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/*
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* mmap support for qemu
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*
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* Copyright (c) 2003 - 2008 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, write to the Free Software
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* Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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* MA 02110-1301, 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 <unistd.h> |
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#include <errno.h> |
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#include <sys/mman.h> |
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|
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#include "qemu.h" |
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#include "qemu-common.h" |
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#include "bsd-mman.h" |
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//#define DEBUG_MMAP
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|
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#if defined(USE_NPTL)
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pthread_mutex_t mmap_mutex; |
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static int __thread mmap_lock_count; |
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|
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void mmap_lock(void) |
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{ |
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if (mmap_lock_count++ == 0) { |
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pthread_mutex_lock(&mmap_mutex); |
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} |
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} |
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|
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void mmap_unlock(void) |
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{ |
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if (--mmap_lock_count == 0) { |
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pthread_mutex_unlock(&mmap_mutex); |
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} |
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} |
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|
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/* Grab lock to make sure things are in a consistent state after fork(). */
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void mmap_fork_start(void) |
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{ |
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if (mmap_lock_count)
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abort(); |
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pthread_mutex_lock(&mmap_mutex); |
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} |
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|
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void mmap_fork_end(int child) |
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{ |
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if (child)
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pthread_mutex_init(&mmap_mutex, NULL);
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else
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pthread_mutex_unlock(&mmap_mutex); |
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} |
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#else
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/* We aren't threadsafe to start with, so no need to worry about locking. */
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void mmap_lock(void) |
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{ |
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} |
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|
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void mmap_unlock(void) |
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{ |
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} |
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#endif
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|
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void *qemu_vmalloc(size_t size)
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{ |
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void *p;
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unsigned long addr; |
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mmap_lock(); |
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/* Use map and mark the pages as used. */
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p = mmap(NULL, size, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANON, -1, 0); |
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|
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addr = (unsigned long)p; |
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if (addr == (target_ulong) addr) {
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/* Allocated region overlaps guest address space.
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This may recurse. */
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page_set_flags(addr & TARGET_PAGE_MASK, TARGET_PAGE_ALIGN(addr + size), |
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PAGE_RESERVED); |
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} |
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|
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mmap_unlock(); |
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return p;
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} |
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void *qemu_malloc(size_t size)
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{ |
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char * p;
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size += 16;
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p = qemu_vmalloc(size); |
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*(size_t *)p = size; |
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return p + 16; |
