/*
* virtual page mapping and translated block handling
*
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <inttypes.h>
#include <sys/mman.h>
#include "cpu-i386.h"
//#define DEBUG_TB_INVALIDATE
#define DEBUG_FLUSH
/* make various TB consistency checks */
//#define DEBUG_TB_CHECK
/* threshold to flush the translated code buffer */
#define CODE_GEN_BUFFER_MAX_SIZE (CODE_GEN_BUFFER_SIZE - CODE_GEN_MAX_SIZE)
#define CODE_GEN_MAX_BLOCKS (CODE_GEN_BUFFER_SIZE / 64)
TranslationBlock tbs[CODE_GEN_MAX_BLOCKS];
TranslationBlock *tb_hash[CODE_GEN_HASH_SIZE];
int nb_tbs;
uint8_t code_gen_buffer[CODE_GEN_BUFFER_SIZE];
uint8_t *code_gen_ptr;
/* XXX: pack the flags in the low bits of the pointer ? */
typedef struct PageDesc {
unsigned long flags;
TranslationBlock *first_tb;
} PageDesc;
#define L2_BITS 10
#define L1_BITS (32 - L2_BITS - TARGET_PAGE_BITS)
#define L1_SIZE (1 << L1_BITS)
#define L2_SIZE (1 << L2_BITS)
static void tb_invalidate_page(unsigned long address);
unsigned long real_host_page_size;
unsigned long host_page_bits;
unsigned long host_page_size;
unsigned long host_page_mask;
static PageDesc *l1_map[L1_SIZE];
void page_init(void)
{
/* NOTE: we can always suppose that host_page_size >=
TARGET_PAGE_SIZE */
real_host_page_size = getpagesize();
if (host_page_size == 0)
host_page_size = real_host_page_size;
if (host_page_size < TARGET_PAGE_SIZE)
host_page_size = TARGET_PAGE_SIZE;
host_page_bits = 0;
while ((1 << host_page_bits) < host_page_size)
host_page_bits++;
host_page_mask = ~(host_page_size - 1);
}
/* dump memory mappings */
void page_dump(FILE *f)
{
unsigned long start, end;
int i, j, prot, prot1;
PageDesc *p;
fprintf(f, "%-8s %-8s %-8s %s\n",
"start", "end", "size", "prot");
start = -1;
end = -1;
prot = 0;
for(i = 0; i <= L1_SIZE; i++) {
if (i < L1_SIZE)
p = l1_map[i];
else
p = NULL;
for(j = 0;j < L2_SIZE; j++) {
if (!p)
prot1 = 0;
else
prot1 = p[j].flags;
if (prot1 != prot) {
end = (i << (32 - L1_BITS)) | (j << TARGET_PAGE_BITS);
if (start != -1) {
fprintf(f, "%08lx-%08lx %08lx %c%c%c\n",
start, end, end - start,
prot & PAGE_READ ? 'r' : '-',
prot & PAGE_WRITE ? 'w' : '-',
prot & PAGE_EXEC ? 'x' : '-');
}
if (prot1 != 0)
start = end;
else
start = -1;
prot = prot1;
}
if (!p)
break;
}
}
}
static inline PageDesc *page_find_alloc(unsigned int index)
{
PageDesc **lp, *p;
lp = &l1_map[index >> L2_BITS];
p = *lp;
if (!p) {
/* allocate if not found */
p = malloc(sizeof(PageDesc) * L2_SIZE);
memset(p, 0, sizeof(PageDesc) * L2_SIZE);
*lp = p;
}
return p + (index & (L2_SIZE - 1));
}
static inline PageDesc *page_find(unsigned int index)
{
PageDesc *p;
p = l1_map[index >> L2_BITS];
if (!p)
return 0;
return p + (index & (L2_SIZE - 1));
}
int page_get_flags(unsigned long address)
{
PageDesc *p;
p = page_find(address >> TARGET_PAGE_BITS);
if (!p)
return 0;
return p->flags;
}
/* modify the flags of a page and invalidate the code if
necessary. The flag PAGE_WRITE_ORG is positionned automatically
depending on PAGE_WRITE */
void page_set_flags(unsigned long start, unsigned long end, int flags)
{
PageDesc *p;
unsigned long addr;
start = start & TARGET_PAGE_MASK;
end = TARGET_PAGE_ALIGN(end);
if (flags & PAGE_WRITE)
flags |= PAGE_WRITE_ORG;
for(addr = start; addr < end; addr += TARGET_PAGE_SIZE) {
