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/*
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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/types.h> |
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#include <sys/stat.h> |
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#include <sys/mman.h> |
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#include <linux/mman.h> |
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#include <linux/unistd.h> |
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#include "qemu.h" |
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#include "qemu-common.h" |
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//#define DEBUG_MMAP
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#if defined(CONFIG_USE_NPTL)
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static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER;
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static __thread int mmap_lock_count; |
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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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/* 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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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_ANONYMOUS, -1, 0); |
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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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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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/* 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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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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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_ABI_FMT_lx
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"len=0x" TARGET_ABI_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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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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/* 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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/* 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); |
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} |
229 |
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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_ANONYMOUS, -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; |
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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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if ((flags & MAP_TYPE) == MAP_SHARED &&
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(prot & PROT_WRITE)) |
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return -EINVAL;
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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); |
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/* read the corresponding file data */
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pread(fd, g2h(start), end - start, offset); |
254 |
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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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#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; |
275 |
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/*
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* Find and reserve a free memory area of size 'size'. The search
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* starts at 'start'.
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* It must be called with mmap_lock() held.
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* Return -1 if error.
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*/
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abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size) |
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{ |
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void *ptr;
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abi_ulong addr; |
286 |
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size = HOST_PAGE_ALIGN(size); |
288 |
start &= qemu_host_page_mask; |
289 |
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/* If 'start' == 0, then a default start address is used. */
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if (start == 0) |
292 |
start = mmap_next_start; |
293 |
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addr = start; |
295 |
|
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for(;;) {
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/*
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* Reserve needed memory area to avoid a race.
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* It should be discarded using:
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* - mmap() with MAP_FIXED flag
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* - mremap() with MREMAP_FIXED flag
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* - shmat() with SHM_REMAP flag
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*/
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ptr = mmap((void *)(unsigned long)addr, size, PROT_NONE, |
305 |
MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0); |
306 |
|
307 |
/* ENOMEM, if host address space has no memory */
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308 |
if (ptr == MAP_FAILED)
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return (abi_ulong)-1; |
310 |
|
311 |
/* If address fits target address space we've found what we need */
|
312 |
if ((unsigned long)ptr + size - 1 <= (abi_ulong)-1) |
313 |
break;
|
314 |
|
315 |
/* Unmap and try again with new page */
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316 |
munmap(ptr, size); |
317 |
addr += qemu_host_page_size; |
318 |
|
319 |
/* ENOMEM if we check whole of target address space */
|
320 |
if (addr == start)
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return (abi_ulong)-1; |
322 |
} |
323 |
|
324 |
/* Update default start address */
|
325 |
if (start == mmap_next_start)
|
326 |
mmap_next_start = (unsigned long)ptr + size; |
327 |
|
328 |
return h2g(ptr);
|
329 |
} |
330 |
|
331 |
/* NOTE: all the constants are the HOST ones */
|
332 |
abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
|
333 |
int flags, int fd, abi_ulong offset) |
334 |
{ |
335 |
abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; |
336 |
unsigned long host_start; |
337 |
|
338 |
mmap_lock(); |
339 |
#ifdef DEBUG_MMAP
|
340 |
{ |
341 |
printf("mmap: start=0x" TARGET_ABI_FMT_lx
|
342 |
" len=0x" TARGET_ABI_FMT_lx " prot=%c%c%c flags=", |
343 |
start, len, |
344 |
prot & PROT_READ ? 'r' : '-', |
345 |
prot & PROT_WRITE ? 'w' : '-', |
346 |
prot & PROT_EXEC ? 'x' : '-'); |
347 |
if (flags & MAP_FIXED)
|
348 |
printf("MAP_FIXED ");
|
349 |
if (flags & MAP_ANONYMOUS)
|
350 |
printf("MAP_ANON ");
|
351 |
switch(flags & MAP_TYPE) {
|
352 |
case MAP_PRIVATE:
|
353 |
printf("MAP_PRIVATE ");
|
354 |
break;
|
355 |
case MAP_SHARED:
|
356 |
printf("MAP_SHARED ");
|
357 |
break;
|
358 |
default:
|
359 |
printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
|
360 |
break;
|
361 |
} |
362 |
printf("fd=%d offset=" TARGET_ABI_FMT_lx "\n", fd, offset); |
363 |
} |
364 |
#endif
|
365 |
|
366 |
if (offset & ~TARGET_PAGE_MASK) {
|
367 |
errno = EINVAL; |
368 |
goto fail;
|
369 |
} |
370 |
|
371 |
len = TARGET_PAGE_ALIGN(len); |
372 |
if (len == 0) |
373 |
goto the_end;
|
374 |
real_start = start & qemu_host_page_mask; |
375 |
|
376 |
/* When mapping files into a memory area larger than the file, accesses
|
377 |
to pages beyond the file size will cause a SIGBUS.
