lib/libc/i386/gen/getcontextx.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2011 Konstantin Belousov <kib@FreeBSD.org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #include <sys/types.h>
  33 #include <sys/ucontext.h>
  34 #include <errno.h>
  35 #include <stdarg.h>
  36 #include <stdlib.h>
  37 #include <machine/npx.h>
  38 #include <machine/specialreg.h>
  39 #include <machine/sysarch.h>
  40
  41 static int xstate_sz = -1;
  42
  43 int
  44 __getcontextx_size(void)
  45 {
  46         u_int p[4];
  47         int cpuid_supported;
  48
  49         if (xstate_sz == -1) {
  50                 __asm __volatile(
  51                     "   pushfl\n"
  52                     "   popl    %%eax\n"
  53                     "   movl    %%eax,%%ecx\n"
  54                     "   xorl    $0x200000,%%eax\n"
  55                     "   pushl   %%eax\n"
  56                     "   popfl\n"
  57                     "   pushfl\n"
  58                     "   popl    %%eax\n"
  59                     "   xorl    %%eax,%%ecx\n"
  60                     "   je      1f\n"
  61                     "   movl    $1,%0\n"
  62                     "   jmp     2f\n"
  63                     "1: movl    $0,%0\n"
  64                     "2:\n"
  65                     : "=r" (cpuid_supported) : : "eax", "ecx");
  66                 if (cpuid_supported) {
  67                         __asm __volatile(
  68                             "   pushl   %%ebx\n"
  69                             "   cpuid\n"
  70                             "   movl    %%ebx,%1\n"
  71                             "   popl    %%ebx\n"
  72                             : "=a" (p[0]), "=r" (p[1]), "=c" (p[2]), "=d" (p[3])
  73                             :  "0" (0x1));
  74                         if ((p[2] & CPUID2_OSXSAVE) != 0) {
  75                                 __asm __volatile(
  76                                     "   pushl   %%ebx\n"
  77                                     "   cpuid\n"
  78                                     "   movl    %%ebx,%1\n"
  79                                     "   popl    %%ebx\n"
  80                                     : "=a" (p[0]), "=r" (p[1]), "=c" (p[2]),
  81                                         "=d" (p[3])
  82                                     :  "0" (0xd), "2" (0x0));
  83                                 xstate_sz = p[1] - sizeof(struct savexmm);
  84                         } else
  85                                 xstate_sz = 0;
  86                 } else
  87                         xstate_sz = 0;
  88         }
  89
  90         return (sizeof(ucontext_t) + xstate_sz);
  91 }
  92
  93 int
  94 __fillcontextx2(char *ctx)
  95 {
  96         struct i386_get_xfpustate xfpu;
  97         ucontext_t *ucp;
  98
  99         ucp = (ucontext_t *)ctx;
 100         if (xstate_sz != 0) {
 101                 xfpu.addr = (char *)(ucp + 1);
 102                 xfpu.len = xstate_sz;
 103                 if (sysarch(I386_GET_XFPUSTATE, &xfpu) == -1)
 104                         return (-1);
 105                 ucp->uc_mcontext.mc_xfpustate = (__register_t)xfpu.addr;
 106                 ucp->uc_mcontext.mc_xfpustate_len = xstate_sz;
 107                 ucp->uc_mcontext.mc_flags |= _MC_HASFPXSTATE;
 108         } else {
 109                 ucp->uc_mcontext.mc_xfpustate = 0;
 110                 ucp->uc_mcontext.mc_xfpustate_len = 0;
 111         }
 112         return (0);
 113 }
 114
 115 int
 116 __fillcontextx(char *ctx)
 117 {
 118         ucontext_t *ucp;
 119
 120         ucp = (ucontext_t *)ctx;
 121         if (getcontext(ucp) == -1)
 122                 return (-1);
 123         __fillcontextx2(ctx);
 124         return (0);
 125 }
 126
 127 __weak_reference(__getcontextx, getcontextx);
 128
 129 ucontext_t *
 130 __getcontextx(void)
 131 {
 132         char *ctx;
 133         int error;
 134
 135         ctx = malloc(__getcontextx_size());
 136         if (ctx == NULL)
 137                 return (NULL);
 138         if (__fillcontextx(ctx) == -1) {
 139                 error = errno;
 140                 free(ctx);
 141                 errno = error;
 142                 return (NULL);
 143         }
 144         return ((ucontext_t *)ctx);
 145 }