/* * linux/arch/i386/kernel/i387.c * * Copyright (C) 1994 Linus Torvalds * * Pentium III FXSR, SSE support * General FPU state handling cleanups * Gareth Hughes <gareth@valinux.com>, May 2000 */ #include <linux/config.h> #include <linux/sched.h> #include <asm/processor.h> #include <asm/i387.h> #include <asm/math_emu.h> #include <asm/sigcontext.h> #include <asm/user.h> #include <asm/ptrace.h> #include <asm/uaccess.h> #if defined(CONFIG_X86_FXSR) #define HAVE_FXSR 1 #elif defined(CONFIG_X86_RUNTIME_FXSR) #define HAVE_FXSR (cpu_has_fxsr) #else #define HAVE_FXSR 0 #endif #ifdef CONFIG_MATH_EMULATION #define HAVE_HWFP (boot_cpu_data.hard_math) #else #define HAVE_HWFP 1 #endif /* * The _current_ task is using the FPU for the first time * so initialize it and set the mxcsr to its default * value at reset if we support FXSR and then * remeber the current task has used the FPU. */ 41 void init_fpu(void) { __asm__("fninit"); 44 if ( HAVE_FXSR ) 45 load_mxcsr(0x1f80); current->used_math = 1; } /* * FPU lazy state save handling. */ 54 void save_init_fpu( struct task_struct *tsk ) { 56 if ( HAVE_FXSR ) { asm volatile( "fxsave %0 ; fnclex" : "=m" (tsk->thread.i387.fxsave) ); 59 } else { asm volatile( "fnsave %0 ; fwait" : "=m" (tsk->thread.i387.fsave) ); } tsk->flags &= ~PF_USEDFPU; stts(); } 67 void restore_fpu( struct task_struct *tsk ) { 69 if ( HAVE_FXSR ) { asm volatile( "fxrstor %0" : : "m" (tsk->thread.i387.fxsave) ); 72 } else { asm volatile( "frstor %0" : : "m" (tsk->thread.i387.fsave) ); } } /* * FPU tag word conversions. */ 82 static inline unsigned short twd_i387_to_fxsr( unsigned short twd ) { unsigned int tmp; /* to avoid 16 bit prefixes in the code */ /* Transform each pair of bits into 01 (valid) or 00 (empty) */ tmp = ~twd; tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */ /* and move the valid bits to the lower byte. */ tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */ tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */ tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */ 93 return tmp; } 96 static inline unsigned long twd_fxsr_to_i387( struct i387_fxsave_struct *fxsave ) { struct _fpxreg *st = NULL; unsigned long twd = (unsigned long) fxsave->twd; unsigned long tag; unsigned long ret = 0xffff0000; int i; #define FPREG_ADDR(f, n) ((char *)&(f)->st_space + (n) * 16); 106 for ( i = 0 ; i < 8 ; i++ ) { 107 if ( twd & 0x1 ) { st = (struct _fpxreg *) FPREG_ADDR( fxsave, i ); 110 switch ( st->exponent & 0x7fff ) { 111 case 0x7fff: tag = 2; /* Special */ 113 break; 114 case 0x0000: if ( !st->significand[0] && !st->significand[1] && !st->significand[2] && 118 !st->significand[3] ) { tag = 1; /* Zero */ 120 } else { tag = 2; /* Special */ } 123 break; 124 default: 125 if ( st->significand[3] & 0x8000 ) { tag = 0; /* Valid */ 127 } else { tag = 2; /* Special */ } 130 break; } 132 } else { tag = 3; /* Empty */ } ret |= (tag << (2 * i)); twd = twd >> 1; } 138 return ret; } /* * FPU state interaction. */ 145 unsigned short get_fpu_cwd( struct task_struct *tsk ) { 147 if ( HAVE_FXSR ) { 148 return tsk->thread.i387.fxsave.cwd; 149 } else { 150 return (unsigned short)tsk->thread.i387.fsave.cwd; } } 154 unsigned short get_fpu_swd( struct task_struct *tsk ) { 156 if ( HAVE_FXSR ) { 157 return tsk->thread.i387.fxsave.swd; 158 } else { 159 return (unsigned short)tsk->thread.i387.fsave.swd; } } 163 unsigned short get_fpu_twd( struct task_struct *tsk ) { 165 if ( HAVE_FXSR ) { 166 return tsk->thread.i387.fxsave.twd; 167 } else { 168 return (unsigned short)tsk->thread.i387.fsave.twd; } } 172 unsigned short get_fpu_mxcsr( struct task_struct *tsk ) { 174 if ( HAVE_FXSR ) { 175 return tsk->thread.i387.fxsave.mxcsr; 176 } else { 177 return 0x1f80; } } 181 void set_fpu_cwd( struct task_struct *tsk, unsigned short cwd ) { 