|
378 |
|
379 |
For example, if mmaping a file of 100 bytes on a host with 4K pages
|
380 |
emulating a target with 8K pages, the target expects to be able to
|
381 |
access the first 8K. But the host will trap us on any access beyond
|
382 |
4K.
|
383 |
|
384 |
When emulating a target with a larger page-size than the hosts, we
|
385 |
may need to truncate file maps at EOF and add extra anonymous pages
|
386 |
up to the targets page boundary. */
|
387 |
|
388 |
if ((qemu_real_host_page_size < TARGET_PAGE_SIZE)
|
389 |
&& !(flags & MAP_ANONYMOUS)) { |
390 |
struct stat sb;
|
391 |
|
392 |
if (fstat (fd, &sb) == -1) |
393 |
goto fail;
|
394 |
|
395 |
/* Are we trying to create a map beyond EOF?. */
|
396 |
if (offset + len > sb.st_size) {
|
397 |
/* If so, truncate the file map at eof aligned with
|
398 |
the hosts real pagesize. Additional anonymous maps
|
399 |
will be created beyond EOF. */
|
400 |
len = (sb.st_size - offset); |
401 |
len += qemu_real_host_page_size - 1;
|
402 |
len &= ~(qemu_real_host_page_size - 1);
|
403 |
} |
404 |
} |
405 |
|
406 |
if (!(flags & MAP_FIXED)) {
|
407 |
abi_ulong mmap_start; |
408 |
void *p;
|
409 |
host_offset = offset & qemu_host_page_mask; |
410 |
host_len = len + offset - host_offset; |
411 |
host_len = HOST_PAGE_ALIGN(host_len); |
412 |
mmap_start = mmap_find_vma(real_start, host_len); |
413 |
if (mmap_start == (abi_ulong)-1) { |
414 |
errno = ENOMEM; |
415 |
goto fail;
|
416 |
} |
417 |
/* Note: we prefer to control the mapping address. It is
|
418 |
especially important if qemu_host_page_size >
|
419 |
qemu_real_host_page_size */
|
420 |
p = mmap(g2h(mmap_start), |
421 |
host_len, prot, flags | MAP_FIXED | MAP_ANONYMOUS, -1, 0); |
422 |
if (p == MAP_FAILED)
|
423 |
goto fail;
|
424 |
/* update start so that it points to the file position at 'offset' */
|
425 |
host_start = (unsigned long)p; |
426 |
if (!(flags & MAP_ANONYMOUS)) {
|
427 |
p = mmap(g2h(mmap_start), len, prot, |
428 |
flags | MAP_FIXED, fd, host_offset); |
429 |
host_start += offset - host_offset; |
430 |
} |
431 |
start = h2g(host_start); |
432 |
} else {
|
433 |
int flg;
|
434 |
target_ulong addr; |
435 |
|
436 |
if (start & ~TARGET_PAGE_MASK) {
|
437 |
errno = EINVAL; |
438 |
goto fail;
|
439 |
} |
440 |
end = start + len; |
441 |
real_end = HOST_PAGE_ALIGN(end); |
442 |
|
443 |
/*
|
444 |
* Test if requested memory area fits target address space
|
445 |
* It can fail only on 64-bit host with 32-bit target.
|
446 |
* On any other target/host host mmap() handles this error correctly.