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} |
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|
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/* We use map, which is always zero initialized. */
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void * qemu_mallocz(size_t size)
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{ |
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return qemu_malloc(size);
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} |
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void qemu_free(void *ptr) |
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{ |
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/* FIXME: We should unmark the reserved pages here. However this gets
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complicated when one target page spans multiple host pages, so we
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don't bother. */
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size_t *p; |
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p = (size_t *)((char *)ptr - 16); |
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munmap(p, *p); |
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} |
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|
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void *qemu_realloc(void *ptr, size_t size) |
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{ |
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size_t old_size, copy; |
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void *new_ptr;
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|
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if (!ptr)
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return qemu_malloc(size);
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old_size = *(size_t *)((char *)ptr - 16); |
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copy = old_size < size ? old_size : size; |
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new_ptr = qemu_malloc(size); |
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memcpy(new_ptr, ptr, copy); |
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qemu_free(ptr); |
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return new_ptr;
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} |
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/* NOTE: all the constants are the HOST ones, but addresses are target. */
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int target_mprotect(abi_ulong start, abi_ulong len, int prot) |
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{ |
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abi_ulong 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" TARGET_FMT_lx
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" len=0x" TARGET_FMT_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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|
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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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prot &= PROT_READ | PROT_WRITE | PROT_EXEC; |
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if (len == 0) |
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return 0; |
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|
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mmap_lock(); |
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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(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS); |
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if (ret != 0) |
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goto error;
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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(g2h(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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goto error;
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host_end -= qemu_host_page_size; |
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} |
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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(g2h(host_start), host_end - host_start, prot); |
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if (ret != 0) |
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goto error;
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} |
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page_set_flags(start, start + len, prot | PAGE_VALID); |
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mmap_unlock(); |
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return 0; |
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error:
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mmap_unlock(); |
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return ret;
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} |
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|
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/* map an incomplete host page */
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static int mmap_frag(abi_ulong real_start, |
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abi_ulong start, abi_ulong end, |
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int prot, int flags, int fd, abi_ulong offset) |
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{ |
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abi_ulong real_end, addr; |
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void *host_start;
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int prot1, prot_new;
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real_end = real_start + qemu_host_page_size; |
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host_start = g2h(real_start); |
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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 = real_start; addr < real_end; addr++) {
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if (addr < start || addr >= end)
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prot1 |= page_get_flags(addr); |
227 |
} |
228 |
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if (prot1 == 0) { |
