thunk.c

   1 /*
   2  *  Generic thunking code to convert data between host and target CPU
   3  *
   4  *  Copyright (c) 2003 Fabrice Bellard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #include "qemu/osdep.h"
  20
  21 #include "qemu.h"
  22 #include "exec/user/thunk.h"
  23
  24 //#define DEBUG
  25
  26 static unsigned int max_struct_entries;
  27 StructEntry *struct_entries;
  28
  29 static const argtype *thunk_type_next_ptr(const argtype *type_ptr);
  30
  31 static inline const argtype *thunk_type_next(const argtype *type_ptr)
  32 {
  33     int type;
  34
  35     type = *type_ptr++;
  36     switch(type) {
  37     case TYPE_CHAR:
  38     case TYPE_SHORT:
  39     case TYPE_INT:
  40     case TYPE_LONGLONG:
  41     case TYPE_ULONGLONG:
  42     case TYPE_LONG:
  43     case TYPE_ULONG:
  44     case TYPE_PTRVOID:
  45     case TYPE_OLDDEVT:
  46         return type_ptr;
  47     case TYPE_PTR:
  48         return thunk_type_next_ptr(type_ptr);
  49     case TYPE_ARRAY:
  50         return thunk_type_next_ptr(type_ptr + 1);
  51     case TYPE_STRUCT:
  52         return type_ptr + 1;
  53     default:
  54         return NULL;
  55     }
  56 }
  57
  58 static const argtype *thunk_type_next_ptr(const argtype *type_ptr)
  59 {
  60     return thunk_type_next(type_ptr);
  61 }
  62
  63 void thunk_register_struct(int id, const char *name, const argtype *types)
  64 {
  65     const argtype *type_ptr;
  66     StructEntry *se;
  67     int nb_fields, offset, max_align, align, size, i, j;
  68
  69     assert(id < max_struct_entries);
  70     se = struct_entries + id;
  71
  72     /* first we count the number of fields */
  73     type_ptr = types;
  74     nb_fields = 0;
  75     while (*type_ptr != TYPE_NULL) {
  76         type_ptr = thunk_type_next(type_ptr);
  77         nb_fields++;
  78     }
  79     se->field_types = types;
  80     se->nb_fields = nb_fields;
  81     se->name = name;
  82 #ifdef DEBUG
  83     printf("struct %s: id=%d nb_fields=%d\n",
  84            se->name, id, se->nb_fields);
  85 #endif
  86     /* now we can alloc the data */
  87
  88     for(i = 0;i < 2; i++) {
  89         offset = 0;
  90         max_align = 1;
  91         se->field_offsets[i] = malloc(nb_fields * sizeof(int));
  92         type_ptr = se->field_types;
  93         for(j = 0;j < nb_fields; j++) {
  94             size = thunk_type_size(type_ptr, i);
  95             align = thunk_type_align(type_ptr, i);
  96             offset = (offset + align - 1) & ~(align - 1);
  97             se->field_offsets[i][j] = offset;
  98             offset += size;
  99             if (align > max_align)
 100                 max_align = align;
 101             type_ptr = thunk_type_next(type_ptr);
 102         }
 103         offset = (offset + max_align - 1) & ~(max_align - 1);
 104         se->size[i] = offset;
 105         se->align[i] = max_align;
 106 #ifdef DEBUG
 107         printf("%s: size=%d align=%d\n",
 108                i == THUNK_HOST ? "host" : "target", offset, max_align);
 109 #endif
 110     }
 111 }
 112
 113 void thunk_register_struct_direct(int id, const char *name,
 114                                   const StructEntry *se1)
 115 {
 116     StructEntry *se;
 117
 118     assert(id < max_struct_entries);
 119     se = struct_entries + id;
 120     *se = *se1;
 121     se->name = name;
 122 }
 123
 124
 125 /* now we can define the main conversion functions */
 126 const argtype *thunk_convert(void *dst, const void *src,
 127                              const argtype *type_ptr, int to_host)
 128 {
 129     int type;
 130
 131     type = *type_ptr++;
 132     switch(type) {
 133     case TYPE_CHAR:
 134         *(uint8_t *)dst = *(uint8_t *)src;
 135         break;
 136     case TYPE_SHORT:
 137         *(uint16_t *)dst = tswap16(*(uint16_t *)src);
 138         break;
 139     case TYPE_INT:
 140         *(uint32_t *)dst = tswap32(*(uint32_t *)src);
 141         break;
 142     case TYPE_LONGLONG:
 143     case TYPE_ULONGLONG:
 144         *(uint64_t *)dst = tswap64(*(uint64_t *)src);
 145         break;
 146 #if HOST_LONG_BITS == 32 && TARGET_ABI_BITS == 32
 147     case TYPE_LONG:
 148     case TYPE_ULONG:
 149     case TYPE_PTRVOID:
 150         *(uint32_t *)dst = tswap32(*(uint32_t *)src);
 151         break;
 152 #elif HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 32
 153     case TYPE_LONG:
 154     case TYPE_ULONG:
 155     case TYPE_PTRVOID:
 156         if (to_host) {
 157             if (type == TYPE_LONG) {
 158                 /* sign extension */
 159                 *(uint64_t *)dst = (int32_t)tswap32(*(uint32_t *)src);
 160             } else {
 161                 *(uint64_t *)dst = tswap32(*(uint32_t *)src);
 162             }
 163         } else {
 164             *(uint32_t *)dst = tswap32(*(uint64_t *)src & 0xffffffff);
 165         }
 166         break;
 167 #elif HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64
 168     case TYPE_LONG:
 169     case TYPE_ULONG:
 170     case TYPE_PTRVOID:
 171         *(uint64_t *)dst = tswap64(*(uint64_t *)src);
