base/include/asm-x86_64/rtai_fpu.h

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/*
 *   ARTI -- RTAI-compatible Adeos-based Real-Time Interface. Based on
 *   the original RTAI layer for x86.
 *
 *   Copyright (C) 1994 Linus Torvalds
 *   Copyright (C) 2000 Gareth Hughes <gareth@valinux.com>,
 *   Copyright (C) 2000 Pierre Cloutier <pcloutier@PoseidonControls.com>
 *   and others.
 *
 *   Porting to x86_64 architecture:
 *   Copyright &copy; 2005-2008 Paolo Mantegazza, \n
 *   Copyright &copy; 2005 Daniele Gasperini \n
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
 *   USA; either version 2 of the License, or (at your option) any later
 *   version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifndef _RTAI_ASM_X8664_FPU_H
#define _RTAI_ASM_X8664_FPU_H

#ifndef __cplusplus
#include <asm/processor.h>
#endif /* !__cplusplus */

#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,25)
typedef union i387_union FPU_ENV;
#define TASK_FPENV(tsk)  (&(tsk)->thread.i387.fxsave)
#else
typedef union thread_xstate FPU_ENV;
#define TASK_FPENV(tsk)  (&(tsk)->thread.xstate->fxsave)
#endif
   
#ifdef CONFIG_RTAI_FPU_SUPPORT

// RAW FPU MANAGEMENT FOR USAGE FROM WHAT/WHEREVER RTAI DOES IN KERNEL

#define enable_fpu()  do { \
    __asm__ __volatile__ ("clts"); \
} while(0)

#define save_fpcr_and_enable_fpu(fpcr)  do { \
    fpcr = read_cr0(); \
    enable_fpu(); \
} while (0)

#define restore_fpcr(fpcr)  do { \
    if (fpcr & 8) { \
        unsigned long flags; \
        rtai_hw_save_flags_and_cli(flags); \
        fpcr = read_cr0(); \
        write_cr0(8 | fpcr); \
        rtai_hw_restore_flags(flags); \
    } \
} while (0)

// initialise the hard fpu unit directly
#define init_hard_fpenv() do { \
    unsigned long __mxcsr; \
    __asm__ __volatile__ ("clts; fninit"); \
    __mxcsr = 0xffbfUL & 0x1f80UL; \
    __asm__ __volatile__ ("ldmxcsr %0": : "m" (__mxcsr)); \
} while (0)

// initialise the given fpenv union, without touching the related hard fpu unit
#define __init_fpenv(fpenv)  do { \
    memset(fpenv, 0, sizeof(struct i387_fxsave_struct)); \
    (fpenv)->cwd = 0x37f; \
    (fpenv)->mxcsr = 0x1f80; \
} while (0)

/* taken from Linux i387.h */

static inline int __save_fpenv(struct i387_fxsave_struct __user *fx) 
{ 
    int err;

    asm volatile("1:  rex64/fxsave (%[fx])\n\t"
             "2:\n"
             ".section .fixup,\"ax\"\n"
             "3:  movl $-1,%[err]\n"
             "    jmp  2b\n"
             ".previous\n"
             ".section __ex_table,\"a\"\n"
             "   .align 8\n"
             "   .quad  1b,3b\n"
             ".previous"
             : [err] "=r" (err), "=m" (*fx)
             : [fx] "cdaSDb" (fx), "0" (0));

    return err;
} 

static inline int __restore_fpenv(struct i387_fxsave_struct *fx) 
{ 
    int err;

    asm volatile("1:  rex64/fxrstor (%[fx])\n\t"
             "2:\n"
             ".section .fixup,\"ax\"\n"
             "3:  movl $-1,%[err]\n"
             "    jmp  2b\n"
             ".previous\n"
             ".section __ex_table,\"a\"\n"
             "   .align 8\n"
             "   .quad  1b,3b\n"
             ".previous"
             : [err] "=r" (err)
             : [fx] "cdaSDb" (fx), "m" (*fx), "0" (0));

    return err;
} 

#define init_fpenv(fpenv)     do { __init_fpenv(&(fpenv).fxsave); } while (0)
#define save_fpenv(fpenv)     do { __save_fpenv(&(fpenv).fxsave); } while (0)
#define restore_fpenv(fpenv)  do { __restore_fpenv(&(fpenv).fxsave); } while (0)

// FPU MANAGEMENT DRESSED FOR IN KTHREAD/THREAD/PROCESS FPU USAGE FROM RTAI

#define init_hard_fpu(lnxtsk)  do { \
    init_hard_fpenv(); \
    set_lnxtsk_uses_fpu(lnxtsk); \
    set_lnxtsk_using_fpu(lnxtsk); \
} while (0)

#define init_fpu(lnxtsk)  do { \
    __init_fpenv(TASK_FPENV(lnxtsk)); \
    set_lnxtsk_uses_fpu(lnxtsk); \
} while (0)

#define restore_fpu(lnxtsk)  do { \
    enable_fpu(); \
    __restore_fpenv(TASK_FPENV(lnxtsk)); \
    set_lnxtsk_using_fpu(lnxtsk); \
} while (0)

#else /* !CONFIG_RTAI_FPU_SUPPORT */

#define enable_fpu()
#define save_fpcr_and_enable_fpu(fpcr)
#define restore_fpcr(fpcr)
#define init_hard_fpenv()
#define init_fpenv(fpenv)
#define save_fpenv(fpenv)
#define restore_fpenv(fpenv)
#define init_hard_fpu(lnxtsk)
#define init_fpu(lnxtsk)
#define restore_fpu(lnxtsk)

#endif /* CONFIG_RTAI_FPU_SUPPORT */

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0) && LINUX_VERSION_CODE < KERNEL_VERSION(2,6,11)

#define set_lnxtsk_uses_fpu(lnxtsk) \
        do { (lnxtsk)->used_math = 1; } while(0)
#define clear_lnxtsk_uses_fpu(lnxtsk) \
        do { (lnxtsk)->used_math = 0; } while(0)
#define lnxtsk_uses_fpu(lnxtsk)  ((lnxtsk)->used_math)

#define set_lnxtsk_using_fpu(lnxtsk) \
    do { task_thread_info(lnxtsk)->status |= TS_USEDFPU; } while(0)
//  do { (lnxtsk)->thread_info->status |= TS_USEDFPU; } while(0)

#endif /* LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0) && LINUX_VERSION_CODE < KERNEL_VERSION(2,6,11) */


#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,11)

#define set_lnxtsk_uses_fpu(lnxtsk) \
        do { set_stopped_child_used_math(lnxtsk); } while(0)
#define clear_lnxtsk_uses_fpu(lnxtsk) \
        do { clear_stopped_child_used_math(lnxtsk); } while(0)
#define lnxtsk_uses_fpu(lnxtsk)  (tsk_used_math(lnxtsk))

#define set_lnxtsk_using_fpu(lnxtsk) \
    do { task_thread_info(lnxtsk)->status |= TS_USEDFPU; } while(0)
//  do { (lnxtsk)->thread_info->status |= TS_USEDFPU; } while(0)

#endif /* LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,11) */

#endif /* !_RTAI_ASM_X8664_FPU_H */

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