| 1 | /* |
| 2 | * Copyright (c) 2003,2004 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 | * $DragonFly: src/sys/platform/pc32/i386/tls.c,v 1.4 2006/06/05 07:26:10 dillon Exp $ |
| 35 | */ |
| 36 | |
| 37 | #include <sys/param.h> |
| 38 | #include <sys/systm.h> |
| 39 | #include <sys/sysproto.h> |
| 40 | #include <sys/kernel.h> |
| 41 | #include <sys/proc.h> |
| 42 | #include <sys/sysent.h> |
| 43 | #include <sys/sysctl.h> |
| 44 | #include <sys/tls.h> |
| 45 | #include <sys/thread2.h> |
| 46 | |
| 47 | #include <machine/cpu.h> |
| 48 | #include <machine/reg.h> |
| 49 | #include <machine/clock.h> |
| 50 | #include <machine/specialreg.h> |
| 51 | #include <machine/bootinfo.h> |
| 52 | #include <machine/ipl.h> |
| 53 | #include <machine/md_var.h> |
| 54 | #include <machine/pcb_ext.h> /* pcb.h included via sys/user.h */ |
| 55 | #include <machine/globaldata.h> /* CPU_prvspace */ |
| 56 | #include <machine/smp.h> |
| 57 | |
| 58 | /* |
| 59 | * set a TLS descriptor and resync the GDT. A descriptor may be cleared |
| 60 | * by passing info=NULL and infosize=0. Note that hardware limitations may |
| 61 | * cause the size passed in tls_info to be approximated. |
| 62 | * |
| 63 | * Returns the value userland needs to load into %gs representing the |
| 64 | * TLS descriptor or -1 on error. |
| 65 | * |
| 66 | * (struct tls_info *info, int infosize, int which) |
| 67 | */ |
| 68 | int |
| 69 | sys_sys_set_tls_area(struct sys_set_tls_area_args *uap) |
| 70 | { |
| 71 | struct tls_info info; |
| 72 | struct segment_descriptor *desc; |
| 73 | int error; |
| 74 | int i; |
| 75 | |
| 76 | /* |
| 77 | * Sanity checks |
| 78 | */ |
| 79 | i = uap->which; |
| 80 | if (i < 0 || i >= NGTLS) |
| 81 | return (ERANGE); |
| 82 | if (uap->infosize < 0) |
| 83 | return (EINVAL); |
| 84 | |
| 85 | /* |
| 86 | * Maintain forwards compatibility with future extensions. |
| 87 | */ |
| 88 | if (uap->infosize != sizeof(info)) { |
| 89 | bzero(&info, sizeof(info)); |
| 90 | error = copyin(uap->info, &info, |
| 91 | min(sizeof(info), uap->infosize)); |
| 92 | } else { |
| 93 | error = copyin(uap->info, &info, sizeof(info)); |
| 94 | } |
| 95 | if (error) |
| 96 | return (error); |
| 97 | if (info.size < -1) |
| 98 | return (EINVAL); |
| 99 | if (info.size > (1 << 20)) |
| 100 | info.size = (info.size + PAGE_MASK) & ~PAGE_MASK; |
| 101 | |
| 102 | /* |
| 103 | * Load the descriptor. A critical section is required in case |
| 104 | * an interrupt thread comes along and switches us out and then back |
| 105 | * in. |
| 106 | */ |
| 107 | desc = &curthread->td_tls[i]; |
| 108 | crit_enter(); |
| 109 | if (info.size == 0) { |
| 110 | bzero(desc, sizeof(*desc)); |
| 111 | } else { |
| 112 | desc->sd_lobase = (intptr_t)info.base; |
| 113 | desc->sd_hibase = (intptr_t)info.base >> 24; |
| 114 | desc->sd_def32 = 1; |
| 115 | desc->sd_type = SDT_MEMRWA; |
| 116 | desc->sd_dpl = SEL_UPL; |
| 117 | desc->sd_xx = 0; |
| 118 | desc->sd_p = 1; |
| 119 | if (info.size == -1) { |
| 120 | /* |
| 121 | * A descriptor size of -1 is a hack to map the |
| 122 | * whole address space. This type of mapping is |
| 123 | * required for direct-tls accesses of variable |
| 124 | * data, e.g. %gs:OFFSET where OFFSET is negative. |
| 125 | */ |
| 126 | desc->sd_lolimit = -1; |
| 127 | desc->sd_hilimit = -1; |
| 128 | desc->sd_gran = 1; |
| 129 | } else if (info.size >= (1 << 20)) { |
| 130 | /* |
| 131 | * A descriptor size greater then 1MB requires page |
| 132 | * granularity (the lo+hilimit field is only 20 bits) |
| 133 | */ |
| 134 | desc->sd_lolimit = info.size >> PAGE_SHIFT; |
| 135 | desc->sd_hilimit = info.size >> (PAGE_SHIFT + 16); |
| 136 | desc->sd_gran = 1; |
| 137 | } else { |
| 138 | /* |
| 139 | * Otherwise a byte-granular size is supported. |
| 140 | */ |
| 141 | desc->sd_lolimit = info.size; |
| 142 | desc->sd_hilimit = info.size >> 16; |
| 143 | desc->sd_gran = 0; |
| 144 | } |
| 145 | } |
| 146 | crit_exit(); |
| 147 | uap->sysmsg_result = GSEL(GTLS_START + i, SEL_UPL); |
| 148 | set_user_TLS(); |
| 149 | return(0); |
| 150 | } |
| 151 | |
| 152 | /* |
| 153 | * Return the specified TLS descriptor to userland. |
| 154 | * |
| 155 | * Returns the value userland needs to load into %gs representing the |
| 156 | * TLS descriptor or -1 on error. |
| 157 | * |
| 158 | * (struct tls_info *info, int infosize, int which) |
| 159 | */ |
| 160 | int |
| 161 | sys_sys_get_tls_area(struct sys_get_tls_area_args *uap) |
| 162 | { |
| 163 | struct tls_info info; |
| 164 | struct segment_descriptor *desc; |
| 165 | int error; |
| 166 | int i; |
| 167 | |
| 168 | /* |
| 169 | * Sanity checks |
| 170 | */ |
| 171 | i = uap->which; |
| 172 | if (i < 0 || i >= NGTLS) |
| 173 | return (ERANGE); |
| 174 | if (uap->infosize < 0) |
| 175 | return (EINVAL); |
| 176 | |
| 177 | /* |
| 178 | * unpack the descriptor, ENOENT is returned for any descriptor |
| 179 | * which has not been loaded. uap->info may be NULL. |
| 180 | */ |
| 181 | desc = &curthread->td_tls[i]; |
| 182 | if (desc->sd_p) { |
| 183 | if (uap->info && uap->infosize > 0) { |
| 184 | bzero(&info, sizeof(info)); |
| 185 | info.base = (void *)(intptr_t) |
| 186 | ((desc->sd_hibase << 24) | desc->sd_lobase); |
| 187 | info.size = (desc->sd_hilimit << 16) | desc->sd_lolimit; |
| 188 | if (desc->sd_gran) |
| 189 | info.size <<= PAGE_SHIFT; |
| 190 | error = copyout(&info, uap->info, |
| 191 | min(sizeof(info), uap->infosize)); |
| 192 | } else { |
| 193 | error = 0; |
| 194 | } |
| 195 | uap->sysmsg_result = GSEL(GTLS_START + i, SEL_UPL); |
| 196 | } else { |
| 197 | error = ENOENT; |
| 198 | } |
| 199 | return(error); |
| 200 | } |
| 201 | |