1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2010, 2012 Konstantin Belousov <kib@FreeBSD.org> 5 * Copyright (c) 2015 The FreeBSD Foundation 6 * All rights reserved. 7 * 8 * Portions of this software were developed by Konstantin Belousov 9 * under sponsorship from the FreeBSD Foundation. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include "opt_vm.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/kernel.h> 41 #include <sys/lock.h> 42 #include <sys/malloc.h> 43 #include <sys/rwlock.h> 44 #include <sys/sysent.h> 45 #include <sys/sysctl.h> 46 #include <sys/vdso.h> 47 48 #include <vm/vm.h> 49 #include <vm/vm_param.h> 50 #include <vm/pmap.h> 51 #include <vm/vm_extern.h> 52 #include <vm/vm_kern.h> 53 #include <vm/vm_map.h> 54 #include <vm/vm_object.h> 55 #include <vm/vm_page.h> 56 #include <vm/vm_pager.h> 57 58 static struct sx shared_page_alloc_sx; 59 static vm_object_t shared_page_obj; 60 static int shared_page_free; 61 char *shared_page_mapping; 62 63 void 64 shared_page_write(int base, int size, const void *data) 65 { 66 67 bcopy(data, shared_page_mapping + base, size); 68 } 69 70 static int 71 shared_page_alloc_locked(int size, int align) 72 { 73 int res; 74 75 res = roundup(shared_page_free, align); 76 if (res + size >= IDX_TO_OFF(shared_page_obj->size)) 77 res = -1; 78 else 79 shared_page_free = res + size; 80 return (res); 81 } 82 83 int 84 shared_page_alloc(int size, int align) 85 { 86 int res; 87 88 sx_xlock(&shared_page_alloc_sx); 89 res = shared_page_alloc_locked(size, align); 90 sx_xunlock(&shared_page_alloc_sx); 91 return (res); 92 } 93 94 int 95 shared_page_fill(int size, int align, const void *data) 96 { 97 int res; 98 99 sx_xlock(&shared_page_alloc_sx); 100 res = shared_page_alloc_locked(size, align); 101 if (res != -1) 102 shared_page_write(res, size, data); 103 sx_xunlock(&shared_page_alloc_sx); 104 return (res); 105 } 106 107 static void 108 shared_page_init(void *dummy __unused) 109 { 110 vm_page_t m; 111 vm_offset_t addr; 112 113 sx_init(&shared_page_alloc_sx, "shpsx"); 114 shared_page_obj = vm_pager_allocate(OBJT_PHYS, 0, PAGE_SIZE, 115 VM_PROT_DEFAULT, 0, NULL); 116 VM_OBJECT_WLOCK(shared_page_obj); 117 m = vm_page_grab(shared_page_obj, 0, VM_ALLOC_ZERO); 118 VM_OBJECT_WUNLOCK(shared_page_obj); 119 vm_page_valid(m); 120 vm_page_xunbusy(m); 121 addr = kva_alloc(PAGE_SIZE); 122 pmap_qenter(addr, &m, 1); 123 shared_page_mapping = (char *)addr; 124 } 125 126 SYSINIT(shp, SI_SUB_EXEC, SI_ORDER_FIRST, (sysinit_cfunc_t)shared_page_init, 127 NULL); 128 129 /* 130 * Push the timehands update to the shared page. 131 * 132 * The lockless update scheme is similar to the one used to update the 133 * in-kernel timehands, see sys/kern/kern_tc.c:tc_windup() (which 134 * calls us after the timehands are updated). 135 */ 136 static void 137 timehands_update(struct vdso_sv_tk *svtk) 138 { 139 struct vdso_timehands th; 140 struct vdso_timekeep *tk; 141 uint32_t enabled, idx; 142 143 enabled = tc_fill_vdso_timehands(&th); 144 th.th_gen = 0; 145 idx = svtk->sv_timekeep_curr; 146 if (++idx >= VDSO_TH_NUM) 147 idx = 0; 148 svtk->sv_timekeep_curr = idx; 149 if (++svtk->sv_timekeep_gen == 0) 150 svtk->sv_timekeep_gen = 1; 151 152 tk = (struct vdso_timekeep *)(shared_page_mapping + 153 svtk->sv_timekeep_off); 154 tk->tk_th[idx].th_gen = 0; 155 atomic_thread_fence_rel(); 156 if (enabled) 157 tk->tk_th[idx] = th; 158 atomic_store_rel_32(&tk->tk_th[idx].th_gen, svtk->sv_timekeep_gen); 159 atomic_store_rel_32(&tk->tk_current, idx); 160 161 /* 162 * The ordering of the assignment to tk_enabled relative to 163 * the update of the vdso_timehands is not important. 