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qemu/thunk.c
Alexander Graf 8be656b87c linux-user: Allocate thunk size dynamically 
We store all struct types in an array of static size without ever
checking whether we overrun it. Of course some day someone (like me
in another, ancient ALSA enabling patch set) will run into the limit
without realizing it.

So let's make the allocation dynamic. We already know the number of
structs that we want to allocate, so we only need to pass the variable
into the respective piece of code.

Also, to ensure we don't accidently overwrite random memory, add some
asserts to sanity check whether a thunk is actually part of our array.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2015-06-15 11:36:58 +03:00

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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 <stdlib.h>
#include <stdio.h>
#include <stdarg.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);
se = struct_entries + id;
/* 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++;
}
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 < 2; i++) {
offset = 0;
max_align = 1;
se->field_offsets[i] = malloc(nb_fields * sizeof(int));
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 X86 and Alpha formats...
*/
unsigned int target_to_host_bitmask(unsigned int x86_mask,
const bitmask_transtbl * trans_tbl)
{
const bitmask_transtbl *btp;
unsigned int alpha_mask = 0;
for(btp = trans_tbl; btp->x86_mask && btp->alpha_mask; btp++) {
if((x86_mask & btp->x86_mask) == btp->x86_bits) {
alpha_mask |= btp->alpha_bits;
}
}
return(alpha_mask);
}
unsigned int host_to_target_bitmask(unsigned int alpha_mask,
const bitmask_transtbl * trans_tbl)
{
const bitmask_transtbl *btp;
unsigned int x86_mask = 0;
for(btp = trans_tbl; btp->x86_mask && btp->alpha_mask; btp++) {
if((alpha_mask & btp->alpha_mask) == btp->alpha_bits) {
x86_mask |= btp->x86_bits;
}
}
return(x86_mask);
}
#ifndef NO_THUNK_TYPE_SIZE
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);
}
#endif /* ndef NO_THUNK_TYPE_SIZE */
void thunk_init(unsigned int max_structs)
{
max_struct_entries = max_structs;
struct_entries = g_new0(StructEntry, max_structs);
}
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