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   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@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 } while (0)
  81
  82 #define __clear_fpu( tsk )                                      \
  83 do {                                                            \
  84         if (task_thread_info(tsk)->status & TS_USEDFPU) {               \
  85                 asm volatile("fnclex ; fwait");                         \
  86                 task_thread_info(tsk)->status &= ~TS_USEDFPU;   \
  87                 stts();                                         \
  88         }                                                       \
  89 } while (0)
  90
  91
  92 /*
  93  * These disable preemption on their own and are safe
  94  */
  95 static inline void save_init_fpu( struct task_struct *tsk )
  96 {
  97         preempt_disable();
  98         __save_init_fpu(tsk);
  99         stts();
 100         preempt_enable();
 101 }
 102
 103 #define unlazy_fpu( tsk ) do {  \
 104         preempt_disable();      \
 105         __unlazy_fpu(tsk);      \
 106         preempt_enable();       \
 107 } while (0)
 108
 109 #define clear_fpu( tsk ) do {   \
 110         preempt_disable();      \
 111         __clear_fpu( tsk );     \
 112         preempt_enable();       \
 113 } while (0)
 114                                         \
 115 /*
 116  * FPU state interaction...
 117  */
 118 extern unsigned short get_fpu_cwd( struct task_struct *tsk );
 119 extern unsigned short get_fpu_swd( struct task_struct *tsk );
 120 extern unsigned short get_fpu_mxcsr( struct task_struct *tsk );
 121
 122 /*
 123  * Signal frame handlers...
 124  */
 125 extern int save_i387( struct _fpstate __user *buf );
 126 extern int restore_i387( struct _fpstate __user *buf );
 127
 128 /*
 129  * ptrace request handers...
 130  */
 131 extern int get_fpregs( struct user_i387_struct __user *buf,
 132                        struct task_struct *tsk );
 133 extern int set_fpregs( struct task_struct *tsk,
 134                        struct user_i387_struct __user *buf );
 135
 136 extern int get_fpxregs( struct user_fxsr_struct __user *buf,
 137                         struct task_struct *tsk );
 138 extern int set_fpxregs( struct task_struct *tsk,
 139                         struct user_fxsr_struct __user *buf );
 140
 141 /*
 142  * FPU state for core dumps...
 143  */
 144 extern int dump_fpu( struct pt_regs *regs,
 145                      struct user_i387_struct *fpu );
 146
 147 #endif /* __ASM_I386_I387_H */