lib/libc/i386/gen/getcontextx.c

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