|
447 |
*/
|
448 |
if ((unsigned long)start + len - 1 > (abi_ulong) -1) { |
449 |
errno = EINVAL; |
450 |
goto fail;
|
451 |
} |
452 |
|
453 |
for(addr = real_start; addr < real_end; addr += TARGET_PAGE_SIZE) {
|
454 |
flg = page_get_flags(addr); |
455 |
if (flg & PAGE_RESERVED) {
|
456 |
errno = ENXIO; |
457 |
goto fail;
|
458 |
} |
459 |
} |
460 |
|
461 |
/* worst case: we cannot map the file because the offset is not
|
462 |
aligned, so we read it */
|
463 |
if (!(flags & MAP_ANONYMOUS) &&
|
464 |
(offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) { |
465 |
/* msync() won't work here, so we return an error if write is
|
466 |
possible while it is a shared mapping */
|
467 |
if ((flags & MAP_TYPE) == MAP_SHARED &&
|
468 |
(prot & PROT_WRITE)) { |
469 |
errno = EINVAL; |
470 |
goto fail;
|
471 |
} |
472 |
retaddr = target_mmap(start, len, prot | PROT_WRITE, |
473 |
MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, |
474 |
-1, 0); |
475 |
if (retaddr == -1) |
476 |
goto fail;
|
477 |
pread(fd, g2h(start), len, offset); |
478 |
if (!(prot & PROT_WRITE)) {
|
479 |
ret = target_mprotect(start, len, prot); |
480 |
if (ret != 0) { |
481 |
start = ret; |
482 |
goto the_end;
|
483 |
} |
484 |
} |
485 |
goto the_end;
|
486 |
} |
487 |
|
488 |
/* handle the start of the mapping */
|
489 |
if (start > real_start) {
|
490 |
if (real_end == real_start + qemu_host_page_size) {
|
491 |
/* one single host page */
|
492 |
ret = mmap_frag(real_start, start, end, |
493 |
prot, flags, fd, offset); |
494 |
if (ret == -1) |
495 |
goto fail;
|
496 |
goto the_end1;
|
497 |
} |
498 |
ret = mmap_frag(real_start, start, real_start + qemu_host_page_size, |
499 |
prot, flags, fd, offset); |
500 |
if (ret == -1) |
501 |
goto fail;
|
502 |
real_start += qemu_host_page_size; |
503 |
} |
504 |
/* handle the end of the mapping */
|
505 |
if (end < real_end) {
|
506 |
ret = mmap_frag(real_end - qemu_host_page_size, |
507 |
real_end - qemu_host_page_size, real_end, |
508 |
prot, flags, fd, |
509 |
offset + real_end - qemu_host_page_size - start); |
510 |
if (ret == -1) |
511 |
goto fail;
|
512 |
real_end -= qemu_host_page_size; |
513 |
} |
514 |
|
515 |
/* map the middle (easier) */
|
516 |
if (real_start < real_end) {
|
517 |
void *p;
|
518 |
unsigned long offset1; |
519 |
if (flags & MAP_ANONYMOUS)
|
520 |
offset1 = 0;
|
521 |
else
|
522 |
offset1 = offset + real_start - start; |
523 |
p = mmap(g2h(real_start), real_end - real_start, |
524 |
prot, flags, fd, offset1); |
525 |
if (p == MAP_FAILED)
|
526 |
goto fail;
|
527 |
} |
528 |
} |
529 |
the_end1:
|
530 |
page_set_flags(start, start + len, prot | PAGE_VALID); |
531 |
the_end:
|
532 |
#ifdef DEBUG_MMAP
|
533 |
printf("ret=0x" TARGET_ABI_FMT_lx "\n", start); |
534 |
page_dump(stdout); |
535 |
printf("\n");
|
536 |
#endif
|
537 |
mmap_unlock(); |
538 |
return start;
|
539 |
fail:
|
540 |
mmap_unlock(); |
541 |
return -1; |
542 |
} |
543 |
|
544 |
int target_munmap(abi_ulong start, abi_ulong len)
|
545 |
{ |
546 |
abi_ulong end, real_start, real_end, addr; |
547 |
int prot, ret;
|
548 |
|
549 |
#ifdef DEBUG_MMAP
|
550 |
printf("munmap: start=0x" TARGET_ABI_FMT_lx " len=0x" |
551 |
TARGET_ABI_FMT_lx "\n",
|
552 |
start, len); |
553 |
#endif
|
554 |
if (start & ~TARGET_PAGE_MASK)
|
