eb51d102bb
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@169 c046a42c-6fe2-441c-8c8c-71466251a162
442 lines
12 KiB
C
442 lines
12 KiB
C
/*
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* virtual page mapping and translated block handling
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*
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* Copyright (c) 2003 Fabrice Bellard
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <stdarg.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <inttypes.h>
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#include <sys/mman.h>
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#include "cpu-i386.h"
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//#define DEBUG_TB_INVALIDATE
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#define DEBUG_FLUSH
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/* make various TB consistency checks */
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//#define DEBUG_TB_CHECK
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/* threshold to flush the translated code buffer */
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#define CODE_GEN_BUFFER_MAX_SIZE (CODE_GEN_BUFFER_SIZE - CODE_GEN_MAX_SIZE)
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#define CODE_GEN_MAX_BLOCKS (CODE_GEN_BUFFER_SIZE / 64)
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TranslationBlock tbs[CODE_GEN_MAX_BLOCKS];
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TranslationBlock *tb_hash[CODE_GEN_HASH_SIZE];
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int nb_tbs;
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/* any access to the tbs or the page table must use this lock */
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spinlock_t tb_lock = SPIN_LOCK_UNLOCKED;
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uint8_t code_gen_buffer[CODE_GEN_BUFFER_SIZE];
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uint8_t *code_gen_ptr;
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/* XXX: pack the flags in the low bits of the pointer ? */
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typedef struct PageDesc {
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unsigned long flags;
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TranslationBlock *first_tb;
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} PageDesc;
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#define L2_BITS 10
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#define L1_BITS (32 - L2_BITS - TARGET_PAGE_BITS)
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#define L1_SIZE (1 << L1_BITS)
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#define L2_SIZE (1 << L2_BITS)
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static void tb_invalidate_page(unsigned long address);
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unsigned long real_host_page_size;
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unsigned long host_page_bits;
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unsigned long host_page_size;
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unsigned long host_page_mask;
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static PageDesc *l1_map[L1_SIZE];
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void page_init(void)
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{
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/* NOTE: we can always suppose that host_page_size >=
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TARGET_PAGE_SIZE */
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real_host_page_size = getpagesize();
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if (host_page_size == 0)
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host_page_size = real_host_page_size;
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if (host_page_size < TARGET_PAGE_SIZE)
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host_page_size = TARGET_PAGE_SIZE;
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host_page_bits = 0;
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while ((1 << host_page_bits) < host_page_size)
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host_page_bits++;
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host_page_mask = ~(host_page_size - 1);
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}
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/* dump memory mappings */
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void page_dump(FILE *f)
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{
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unsigned long start, end;
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int i, j, prot, prot1;
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PageDesc *p;
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fprintf(f, "%-8s %-8s %-8s %s\n",
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"start", "end", "size", "prot");
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start = -1;
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end = -1;
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prot = 0;
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for(i = 0; i <= L1_SIZE; i++) {
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if (i < L1_SIZE)
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p = l1_map[i];
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else
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p = NULL;
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for(j = 0;j < L2_SIZE; j++) {
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if (!p)
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prot1 = 0;
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else
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prot1 = p[j].flags;
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if (prot1 != prot) {
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end = (i << (32 - L1_BITS)) | (j << TARGET_PAGE_BITS);
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if (start != -1) {
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fprintf(f, "%08lx-%08lx %08lx %c%c%c\n",
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start, end, end - start,
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prot & PAGE_READ ? 'r' : '-',
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prot & PAGE_WRITE ? 'w' : '-',
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prot & PAGE_EXEC ? 'x' : '-');
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}
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if (prot1 != 0)
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start = end;
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else
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start = -1;
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prot = prot1;
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}
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if (!p)
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break;
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}
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}
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}
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static inline PageDesc *page_find_alloc(unsigned int index)
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{
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PageDesc **lp, *p;
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lp = &l1_map[index >> L2_BITS];
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p = *lp;
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if (!p) {
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/* allocate if not found */
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p = malloc(sizeof(PageDesc) * L2_SIZE);
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memset(p, 0, sizeof(PageDesc) * L2_SIZE);
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*lp = p;
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}
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return p + (index & (L2_SIZE - 1));
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}
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static inline PageDesc *page_find(unsigned int index)
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{
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PageDesc *p;
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p = l1_map[index >> L2_BITS];
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if (!p)
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return 0;
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return p + (index & (L2_SIZE - 1));
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}
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int page_get_flags(unsigned long address)
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{
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PageDesc *p;
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p = page_find(address >> TARGET_PAGE_BITS);
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if (!p)
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return 0;
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return p->flags;
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}
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/* modify the flags of a page and invalidate the code if
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necessary. The flag PAGE_WRITE_ORG is positionned automatically
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depending on PAGE_WRITE */
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void page_set_flags(unsigned long start, unsigned long end, int flags)
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{