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/* no page was there, so we allocate one */
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void *p = mmap(host_start, qemu_host_page_size, prot,
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flags | MAP_ANON, -1, 0); |
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if (p == MAP_FAILED)
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return -1; |
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prot1 = prot; |
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} |
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prot1 &= PAGE_BITS; |
238 |
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prot_new = prot | prot1; |
240 |
if (!(flags & MAP_ANON)) {
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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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if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED &&
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(prot & PROT_WRITE)) |
245 |
return -EINVAL;
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|
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/* adjust protection to be able to read */
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if (!(prot1 & PROT_WRITE))
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mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE); |
250 |
|
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/* read the corresponding file data */
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pread(fd, g2h(start), end - start, offset); |
253 |
|
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/* put final protection */
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if (prot_new != (prot1 | PROT_WRITE))
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mprotect(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(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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|
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#if defined(__CYGWIN__)
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/* Cygwin doesn't have a whole lot of address space. */
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static abi_ulong mmap_next_start = 0x18000000; |
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#else
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static abi_ulong mmap_next_start = 0x40000000; |
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#endif
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|
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unsigned long last_brk; |
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|
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/* find a free memory area of size 'size'. The search starts at
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'start'. If 'start' == 0, then a default start address is used.
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Return -1 if error.
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*/
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/* page_init() marks pages used by the host as reserved to be sure not
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to use them. */
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static abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
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{ |
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abi_ulong addr, addr1, addr_start; |
284 |
int prot;
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unsigned long new_brk; |
286 |
|
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new_brk = (unsigned long)sbrk(0); |
288 |
if (last_brk && last_brk < new_brk && last_brk == (target_ulong)last_brk) {
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/* This is a hack to catch the host allocating memory with brk().
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If it uses mmap then we loose.
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FIXME: We really want to avoid the host allocating memory in
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the first place, and maybe leave some slack to avoid switching
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to mmap. */
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page_set_flags(last_brk & TARGET_PAGE_MASK, |
295 |
TARGET_PAGE_ALIGN(new_brk), |
296 |
PAGE_RESERVED); |
297 |
} |
298 |
last_brk = new_brk; |
299 |
|
300 |
size = HOST_PAGE_ALIGN(size); |
301 |
start = start & qemu_host_page_mask; |
302 |
addr = start; |
303 |
if (addr == 0) |
304 |
addr = mmap_next_start; |
305 |
addr_start = addr; |
306 |
for(;;) {
|
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prot = 0;
|
308 |
for(addr1 = addr; addr1 < (addr + size); addr1 += TARGET_PAGE_SIZE) {
|
309 |
prot |= page_get_flags(addr1); |
310 |
} |
311 |
if (prot == 0) |
312 |
break;
|
313 |
addr += qemu_host_page_size; |
314 |
/* we found nothing */
|
315 |
if (addr == addr_start)
|
316 |
return (abi_ulong)-1; |
317 |
} |
318 |
if (start == 0) |
319 |
mmap_next_start = addr + size; |
320 |
return addr;
|
321 |
} |
322 |
|
323 |
/* NOTE: all the constants are the HOST ones */
|
324 |
abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
|
325 |
int flags, int fd, abi_ulong offset) |
326 |
{ |
327 |
abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; |
328 |
unsigned long host_start; |
329 |
|
330 |
mmap_lock(); |
331 |
#ifdef DEBUG_MMAP
|
332 |
{ |
333 |
printf("mmap: start=0x" TARGET_FMT_lx
|
334 |
" len=0x" TARGET_FMT_lx " prot=%c%c%c flags=", |
335 |
start, len, |
336 |
prot & PROT_READ ? 'r' : '-', |
337 |
prot & PROT_WRITE ? 'w' : '-', |
338 |
prot & PROT_EXEC ? 'x' : '-'); |
339 |
if (flags & MAP_FIXED)
|
340 |
printf("MAP_FIXED ");
|
341 |
if (flags & MAP_ANON)
|
342 |
printf("MAP_ANON ");
|
343 |
switch(flags & TARGET_BSD_MAP_FLAGMASK) {
|
344 |
case MAP_PRIVATE:
|
345 |
printf("MAP_PRIVATE ");
|
346 |
break;
|
347 |
case MAP_SHARED:
|
348 |
printf("MAP_SHARED ");
|
349 |
break;
|
350 |
default:
|
351 |
printf("[MAP_FLAGMASK=0x%x] ", flags & TARGET_BSD_MAP_FLAGMASK);
|
352 |
break;
|
353 |
} |
354 |
printf("fd=%d offset=" TARGET_FMT_lx "\n", fd, offset); |