183 if ( HAVE_FXSR ) { tsk->thread.i387.fxsave.cwd = cwd; 185 } else { tsk->thread.i387.fsave.cwd = ((long)cwd | 0xffff0000); } } 190 void set_fpu_swd( struct task_struct *tsk, unsigned short swd ) { 192 if ( HAVE_FXSR ) { tsk->thread.i387.fxsave.swd = swd; 194 } else { tsk->thread.i387.fsave.swd = ((long)swd | 0xffff0000); } } 199 void set_fpu_twd( struct task_struct *tsk, unsigned short twd ) { 201 if ( HAVE_FXSR ) { tsk->thread.i387.fxsave.twd = twd_i387_to_fxsr(twd); 203 } else { tsk->thread.i387.fsave.twd = ((long)twd | 0xffff0000); } } 208 void set_fpu_mxcsr( struct task_struct *tsk, unsigned short mxcsr ) { 210 if ( HAVE_FXSR ) { tsk->thread.i387.fxsave.mxcsr = mxcsr; } } /* * FXSR floating point environment conversions. */ 219 static inline int convert_fxsr_to_user( struct _fpstate *buf, struct i387_fxsave_struct *fxsave ) { unsigned long env[7]; struct _fpreg *to; struct _fpxreg *from; int i; env[0] = (unsigned long)fxsave->cwd | 0xffff0000; env[1] = (unsigned long)fxsave->swd | 0xffff0000; env[2] = twd_fxsr_to_i387(fxsave); env[3] = fxsave->fip; env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16); env[5] = fxsave->foo; env[6] = fxsave->fos; 235 if ( __copy_to_user( buf, env, 7 * sizeof(unsigned long) ) ) 236 return 1; to = &buf->_st[0]; from = (struct _fpxreg *) &fxsave->st_space[0]; 240 for ( i = 0 ; i < 8 ; i++, to++, from++ ) { 241 if ( __copy_to_user( to, from, sizeof(*to) ) ) 242 return 1; } 244 return 0; } 247 static inline int convert_fxsr_from_user( struct i387_fxsave_struct *fxsave, struct _fpstate *buf ) { unsigned long env[7]; struct _fpxreg *to; struct _fpreg *from; int i; 255 if ( __copy_from_user( env, buf, 7 * sizeof(long) ) ) 256 return 1; fxsave->cwd = (unsigned short)(env[0] & 0xffff); fxsave->swd = (unsigned short)(env[1] & 0xffff); fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff)); fxsave->fip = env[3]; fxsave->fop = (unsigned short)((env[4] & 0xffff0000) >> 16); fxsave->fcs = (env[4] & 0xffff); fxsave->foo = env[5]; fxsave->fos = env[6]; to = (struct _fpxreg *) &fxsave->st_space[0]; from = &buf->_st[0]; 269 for ( i = 0 ; i < 8 ; i++, to++, from++ ) { 270 if ( __copy_from_user( to, from, sizeof(*from) ) ) 271 return 1; } 273 return 0; } /* * Signal frame handlers. */ 280 static inline int save_i387_fsave( struct _fpstate *buf ) { struct task_struct *tsk = current; 284 unlazy_fpu( tsk ); tsk->thread.i387.fsave.status = tsk->thread.i387.fsave.swd; if ( __copy_to_user( buf, &tsk->thread.i387.fsave, 287 sizeof(struct i387_fsave_struct) ) ) 288 return -1; 289 return 1; } 292 static inline int save_i387_fxsave( struct _fpstate *buf ) { struct task_struct *tsk = current; int err = 0; 297 unlazy_fpu( tsk ); 299 if ( convert_fxsr_to_user( buf, &tsk->thread.i387.fxsave ) ) 300 return -1; err |= __put_user( tsk->thread.i387.fxsave.swd, &buf->status ); err |= __put_user( X86_FXSR_MAGIC, &buf->magic ); 304 if ( err ) 305 return -1; if ( __copy_to_user( &buf->_fxsr_env[0], &tsk->thread.i387.fxsave, 308 sizeof(struct i387_fxsave_struct) ) ) 309 return -1; 310 return 1; } 313 int save_i387( struct _fpstate *buf ) { 315 if ( !current->used_math ) 316 return 0; /* This will cause a "finit" to be triggered by the next * attempted FPU operation by the 'current' process. */ current->used_math = 0; 323 if ( HAVE_HWFP ) { 324 if ( HAVE_FXSR ) { 325 return save_i387_fxsave( buf ); 326 } else { 327 return save_i387_fsave( buf ); } 329 } else { 330 return save_i387_soft( ¤t->thread.i387.soft, buf ); } } 334 static inline int restore_i387_fsave( struct _fpstate *buf ) { struct task_struct *tsk = current; 337 clear_fpu( tsk ); return __copy_from_user( &tsk->thread.i387.fsave, buf, 339 sizeof(struct i387_fsave_struct) ); } 342 static inline int restore_i387_fxsave( struct _fpstate *buf ) { struct