getcontextx.c revision 230864
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: head/lib/libc/i386/gen/getcontextx.c 230864 2012-02-01 13:33:53Z kib $"); 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 39static int xstate_sz = -1; 40 41int 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" (0x0)); 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 91int 92__fillcontextx(char *ctx) 93{ 94 struct i386_get_xfpustate xfpu; 95 ucontext_t *ucp; 96 97 ucp = (ucontext_t *)ctx; 98 if (getcontext(ucp) == -1) 99 return (-1); 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__weak_reference(__getcontextx, getcontextx); 116 117ucontext_t * 118__getcontextx(void) 119{ 120 char *ctx; 121 int error; 122 123 ctx = malloc(__getcontextx_size()); 124 if (ctx == NULL) 125 return (NULL); 126 if (__fillcontextx(ctx) == -1) { 127 error = errno; 128 free(ctx); 129 errno = error; 130 return (NULL); 131 } 132 return ((ucontext_t *)ctx); 133} 134