1 /*-
2 * Copyright (c) 2010, 2012 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 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/10.1/sys/kern/kern_sharedpage.c 254649 2013-08-22 07:39:53Z kib $");
29
30 #include "opt_compat.h"
31 #include "opt_vm.h"
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/kernel.h>
36 #include <sys/lock.h>
37 #include <sys/rwlock.h>
38 #include <sys/sysent.h>
39 #include <sys/sysctl.h>
40 #include <sys/vdso.h>
41
42 #include <vm/vm.h>
43 #include <vm/vm_param.h>
44 #include <vm/pmap.h>
45 #include <vm/vm_extern.h>
46 #include <vm/vm_kern.h>
47 #include <vm/vm_map.h>
48 #include <vm/vm_object.h>
49 #include <vm/vm_page.h>
50 #include <vm/vm_pager.h>
51
52 static struct sx shared_page_alloc_sx;
53 static vm_object_t shared_page_obj;
54 static int shared_page_free;
55 char *shared_page_mapping;
56
57 void
58 shared_page_write(int base, int size, const void *data)
59 {
60
61 bcopy(data, shared_page_mapping + base, size);
62 }
63
64 static int
65 shared_page_alloc_locked(int size, int align)
66 {
67 int res;
68
69 res = roundup(shared_page_free, align);
70 if (res + size >= IDX_TO_OFF(shared_page_obj->size))
71 res = -1;
72 else
73 shared_page_free = res + size;
74 return (res);
75 }
76
77 int
78 shared_page_alloc(int size, int align)
79 {
80 int res;
81
82 sx_xlock(&shared_page_alloc_sx);
83 res = shared_page_alloc_locked(size, align);
84 sx_xunlock(&shared_page_alloc_sx);
85 return (res);
86 }
87
88 int
89 shared_page_fill(int size, int align, const void *data)
90 {
91 int res;
92
93 sx_xlock(&shared_page_alloc_sx);
94 res = shared_page_alloc_locked(size, align);
95 if (res != -1)
96 shared_page_write(res, size, data);
97 sx_xunlock(&shared_page_alloc_sx);
98 return (res);
99 }
100
101 static void
102 shared_page_init(void *dummy __unused)
103 {
104 vm_page_t m;
105 vm_offset_t addr;
106
107 sx_init(&shared_page_alloc_sx, "shpsx");
108 shared_page_obj = vm_pager_allocate(OBJT_PHYS, 0, PAGE_SIZE,
109 VM_PROT_DEFAULT, 0, NULL);
110 VM_OBJECT_WLOCK(shared_page_obj);
111 m = vm_page_grab(shared_page_obj, 0, VM_ALLOC_NOBUSY | VM_ALLOC_ZERO);
112 m->valid = VM_PAGE_BITS_ALL;
113 VM_OBJECT_WUNLOCK(shared_page_obj);
114 addr = kva_alloc(PAGE_SIZE);
115 pmap_qenter(addr, &m, 1);
116 shared_page_mapping = (char *)addr;
117 }
118
119 SYSINIT(shp, SI_SUB_EXEC, SI_ORDER_FIRST, (sysinit_cfunc_t)shared_page_init,
120 NULL);
121
122 static void
123 timehands_update(struct sysentvec *sv)
124 {
125 struct vdso_timehands th;
126 struct vdso_timekeep *tk;
127 uint32_t enabled, idx;
128
129 enabled = tc_fill_vdso_timehands(&th);
130 tk = (struct vdso_timekeep *)(shared_page_mapping +
131 sv->sv_timekeep_off);
132 idx = sv->sv_timekeep_curr;
133 atomic_store_rel_32(&tk->tk_th[idx].th_gen, 0);
134 if (++idx >= VDSO_TH_NUM)
135 idx = 0;
136 sv->sv_timekeep_curr = idx;
137 if (++sv->sv_timekeep_gen == 0)
138 sv->sv_timekeep_gen = 1;
139 th.th_gen = 0;
140 if (enabled)
141 tk->tk_th[idx] = th;
142 tk->tk_enabled = enabled;
