410 lines
13 KiB
C
410 lines
13 KiB
C
/*
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* mmap support for qemu
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*
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* Copyright (c) 2003 Fabrice Bellard
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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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 <unistd.h>
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#include <errno.h>
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#include <sys/mman.h>
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#include "qemu.h"
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//#define DEBUG_MMAP
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/* NOTE: all the constants are the HOST ones */
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int target_mprotect(unsigned long start, unsigned long len, int prot)
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{
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unsigned long end, host_start, host_end, addr;
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int prot1, ret;
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#ifdef DEBUG_MMAP
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printf("mprotect: start=0x%lx len=0x%lx prot=%c%c%c\n", start, len,
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prot & PROT_READ ? 'r' : '-',
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prot & PROT_WRITE ? 'w' : '-',
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prot & PROT_EXEC ? 'x' : '-');
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#endif
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if ((start & ~TARGET_PAGE_MASK) != 0)
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return -EINVAL;
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len = TARGET_PAGE_ALIGN(len);
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end = start + len;
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if (end < start)
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return -EINVAL;
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if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
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return -EINVAL;
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if (len == 0)
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return 0;
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host_start = start & qemu_host_page_mask;
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host_end = HOST_PAGE_ALIGN(end);
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if (start > host_start) {
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/* handle host page containing start */
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prot1 = prot;
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for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
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prot1 |= page_get_flags(addr);
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}
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if (host_end == host_start + qemu_host_page_size) {
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for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
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prot1 |= page_get_flags(addr);
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}
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end = host_end;
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}
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ret = mprotect((void *)host_start, qemu_host_page_size, prot1 & PAGE_BITS);
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if (ret != 0)
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return ret;
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host_start += qemu_host_page_size;
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}
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if (end < host_end) {
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prot1 = prot;
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for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
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prot1 |= page_get_flags(addr);
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}
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ret = mprotect((void *)(host_end - qemu_host_page_size), qemu_host_page_size,
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prot1 & PAGE_BITS);
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if (ret != 0)
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return ret;
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host_end -= qemu_host_page_size;
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}
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/* handle the pages in the middle */
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if (host_start < host_end) {
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ret = mprotect((void *)host_start, host_end - host_start, prot);
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if (ret != 0)
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return ret;
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}
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page_set_flags(start, start + len, prot | PAGE_VALID);
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return 0;
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}
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/* map an incomplete host page */
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int mmap_frag(unsigned long host_start,
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unsigned long start, unsigned long end,
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int prot, int flags, int fd, unsigned long offset)
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{
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unsigned long host_end, ret, addr;
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int prot1, prot_new;
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host_end = host_start + qemu_host_page_size;
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/* get the protection of the target pages outside the mapping */
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prot1 = 0;
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for(addr = host_start; addr < host_end; addr++) {
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if (addr < start || addr >= end)
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prot1 |= page_get_flags(addr);
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}
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if (prot1 == 0) {
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/* no page was there, so we allocate one */
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ret = (long)mmap((void *)host_start, qemu_host_page_size, prot,
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flags | MAP_ANONYMOUS, -1, 0);
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if (ret == -1)
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return ret;
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}
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prot1 &= PAGE_BITS;
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prot_new = prot | prot1;
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if (!(flags & MAP_ANONYMOUS)) {
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/* msync() won't work here, so we return an error if write is
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possible while it is a shared mapping */
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#ifndef __APPLE__
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if ((flags & MAP_TYPE) == MAP_SHARED &&
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#else
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if ((flags & MAP_SHARED) &&
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#endif
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(prot & PROT_WRITE))
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return -1;
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/* adjust protection to be able to read */
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if (!(prot1 & PROT_WRITE))
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mprotect((void *)host_start, qemu_host_page_size, prot1 | PROT_WRITE);
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/* read the corresponding file data */
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pread(fd, (void *)start, end - start, offset);
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/* put final protection */
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if (prot_new != (prot1 | PROT_WRITE))
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mprotect((void *)host_start, qemu_host_page_size, prot_new);
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} else {
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/* just update the protection */
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if (prot_new != prot1) {
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mprotect((void *)host_start, qemu_host_page_size, prot_new);
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}
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}
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return 0;
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}