164 */ 165 tk->tk_enabled = enabled; 166 } 167 168 #ifdef COMPAT_FREEBSD32 169 static void 170 timehands_update32(struct vdso_sv_tk *svtk) 171 { 172 struct vdso_timehands32 th; 173 struct vdso_timekeep32 *tk; 174 uint32_t enabled, idx; 175 176 enabled = tc_fill_vdso_timehands32(&th); 177 th.th_gen = 0; 178 idx = svtk->sv_timekeep_curr; 179 if (++idx >= VDSO_TH_NUM) 180 idx = 0; 181 svtk->sv_timekeep_curr = idx; 182 if (++svtk->sv_timekeep_gen == 0) 183 svtk->sv_timekeep_gen = 1; 184 185 tk = (struct vdso_timekeep32 *)(shared_page_mapping + 186 svtk->sv_timekeep_off); 187 tk->tk_th[idx].th_gen = 0; 188 atomic_thread_fence_rel(); 189 if (enabled) 190 tk->tk_th[idx] = th; 191 atomic_store_rel_32(&tk->tk_th[idx].th_gen, svtk->sv_timekeep_gen); 192 atomic_store_rel_32(&tk->tk_current, idx); 193 tk->tk_enabled = enabled; 194 } 195 #endif 196 197 /* 198 * This is hackish, but easiest way to avoid creating list structures 199 * that needs to be iterated over from the hardclock interrupt 200 * context. 201 */ 202 static struct vdso_sv_tk *host_svtk; 203 #ifdef COMPAT_FREEBSD32 204 static struct vdso_sv_tk *compat32_svtk; 205 #endif 206 207 void 208 timekeep_push_vdso(void) 209 { 210 211 if (host_svtk != NULL) 212 timehands_update(host_svtk); 213 #ifdef COMPAT_FREEBSD32 214 if (compat32_svtk != NULL) 215 timehands_update32(compat32_svtk); 216 #endif 217 } 218 219 struct vdso_sv_tk * 220 alloc_sv_tk(void) 221 { 222 struct vdso_sv_tk *svtk; 223 int tk_base; 224 uint32_t tk_ver; 225 226 tk_ver = VDSO_TK_VER_CURR; 227 svtk = malloc(sizeof(struct vdso_sv_tk), M_TEMP, M_WAITOK | M_ZERO); 228 tk_base = shared_page_alloc(sizeof(struct vdso_timekeep) + 229 sizeof(struct vdso_timehands) * VDSO_TH_NUM, 16); 230 KASSERT(tk_base != -1, ("tk_base -1 for native")); 231 shared_page_write(tk_base + offsetof(struct vdso_timekeep, tk_ver), 232 sizeof(uint32_t), &tk_ver); 233 svtk->sv_timekeep_off = tk_base; 234 timekeep_push_vdso(); 235 return (svtk); 236 } 237 238 #ifdef COMPAT_FREEBSD32 239 struct vdso_sv_tk * 240 alloc_sv_tk_compat32(void) 241 { 242 struct vdso_sv_tk *svtk; 243 int tk_base; 244 uint32_t tk_ver; 245 246 svtk = malloc(sizeof(struct vdso_sv_tk), M_TEMP, M_WAITOK | M_ZERO); 247 tk_ver = VDSO_TK_VER_CURR; 248 tk_base = shared_page_alloc(sizeof(struct vdso_timekeep32) + 249 sizeof(struct vdso_timehands32) * VDSO_TH_NUM, 16); 250 KASSERT(tk_base != -1, ("tk_base -1 for 32bit")); 251 shared_page_write(tk_base + offsetof(struct vdso_timekeep32, 252 tk_ver), sizeof(uint32_t), &tk_ver); 253 svtk->sv_timekeep_off = tk_base; 254 timekeep_push_vdso(); 255 return (svtk); 256 } 257 #endif 258 259 void 260 exec_sysvec_init(void *param) 261 { 262 struct sysentvec *sv; 263 264 sv = (struct sysentvec *)param; 265 if ((sv->sv_flags & SV_SHP) == 0) 266 return; 267 sv->sv_shared_page_obj = shared_page_obj; 268 sv->sv_sigcode_base = sv->sv_shared_page_base + 269 shared_page_fill(*(sv->sv_szsigcode), 16, sv->sv_sigcode); 270 if ((sv->sv_flags & SV_ABI_MASK) != SV_ABI_FREEBSD) 271 return; 272 if ((sv->sv_flags & SV_TIMEKEEP) != 0) { 273 #ifdef COMPAT_FREEBSD32 274 if ((sv->sv_flags & SV_ILP32) != 0) { 275 KASSERT(compat32_svtk == NULL, 276 ("Compat32 already registered")); 277 compat32_svtk = alloc_sv_tk_compat32(); 278 sv->sv_timekeep_base = sv->sv_shared_page_base + 279 compat32_svtk->sv_timekeep_off; 280 } else { 281 #endif 282 KASSERT(host_svtk == NULL, ("Host already registered")); 283 host_svtk = alloc_sv_tk(); 284 sv->sv_timekeep_base = sv->sv_shared_page_base + 285 host_svtk->sv_timekeep_off; 286 #ifdef COMPAT_FREEBSD32 287 } 288 #endif 289 } 290 } 291