143 atomic_store_rel_32(&tk->tk_th[idx].th_gen, sv->sv_timekeep_gen);
144 tk->tk_current = idx;
145 }
146
147 #ifdef COMPAT_FREEBSD32
148 static void
149 timehands_update32(struct sysentvec *sv)
150 {
151 struct vdso_timekeep32 *tk;
152 struct vdso_timehands32 th;
153 uint32_t enabled, idx;
154
155 enabled = tc_fill_vdso_timehands32(&th);
156 tk = (struct vdso_timekeep32 *)(shared_page_mapping +
157 sv->sv_timekeep_off);
158 idx = sv->sv_timekeep_curr;
159 atomic_store_rel_32(&tk->tk_th[idx].th_gen, 0);
160 if (++idx >= VDSO_TH_NUM)
161 idx = 0;
162 sv->sv_timekeep_curr = idx;
163 if (++sv->sv_timekeep_gen == 0)
164 sv->sv_timekeep_gen = 1;
165 th.th_gen = 0;
166 if (enabled)
167 tk->tk_th[idx] = th;
168 tk->tk_enabled = enabled;
169 atomic_store_rel_32(&tk->tk_th[idx].th_gen, sv->sv_timekeep_gen);
170 tk->tk_current = idx;
171 }
172 #endif
173
174 /*
175 * This is hackish, but easiest way to avoid creating list structures
176 * that needs to be iterated over from the hardclock interrupt
177 * context.
178 */
179 static struct sysentvec *host_sysentvec;
180 #ifdef COMPAT_FREEBSD32
181 static struct sysentvec *compat32_sysentvec;
182 #endif
183
184 void
185 timekeep_push_vdso(void)
186 {
187
188 if (host_sysentvec != NULL && host_sysentvec->sv_timekeep_base != 0)
189 timehands_update(host_sysentvec);
190 #ifdef COMPAT_FREEBSD32
191 if (compat32_sysentvec != NULL &&
192 compat32_sysentvec->sv_timekeep_base != 0)
193 timehands_update32(compat32_sysentvec);
194 #endif
195 }
196
197 void
198 exec_sysvec_init(void *param)
199 {
200 struct sysentvec *sv;
201 int tk_base;
202 uint32_t tk_ver;
203
204 sv = (struct sysentvec *)param;
205
206 if ((sv->sv_flags & SV_SHP) == 0)
207 return;
208 sv->sv_shared_page_obj = shared_page_obj;
209 sv->sv_sigcode_base = sv->sv_shared_page_base +
210 shared_page_fill(*(sv->sv_szsigcode), 16, sv->sv_sigcode);
211 if ((sv->sv_flags & SV_ABI_MASK) != SV_ABI_FREEBSD)
212 return;
213 tk_ver = VDSO_TK_VER_CURR;
214 #ifdef COMPAT_FREEBSD32
215 if ((sv->sv_flags & SV_ILP32) != 0) {
216 tk_base = shared_page_alloc(sizeof(struct vdso_timekeep32) +
217 sizeof(struct vdso_timehands32) * VDSO_TH_NUM, 16);
218 KASSERT(tk_base != -1, ("tk_base -1 for 32bit"));
219 shared_page_write(tk_base + offsetof(struct vdso_timekeep32,
220 tk_ver), sizeof(uint32_t), &tk_ver);
221 KASSERT(compat32_sysentvec == 0,
222 ("Native compat32 already registered"));
223 compat32_sysentvec = sv;
224 } else {
225 #endif
226 tk_base = shared_page_alloc(sizeof(struct vdso_timekeep) +
227 sizeof(struct vdso_timehands) * VDSO_TH_NUM, 16);
228 KASSERT(tk_base != -1, ("tk_base -1 for native"));
229 shared_page_write(tk_base + offsetof(struct vdso_timekeep,
230 tk_ver), sizeof(uint32_t), &tk_ver);
231 KASSERT(host_sysentvec == 0, ("Native already registered"));
232 host_sysentvec = sv;
233 #ifdef COMPAT_FREEBSD32
234 }
235 #endif
236 sv->sv_timekeep_base = sv->sv_shared_page_base + tk_base;
237 sv->sv_timekeep_off = tk_base;
238 timekeep_push_vdso();
239 }
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