1 /* 2 * Copyright (c) 2003,2004,2008 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by David Xu <davidxu@t2t2.com> and Matthew Dillon <dillon@backplane.com> 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 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 */ 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/sysproto.h> 39 #include <sys/kernel.h> 40 #include <sys/proc.h> 41 #include <sys/sysent.h> 42 #include <sys/sysctl.h> 43 #include <sys/tls.h> 44 #include <sys/reg.h> 45 #include <sys/globaldata.h> 46 47 #include <machine/cpu.h> 48 #include <machine/clock.h> 49 #include <machine/specialreg.h> 50 #include <machine/segments.h> 51 #include <machine/md_var.h> 52 #include <machine/pcb_ext.h> 53 #include <machine/globaldata.h> /* CPU_prvspace */ 54 #include <machine/smp.h> 55 #include <machine/pcb.h> 56 57 /* 58 * set a TLS descriptor. For x86_64 descriptor 0 identifies %fs and 59 * descriptor 1 identifies %gs, and 0 is returned in sysmsg_result. 60 * 61 * Returns the value userland needs to load into %gs representing the 62 * TLS descriptor or -1 on error. 63 * 64 * (int which, struct tls_info *info, size_t infosize) 65 */ 66 int 67 sys_set_tls_area(struct set_tls_area_args *uap) 68 { 69 struct tls_info info; 70 int error; 71 int i; 72 73 /* 74 * Sanity checks 75 * 76 * which 0 == %fs, which 1 == %gs 77 */ 78 i = uap->which; 79 if (i < 0 || i > 1) 80 return (ERANGE); 81 if (uap->infosize < 0) 82 return (EINVAL); 83 84 /* 85 * Maintain forwards compatibility with future extensions. 86 */ 87 if (uap->infosize != sizeof(info)) { 88 bzero(&info, sizeof(info)); 89 error = copyin(uap->info, &info, 90 min(sizeof(info), uap->infosize)); 91 } else { 92 error = copyin(uap->info, &info, sizeof(info)); 93 } 94 if (error) 95 return (error); 96 if (info.size < -1) 97 return (EINVAL); 98 99 /* 100 * For x86_64 we can only adjust FSBASE and GSBASE 101 */ 102 curthread->td_tls.info[i] = info; 103 set_user_TLS(); 104 uap->sysmsg_result = 0; /* segment descriptor $0 */ 105 return(0); 106 } 107 108 /* 109 * Return the specified TLS descriptor to userland. 110 * 111 * Returns the value userland needs to load into %gs representing the 112 * TLS descriptor or -1 on error. 113 * 114 * (int which, struct tls_info *info, size_t infosize) 115 */ 116 int 117 sys_get_tls_area(struct get_tls_area_args *uap) 118 { 119 struct tls_info info; 120 int error; 121 int i; 122 123 /* 124 * Sanity checks 125 */ 126 i = uap->which; 127 if (i < 0 || i > 1) 128 return (ERANGE); 129 if (uap->infosize < 0) 130 return (EINVAL); 131 132 info = curthread->td_tls.info[i]; 133 134 error = copyout(&info, uap->info, min(sizeof(info), uap->infosize)); 135 return(error); 136 } 137 138 /* 139 * This function is a NOP because the TLS segments are proactively copied 140 * by vmspace_ctl() when we switch to the (emulated) user process. 141 */ 142 void 143 set_user_TLS(void) 144 { 145 } 146