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