 172         break;
 173 #elif HOST_LONG_BITS == 32 && TARGET_ABI_BITS == 64
 174     case TYPE_LONG:
 175     case TYPE_ULONG:
 176     case TYPE_PTRVOID:
 177         if (to_host) {
 178             *(uint32_t *)dst = tswap64(*(uint64_t *)src);
 179         } else {
 180             if (type == TYPE_LONG) {
 181                 /* sign extension */
 182                 *(uint64_t *)dst = tswap64(*(int32_t *)src);
 183             } else {
 184                 *(uint64_t *)dst = tswap64(*(uint32_t *)src);
 185             }
 186         }
 187         break;
 188 #else
 189 #warning unsupported conversion
 190 #endif
 191     case TYPE_OLDDEVT:
 192     {
 193         uint64_t val = 0;
 194         switch (thunk_type_size(type_ptr - 1, !to_host)) {
 195         case 2:
 196             val = *(uint16_t *)src;
 197             break;
 198         case 4:
 199             val = *(uint32_t *)src;
 200             break;
 201         case 8:
 202             val = *(uint64_t *)src;
 203             break;
 204         }
 205         switch (thunk_type_size(type_ptr - 1, to_host)) {
 206         case 2:
 207             *(uint16_t *)dst = tswap16(val);
 208             break;
 209         case 4:
 210             *(uint32_t *)dst = tswap32(val);
 211             break;
 212         case 8:
 213             *(uint64_t *)dst = tswap64(val);
 214             break;
 215         }
 216         break;
 217     }
 218     case TYPE_ARRAY:
 219         {
 220             int array_length, i, dst_size, src_size;
 221             const uint8_t *s;
 222             uint8_t  *d;
 223
 224             array_length = *type_ptr++;
 225             dst_size = thunk_type_size(type_ptr, to_host);
 226             src_size = thunk_type_size(type_ptr, 1 - to_host);
 227             d = dst;
 228             s = src;
 229             for(i = 0;i < array_length; i++) {
 230                 thunk_convert(d, s, type_ptr, to_host);
 231                 d += dst_size;
 232                 s += src_size;
 233             }
 234             type_ptr = thunk_type_next(type_ptr);
 235         }
 236         break;
 237     case TYPE_STRUCT:
 238         {
 239             int i;
 240             const StructEntry *se;
 241             const uint8_t *s;
 242             uint8_t  *d;
 243             const argtype *field_types;
 244             const int *dst_offsets, *src_offsets;
 245
 246             assert(*type_ptr < max_struct_entries);
 247             se = struct_entries + *type_ptr++;
 248             if (se->convert[0] != NULL) {
 249                 /* specific conversion is needed */
 250                 (*se->convert[to_host])(dst, src);
 251             } else {
 252                 /* standard struct conversion */
 253                 field_types = se->field_types;
 254                 dst_offsets = se->field_offsets[to_host];
 255                 src_offsets = se->field_offsets[1 - to_host];
 256                 d = dst;
 257                 s = src;
 258                 for(i = 0;i < se->nb_fields; i++) {
 259                     field_types = thunk_convert(d + dst_offsets[i],
 260                                                 s + src_offsets[i],
 261                                                 field_types, to_host);
 262                 }
 263             }
 264         }
 265         break;
 266     default:
 267         fprintf(stderr, "Invalid type 0x%x\n", type);
 268         break;
 269     }
 270     return type_ptr;
 271 }
 272
 273 /* from em86 */
 274
 275 /* Utility function: Table-driven functions to translate bitmasks
 276  * between host and target formats
 277  */
 278 unsigned int target_to_host_bitmask(unsigned int target_mask,
 279                                     const bitmask_transtbl * trans_tbl)
 280 {
 281     const bitmask_transtbl *btp;
 282     unsigned int host_mask = 0;
 283
 284     for (btp = trans_tbl; btp->target_mask && btp->host_mask; btp++) {
 285         if ((target_mask & btp->target_mask) == btp->target_bits) {
 286             host_mask |= btp->host_bits;
 287         }
 288     }
 289     return host_mask;
 290 }
 291
 292 unsigned int host_to_target_bitmask(unsigned int host_mask,
 293                                     const bitmask_transtbl * trans_tbl)
 294 {
 295     const bitmask_transtbl *btp;
 296     unsigned int target_mask = 0;
 297
 298     for (btp = trans_tbl; btp->target_mask && btp->host_mask; btp++) {
 299         if ((host_mask & btp->host_mask) == btp->host_bits) {
 300             target_mask |= btp->target_bits;
 301         }
 302     }
 303     return target_mask;
 304 }
 305
 306 int thunk_type_size_array(const argtype *type_ptr, int is_host)
 307 {
 308     return thunk_type_size(type_ptr, is_host);
 309 }
 310
 311 int thunk_type_align_array(const argtype *type_ptr, int is_host)
 312 {
 313     return thunk_type_align(type_ptr, is_host);
 314 }
 315
 316 void thunk_init(unsigned int max_structs)
 317 {
 318     max_struct_entries = max_structs;
 319     struct_entries = g_new0(StructEntry, max_structs);
 320 }