu(tsk); 102 stts(); 103 preempt_enable(); 104 } 105 106 #define unlazy_fpu( tsk ) do { \ 107 preempt_disable(); \ 108 __unlazy_fpu(tsk); \ 109 preempt_enable(); \ 110 } while (0) 111 112 #define clear_fpu( tsk ) do { \ 113 preempt_disable(); \ 114 __clear_fpu( tsk ); \ 115 preempt_enable(); \ 116 } while (0) 117 118 /* 119 * FPU state interaction... 120 */ 121 extern unsigned short get_fpu_cwd( struct task_struct *tsk ); 122 extern unsigned short get_fpu_swd( struct task_struct *tsk ); 123 extern unsigned short get_fpu_mxcsr( struct task_struct *tsk ); 124 extern asmlinkage void math_state_restore(void); 125 126 /* 127 * Signal frame handlers... 128 */ 129 extern int save_i387( struct _fpstate __user *buf ); 130 extern int restore_i387( struct _fpstate __user *buf ); 131 132 /* 133 * ptrace request handers... 134 */ 135 extern int get_fpregs( struct user_i387_struct __user *buf, 136 struct task_struct *tsk ); 137 extern int set_fpregs( struct task_struct *tsk, 138 struct user_i387_struct __user *buf ); 139 140 extern int get_fpxregs( struct user_fxsr_struct __user *buf, 141 struct task_struct *tsk ); 142 extern int set_fpxregs( struct task_struct *tsk, 143 struct user_fxsr_struct __user *buf ); 144 145 /* 146 * FPU state for core dumps... 147 */ 148 extern int dump_fpu( struct pt_regs *regs, 149 struct user_i387_struct *fpu ); 150 151 #endif /* __ASM_I386_I387_H */ 152