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PageDesc *p;
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unsigned long addr;
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start = start & TARGET_PAGE_MASK;
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end = TARGET_PAGE_ALIGN(end);
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if (flags & PAGE_WRITE)
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flags |= PAGE_WRITE_ORG;
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spin_lock(&tb_lock);
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for(addr = start; addr < end; addr += TARGET_PAGE_SIZE) {
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p = page_find_alloc(addr >> TARGET_PAGE_BITS);
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/* if the write protection is set, then we invalidate the code
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inside */
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if (!(p->flags & PAGE_WRITE) &&
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(flags & PAGE_WRITE) &&
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p->first_tb) {
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tb_invalidate_page(addr);
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}
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p->flags = flags;
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}
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spin_unlock(&tb_lock);
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}
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void cpu_x86_tblocks_init(void)
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{
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if (!code_gen_ptr) {
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code_gen_ptr = code_gen_buffer;
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}
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}
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/* set to NULL all the 'first_tb' fields in all PageDescs */
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static void page_flush_tb(void)
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{
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int i, j;
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PageDesc *p;
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for(i = 0; i < L1_SIZE; i++) {
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p = l1_map[i];
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if (p) {
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for(j = 0; j < L2_SIZE; j++)
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p[j].first_tb = NULL;
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}
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}
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}
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/* flush all the translation blocks */
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void tb_flush(void)
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{
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int i;
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#ifdef DEBUG_FLUSH
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printf("qemu: flush code_size=%d nb_tbs=%d avg_tb_size=%d\n",
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code_gen_ptr - code_gen_buffer,
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nb_tbs,
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(code_gen_ptr - code_gen_buffer) / nb_tbs);
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#endif
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nb_tbs = 0;
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for(i = 0;i < CODE_GEN_HASH_SIZE; i++)
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tb_hash[i] = NULL;
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page_flush_tb();
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code_gen_ptr = code_gen_buffer;
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/* XXX: flush processor icache at this point */
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}
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#ifdef DEBUG_TB_CHECK
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static void tb_invalidate_check(unsigned long address)
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{
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TranslationBlock *tb;
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int i;
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address &= TARGET_PAGE_MASK;
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for(i = 0;i < CODE_GEN_HASH_SIZE; i++) {
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for(tb = tb_hash[i]; tb != NULL; tb = tb->hash_next) {
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if (!(address + TARGET_PAGE_SIZE <= tb->pc ||
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address >= tb->pc + tb->size)) {
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printf("ERROR invalidate: address=%08lx PC=%08lx size=%04x\n",
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address, tb->pc, tb->size);
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}
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}
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}
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}
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/* verify that all the pages have correct rights for code */
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static void tb_page_check(void)
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{
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TranslationBlock *tb;
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int i, flags1, flags2;
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for(i = 0;i < CODE_GEN_HASH_SIZE; i++) {
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for(tb = tb_hash[i]; tb != NULL; tb = tb->hash_next) {
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flags1 = page_get_flags(tb->pc);
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flags2 = page_get_flags(tb->pc + tb->size - 1);
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if ((flags1 & PAGE_WRITE) || (flags2 & PAGE_WRITE)) {
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printf("ERROR page flags: PC=%08lx size=%04x f1=%x f2=%x\n",
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tb->pc, tb->size, flags1, flags2);
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}
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}
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}
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}
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#endif
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/* invalidate one TB */
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static inline void tb_remove(TranslationBlock **ptb, TranslationBlock *tb,
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int next_offset)
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{
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TranslationBlock *tb1;
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for(;;) {
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tb1 = *ptb;
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if (tb1 == tb) {
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*ptb = *(TranslationBlock **)((char *)tb1 + next_offset);
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break;
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}
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ptb = (TranslationBlock **)((char *)tb1 + next_offset);
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}
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}
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static inline void tb_invalidate(TranslationBlock *tb, int parity)
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{
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PageDesc *p;
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unsigned int page_index1, page_index2;
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unsigned int h;
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/* remove the TB from the hash list */
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h = tb_hash_func(tb->pc);
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tb_remove(&tb_hash[h], tb,
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offsetof(TranslationBlock, hash_next));
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/* remove the TB from the page list */
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page_index1 = tb->pc >> TARGET_PAGE_BITS;
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if ((page_index1 & 1) == parity) {
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p = page_find(page_index1);
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tb_remove(&p->first_tb, tb,
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offsetof(TranslationBlock, page_next[page_index1 & 1]));
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}
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page_index2 = (tb->pc + tb->size - 1) >> TARGET_PAGE_BITS;
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if ((page_index2 & 1) == parity) {
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p = page_find(page_index2);
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tb_remove(&p->first_tb, tb,
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offsetof(TranslationBlock, page_next[page_index2 & 1]));
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}
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}
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/* invalidate all TBs which intersect with the target page starting at addr */