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/* NOTE: all the constants are the HOST ones */
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long target_mmap(unsigned long start, unsigned long len, int prot,
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int flags, int fd, unsigned long offset)
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{
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unsigned long ret, end, host_start, host_end, retaddr, host_offset, host_len;
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#if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
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static unsigned long last_start = 0x40000000;
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#endif
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#ifdef DEBUG_MMAP
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{
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printf("mmap: start=0x%lx len=0x%lx prot=%c%c%c flags=",
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start, len,
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prot & PROT_READ ? 'r' : '-',
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prot & PROT_WRITE ? 'w' : '-',
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prot & PROT_EXEC ? 'x' : '-');
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if (flags & MAP_FIXED)
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printf("MAP_FIXED ");
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if (flags & MAP_ANONYMOUS)
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printf("MAP_ANON ");
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#ifndef MAP_TYPE
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# define MAP_TYPE 0x3
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#endif
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switch(flags & MAP_TYPE) {
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case MAP_PRIVATE:
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printf("MAP_PRIVATE ");
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break;
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case MAP_SHARED:
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printf("MAP_SHARED ");
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break;
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default:
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printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
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break;
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}
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printf("fd=%d offset=%lx\n", fd, offset);
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}
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#endif
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if (offset & ~TARGET_PAGE_MASK)
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return -EINVAL;
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len = TARGET_PAGE_ALIGN(len);
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if (len == 0)
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return start;
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host_start = start & qemu_host_page_mask;
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if (!(flags & MAP_FIXED)) {
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#if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
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/* tell the kernel to search at the same place as i386 */
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if (host_start == 0) {
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host_start = last_start;
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last_start += HOST_PAGE_ALIGN(len);
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}
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#endif
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if (qemu_host_page_size != qemu_real_host_page_size) {
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/* NOTE: this code is only for debugging with '-p' option */
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/* reserve a memory area */
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host_len = HOST_PAGE_ALIGN(len) + qemu_host_page_size - TARGET_PAGE_SIZE;
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host_start = (long)mmap((void *)host_start, host_len, PROT_NONE,
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MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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if (host_start == -1)
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return host_start;
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host_end = host_start + host_len;
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start = HOST_PAGE_ALIGN(host_start);
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end = start + HOST_PAGE_ALIGN(len);
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if (start > host_start)
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munmap((void *)host_start, start - host_start);
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if (end < host_end)
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munmap((void *)end, host_end - end);
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/* use it as a fixed mapping */
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flags |= MAP_FIXED;
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} else {
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/* if not fixed, no need to do anything */
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host_offset = offset & qemu_host_page_mask;
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host_len = len + offset - host_offset;
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start = (long)mmap((void *)host_start, host_len,
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prot, flags, fd, host_offset);
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if (start == -1)
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return start;
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/* update start so that it points to the file position at 'offset' */
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if (!(flags & MAP_ANONYMOUS))
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start += offset - host_offset;
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goto the_end1;
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}
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}
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if (start & ~TARGET_PAGE_MASK)
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return -EINVAL;
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end = start + len;
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host_end = HOST_PAGE_ALIGN(end);
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/* worst case: we cannot map the file because the offset is not
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aligned, so we read it */
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if (!(flags & MAP_ANONYMOUS) &&
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(offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
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/* msync() won't work here, so we return an error if write is
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possible while it is a shared mapping */
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#ifndef __APPLE__
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if ((flags & MAP_TYPE) == MAP_SHARED &&
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#else
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if ((flags & MAP_SHARED) &&
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#endif
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(prot & PROT_WRITE))
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return -EINVAL;
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retaddr = target_mmap(start, len, prot | PROT_WRITE,
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MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
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-1, 0);
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if (retaddr == -1)
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return retaddr;
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pread(fd, (void *)start, len, offset);
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if (!(prot & PROT_WRITE)) {
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ret = target_mprotect(start, len, prot);
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if (ret != 0)
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return ret;
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}
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goto the_end;
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}
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/* handle the start of the mapping */
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if (start > host_start) {
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if (host_end == host_start + qemu_host_page_size) {
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/* one single host page */
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ret = mmap_frag(host_start, start, end,
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prot, flags, fd, offset);