555 |
return -EINVAL;
|
556 |
len = TARGET_PAGE_ALIGN(len); |
557 |
if (len == 0) |
558 |
return -EINVAL;
|
559 |
mmap_lock(); |
560 |
end = start + len; |
561 |
real_start = start & qemu_host_page_mask; |
562 |
real_end = HOST_PAGE_ALIGN(end); |
563 |
|
564 |
if (start > real_start) {
|
565 |
/* handle host page containing start */
|
566 |
prot = 0;
|
567 |
for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
|
568 |
prot |= page_get_flags(addr); |
569 |
} |
570 |
if (real_end == real_start + qemu_host_page_size) {
|
571 |
for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
|
572 |
prot |= page_get_flags(addr); |
573 |
} |
574 |
end = real_end; |
575 |
} |
576 |
if (prot != 0) |
577 |
real_start += qemu_host_page_size; |
578 |
} |
579 |
if (end < real_end) {
|
580 |
prot = 0;
|
581 |
for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
|
582 |
prot |= page_get_flags(addr); |
583 |
} |
584 |
if (prot != 0) |
585 |
real_end -= qemu_host_page_size; |
586 |
} |
587 |
|
588 |
ret = 0;
|
589 |
/* unmap what we can */
|
590 |
if (real_start < real_end) {
|
591 |
ret = munmap(g2h(real_start), real_end - real_start); |
592 |
} |
593 |
|
594 |
if (ret == 0) |
595 |
page_set_flags(start, start + len, 0);
|
596 |
mmap_unlock(); |
597 |
return ret;
|
598 |
} |
599 |
|
600 |
abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size, |
601 |
abi_ulong new_size, unsigned long flags, |
602 |
abi_ulong new_addr) |
603 |
{ |
604 |
int prot;
|
605 |
void *host_addr;
|
606 |
|
607 |
mmap_lock(); |
608 |
|
609 |
if (flags & MREMAP_FIXED)
|
610 |
host_addr = (void *) syscall(__NR_mremap, g2h(old_addr),
|
611 |
old_size, new_size, |
612 |
flags, |
613 |
new_addr); |
614 |
else if (flags & MREMAP_MAYMOVE) { |
615 |
abi_ulong mmap_start; |
616 |
|
617 |
mmap_start = mmap_find_vma(0, new_size);
|
618 |
|
619 |
if (mmap_start == -1) { |
620 |
errno = ENOMEM; |
621 |
host_addr = MAP_FAILED; |
622 |
} else
|
623 |
host_addr = (void *) syscall(__NR_mremap, g2h(old_addr),
|
624 |
old_size, new_size, |
625 |
flags | MREMAP_FIXED, |
626 |
g2h(mmap_start)); |
627 |
} else {
|
628 |
host_addr = mremap(g2h(old_addr), old_size, new_size, flags); |
629 |
/* Check if address fits target address space */
|
630 |
if ((unsigned long)host_addr + new_size > (abi_ulong)-1) { |
631 |
/* Revert mremap() changes */
|
632 |
host_addr = mremap(g2h(old_addr), new_size, old_size, flags); |
633 |
errno = ENOMEM; |
634 |
host_addr = MAP_FAILED; |
635 |
} |
636 |
} |
637 |
|
638 |
if (host_addr == MAP_FAILED) {
|
639 |
new_addr = -1;
|
640 |
} else {
|
641 |
new_addr = h2g(host_addr); |
642 |
prot = page_get_flags(old_addr); |
643 |
page_set_flags(old_addr, old_addr + old_size, 0);
|
644 |
page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID); |
645 |
} |
646 |
mmap_unlock(); |
647 |
return new_addr;
|
648 |
} |
649 |
|
650 |
int target_msync(abi_ulong start, abi_ulong len, int flags) |
651 |
{ |
652 |
abi_ulong end; |
653 |
|
654 |
if (start & ~TARGET_PAGE_MASK)
|
655 |
return -EINVAL;
|
656 |
len = TARGET_PAGE_ALIGN(len); |
657 |
end = start + len; |
658 |
if (end < start)
|
659 |
return -EINVAL;
|
660 |
if (end == start)
|
661 |
return 0; |
662 |
|
663 |
start &= qemu_host_page_mask; |
664 |
return msync(g2h(start), end - start, flags);
|
665 |
} |