2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
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>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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
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.
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
34 * $DragonFly: src/sys/i386/i386/Attic/tls.c,v 1.2 2005/03/23 01:13:20 dillon Exp $
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/sysproto.h>
40 #include <sys/kernel.h>
42 #include <sys/sysent.h>
43 #include <sys/sysctl.h>
45 #include <sys/thread2.h>
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 */
57 #include <machine/smp.h>
61 * set a TLS descriptor and resync the GDT. A descriptor may be cleared
62 * by passing info=NULL and infosize=0. Note that hardware limitations may
63 * cause the size passed in tls_info to be approximated.
65 * Returns the value userland needs to load into %gs representing the
66 * TLS descriptor or -1 on error.
68 * (struct tls_info *info, int infosize, int which)
71 sys_set_tls_area(struct sys_set_tls_area_args *uap)
74 struct segment_descriptor *desc;
82 if (i < 0 || i >= NGTLS)
84 if (uap->infosize < 0)
88 * Maintain forwards compatibility with future extensions.
90 if (uap->infosize != sizeof(info)) {
91 bzero(&info, sizeof(info));
92 error = copyin(uap->info, &info,
93 min(sizeof(info), uap->infosize));
95 error = copyin(uap->info, &info, sizeof(info));
101 if (info.size > (1 << 20))
102 info.size = (info.size + PAGE_MASK) & ~PAGE_MASK;
105 * Load the descriptor. A critical section is required in case
106 * an interrupt thread comes along and switches us out and then back
109 desc = &curthread->td_tls[i];
111 if (info.size == 0) {
112 bzero(desc, sizeof(*desc));
114 desc->sd_lobase = (intptr_t)info.base;
115 desc->sd_hibase = (intptr_t)info.base >> 24;
117 desc->sd_type = SDT_MEMRWA;
118 desc->sd_dpl = SEL_UPL;
121 if (info.size == -1) {
123 * A descriptor size of -1 is a hack to map the
124 * whole address space. This type of mapping is
125 * required for direct-tls accesses of variable
126 * data, e.g. %gs:OFFSET where OFFSET is negative.
128 desc->sd_lolimit = -1;
129 desc->sd_hilimit = -1;
131 } else if (info.size >= (1 << 20)) {
133 * A descriptor size greater then 1MB requires page
134 * granularity (the lo+hilimit field is only 20 bits)
136 desc->sd_lolimit = info.size >> PAGE_SHIFT;
137 desc->sd_hilimit = info.size >> (PAGE_SHIFT + 16);
141 * Otherwise a byte-granular size is supported.
143 desc->sd_lolimit = info.size;
144 desc->sd_hilimit = info.size >> 16;
149 uap->sysmsg_result = GSEL(GTLS_START + i, SEL_UPL);
155 * Return the specified TLS descriptor to userland.
157 * Returns the value userland needs to load into %gs representing the
158 * TLS descriptor or -1 on error.
160 * (struct tls_info *info, int infosize, int which)
163 sys_get_tls_area(struct sys_get_tls_area_args *uap)
165 struct tls_info info;
166 struct segment_descriptor *desc;
174 if (i < 0 || i >= NGTLS)
176 if (uap->infosize < 0)
180 * unpack the descriptor, ENOENT is returned for any descriptor
181 * which has not been loaded. uap->info may be NULL.
183 desc = &curthread->td_tls[i];
185 if (uap->info && uap->infosize > 0) {
186 bzero(&info, sizeof(info));
187 info.base = (void *)(intptr_t)
188 ((desc->sd_hibase << 24) | desc->sd_lobase);
189 info.size = (desc->sd_hilimit << 16) | desc->sd_lolimit;
191 info.size <<= PAGE_SHIFT;
192 error = copyout(&info, uap->info,
193 min(sizeof(info), uap->infosize));
197 uap->sysmsg_result = GSEL(GTLS_START + i, SEL_UPL);