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if (ret == -1)
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return ret;
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goto the_end1;
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}
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ret = mmap_frag(host_start, start, host_start + qemu_host_page_size,
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prot, flags, fd, offset);
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if (ret == -1)
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return ret;
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host_start += qemu_host_page_size;
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}
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/* handle the end of the mapping */
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if (end < host_end) {
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ret = mmap_frag(host_end - qemu_host_page_size,
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host_end - qemu_host_page_size, host_end,
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prot, flags, fd,
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offset + host_end - qemu_host_page_size - start);
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if (ret == -1)
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return ret;
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host_end -= qemu_host_page_size;
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}
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/* map the middle (easier) */
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if (host_start < host_end) {
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unsigned long offset1;
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if (flags & MAP_ANONYMOUS)
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offset1 = 0;
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else
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offset1 = offset + host_start - start;
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ret = (long)mmap((void *)host_start, host_end - host_start,
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prot, flags, fd, offset1);
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if (ret == -1)
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return ret;
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}
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the_end1:
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page_set_flags(start, start + len, prot | PAGE_VALID);
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the_end:
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#ifdef DEBUG_MMAP
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printf("target_mmap: ret=0x%lx\n", (long)start);
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page_dump(stdout);
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printf("\n");
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#endif
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return start;
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}
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int target_munmap(unsigned long start, unsigned long len)
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{
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unsigned long end, host_start, host_end, addr;
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int prot, ret;
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#ifdef DEBUG_MMAP
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printf("munmap: start=0x%lx len=0x%lx\n", start, len);
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#endif
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if (start & ~TARGET_PAGE_MASK)
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return -EINVAL;
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len = TARGET_PAGE_ALIGN(len);
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if (len == 0)
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return -EINVAL;
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end = start + len;
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host_start = start & qemu_host_page_mask;
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host_end = HOST_PAGE_ALIGN(end);
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if (start > host_start) {
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/* handle host page containing start */
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prot = 0;
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for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
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prot |= page_get_flags(addr);
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}
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if (host_end == host_start + qemu_host_page_size) {
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for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
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prot |= page_get_flags(addr);
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}
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end = host_end;
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}
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if (prot != 0)
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host_start += qemu_host_page_size;
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}
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if (end < host_end) {
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prot = 0;
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for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
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prot |= page_get_flags(addr);
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}
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if (prot != 0)
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host_end -= qemu_host_page_size;
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}
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/* unmap what we can */
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if (host_start < host_end) {
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ret = munmap((void *)host_start, host_end - host_start);
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if (ret != 0)
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return ret;
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}
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page_set_flags(start, start + len, 0);
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return 0;
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}
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/* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
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blocks which have been allocated starting on a host page */
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long target_mremap(unsigned long old_addr, unsigned long old_size,
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unsigned long new_size, unsigned long flags,
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unsigned long new_addr)
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{
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#ifndef __APPLE__
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/* XXX: use 5 args syscall */
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new_addr = (long)mremap((void *)old_addr, old_size, new_size, flags);
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if (new_addr == -1)
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return new_addr;
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prot = page_get_flags(old_addr);
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page_set_flags(old_addr, old_addr + old_size, 0);
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page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
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return new_addr;
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#else
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qerror("target_mremap: unsupported\n");
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#endif
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}
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int target_msync(unsigned long start, unsigned long len, int flags)
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{
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unsigned long end;
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if (start & ~TARGET_PAGE_MASK)
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return -EINVAL;
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len = TARGET_PAGE_ALIGN(len);
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end = start + len;
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if (end < start)
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return -EINVAL;
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if (end == start)
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return 0;
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start &= qemu_host_page_mask;
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return msync((void *)start, end - start, flags);
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}
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