src/libs/libunwind/x86/Ginit.c

   1 /* libunwind - a platform-independent unwind library
   2    Copyright (C) 2002 Hewlett-Packard Co
   3    Copyright (C) 2007 David Mosberger-Tang
   4         Contributed by David Mosberger-Tang <dmosberger@gmail.com>
   5
   6 This file is part of libunwind.
   7
   8 Permission is hereby granted, free of charge, to any person obtaining
   9 a copy of this software and associated documentation files (the
  10 "Software"), to deal in the Software without restriction, including
  11 without limitation the rights to use, copy, modify, merge, publish,
  12 distribute, sublicense, and/or sell copies of the Software, and to
  13 permit persons to whom the Software is furnished to do so, subject to
  14 the following conditions:
  15
  16 The above copyright notice and this permission notice shall be
  17 included in all copies or substantial portions of the Software.
  18
  19 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  20 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  21 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  22 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  23 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  24 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  25 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <stdlib.h>
  32 #include <string.h>
  33
  34 #include "unwind_i.h"
  35
  36 #ifdef UNW_REMOTE_ONLY
  37
  38 /* unw_local_addr_space is a NULL pointer in this case.  */
  39 PROTECTED unw_addr_space_t unw_local_addr_space;
  40
  41 #else /* !UNW_REMOTE_ONLY */
  42
  43 static struct unw_addr_space local_addr_space;
  44
  45 PROTECTED unw_addr_space_t unw_local_addr_space = &local_addr_space;
  46
  47 # ifdef UNW_LOCAL_ONLY
  48
  49 HIDDEN void *
  50 tdep_uc_addr (ucontext_t *uc, int reg)
  51 {
  52   return x86_r_uc_addr (uc, reg);
  53 }
  54
  55 # endif /* UNW_LOCAL_ONLY */
  56
  57 HIDDEN unw_dyn_info_list_t _U_dyn_info_list;
  58
  59 /* XXX fix me: there is currently no way to locate the dyn-info list
  60        by a remote unwinder.  On ia64, this is done via a special
  61        unwind-table entry.  Perhaps something similar can be done with
  62        DWARF2 unwind info.  */
  63
  64 static void
  65 put_unwind_info (unw_addr_space_t as, unw_proc_info_t *proc_info, void *arg)
  66 {
  67   /* it's a no-op */
  68 }
  69
  70 static int
  71 get_dyn_info_list_addr (unw_addr_space_t as, unw_word_t *dyn_info_list_addr,
  72                         void *arg)
  73 {
  74   *dyn_info_list_addr = (unw_word_t) &_U_dyn_info_list;
  75   return 0;
  76 }
  77
  78 #define PAGE_SIZE 4096
  79 #define PAGE_START(a)   ((a) & ~(PAGE_SIZE-1))
  80
  81 /* Cache of already validated addresses */
  82 #define NLGA 4
  83 static unw_word_t last_good_addr[NLGA];
  84 static int lga_victim;
  85
  86 static int
  87 validate_mem (unw_word_t addr)
  88 {
  89   int i, victim;
  90 #ifdef HAVE_MINCORE
  91   unsigned char mvec[2]; /* Unaligned access may cross page boundary */
  92 #endif
  93   size_t len;
  94
  95   if (PAGE_START(addr + sizeof (unw_word_t) - 1) == PAGE_START(addr))
  96     len = PAGE_SIZE;
  97   else
  98     len = PAGE_SIZE * 2;
  99
 100   addr = PAGE_START(addr);
 101
 102   if (addr == 0)
 103     return -1;
 104
 105   for (i = 0; i < NLGA; i++)
 106     {
 107       if (last_good_addr[i] && (addr == last_good_addr[i]))
 108         return 0;
 109     }
 110
 111 #ifdef HAVE_MINCORE
 112   if (mincore ((void *) addr, len, mvec) == -1)
 113 #else
 114   if (msync ((void *) addr, len, MS_ASYNC) == -1)
 115 #endif
 116     return -1;
 117
 118   victim = lga_victim;
 119   for (i = 0; i < NLGA; i++) {
 120     if (!last_good_addr[victim]) {
