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qemu/thunk.c
Aarushi Mehta a8df4845a0 thunk: improve readability of allocation loop 
Signed-off-by: Aarushi Mehta <mehta.aaru20@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <a09acf9e093c09a70896bb9886370cf7f049f941.camel@gmail.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2019-03-11 18:48:20 +01:00

322 lines
9.1 KiB
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/*
* Generic thunking code to convert data between host and target CPU
*
* Copyright (c) 2003 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu.h"
#include "exec/user/thunk.h"
//#define DEBUG
static unsigned int max_struct_entries;
StructEntry *struct_entries;
static const argtype *thunk_type_next_ptr(const argtype *type_ptr);
static inline const argtype *thunk_type_next(const argtype *type_ptr)
{
int type;
type = *type_ptr++;
switch(type) {
case TYPE_CHAR:
case TYPE_SHORT:
case TYPE_INT:
case TYPE_LONGLONG:
case TYPE_ULONGLONG:
case TYPE_LONG:
case TYPE_ULONG:
case TYPE_PTRVOID:
case TYPE_OLDDEVT:
return type_ptr;
case TYPE_PTR:
return thunk_type_next_ptr(type_ptr);
case TYPE_ARRAY:
return thunk_type_next_ptr(type_ptr + 1);
case TYPE_STRUCT:
return type_ptr + 1;
default:
return NULL;
}
}
static const argtype *thunk_type_next_ptr(const argtype *type_ptr)
{
return thunk_type_next(type_ptr);
}
void thunk_register_struct(int id, const char *name, const argtype *types)
{
const argtype *type_ptr;
StructEntry *se;
int nb_fields, offset, max_align, align, size, i, j;
assert(id < max_struct_entries);
/* first we count the number of fields */
type_ptr = types;
nb_fields = 0;
while (*type_ptr != TYPE_NULL) {
type_ptr = thunk_type_next(type_ptr);
nb_fields++;
}
assert(nb_fields > 0);
se = struct_entries + id;
se->field_types = types;
se->nb_fields = nb_fields;
se->name = name;
#ifdef DEBUG
printf("struct %s: id=%d nb_fields=%d\n",
se->name, id, se->nb_fields);
#endif
/* now we can alloc the data */
for (i = 0; i < ARRAY_SIZE(se->field_offsets); i++) {
offset = 0;
max_align = 1;
se->field_offsets[i] = g_new(int, nb_fields);
type_ptr = se->field_types;
for(j = 0;j < nb_fields; j++) {
size = thunk_type_size(type_ptr, i);
align = thunk_type_align(type_ptr, i);
offset = (offset + align - 1) & ~(align - 1);
se->field_offsets[i][j] = offset;
offset += size;
if (align > max_align)
max_align = align;
type_ptr = thunk_type_next(type_ptr);
}
offset = (offset + max_align - 1) & ~(max_align - 1);
se->size[i] = offset;
se->align[i] = max_align;
#ifdef DEBUG
printf("%s: size=%d align=%d\n",
i == THUNK_HOST ? "host" : "target", offset, max_align);
#endif
}
}
void thunk_register_struct_direct(int id, const char *name,
const StructEntry *se1)
{
StructEntry *se;
assert(id < max_struct_entries);
se = struct_entries + id;
*se = *se1;
se->name = name;
}
/* now we can define the main conversion functions */
const argtype *thunk_convert(void *dst, const void *src,
const argtype *type_ptr, int to_host)
{
int type;
type = *type_ptr++;
switch(type) {
case TYPE_CHAR:
*(uint8_t *)dst = *(uint8_t *)src;
break;
case TYPE_SHORT:
*(uint16_t *)dst = tswap16(*(uint16_t *)src);
break;
case TYPE_INT:
*(uint32_t *)dst = tswap32(*(uint32_t *)src);
break;
case TYPE_LONGLONG:
case TYPE_ULONGLONG:
*(uint64_t *)dst = tswap64(*(uint64_t *)src);
break;
#if HOST_LONG_BITS == 32 && TARGET_ABI_BITS == 32
case TYPE_LONG:
case TYPE_ULONG:
case TYPE_PTRVOID:
*(uint32_t *)dst = tswap32(*(uint32_t *)src);
break;
#elif HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 32
case TYPE_LONG:
case TYPE_ULONG:
