547 строки
13 KiB
C
547 строки
13 KiB
C
/*
|
|
* 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/sched.h>
|
|
#include <linux/module.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 __read_mostly = 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();
|
|
}
|
|
EXPORT_SYMBOL_GPL(kernel_fpu_begin);
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
EXPORT_SYMBOL(dump_fpu);
|
|
|
|
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;
|
|
}
|