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/*
* linux/arch/x86_64/kernel/i387.c
*
* Copyright (C) 1994 Linus Torvalds
* Copyright (C) 2002 Andi Kleen, SuSE Labs
*
* Pentium III FXSR, SSE support
* General FPU state handling cleanups
* Gareth Hughes <gareth@valinux.com>, May 2000
*
* x86-64 rework 2002 Andi Kleen.
* Does direct fxsave in and out of user space now for signal handlers.
* All the FSAVE<->FXSAVE conversion code has been moved to the 32bit emulation,
* the 64bit user space sees a FXSAVE frame directly.
*/
#include <linux/sched.h>
#include <linux/init.h>
#include <asm/processor.h>
#include <asm/i387.h>
#include <asm/sigcontext.h>
#include <asm/user.h>
#include <asm/ptrace.h>
#include <asm/uaccess.h>
unsigned int mxcsr_feature_mask __read_mostly = 0xffffffff;
void mxcsr_feature_mask_init(void)
{
unsigned int mask;
clts();
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();
}
/*
* Called at bootup to set up the initial FPU state that is later cloned
* into all processes.
*/
void __cpuinit fpu_init(void)
{
unsigned long oldcr0 = read_cr0();
extern void __bad_fxsave_alignment(void);
if (offsetof(struct task_struct, thread.i387.fxsave) & 15)
__bad_fxsave_alignment();
set_in_cr4(X86_CR4_OSFXSR);
set_in_cr4(X86_CR4_OSXMMEXCPT);
write_cr0(oldcr0 & ~((1UL<<3)|(1UL<<2))); /* clear TS and EM */
mxcsr_feature_mask_init();
/* clean state in init */
current_thread_info()->status = 0;
clear_used_math();
}
void init_fpu(struct task_struct *child)
{
if (tsk_used_math(child)) {
if (child == current)
unlazy_fpu(child);
return;
}
memset(&child->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct));
child->thread.i387.fxsave.cwd = 0x37f;
child->thread.i387.fxsave.mxcsr = 0x1f80;
/* only the device not available exception or ptrace can call init_fpu */
set_stopped_child_used_math(child);
}
/*
* Signal frame handlers.
*/
int save_i387(struct _fpstate __user *buf)
{
struct task_struct *tsk = current;
int err = 0;
BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
sizeof(tsk->thread.i387.fxsave));
if ((unsigned long)buf % 16)
printk("save_i387: bad fpstate %p\n",buf);
if (!used_math())
return 0;
clear_used_math(); /* trigger finit */
if (task_thread_info(tsk)->status & TS_USEDFPU) {
err = save_i387_checking((struct i387_fxsave_struct __user *)buf);
if (err) return err;
stts();
} else {
if (__copy_to_user(buf, &tsk->thread.i387.fxsave,
sizeof(struct i387_fxsave_struct)))
return -1;
}
return 1;
}
/*
* ptrace request handlers.
*/
int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *tsk)
{
init_fpu(tsk);
return __copy_to_user(buf, &tsk->thread.i387.fxsave,
sizeof(struct user_i387_struct)) ? -EFAULT : 0;
}
int set_fpregs(struct task_struct *tsk, struct user_i387_struct __user *buf)
{
if (__copy_from_user(&tsk->thread.i387.fxsave, buf,
sizeof(struct user_i387_struct)))
return -EFAULT;
return 0;
}
/*
* FPU state for core dumps.
*/
int dump_fpu( struct pt_regs *regs, struct user_i387_struct *fpu )
{
struct task_struct *tsk = current;
if (!used_math())
return 0;
unlazy_fpu(tsk);
memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(struct user_i387_struct));
return 1;
}
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);
memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(struct user_i387_struct));
}
return fpvalid;
}
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