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 <stdlib.h>
  20 #include <stdio.h>
  21 #include <stdarg.h>
  22
  23 #include "qemu.h"
  24 #include "exec/user/thunk.h"
  25
  26 //#define DEBUG
  27
  28 #define MAX_STRUCTS 128
  29
  30 /* XXX: make it dynamic */
  31 StructEntry struct_entries[MAX_STRUCTS];
  32
  33 static const argtype *thunk_type_next_ptr(const argtype *type_ptr);
  34
  35 static inline const argtype *thunk_type_next(const argtype *type_ptr)
  36 {
  37     int type;
  38
  39     type = *type_ptr++;
  40     switch(type) {
  41     case TYPE_CHAR:
  42     case TYPE_SHORT:
  43     case TYPE_INT:
  44     case TYPE_LONGLONG:
  45     case TYPE_ULONGLONG:
  46     case TYPE_LONG:
  47     case TYPE_ULONG:
  48     case TYPE_PTRVOID:
  49     case TYPE_OLDDEVT:
  50         return type_ptr;
  51     case TYPE_PTR:
  52         return thunk_type_next_ptr(type_ptr);
  53     case TYPE_ARRAY:
  54         return thunk_type_next_ptr(type_ptr + 1);
  55     case TYPE_STRUCT:
  56         return type_ptr + 1;
  57     default:
  58         return NULL;
  59     }
  60 }
  61
  62 static const argtype *thunk_type_next_ptr(const argtype *type_ptr)
  63 {
  64     return thunk_type_next(type_ptr);
  65 }
  66
  67 void thunk_register_struct(int id, const char *name, const argtype *types)
  68 {
  69     const argtype *type_ptr;
  70     StructEntry *se;
  71     int nb_fields, offset, max_align, align, size, i, j;
  72
  73     se = struct_entries + id;
  74
  75     /* first we count the number of fields */
  76     type_ptr = types;
  77     nb_fields = 0;
  78     while (*type_ptr != TYPE_NULL) {
  79         type_ptr = thunk_type_next(type_ptr);
  80         nb_fields++;
  81     }
  82     se->field_types = types;
  83     se->nb_fields = nb_fields;
  84     se->name = name;
  85 #ifdef DEBUG
  86     printf("struct %s: id=%d nb_fields=%d\n",
  87            se->name, id, se->nb_fields);
  88 #endif
  89     /* now we can alloc the data */
  90
  91     for(i = 0;i < 2; i++) {
  92         offset = 0;
  93         max_align = 1;
  94         se->field_offsets[i] = malloc(nb_fields * sizeof(int));
  95         type_ptr = se->field_types;
  96         for(j = 0;j < nb_fields; j++) {
  97             size = thunk_type_size(type_ptr, i);
  98             align = thunk_type_align(type_ptr, i);
  99             offset = (offset + align - 1) & ~(align - 1);
 100             se->field_offsets[i][j] = offset;
 101             offset += size;
 102             if (align > max_align)
 103                 max_align = align;
 104             type_ptr = thunk_type_next(type_ptr);
 105         }
 106         offset = (offset + max_align - 1) & ~(max_align - 1);
 107         se->size[i] = offset;
 108         se->align[i] = max_align;
 109 #ifdef DEBUG
 110         printf("%s: size=%d align=%d\n",
 111                i == THUNK_HOST ? "host" : "target", offset, max_align);
 112 #endif
 113     }
 114 }
 115
 116 void thunk_register_struct_direct(int id, const char *name,
 117                                   const StructEntry *se1)
 118 {
 119     StructEntry *se;
 120     se = struct_entries + id;
 121     *se = *se1;
 122     se->name = name;
 123 }
 124
 125
 126 /* now we can define the main conversion functions */
 127 const argtype *thunk_convert(void *dst, const void *src,
 128                              const argtype *type_ptr, int to_host)
 129 {
 130     int type;
 131
 132     type = *type_ptr++;
 133     switch(type) {
 134     case TYPE_CHAR:
 135         *(uint8_t *)dst = *(uint8_t *)src;
 136         break;
 137     case TYPE_SHORT:
 138         *(uint16_t *)dst = tswap16(*(uint16_t *)src);
 139         break;
 140     case TYPE_INT:
 141         *(uint32_t *)dst = tswap32(*(uint32_t *)src);
 142         break;
 143     case TYPE_LONGLONG:
 144     case TYPE_ULONGLONG:
 145         *(uint64_t *)dst = tswap64(*(uint64_t *)src);
 146         break;
 147 #if HOST_LONG_BITS == 32 && TARGET_ABI_BITS == 32
 148     case TYPE_LONG:
 149     case TYPE_ULONG:
 150     case TYPE_PTRVOID:
 151         *(uint32_t *)dst = tswap32(*(uint32_t *)src);
 152         break;
 153 #elif HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 32
 154     case TYPE_LONG:
 155     case TYPE_ULONG:
 156     case TYPE_PTRVOID:
 157         if (to_host) {
 158             if (type == TYPE_LONG) {
