sys/kern/kern_sharedpage.c

   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("$FreeBSD$");
  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/mutex.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_LOCK(shared_page_obj);
 111         m = vm_page_grab(shared_page_obj, 0, VM_ALLOC_RETRY | VM_ALLOC_NOBUSY |
 112             VM_ALLOC_ZERO);
 113         m->valid = VM_PAGE_BITS_ALL;
 114         VM_OBJECT_UNLOCK(shared_page_obj);
 115         addr = kmem_alloc_nofault(kernel_map, PAGE_SIZE);
 116         pmap_qenter(addr, &m, 1);
 117         shared_page_mapping = (char *)addr;
 118 }
 119
 120 SYSINIT(shp, SI_SUB_EXEC, SI_ORDER_FIRST, (sysinit_cfunc_t)shared_page_init,
 121     NULL);
 122
 123 static void
 124 timehands_update(struct sysentvec *sv)
 125 {
 126         struct vdso_timehands th;
 127         struct vdso_timekeep *tk;
 128         uint32_t enabled, idx;
 129
 130         enabled = tc_fill_vdso_timehands(&th);
 131         tk = (struct vdso_timekeep *)(shared_page_mapping +
 132             sv->sv_timekeep_off);
 133         idx = sv->sv_timekeep_curr;
 134         atomic_store_rel_32(&tk->tk_th[idx].th_gen, 0);
 135         if (++idx >= VDSO_TH_NUM)
 136                 idx = 0;
 137         sv->sv_timekeep_curr = idx;
 138         if (++sv->sv_timekeep_gen == 0)
 139                 sv->sv_timekeep_gen = 1;
 140         th.th_gen = 0;
 141         if (enabled)
 142                 tk->tk_th[idx] = th;
 143         tk->tk_enabled = enabled;
 144         atomic_store_rel_32(&tk->tk_th[idx].th_gen, sv->sv_timekeep_gen);
 145         tk->tk_current = idx;
 146 }
 147
 148 #ifdef COMPAT_FREEBSD32
 149 static void
 150 timehands_update32(struct sysentvec *sv)
 151 {
 152         struct vdso_timekeep32 *tk;
 153         struct vdso_timehands32 th;
 154         uint32_t enabled, idx;
 155
 156         enabled = tc_fill_vdso_timehands32(&th);
 157         tk = (struct vdso_timekeep32 *)(shared_page_mapping +
 158             sv->sv_timekeep_off);
 159         idx = sv->sv_timekeep_curr;
 160         atomic_store_rel_32(&tk->tk_th[idx].th_gen, 0);
 161         if (++idx >= VDSO_TH_NUM)
 162                 idx = 0;
 163         sv->sv_timekeep_curr = idx;
 164         if (++sv->sv_timekeep_gen == 0)
 165                 sv->sv_timekeep_gen = 1;
 166         th.th_gen = 0;
 167         if (enabled)
 168                 tk->tk_th[idx] = th;
 169         tk->tk_enabled = enabled;
 170         atomic_store_rel_32(&tk->tk_th[idx].th_gen, sv->sv_timekeep_gen);
 171         tk->tk_current = idx;
 172 }
 173 #endif
 174
 175 /*
 176  * This is hackish, but easiest way to avoid creating list structures
 177  * that needs to be iterated over from the hardclock interrupt
 178  * context.
 179  */
 180 static struct sysentvec *host_sysentvec;
 181 #ifdef COMPAT_FREEBSD32
 182 static struct sysentvec *compat32_sysentvec;
 183 #endif
 184
 185 void
 186 timekeep_push_vdso(void)
 187 {
 188
 189         if (host_sysentvec != NULL && host_sysentvec->sv_timekeep_base != 0)
 190                 timehands_update(host_sysentvec);
 191 #ifdef COMPAT_FREEBSD32
 192         if (compat32_sysentvec != NULL &&
 193             compat32_sysentvec->sv_timekeep_base != 0)
 194                 timehands_update32(compat32_sysentvec);
 195 #endif
 196 }
 197
 198 void
 199 exec_sysvec_init(void *param)
 200 {
 201         struct sysentvec *sv;
 202         int tk_base;
 203         uint32_t tk_ver;
 204
 205         sv = (struct sysentvec *)param;
 206
 207         if ((sv->sv_flags & SV_SHP) == 0)
 208                 return;
 209         sv->sv_shared_page_obj = shared_page_obj;
 210         sv->sv_sigcode_base = sv->sv_shared_page_base +
 211             shared_page_fill(*(sv->sv_szsigcode), 16, sv->sv_sigcode);
 212         if ((sv->sv_flags & SV_ABI_MASK) != SV_ABI_FREEBSD)
 213                 return;
 214         tk_ver = VDSO_TK_VER_CURR;
 215 #ifdef COMPAT_FREEBSD32
 216         if ((sv->sv_flags & SV_ILP32) != 0) {
 217                 tk_base = shared_page_alloc(sizeof(struct vdso_timekeep32) +
 218                     sizeof(struct vdso_timehands32) * VDSO_TH_NUM, 16);
 219                 KASSERT(tk_base != -1, ("tk_base -1 for 32bit"));
 220                 shared_page_write(tk_base + offsetof(struct vdso_timekeep32,
 221                     tk_ver), sizeof(uint32_t), &tk_ver);
 222                 KASSERT(compat32_sysentvec == 0,
 223                     ("Native compat32 already registered"));
 224                 compat32_sysentvec = sv;
 225         } else {
 226 #endif
 227                 tk_base = shared_page_alloc(sizeof(struct vdso_timekeep) +
 228                     sizeof(struct vdso_timehands) * VDSO_TH_NUM, 16);
 229                 KASSERT(tk_base != -1, ("tk_base -1 for native"));
 230                 shared_page_write(tk_base + offsetof(struct vdso_timekeep,
 231                     tk_ver), sizeof(uint32_t), &tk_ver);
 232                 KASSERT(host_sysentvec == 0, ("Native already registered"));
 233                 host_sysentvec = sv;
 234 #ifdef COMPAT_FREEBSD32
 235         }
 236 #endif
 237         sv->sv_timekeep_base = sv->sv_shared_page_base + tk_base;
 238         sv->sv_timekeep_off = tk_base;
 239         timekeep_push_vdso();
 240 }