/* * linux/arch/i386/kernel/i387.c * * Copyright (C) 1994 Linus Torvalds * * Pentium III FXSR, SSE support * General FPU state handling cleanups * Gareth Hughes , May 2000 */ #include #include #include #include #include #include #include #include #include #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 XMM instructions and then * remeber the current task has used the FPU. */ void init_fpu(void) { __asm__("fninit"); if ( cpu_has_xmm ) load_mxcsr(0x1f80); current->used_math = 1; } /* * FPU lazy state save handling. */ static inline void __save_init_fpu( struct task_struct *tsk ) { if ( cpu_has_fxsr ) { asm volatile( "fxsave %0 ; fnclex" : "=m" (tsk->thread.i387.fxsave) ); } else { asm volatile( "fnsave %0 ; fwait" : "=m" (tsk->thread.i387.fsave) ); } tsk->flags &= ~PF_USEDFPU; } void save_init_fpu( struct task_struct *tsk ) { __save_init_fpu(tsk); stts(); } void kernel_fpu_begin(void) { struct task_struct *tsk = current; if (tsk->flags & PF_USEDFPU) { __save_init_fpu(tsk); return; } clts(); } void restore_fpu( struct task_struct *tsk ) { if ( cpu_has_fxsr ) { asm volatile( "fxrstor %0" : : "m" (tsk->thread.i387.fxsave) ); } else { asm volatile( "frstor %0" : : "m" (tsk->thread.i387.fsave) ); } } /* * FPU tag word conversions. */ 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 */ return tmp; } 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); for ( i = 0 ; i < 8 ; i++ ) { if ( twd & 0x1 ) { st = (struct _fpxreg *) FPREG_ADDR( fxsave, i ); switch ( st->exponent & 0x7fff ) { case 0x7fff: tag = 2; /* Special */ break; case 0x0000: if ( !st->significand[0] && !st->significand[1] && !st->significand[2] && !st->significand[3] ) { tag = 1; /* Zero */ } else { tag = 2; /* Special */ } break; default: if ( st->significand[3] & 0x8000 ) { tag = 0; /* Valid */ } else { tag = 2; /* Special */ } break; } } else { tag = 3; /* Empty */ } ret |= (tag << (2 * i)); twd = twd >> 1; } return ret; } /* * FPU state interaction. */ unsigned short get_fpu_cwd( struct task_struct *tsk ) { if ( cpu_has_fxsr ) { return tsk->thread.i387.fxsave.cwd; } else { return (unsigned short)tsk->thread.i387.fsave.cwd; } } unsigned short get_fpu_swd( struct task_struct *tsk ) { if ( cpu_has_fxsr ) { return tsk->thread.i387.fxsave.swd; } else { return (unsigned short)tsk->thread.i387.fsave.swd; } } unsigned short get_fpu_twd( struct task_struct *tsk ) { if ( cpu_has_fxsr ) { return tsk->thread.i387.fxsave.twd; } else { return (unsigned short)tsk->thread.i387.fsave.twd; } } unsigned short get_fpu_mxcsr( struct task_struct *tsk ) { if ( cpu_has_fxsr ) { return tsk->thread.i387.fxsave.mxcsr; } else { return 0x1f80; } } void set_fpu_cwd( struct task_struct *tsk, unsigned short cwd ) { if ( cpu_has_fxsr ) { tsk->thread.i387.fxsave.cwd = cwd; } else { tsk->thread.i387.fsave.cwd = ((long)cwd | 0xffff0000); } } void set_fpu_swd( struct task_struct *tsk, unsigned short swd ) { if ( cpu_has_fxsr ) { tsk->thread.i387.fxsave.swd = swd; } else { tsk->thread.i387.fsave.swd = ((long)swd | 0xffff0000); } } void set_fpu_twd( struct task_struct *tsk, unsigned short twd ) { if ( cpu_has_fxsr ) { tsk->thread.i387.fxsave.twd = twd_i387_to_fxsr(twd); } else { tsk->thread.i387.fsave.twd = ((long)twd | 0xffff0000); } } void set_fpu_mxcsr( struct task_struct *tsk, unsigned short mxcsr ) { if ( cpu_has_xmm ) { tsk->thread.i387.fxsave.mxcsr = (mxcsr & 0xffbf); } } /* * FXSR floating point environment conversions. */ 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; if ( __copy_to_user( buf, env, 7 * sizeof(unsigned long) ) ) return 1; to = &buf->_st[0]; from = (struct _fpxreg *) &fxsave->st_space[0]; for ( i = 0 ; i < 8 ; i++, to++, from++ ) { if ( __copy_to_user( to, from, sizeof(*to) ) ) return 1; } return 0; } 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; if ( __copy_from_user( env, buf, 7 * sizeof(long) ) ) 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]; for ( i = 0 ; i < 8 ; i++, to++, from++ ) { if ( __copy_from_user( to, from, sizeof(*from) ) ) return 1; } return 0; } /* * Signal frame handlers. */ static inline int save_i387_fsave( struct _fpstate *buf ) { struct task_struct *tsk = current; unlazy_fpu( tsk ); tsk->thread.i387.fsave.status = tsk->thread.i387.fsave.swd; if ( __copy_to_user( buf, &tsk->thread.i387.fsave, sizeof(struct i387_fsave_struct) ) ) return -1; return 1; } static