diff options
Diffstat (limited to 'arch/i386/kernel/i387.c')
| -rw-r--r-- | arch/i386/kernel/i387.c | 555 |
1 files changed, 555 insertions, 0 deletions
diff --git a/arch/i386/kernel/i387.c b/arch/i386/kernel/i387.c new file mode 100644 index 00000000000..c55e037f08f --- /dev/null +++ b/arch/i386/kernel/i387.c @@ -0,0 +1,555 @@ +/* + * 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> + +#ifdef CONFIG_MATH_EMULATION +#define HAVE_HWFP (boot_cpu_data.hard_math) +#else +#define HAVE_HWFP 1 +#endif + +static unsigned long mxcsr_feature_mask = 0xffffffff; + +void mxcsr_feature_mask_init(void) +{ + unsigned long mask = 0; + clts(); + if (cpu_has_fxsr) { + memset(¤t->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct)); + asm volatile("fxsave %0" : : "m" (current->thread.i387.fxsave)); + mask = current->thread.i387.fxsave.mxcsr_mask; + if (mask == 0) mask = 0x0000ffbf; + } + mxcsr_feature_mask &= mask; + stts(); +} + +/* + * 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(struct task_struct *tsk) +{ + if (cpu_has_fxsr) { + memset(&tsk->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct)); + tsk->thread.i387.fxsave.cwd = 0x37f; + if (cpu_has_xmm) + tsk->thread.i387.fxsave.mxcsr = 0x1f80; + } else { + memset(&tsk->thread.i387.fsave, 0, sizeof(struct i387_fsave_struct)); + tsk->thread.i387.fsave.cwd = 0xffff037fu; + tsk->thread.i387.fsave.swd = 0xffff0000u; + tsk->thread.i387.fsave.twd = 0xffffffffu; + tsk->thread.i387.fsave.fos = 0xffff0000u; + } + /* only the device not available exception or ptrace can call init_fpu */ + set_stopped_child_used_math(tsk); +} + +/* + * FPU lazy state save handling. + */ + +void kernel_fpu_begin(void) +{ + struct thread_info *thread = current_thread_info(); + + preempt_disable(); + if (thread->status & TS_USEDFPU) { + __save_init_fpu(thread->task); + 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 tos = (fxsave->swd >> 11) & 7; + unsigned long twd = (unsigned long) fxsave->twd; + unsigned long tag; + unsigned long ret = 0xffff0000u; + int i; + +#define FPREG_ADDR(f, n) ((void *)&(f)->st_space + (n) * 16); + + for ( i = 0 ; i < 8 ; i++ ) { + if ( twd & 0x1 ) { + st = FPREG_ADDR( fxsave, (i - tos) & 7 ); + + 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; + } +} + +#if 0 +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; + } +} +#endif /* 0 */ + +unsigned short get_fpu_mxcsr( struct task_struct *tsk ) +{ + if ( cpu_has_xmm ) { + return tsk->thread.i387.fxsave.mxcsr; + } else { + return 0x1f80; + } +} + +#if 0 + +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 | 0xffff0000u); + } +} + +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 | 0xffff0000u); + } +} + +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 | 0xffff0000u); + } +} + +#endif /* 0 */ + +/* + * FXSR floating point environment conversions. + */ + +static int convert_fxsr_to_user( struct _fpstate __user *buf, + struct i387_fxsave_struct *fxsave ) +{ + unsigned long env[7]; + struct _fpreg __user *to; + struct _fpxreg *from; + int i; + + env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul; + env[1] = (unsigned long)fxsave->swd | 0xffff0000ul; + 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++ ) { + unsigned long __user *t = (unsigned long __user *)to; + unsigned long *f = (unsigned long *)from; + + if (__put_user(*f, t) || + __put_user(*(f + 1), t + 1) || + __put_user(from->exponent, &to->exponent)) + return 1; + } + return 0; +} + +static int convert_fxsr_from_user( struct i387_fxsave_struct *fxsave, + struct _fpstate __user *buf ) +{ + unsigned long env[7]; + struct _fpxreg *to; + struct _fpreg __user *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] & 0xffff0000ul) >> 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++ ) { + unsigned long *t = (unsigned long *)to; + unsigned long __user *f = (unsigned long __user *)from; + + if (__get_user(*t, f) || + __get_user(*(t + 1), f + 1) || + __get_user(to->exponent, &from->exponent)) + return 1; + } + return 0; +} + +/* + * Signal frame handlers. + */ + +static inline int save_i387_fsave( struct _fpstate __user *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 int save_i387_fxsave( struct _fpstate __user *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 __user *buf ) +{ + if ( !used_math() ) + return 0; + + /* This will cause a "finit" to be triggered by the next + * attempted FPU operation by the 'current' process. + */ + clear_used_math(); + + 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 __user *buf ) +{ + struct task_struct *tsk = current; + clear_fpu( tsk ); + return __copy_from_user( &tsk->thread.i387.fsave, buf, + sizeof(struct i387_fsave_struct) ); +} + +static int restore_i387_fxsave( struct _fpstate __user *buf ) +{ + int err; + struct task_struct *tsk = current; + clear_fpu( tsk ); + err = __copy_from_user( &tsk->thread.i387.fxsave, &buf->_fxsr_env[0], + sizeof(struct i387_fxsave_struct) ); + /* mxcsr reserved bits must be masked to zero for security reasons */ + tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask; + return err ? 1 : convert_fxsr_from_user( &tsk->thread.i387.fxsave, buf ); +} + +int restore_i387( struct _fpstate __user *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 ); + } + set_used_math(); + return err; +} + +/* + * ptrace request handlers. + */ + +static inline int get_fpregs_fsave( struct user_i387_struct __user *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 __user *buf, + struct task_struct *tsk ) +{ + return convert_fxsr_to_user( (struct _fpstate __user *)buf, + &tsk->thread.i387.fxsave ); +} + +int get_fpregs( struct user_i387_struct __user *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 __user *)buf ); + } +} + +static inline int set_fpregs_fsave( struct task_struct *tsk, + struct user_i387_struct __user *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 __user *buf ) +{ + return convert_fxsr_from_user( &tsk->thread.i387.fxsave, + (struct _fpstate __user *)buf ); +} + +int set_fpregs( struct task_struct *tsk, struct user_i387_struct __user *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 __user *)buf ); + } +} + +int get_fpxregs( struct user_fxsr_struct __user *buf, struct task_struct *tsk ) +{ + if ( cpu_has_fxsr ) { + if (__copy_to_user( 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 __user *buf ) +{ + int ret = 0; + + if ( cpu_has_fxsr ) { + if (__copy_from_user( &tsk->thread.i387.fxsave, buf, + sizeof(struct user_fxsr_struct) )) + ret = -EFAULT; + /* mxcsr reserved bits must be masked to zero for security reasons */ + tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask; + } else { + ret = -EIO; + } + return ret; +} + +/* + * 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 = !!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_task_fpu(struct task_struct *tsk, struct user_i387_struct *fpu) +{ + int fpvalid = !!tsk_used_math(tsk); + + if (fpvalid) { + if (tsk == current) + unlazy_fpu(tsk); + if (cpu_has_fxsr) + copy_fpu_fxsave(tsk, fpu); + else + copy_fpu_fsave(tsk, fpu); + } + return fpvalid; +} + +int dump_task_extended_fpu(struct task_struct *tsk, struct user_fxsr_struct *fpu) +{ + int fpvalid = tsk_used_math(tsk) && cpu_has_fxsr; + + if (fpvalid) { + if (tsk == current) + unlazy_fpu(tsk); + memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(*fpu)); + } + return fpvalid; +} |