task_struct *tsk = current; 345 clear_fpu( tsk ); if ( __copy_from_user( &tsk->thread.i387.fxsave, &buf->_fxsr_env[0], 347 sizeof(struct i387_fxsave_struct) ) ) 348 return 1; 349 return convert_fxsr_from_user( &tsk->thread.i387.fxsave, buf ); } 352 int restore_i387( struct _fpstate *buf ) { int err; 356 if ( HAVE_HWFP ) { 357 if ( HAVE_FXSR ) { err = restore_i387_fxsave( buf ); 359 } else { err = restore_i387_fsave( buf ); } 362 } else { err = restore_i387_soft( ¤t->thread.i387.soft, buf ); } current->used_math = 1; 366 return err; } /* * ptrace request handlers. */ 373 static inline int get_fpregs_fsave( struct user_i387_struct *buf, struct task_struct *tsk ) { return __copy_to_user( buf, &tsk->thread.i387.fsave, 377 sizeof(struct user_i387_struct) ); } 380 static inline int get_fpregs_fxsave( struct user_i387_struct *buf, struct task_struct *tsk ) { return convert_fxsr_to_user( (struct _fpstate *)buf, 384 &tsk->thread.i387.fxsave ); } 387 int get_fpregs( struct user_i387_struct *buf, struct task_struct *tsk ) { 389 if ( HAVE_HWFP ) { 390 if ( HAVE_FXSR ) { 391 return get_fpregs_fxsave( buf, tsk ); 392 } else { 393 return get_fpregs_fsave( buf, tsk ); } 395 } else { return save_i387_soft( &tsk->thread.i387.soft, 397 (struct _fpstate *)buf ); } } 401 static inline int set_fpregs_fsave( struct task_struct *tsk, struct user_i387_struct *buf ) { return __copy_from_user( &tsk->thread.i387.fsave, buf, 405 sizeof(struct user_i387_struct) ); } 408 static inline int set_fpregs_fxsave( struct task_struct *tsk, struct user_i387_struct *buf ) { return convert_fxsr_from_user( &tsk->thread.i387.fxsave, 412 (struct _fpstate *)buf ); } 415 int set_fpregs( struct task_struct *tsk, struct user_i387_struct *buf ) { 417 if ( HAVE_HWFP ) { 418 if ( HAVE_FXSR ) { 419 return set_fpregs_fxsave( tsk, buf ); 420 } else { 421 return set_fpregs_fsave( tsk, buf ); } 423 } else { return restore_i387_soft( &tsk->thread.i387.soft, 425 (struct _fpstate *)buf ); } } 429 int get_fpxregs( struct user_fxsr_struct *buf, struct task_struct *tsk ) { 431 if ( HAVE_FXSR ) { __copy_to_user( (void *)buf, &tsk->thread.i387.fxsave, sizeof(struct user_fxsr_struct) ); 434 return 0; 435 } else { 436 return -EIO; } } 440 int set_fpxregs( struct task_struct *tsk, struct user_fxsr_struct *buf ) { 442 if ( HAVE_FXSR ) { __copy_from_user( &tsk->thread.i387.fxsave, (void *)buf, sizeof(struct user_fxsr_struct) ); /* mxcsr bit 6 and 31-16 must be zero for security reasons */ tsk->thread.i387.fxsave.mxcsr &= 0xffbf; 447 return 0; 448 } else { 449 return -EIO; } } /* * FPU state for core dumps. */ 457 static inline void copy_fpu_fsave( struct task_struct *tsk, struct user_i387_struct *fpu ) { memcpy( fpu, &tsk->thread.i387.fsave, sizeof(struct user_i387_struct) ); } 464 static inline void copy_fpu_fxsave( struct task_struct *tsk, struct user_i387_struct *fpu ) { unsigned short *to; unsigned short *from; int i; memcpy( fpu, &tsk->thread.i387.fxsave, 7 * sizeof(long) ); to = (unsigned short *)&fpu->st_space[0]; from = (unsigned short *)&tsk->thread.i387.fxsave.st_space[0]; 475 for ( i = 0 ; i < 8 ; i++, to += 5, from += 8 ) { memcpy( to, from, 5 * sizeof(unsigned short) ); } } 480 int dump_fpu( struct pt_regs *regs, struct user_i387_struct *fpu ) { int fpvalid; struct task_struct *tsk = current; fpvalid = tsk->used_math; 486 if ( fpvalid ) { 487 unlazy_fpu( tsk ); 488 if ( HAVE_FXSR ) { copy_fpu_fxsave( tsk, fpu ); 490 } else { copy_fpu_fsave( tsk, fpu ); } } 495 return fpvalid; } 498 int dump_extended_fpu( struct pt_regs *regs, struct user_fxsr_struct *fpu ) { int fpvalid; struct task_struct *tsk = current; fpvalid = tsk->used_math && HAVE_FXSR; 504 if ( fpvalid ) { 505 unlazy_fpu( tsk ); memcpy( fpu, &tsk->thread.i387.fxsave, sizeof(struct user_fxsr_struct) ); } 510 return fpvalid; }