p = page_find_alloc(addr >> TARGET_PAGE_BITS);
/* if the write protection is set, then we invalidate the code
inside */
if (!(p->flags & PAGE_WRITE) &&
(flags & PAGE_WRITE) &&
p->first_tb) {
tb_invalidate_page(addr);
}
p->flags = flags;
}
}
void cpu_x86_tblocks_init(void)
{
if (!code_gen_ptr) {
code_gen_ptr = code_gen_buffer;
}
}
/* set to NULL all the 'first_tb' fields in all PageDescs */
static void page_flush_tb(void)
{
int i, j;
PageDesc *p;
for(i = 0; i < L1_SIZE; i++) {
p = l1_map[i];
if (p) {
for(j = 0; j < L2_SIZE; j++)
p[j].first_tb = NULL;
}
}
}
/* flush all the translation blocks */
void tb_flush(void)
{
int i;
#ifdef DEBUG_FLUSH
printf("qemu: flush code_size=%d nb_tbs=%d avg_tb_size=%d\n",
code_gen_ptr - code_gen_buffer,
nb_tbs,
(code_gen_ptr - code_gen_buffer) / nb_tbs);
#endif
nb_tbs = 0;
for(i = 0;i < CODE_GEN_HASH_SIZE; i++)
tb_hash[i] = NULL;
page_flush_tb();
code_gen_ptr = code_gen_buffer;
/* XXX: flush processor icache at this point */
}
#ifdef DEBUG_TB_CHECK
static void tb_invalidate_check(unsigned long address)
{
TranslationBlock *tb;
int i;
address &= TARGET_PAGE_MASK;
for(i = 0;i < CODE_GEN_HASH_SIZE; i++) {
for(tb = tb_hash[i]; tb != NULL; tb = tb->hash_next) {
if (!(address + TARGET_PAGE_SIZE <= tb->pc ||
address >= tb->pc + tb->size)) {
printf("ERROR invalidate: address=%08lx PC=%08lx size=%04x\n",
address, tb->pc, tb->size);
}
}
}
}
/* verify that all the pages have correct rights for code */
static void tb_page_check(void)
{
TranslationBlock *tb;
int i, flags1, flags2;
for(i = 0;i < CODE_GEN_HASH_SIZE; i++) {
for(tb = tb_hash[i]; tb != NULL; tb = tb->hash_next) {
flags1 = page_get_flags(tb->pc);
flags2 = page_get_flags(tb->pc + tb->size - 1);
if ((flags1 & PAGE_WRITE) || (flags2 & PAGE_WRITE)) {
printf("ERROR page flags: PC=%08lx size=%04x f1=%x f2=%x\n",
tb->pc, tb->size, flags1, flags2);
}
}
}
}
#endif
/* invalidate one TB */
static inline void tb_remove(TranslationBlock **ptb, TranslationBlock *tb,
int next_offset)
{
TranslationBlock *tb1;
for(;;) {
tb1 = *ptb;
if (tb1 == tb) {
*ptb = *(TranslationBlock **)((char *)tb1 + next_offset);
break;
}
ptb = (TranslationBlock **)((char *)tb1 + next_offset);
}
}
static inline void tb_invalidate(TranslationBlock *tb, int parity)
{
PageDesc *p;
unsigned int page_index1, page_index2;
unsigned int h;
/* remove the TB from the hash list */
h = tb_hash_func(tb->pc);
tb_remove(&tb_hash[h], tb,
offsetof(TranslationBlock, hash_next));
/* remove the TB from the page list */
page_index1 = tb->pc >> TARGET_PAGE_BITS;
if ((page_index1 & 1) == parity) {
p = page_find(page_index1);
tb_remove(&p->first_tb, tb,
offsetof(TranslationBlock, page_next[page_index1 & 1]));
}
page_index2 = (tb->pc + tb->size - 1) >> TARGET_PAGE_BITS;
if ((page_index2 & 1) == parity) {
p = page_find(page_index2);
tb_remove(&p->first_tb, tb,
offsetof(TranslationBlock, page_next[page_index2 & 1]));
}
}
/* invalidate all TBs which intersect with the target page starting at addr */
static void tb_invalidate_page(unsigned long address)
{
TranslationBlock *tb_next, *tb;
unsigned int page_index;
int parity1, parity2;
PageDesc *p;
#ifdef DEBUG_TB_INVALIDATE
printf("tb_invalidate_page: %lx\n", address);
#endif
