/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2011 Konstantin Belousov <kib@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/ucontext.h>
#include <errno.h>
#include <stdarg.h>
#include <stdlib.h>
#include <machine/cpufunc.h>
#include <machine/specialreg.h>
#include <machine/sysarch.h>
#include <x86/ifunc.h>
#include <x86/fpu.h>

#if defined __i386__
#define X86_GET_XFPUSTATE       I386_GET_XFPUSTATE
typedef struct savexmm savex86_t ;
typedef struct i386_get_xfpustate x86_get_xfpustate_t;
#elif defined __amd64__
#define X86_GET_XFPUSTATE       AMD64_GET_XFPUSTATE
typedef struct savefpu savex86_t;
typedef struct amd64_get_xfpustate x86_get_xfpustate_t;
#else
#error "Wrong arch"
#endif

static int xstate_sz = 0;

static int
__getcontextx_size_xfpu(void)
{

        return (sizeof(ucontext_t) + xstate_sz);
}

DEFINE_UIFUNC(, int, __getcontextx_size, (void))
{
        u_int p[4];

        if ((cpu_feature2 & CPUID2_OSXSAVE) != 0) {
                cpuid_count(0xd, 0x0, p);
                xstate_sz = p[1] - sizeof(savex86_t);
        }
        return (__getcontextx_size_xfpu);
}

static int
__fillcontextx2_xfpu(char *ctx)
{
        x86_get_xfpustate_t xfpu;
        ucontext_t *ucp;

        ucp = (ucontext_t *)ctx;
        xfpu.addr = (char *)(ucp + 1);
        xfpu.len = xstate_sz;
        if (sysarch(X86_GET_XFPUSTATE, &xfpu) == -1)
                return (-1);
        ucp->uc_mcontext.mc_xfpustate = (__register_t)xfpu.addr;
        ucp->uc_mcontext.mc_xfpustate_len = xstate_sz;
        ucp->uc_mcontext.mc_flags |= _MC_HASFPXSTATE;
        return (0);
}

static int
__fillcontextx2_noxfpu(char *ctx)
{
        ucontext_t *ucp;

        ucp = (ucontext_t *)ctx;
        ucp->uc_mcontext.mc_xfpustate = 0;
        ucp->uc_mcontext.mc_xfpustate_len = 0;
        return (0);
}

DEFINE_UIFUNC(, int, __fillcontextx2, (char *))
{

        return ((cpu_feature2 & CPUID2_OSXSAVE) != 0 ? __fillcontextx2_xfpu : 
            __fillcontextx2_noxfpu);
}

int
__fillcontextx(char *ctx)
{
        ucontext_t *ucp;

        ucp = (ucontext_t *)ctx;
        if (getcontext(ucp) == -1)
                return (-1);
        __fillcontextx2(ctx);
        return (0);
}

__weak_reference(__getcontextx, getcontextx);

ucontext_t *
__getcontextx(void)
{
        char *ctx;
        int error;

        ctx = malloc(__getcontextx_size());
        if (ctx == NULL)
                return (NULL);
        if (__fillcontextx(ctx) == -1) {
                error = errno;
                free(ctx);
                errno = error;
                return (NULL);
        }
        return ((ucontext_t *)ctx);
}