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static void tb_invalidate_page(unsigned long address)
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{
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TranslationBlock *tb_next, *tb;
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unsigned int page_index;
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int parity1, parity2;
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PageDesc *p;
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#ifdef DEBUG_TB_INVALIDATE
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printf("tb_invalidate_page: %lx\n", address);
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#endif
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page_index = address >> TARGET_PAGE_BITS;
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p = page_find(page_index);
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if (!p)
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return;
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tb = p->first_tb;
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parity1 = page_index & 1;
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parity2 = parity1 ^ 1;
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while (tb != NULL) {
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tb_next = tb->page_next[parity1];
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tb_invalidate(tb, parity2);
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tb = tb_next;
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}
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p->first_tb = NULL;
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}
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/* add the tb in the target page and protect it if necessary */
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static inline void tb_alloc_page(TranslationBlock *tb, unsigned int page_index)
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{
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PageDesc *p;
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unsigned long host_start, host_end, addr, page_addr;
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int prot;
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p = page_find_alloc(page_index);
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tb->page_next[page_index & 1] = p->first_tb;
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p->first_tb = tb;
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if (p->flags & PAGE_WRITE) {
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/* force the host page as non writable (writes will have a
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page fault + mprotect overhead) */
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page_addr = (page_index << TARGET_PAGE_BITS);
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host_start = page_addr & host_page_mask;
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host_end = host_start + host_page_size;
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prot = 0;
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for(addr = host_start; addr < host_end; addr += TARGET_PAGE_SIZE)
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prot |= page_get_flags(addr);
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mprotect((void *)host_start, host_page_size,
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(prot & PAGE_BITS) & ~PAGE_WRITE);
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#ifdef DEBUG_TB_INVALIDATE
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printf("protecting code page: 0x%08lx\n",
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host_start);
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#endif
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p->flags &= ~PAGE_WRITE;
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#ifdef DEBUG_TB_CHECK
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tb_page_check();
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#endif
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}
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}
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/* Allocate a new translation block. Flush the translation buffer if
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too many translation blocks or too much generated code. */
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TranslationBlock *tb_alloc(unsigned long pc,
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unsigned long size)
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{
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TranslationBlock *tb;
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unsigned int page_index1, page_index2;
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if (nb_tbs >= CODE_GEN_MAX_BLOCKS ||
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(code_gen_ptr - code_gen_buffer) >= CODE_GEN_BUFFER_MAX_SIZE)
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tb_flush();
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tb = &tbs[nb_tbs++];
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tb->pc = pc;
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tb->size = size;
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/* add in the page list */
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page_index1 = pc >> TARGET_PAGE_BITS;
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tb_alloc_page(tb, page_index1);
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page_index2 = (pc + size - 1) >> TARGET_PAGE_BITS;
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if (page_index2 != page_index1) {
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tb_alloc_page(tb, page_index2);
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}
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return tb;
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}
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/* called from signal handler: invalidate the code and unprotect the
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page. Return TRUE if the fault was succesfully handled. */
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int page_unprotect(unsigned long address)
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{
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unsigned int page_index, prot;
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PageDesc *p;
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unsigned long host_start, host_end, addr;
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page_index = address >> TARGET_PAGE_BITS;
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p = page_find(page_index);
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if (!p)
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return 0;
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if ((p->flags & (PAGE_WRITE_ORG | PAGE_WRITE)) == PAGE_WRITE_ORG) {
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/* if the page was really writable, then we change its
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protection back to writable */
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host_start = address & host_page_mask;
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host_end = host_start + host_page_size;
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prot = 0;
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for(addr = host_start; addr < host_end; addr += TARGET_PAGE_SIZE)
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prot |= page_get_flags(addr);
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mprotect((void *)host_start, host_page_size,
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(prot & PAGE_BITS) | PAGE_WRITE);
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p->flags |= PAGE_WRITE;
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/* and since the content will be modified, we must invalidate
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the corresponding translated code. */
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tb_invalidate_page(address);
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#ifdef DEBUG_TB_CHECK
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tb_invalidate_check(address);
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#endif
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return 1;
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} else {
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return 0;
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}
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}
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/* call this function when system calls directly modify a memory area */
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void page_unprotect_range(uint8_t *data, unsigned long data_size)
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{
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unsigned long start, end, addr;
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start = (unsigned long)data;
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end = start + data_size;
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start &= TARGET_PAGE_MASK;
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end = TARGET_PAGE_ALIGN(end);
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for(addr = start; addr < end; addr += TARGET_PAGE_SIZE) {
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page_unprotect(addr);
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}
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}
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