page_index = address >> TARGET_PAGE_BITS;
p = page_find(page_index);
if (!p)
return;
tb = p->first_tb;
parity1 = page_index & 1;
parity2 = parity1 ^ 1;
while (tb != NULL) {
tb_next = tb->page_next[parity1];
tb_invalidate(tb, parity2);
tb = tb_next;
}
p->first_tb = NULL;
}
/* add the tb in the target page and protect it if necessary */
static inline void tb_alloc_page(TranslationBlock *tb, unsigned int page_index)
{
PageDesc *p;
unsigned long host_start, host_end, addr, page_addr;
int prot;
p = page_find_alloc(page_index);
tb->page_next[page_index & 1] = p->first_tb;
p->first_tb = tb;
if (p->flags & PAGE_WRITE) {
/* force the host page as non writable (writes will have a
page fault + mprotect overhead) */
page_addr = (page_index << TARGET_PAGE_BITS);
host_start = page_addr & host_page_mask;
host_end = host_start + host_page_size;
prot = 0;
for(addr = host_start; addr < host_end; addr += TARGET_PAGE_SIZE)
prot |= page_get_flags(addr);
mprotect((void *)host_start, host_page_size,
(prot & PAGE_BITS) & ~PAGE_WRITE);
#ifdef DEBUG_TB_INVALIDATE
printf("protecting code page: 0x%08lx\n",
host_start);
#endif
p->flags &= ~PAGE_WRITE;
#ifdef DEBUG_TB_CHECK
tb_page_check();
#endif
}
}
/* Allocate a new translation block. Flush the translation buffer if
too many translation blocks or too much generated code. */
TranslationBlock *tb_alloc(unsigned long pc,
unsigned long size)
{
TranslationBlock *tb;
unsigned int page_index1, page_index2;
if (nb_tbs >= CODE_GEN_MAX_BLOCKS ||
(code_gen_ptr - code_gen_buffer) >= CODE_GEN_BUFFER_MAX_SIZE)
tb_flush();
tb = &tbs[nb_tbs++];
tb->pc = pc;
tb->size = size;
/* add in the page list */
page_index1 = pc >> TARGET_PAGE_BITS;
tb_alloc_page(tb, page_index1);
page_index2 = (pc + size - 1) >> TARGET_PAGE_BITS;
if (page_index2 != page_index1) {
tb_alloc_page(tb, page_index2);
}
return tb;
}
/* called from signal handler: invalidate the code and unprotect the
page. Return TRUE if the fault was succesfully handled. */
int page_unprotect(unsigned long address)
{
unsigned int page_index, prot;
PageDesc *p;
unsigned long host_start, host_end, addr;
page_index = address >> TARGET_PAGE_BITS;
p = page_find(page_index);
if (!p)
return 0;
if ((p->flags & (PAGE_WRITE_ORG | PAGE_WRITE)) == PAGE_WRITE_ORG) {
/* if the page was really writable, then we change its
protection back to writable */
host_start = address & host_page_mask;
host_end = host_start + host_page_size;
prot = 0;
for(addr = host_start; addr < host_end; addr += TARGET_PAGE_SIZE)
prot |= page_get_flags(addr);
mprotect((void *)host_start, host_page_size,
(prot & PAGE_BITS) | PAGE_WRITE);
p->flags |= PAGE_WRITE;
/* and since the content will be modified, we must invalidate
the corresponding translated code. */
tb_invalidate_page(address);
#ifdef DEBUG_TB_CHECK
tb_invalidate_check(address);
#endif
return 1;
} else {
return 0;
}
}
/* call this function when system calls directly modify a memory area */
void page_unprotect_range(uint8_t *data, unsigned long data_size)
{
unsigned long start, end, addr;
start = (unsigned long)data;
end = start + data_size;
start &= TARGET_PAGE_MASK;
end = TARGET_PAGE_ALIGN(end);
for(addr = start; addr < end; addr += TARGET_PAGE_SIZE) {
page_unprotect(addr);
}
}