case TYPE_PTRVOID:
if (to_host) {
if (type == TYPE_LONG) {
/* sign extension */
*(uint64_t *)dst = (int32_t)tswap32(*(uint32_t *)src);
} else {
*(uint64_t *)dst = tswap32(*(uint32_t *)src);
}
} else {
*(uint32_t *)dst = tswap32(*(uint64_t *)src & 0xffffffff);
}
break;
#elif HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64
case TYPE_LONG:
case TYPE_ULONG:
case TYPE_PTRVOID:
*(uint64_t *)dst = tswap64(*(uint64_t *)src);
break;
#elif HOST_LONG_BITS == 32 && TARGET_ABI_BITS == 64
case TYPE_LONG:
case TYPE_ULONG:
case TYPE_PTRVOID:
if (to_host) {
*(uint32_t *)dst = tswap64(*(uint64_t *)src);
} else {
if (type == TYPE_LONG) {
/* sign extension */
*(uint64_t *)dst = tswap64(*(int32_t *)src);
} else {
*(uint64_t *)dst = tswap64(*(uint32_t *)src);
}
}
break;
#else
#warning unsupported conversion
#endif
case TYPE_OLDDEVT:
{
uint64_t val = 0;
switch (thunk_type_size(type_ptr - 1, !to_host)) {
case 2:
val = *(uint16_t *)src;
break;
case 4:
val = *(uint32_t *)src;
break;
case 8:
val = *(uint64_t *)src;
break;
}
switch (thunk_type_size(type_ptr - 1, to_host)) {
case 2:
*(uint16_t *)dst = tswap16(val);
break;
case 4:
*(uint32_t *)dst = tswap32(val);
break;
case 8:
*(uint64_t *)dst = tswap64(val);
break;
}
break;
}
case TYPE_ARRAY:
{
int array_length, i, dst_size, src_size;
const uint8_t *s;
uint8_t *d;
array_length = *type_ptr++;
dst_size = thunk_type_size(type_ptr, to_host);
src_size = thunk_type_size(type_ptr, 1 - to_host);
d = dst;
s = src;
for(i = 0;i < array_length; i++) {
thunk_convert(d, s, type_ptr, to_host);
d += dst_size;
s += src_size;
}
type_ptr = thunk_type_next(type_ptr);
}
break;
case TYPE_STRUCT:
{
int i;
const StructEntry *se;
const uint8_t *s;
uint8_t *d;
const argtype *field_types;
const int *dst_offsets, *src_offsets;
assert(*type_ptr < max_struct_entries);
se = struct_entries + *type_ptr++;
if (se->convert[0] != NULL) {
/* specific conversion is needed */
(*se->convert[to_host])(dst, src);
} else {
/* standard struct conversion */
field_types = se->field_types;
dst_offsets = se->field_offsets[to_host];
src_offsets = se->field_offsets[1 - to_host];
d = dst;
s = src;
for(i = 0;i < se->nb_fields; i++) {
field_types = thunk_convert(d + dst_offsets[i],
s + src_offsets[i],
field_types, to_host);
}
}
}
break;
default:
fprintf(stderr, "Invalid type 0x%x\n", type);
break;
}
return type_ptr;
}
/* from em86 */
/* Utility function: Table-driven functions to translate bitmasks
* between host and target formats
*/
unsigned int target_to_host_bitmask(unsigned int target_mask,
const bitmask_transtbl * trans_tbl)
{
const bitmask_transtbl *btp;
unsigned int host_mask = 0;
for (btp = trans_tbl; btp->target_mask && btp->host_mask; btp++) {
if ((target_mask & btp->target_mask) == btp->target_bits) {
host_mask |= btp->host_bits;
}
}
return host_mask;
}
unsigned int host_to_target_bitmask(unsigned int host_mask,
const bitmask_transtbl * trans_tbl)
{
const bitmask_transtbl *btp;
unsigned int target_mask = 0;
for (btp = trans_tbl; btp->target_mask && btp->host_mask; btp++) {
if ((host_mask & btp->host_mask) == btp->host_bits) {
target_mask |= btp->target_bits;
}
}
return target_mask;
}
int thunk_type_size_array(const argtype *type_ptr, int is_host)
{
return thunk_type_size(type_ptr, is_host);
}
int thunk_type_align_array(const argtype *type_ptr, int is_host)
{
return thunk_type_align(type_ptr, is_host);
}
void thunk_init(unsigned int max_structs)
{
max_struct_entries = max_structs;
struct_entries = g_new0(StructEntry, max_structs);
}
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