 121       last_good_addr[victim++] = addr;
 122       return 0;
 123     }
 124     victim = (victim + 1) % NLGA;
 125   }
 126
 127   /* All slots full. Evict the victim. */
 128   last_good_addr[victim] = addr;
 129   victim = (victim + 1) % NLGA;
 130   lga_victim = victim;
 131
 132   return 0;
 133 }
 134
 135 static int
 136 access_mem (unw_addr_space_t as, unw_word_t addr, unw_word_t *val, int write,
 137             void *arg)
 138 {
 139   if (write)
 140     {
 141       Debug (16, "mem[%x] <- %x\n", addr, *val);
 142       *(unw_word_t *) addr = *val;
 143     }
 144   else
 145     {
 146       /* validate address */
 147       const struct cursor *c = (const struct cursor *)arg;
 148       if (c && c->validate && validate_mem(addr))
 149         return -1;
 150       *val = *(unw_word_t *) addr;
 151       Debug (16, "mem[%x] -> %x\n", addr, *val);
 152     }
 153   return 0;
 154 }
 155
 156 static int
 157 access_reg (unw_addr_space_t as, unw_regnum_t reg, unw_word_t *val, int write,
 158             void *arg)
 159 {
 160   unw_word_t *addr;
 161   ucontext_t *uc = ((struct cursor *)arg)->uc;
 162
 163   if (unw_is_fpreg (reg))
 164     goto badreg;
 165
 166   if (!(addr = x86_r_uc_addr (uc, reg)))
 167     goto badreg;
 168
 169   if (write)
 170     {
 171       *(unw_word_t *) addr = *val;
 172       Debug (12, "%s <- %x\n", unw_regname (reg), *val);
 173     }
 174   else
 175     {
 176       *val = *(unw_word_t *) addr;
 177       Debug (12, "%s -> %x\n", unw_regname (reg), *val);
 178     }
 179   return 0;
 180
 181  badreg:
 182   Debug (1, "bad register number %u\n", reg);
 183   return -UNW_EBADREG;
 184 }
 185
 186 static int
 187 access_fpreg (unw_addr_space_t as, unw_regnum_t reg, unw_fpreg_t *val,
 188               int write, void *arg)
 189 {
 190   ucontext_t *uc = ((struct cursor *)arg)->uc;
 191   unw_fpreg_t *addr;
 192
 193   if (!unw_is_fpreg (reg))
 194     goto badreg;
 195
 196   if (!(addr = x86_r_uc_addr (uc, reg)))
 197     goto badreg;
 198
 199   if (write)
 200     {
 201       Debug (12, "%s <- %08lx.%08lx.%08lx\n", unw_regname (reg),
 202              ((long *)val)[0], ((long *)val)[1], ((long *)val)[2]);
 203       *(unw_fpreg_t *) addr = *val;
 204     }
 205   else
 206     {
 207       *val = *(unw_fpreg_t *) addr;
 208       Debug (12, "%s -> %08lx.%08lx.%08lx\n", unw_regname (reg),
 209              ((long *)val)[0], ((long *)val)[1], ((long *)val)[2]);
 210     }
 211   return 0;
 212
 213  badreg:
 214   Debug (1, "bad register number %u\n", reg);
 215   /* attempt to access a non-preserved register */
 216   return -UNW_EBADREG;
 217 }
 218
 219 static int
 220 get_static_proc_name (unw_addr_space_t as, unw_word_t ip,
 221                       char *buf, size_t buf_len, unw_word_t *offp,
 222                       void *arg)
 223 {
 224   return _Uelf32_get_proc_name (as, getpid (), ip, buf, buf_len, offp);
 225 }
 226
 227 HIDDEN void
 228 x86_local_addr_space_init (void)
 229 {
 230   memset (&local_addr_space, 0, sizeof (local_addr_space));
 231   local_addr_space.caching_policy = UNW_CACHE_GLOBAL;
 232   local_addr_space.acc.find_proc_info = dwarf_find_proc_info;
 233   local_addr_space.acc.put_unwind_info = put_unwind_info;
 234   local_addr_space.acc.get_dyn_info_list_addr = get_dyn_info_list_addr;
 235   local_addr_space.acc.access_mem = access_mem;
 236   local_addr_space.acc.access_reg = access_reg;
 237   local_addr_space.acc.access_fpreg = access_fpreg;
 238   local_addr_space.acc.resume = x86_local_resume;
 239   local_addr_space.acc.get_proc_name = get_static_proc_name;
 240   unw_flush_cache (&local_addr_space, 0, 0);
 241 }
 242
 243 #endif /* !UNW_REMOTE_ONLY */