include/asm-x86/i387_32.h

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