 159                 /* sign extension */
 160                 *(uint64_t *)dst = (int32_t)tswap32(*(uint32_t *)src);
 161             } else {
 162                 *(uint64_t *)dst = tswap32(*(uint32_t *)src);
 163             }
 164         } else {
 165             *(uint32_t *)dst = tswap32(*(uint64_t *)src & 0xffffffff);
 166         }
 167         break;
 168 #elif HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64
 169     case TYPE_LONG:
 170     case TYPE_ULONG:
 171     case TYPE_PTRVOID:
 172         *(uint64_t *)dst = tswap64(*(uint64_t *)src);
 173         break;
 174 #elif HOST_LONG_BITS == 32 && TARGET_ABI_BITS == 64
 175     case TYPE_LONG:
 176     case TYPE_ULONG:
 177     case TYPE_PTRVOID:
 178         if (to_host) {
 179             *(uint32_t *)dst = tswap64(*(uint64_t *)src);
 180         } else {
 181             if (type == TYPE_LONG) {
 182                 /* sign extension */
 183                 *(uint64_t *)dst = tswap64(*(int32_t *)src);
 184             } else {
 185                 *(uint64_t *)dst = tswap64(*(uint32_t *)src);
 186             }
 187         }
 188         break;
 189 #else
 190 #warning unsupported conversion
 191 #endif
 192     case TYPE_OLDDEVT:
 193     {
 194         uint64_t val = 0;
 195         switch (thunk_type_size(type_ptr - 1, !to_host)) {
 196         case 2:
 197             val = *(uint16_t *)src;
 198             break;
 199         case 4:
 200             val = *(uint32_t *)src;
 201             break;
 202         case 8:
 203             val = *(uint64_t *)src;
 204             break;
 205         }
 206         switch (thunk_type_size(type_ptr - 1, to_host)) {
 207         case 2:
 208             *(uint16_t *)dst = tswap16(val);
 209             break;
 210         case 4:
 211             *(uint32_t *)dst = tswap32(val);
 212             break;
 213         case 8:
 214             *(uint64_t *)dst = tswap64(val);
 215             break;
 216         }
 217         break;
 218     }
 219     case TYPE_ARRAY:
 220         {
 221             int array_length, i, dst_size, src_size;
 222             const uint8_t *s;
 223             uint8_t  *d;
 224
 225             array_length = *type_ptr++;
 226             dst_size = thunk_type_size(type_ptr, to_host);
 227             src_size = thunk_type_size(type_ptr, 1 - to_host);
 228             d = dst;
 229             s = src;
 230             for(i = 0;i < array_length; i++) {
 231                 thunk_convert(d, s, type_ptr, to_host);
 232                 d += dst_size;
 233                 s += src_size;
 234             }
 235             type_ptr = thunk_type_next(type_ptr);
 236         }
 237         break;
 238     case TYPE_STRUCT:
 239         {
 240             int i;
 241             const StructEntry *se;
 242             const uint8_t *s;
 243             uint8_t  *d;
 244             const argtype *field_types;
 245             const int *dst_offsets, *src_offsets;
 246
 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 X86 and Alpha formats...
 277  */
 278 unsigned int target_to_host_bitmask(unsigned int x86_mask,
 279                                     const bitmask_transtbl * trans_tbl)
 280 {
 281     const bitmask_transtbl *btp;
 282     unsigned int        alpha_mask = 0;
 283
 284     for(btp = trans_tbl; btp->x86_mask && btp->alpha_mask; btp++) {
 285         if((x86_mask & btp->x86_mask) == btp->x86_bits) {
 286             alpha_mask |= btp->alpha_bits;
 287         }
 288     }
 289     return(alpha_mask);
 290 }
 291
 292 unsigned int host_to_target_bitmask(unsigned int alpha_mask,
 293                                     const bitmask_transtbl * trans_tbl)
 294 {
 295     const bitmask_transtbl *btp;
 296     unsigned int        x86_mask = 0;
 297
 298     for(btp = trans_tbl; btp->x86_mask && btp->alpha_mask; btp++) {
 299         if((alpha_mask & btp->alpha_mask) == btp->alpha_bits) {
 300             x86_mask |= btp->x86_bits;
 301         }
 302     }
 303     return(x86_mask);
 304 }
 305
 306 #ifndef NO_THUNK_TYPE_SIZE
 307 int thunk_type_size_array(const argtype *type_ptr, int is_host)
 308 {
 309     return thunk_type_size(type_ptr, is_host);
 310 }
 311
 312 int thunk_type_align_array(const argtype *type_ptr, int is_host)
 313 {
 314     return thunk_type_align(type_ptr, is_host);
 315 }
 316 #endif /* ndef NO_THUNK_TYPE_SIZE */