355 |
} |
356 |
#endif
|
357 |
|
358 |
if (offset & ~TARGET_PAGE_MASK) {
|
359 |
errno = EINVAL; |
360 |
goto fail;
|
361 |
} |
362 |
|
363 |
len = TARGET_PAGE_ALIGN(len); |
364 |
if (len == 0) |
365 |
goto the_end;
|
366 |
real_start = start & qemu_host_page_mask; |
367 |
|
368 |
if (!(flags & MAP_FIXED)) {
|
369 |
abi_ulong mmap_start; |
370 |
void *p;
|
371 |
host_offset = offset & qemu_host_page_mask; |
372 |
host_len = len + offset - host_offset; |
373 |
host_len = HOST_PAGE_ALIGN(host_len); |
374 |
mmap_start = mmap_find_vma(real_start, host_len); |
375 |
if (mmap_start == (abi_ulong)-1) { |
376 |
errno = ENOMEM; |
377 |
goto fail;
|
378 |
} |
379 |
/* Note: we prefer to control the mapping address. It is
|
380 |
especially important if qemu_host_page_size >
|
381 |
qemu_real_host_page_size */
|
382 |
p = mmap(g2h(mmap_start), |
383 |
host_len, prot, flags | MAP_FIXED, fd, host_offset); |
384 |
if (p == MAP_FAILED)
|
385 |
goto fail;
|
386 |
/* update start so that it points to the file position at 'offset' */
|
387 |
host_start = (unsigned long)p; |
388 |
if (!(flags & MAP_ANON))
|
389 |
host_start += offset - host_offset; |
390 |
start = h2g(host_start); |
391 |
} else {
|
392 |
int flg;
|
393 |
target_ulong addr; |
394 |
|
395 |
if (start & ~TARGET_PAGE_MASK) {
|
396 |
errno = EINVAL; |
397 |
goto fail;
|
398 |
} |
399 |
end = start + len; |
400 |
real_end = HOST_PAGE_ALIGN(end); |
401 |
|
402 |
for(addr = real_start; addr < real_end; addr += TARGET_PAGE_SIZE) {
|
403 |
flg = page_get_flags(addr); |
404 |
if (flg & PAGE_RESERVED) {
|
405 |
errno = ENXIO; |
406 |
goto fail;
|
407 |
} |
408 |
} |
409 |
|
410 |
/* worst case: we cannot map the file because the offset is not
|
411 |
aligned, so we read it */
|
412 |
if (!(flags & MAP_ANON) &&
|
413 |
(offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) { |
414 |
/* msync() won't work here, so we return an error if write is
|
415 |
possible while it is a shared mapping */
|
416 |
if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED &&
|
417 |
(prot & PROT_WRITE)) { |
418 |
errno = EINVAL; |
419 |
goto fail;
|
420 |
} |
421 |
retaddr = target_mmap(start, len, prot | PROT_WRITE, |
422 |
MAP_FIXED | MAP_PRIVATE | MAP_ANON, |
423 |
-1, 0); |
424 |
if (retaddr == -1) |
425 |
goto fail;
|
426 |
pread(fd, g2h(start), len, offset); |
427 |
if (!(prot & PROT_WRITE)) {
|
428 |
ret = target_mprotect(start, len, prot); |
429 |
if (ret != 0) { |
430 |
start = ret; |
431 |
goto the_end;
|
432 |
} |
433 |
} |
434 |
goto the_end;
|
435 |
} |
436 |
|
437 |
/* handle the start of the mapping */
|
438 |
if (start > real_start) {
|
439 |
if (real_end == real_start + qemu_host_page_size) {
|
440 |
/* one single host page */
|
441 |
ret = mmap_frag(real_start, start, end, |
442 |
prot, flags, fd, offset); |
443 |
if (ret == -1) |
444 |
goto fail;
|
445 |
goto the_end1;
|
446 |
} |
447 |
ret = mmap_frag(real_start, start, real_start + qemu_host_page_size, |
448 |
prot, flags, fd, offset); |
449 |
if (ret == -1) |
450 |
goto fail;
|
451 |
real_start += qemu_host_page_size; |
452 |
} |
453 |
/* handle the end of the mapping */
|
454 |
if (end < real_end) {
|
455 |
ret = mmap_frag(real_end - qemu_host_page_size, |
456 |
real_end - qemu_host_page_size, real_end, |
457 |
prot, flags, fd, |
458 |
offset + real_end - qemu_host_page_size - start); |
459 |
if (ret == -1) |
460 |
goto fail;
|
461 |
real_end -= qemu_host_page_size; |
462 |
} |
463 |
|
464 |
/* map the middle (easier) */
|
465 |
if (real_start < real_end) {
|
466 |
void *p;
|
467 |
unsigned long offset1; |
468 |
if (flags & MAP_ANON)
|
469 |
offset1 = 0;
|
470 |
else
|
471 |
offset1 = offset + real_start - start; |
472 |
p = mmap(g2h(real_start), real_end - real_start, |
473 |
prot, flags, fd, offset1); |
474 |
if (p == MAP_FAILED)
|
475 |
goto fail;
|
476 |
} |
477 |
} |
478 |
the_end1:
|
479 |
page_set_flags(start, start + len, prot | PAGE_VALID); |
480 |
the_end:
|
481 |
#ifdef DEBUG_MMAP
|
482 |
printf("ret=0x" TARGET_FMT_lx "\n", start); |
483 |
page_dump(stdout); |
484 |
printf("\n");
|
485 |
#endif
|
486 |
mmap_unlock(); |
487 |
return start;
|
488 |
fail:
|
489 |
mmap_unlock(); |
490 |
return -1; |
491 |
} |
492 |
|
493 |
int target_munmap(abi_ulong start, abi_ulong len)
|
494 |
{ |
495 |
abi_ulong end, real_start, real_end, addr; |
496 |
int prot, ret;
|
497 |
|
498 |
#ifdef DEBUG_MMAP
|
499 |
printf("munmap: start=0x%lx len=0x%lx\n", start, len);
|
500 |
#endif
|
501 |
if (start & ~TARGET_PAGE_MASK)
|
502 |
return -EINVAL;
|
503 |
len = TARGET_PAGE_ALIGN(len); |
504 |
if (len == 0) |
505 |
return -EINVAL;
|
506 |
mmap_lock(); |
507 |
end = start + len; |
508 |
real_start = start & qemu_host_page_mask; |
509 |
real_end = HOST_PAGE_ALIGN(end); |
510 |
|
511 |
if (start > real_start) {
|
512 |
/* handle host page containing start */
|
513 |
prot = 0;
|
514 |
for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
|
515 |
prot |= page_get_flags(addr); |
516 |
} |
517 |
if (real_end == real_start + qemu_host_page_size) {
|
518 |
for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
|
519 |
prot |= page_get_flags(addr); |
520 |
} |
521 |
end = real_end; |
522 |
} |
523 |
if (prot != 0) |
524 |
real_start += qemu_host_page_size; |
525 |
} |
526 |
if (end < real_end) {
|
527 |
prot = 0;
|
528 |
for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
|
529 |
prot |= page_get_flags(addr); |
530 |
} |
531 |
if (prot != 0) |
532 |
real_end -= qemu_host_page_size; |
533 |
} |
534 |
|
535 |
ret = 0;
|
536 |
/* unmap what we can */
|
537 |
if (real_start < real_end) {
|
538 |
ret = munmap(g2h(real_start), real_end - real_start); |
539 |
} |
540 |
|
541 |
if (ret == 0) |
542 |
page_set_flags(start, start + len, 0);
|
543 |
mmap_unlock(); |
544 |
return ret;
|
545 |
} |
546 |
|
547 |
int target_msync(abi_ulong start, abi_ulong len, int flags) |
548 |
{ |
549 |
abi_ulong end; |
550 |
|
551 |
if (start & ~TARGET_PAGE_MASK)
|
552 |
return -EINVAL;
|
553 |
len = TARGET_PAGE_ALIGN(len); |
554 |
end = start + len; |
555 |
if (end < start)
|
556 |
return -EINVAL;
|
557 |
if (end == start)
|
558 |
return 0; |
559 |
|
560 |
start &= qemu_host_page_mask; |
561 |
return msync(g2h(start), end - start, flags);
|
562 |
} |