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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/config.h>

#include <linux/sched.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>

extern int exception_trace;

void init_fpu(struct task_struct *child)

{

        if (child->used_math) {

                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;

        child->used_math = 1;

}

/*

 * Signal frame handlers.

 */

int save_i387(struct _fpstate *buf)

{

        struct task_struct *tsk = current;

        int err = 0;

        {

                extern void bad_user_i387_struct(void);

                if (sizeof(struct user_i387_struct) != sizeof(tsk->thread.i387.fxsave))

                        bad_user_i387_struct();

        }

        if (!tsk->used_math)

                return 0;

        tsk->used_math = 0; /* trigger finit */

        if (tsk->flags & PF_USEDFPU) {

                err = save_i387_checking((struct i387_fxsave_struct *)buf);

                if (err) {

                        if (exception_trace)

                                printk("%s[%d] unaligned signal floating point context %p\n",

                                        tsk->comm, tsk->pid, buf);

                        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 *buf, struct task_struct *tsk)

{

        init_fpu(tsk);

        return __copy_to_user((void *)buf, &tsk->thread.i387.fxsave,

                               sizeof(struct user_i387_struct)) ? -EFAULT : 0;

}

int set_fpregs(struct task_struct *tsk, struct user_i387_struct *buf)

{

        if (__copy_from_user(&tsk->thread.i387.fxsave, buf,

                             sizeof(struct user_i387_struct)))

                return -EFAULT;

        /* mxcsr bit 6 and 31-16 must be zero for security reasons. */

        tsk->thread.i387.fxsave.mxcsr &= 0xffbf;

        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 (!tsk->used_math)

                return 0;

        unlazy_fpu(tsk);

        memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(struct user_i387_struct));

        return 1;

}