inline int save_i387_fxsave( struct _fpstate *buf ) { struct task_struct *tsk = current; int err = 0; unlazy_fpu( tsk ); if ( convert_fxsr_to_user( buf, &tsk->thread.i387.fxsave ) ) return -1; err |= __put_user( tsk->thread.i387.fxsave.swd, &buf->status ); err |= __put_user( X86_FXSR_MAGIC, &buf->magic ); if ( err ) return -1; if ( __copy_to_user( &buf->_fxsr_env[0], &tsk->thread.i387.fxsave, sizeof(struct i387_fxsave_struct) ) ) return -1; return 1; } int save_i387( struct _fpstate *buf ) { if ( !current->used_math ) return 0; /* This will cause a "finit" to be triggered by the next * attempted FPU operation by the 'current' process. */ current->used_math = 0; if ( HAVE_HWFP ) { if ( cpu_has_fxsr ) { return save_i387_fxsave( buf ); } else { return save_i387_fsave( buf ); } } else { return save_i387_soft( ¤t->thread.i387.soft, buf ); } } static inline int restore_i387_fsave( struct _fpstate *buf ) { struct task_struct *tsk = current; clear_fpu( tsk ); return __copy_from_user( &tsk->thread.i387.fsave, buf, sizeof(struct i387_fsave_struct) ); } static inline int restore_i387_fxsave( struct _fpstate *buf ) { struct task_struct *tsk = current; clear_fpu( tsk ); if ( __copy_from_user( &tsk->thread.i387.fxsave, &buf->_fxsr_env[0], sizeof(struct i387_fxsave_struct) ) ) return 1; /* mxcsr bit 6 and 31-16 must be zero for security reasons */ tsk->thread.i387.fxsave.mxcsr &= 0xffbf; return convert_fxsr_from_user( &tsk->thread.i387.fxsave, buf ); } int restore_i387( struct _fpstate *buf ) { int err; if ( HAVE_HWFP ) { if ( cpu_has_fxsr ) { err = restore_i387_fxsave( buf ); } else { err = restore_i387_fsave( buf ); } } else { err = restore_i387_soft( ¤t->thread.i387.soft, buf ); } current->used_math = 1; return err; } /* * ptrace request handlers. */ static inline int get_fpregs_fsave( struct user_i387_struct *buf, struct task_struct *tsk ) { return __copy_to_user( buf, &tsk->thread.i387.fsave, sizeof(struct user_i387_struct) ); } static inline int get_fpregs_fxsave( struct user_i387_struct *buf, struct task_struct *tsk ) { return convert_fxsr_to_user( (struct _fpstate *)buf, &tsk->thread.i387.fxsave ); } int get_fpregs( struct user_i387_struct *buf, struct task_struct *tsk ) { if ( HAVE_HWFP ) { if ( cpu_has_fxsr ) { return get_fpregs_fxsave( buf, tsk ); } else { return get_fpregs_fsave( buf, tsk ); } } else { return save_i387_soft( &tsk->thread.i387.soft, (struct _fpstate *)buf ); } } static inline int set_fpregs_fsave( struct task_struct *tsk, struct user_i387_struct *buf ) { return __copy_from_user( &tsk->thread.i387.fsave, buf, sizeof(struct user_i387_struct) ); } static inline int set_fpregs_fxsave( struct task_struct *tsk, struct user_i387_struct *buf ) { return convert_fxsr_from_user( &tsk->thread.i387.fxsave, (struct _fpstate *)buf ); } int set_fpregs( struct task_struct *tsk, struct user_i387_struct *buf ) { if ( HAVE_HWFP ) { if ( cpu_has_fxsr ) { return set_fpregs_fxsave( tsk, buf ); } else { return set_fpregs_fsave( tsk, buf ); } } else { return restore_i387_soft( &tsk->thread.i387.soft, (struct _fpstate *)buf ); } } int get_fpxregs( struct user_fxsr_struct *buf, struct task_struct *tsk ) { if ( cpu_has_fxsr ) { if (__copy_to_user( (void *)buf, &tsk->thread.i387.fxsave, sizeof(struct user_fxsr_struct) )) return -EFAULT; return 0; } else { return -EIO; } } int set_fpxregs( struct task_struct *tsk, struct user_fxsr_struct *buf ) { if ( cpu_has_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; return 0; } else { return -EIO; } } /* * FPU state for core dumps. */ 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) ); } 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]; for ( i = 0 ; i < 8 ; i++, to += 5, from += 8 ) { memcpy( to, from, 5 * sizeof(unsigned short) ); } } int dump_fpu( struct pt_regs *regs, struct user_i387_struct *fpu ) { int fpvalid; struct task_struct *tsk = current; fpvalid = tsk->used_math; if ( fpvalid ) { unlazy_fpu( tsk ); if ( cpu_has_fxsr ) { copy_fpu_fxsave( tsk, fpu ); } else { copy_fpu_fsave( tsk, fpu ); } } return fpvalid; } int dump_extended_fpu( struct pt_regs *regs, struct user_fxsr_struct *fpu ) { int fpvalid; struct task_struct *tsk = current; fpvalid = tsk->used_math && cpu_has_fxsr; if ( fpvalid ) { unlazy_fpu( tsk ); memcpy( fpu, &tsk->thread.i387.fxsave, sizeof(struct user_fxsr_struct) ); } return fpvalid; }