| /* |
| * mmap support for qemu |
| * |
| * Copyright (c) 2003 - 2008 Fabrice Bellard |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, see <http://www.gnu.org/licenses/>. |
| */ |
| #include "qemu/osdep.h" |
| |
| #include "qemu.h" |
| #include "qemu-common.h" |
| #include "bsd-mman.h" |
| |
| //#define DEBUG_MMAP |
| |
| #if defined(CONFIG_USE_NPTL) |
| pthread_mutex_t mmap_mutex; |
| static int __thread mmap_lock_count; |
| |
| void mmap_lock(void) |
| { |
| if (mmap_lock_count++ == 0) { |
| pthread_mutex_lock(&mmap_mutex); |
| } |
| } |
| |
| void mmap_unlock(void) |
| { |
| if (--mmap_lock_count == 0) { |
| pthread_mutex_unlock(&mmap_mutex); |
| } |
| } |
| |
| bool have_mmap_lock(void) |
| { |
| return mmap_lock_count > 0 ? true : false; |
| } |
| |
| /* Grab lock to make sure things are in a consistent state after fork(). */ |
| void mmap_fork_start(void) |
| { |
| if (mmap_lock_count) |
| abort(); |
| pthread_mutex_lock(&mmap_mutex); |
| } |
| |
| void mmap_fork_end(int child) |
| { |
| if (child) |
| pthread_mutex_init(&mmap_mutex, NULL); |
| else |
| pthread_mutex_unlock(&mmap_mutex); |
| } |
| #else |
| /* We aren't threadsafe to start with, so no need to worry about locking. */ |
| void mmap_lock(void) |
| { |
| } |
| |
| void mmap_unlock(void) |
| { |
| } |
| #endif |
| |
| /* NOTE: all the constants are the HOST ones, but addresses are target. */ |
| int target_mprotect(abi_ulong start, abi_ulong len, int prot) |
| { |
| abi_ulong end, host_start, host_end, addr; |
| int prot1, ret; |
| |
| #ifdef DEBUG_MMAP |
| printf("mprotect: start=0x" TARGET_FMT_lx |
| " len=0x" TARGET_FMT_lx " prot=%c%c%c\n", start, len, |
| prot & PROT_READ ? 'r' : '-', |
| prot & PROT_WRITE ? 'w' : '-', |
| prot & PROT_EXEC ? 'x' : '-'); |
| #endif |
| |
| if ((start & ~TARGET_PAGE_MASK) != 0) |
| return -EINVAL; |
| len = TARGET_PAGE_ALIGN(len); |
| end = start + len; |
| if (end < start) |
| return -EINVAL; |
| prot &= PROT_READ | PROT_WRITE | PROT_EXEC; |
| if (len == 0) |
| return 0; |
| |
| mmap_lock(); |
| host_start = start & qemu_host_page_mask; |
| host_end = HOST_PAGE_ALIGN(end); |
| if (start > host_start) { |
| /* handle host page containing start */ |
| prot1 = prot; |
| for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) { |
| prot1 |= page_get_flags(addr); |
| } |
| if (host_end == host_start + qemu_host_page_size) { |
| for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { |
| prot1 |= page_get_flags(addr); |
| } |
| end = host_end; |
| } |
| ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS); |
| if (ret != 0) |
| goto error; |
| host_start += qemu_host_page_size; |
| } |
| if (end < host_end) { |
| prot1 = prot; |
| for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { |
| prot1 |= page_get_flags(addr); |
| } |
| ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size, |
| prot1 & PAGE_BITS); |
| if (ret != 0) |
| goto error; |
| host_end -= qemu_host_page_size; |
| } |
| |
| /* handle the pages in the middle */ |
| if (host_start < host_end) { |
| ret = mprotect(g2h(host_start), host_end - host_start, prot); |
| if (ret != 0) |
| goto error; |
| } |
| page_set_flags(start, start + len, prot | PAGE_VALID); |
| mmap_unlock(); |
| return 0; |
| error: |
| mmap_unlock(); |
| return ret; |
| } |
| |
| /* map an incomplete host page */ |
| static int mmap_frag(abi_ulong real_start, |
| abi_ulong start, abi_ulong end, |
| int prot, int flags, int fd, abi_ulong offset) |
| { |
| abi_ulong real_end, addr; |
| void *host_start; |
| int prot1, prot_new; |
| |
| real_end = real_start + qemu_host_page_size; |
| host_start = g2h(real_start); |
| |
| /* get the protection of the target pages outside the mapping */ |
| prot1 = 0; |
| for(addr = real_start; addr < real_end; addr++) { |
| if (addr < start || addr >= end) |
| prot1 |= page_get_flags(addr); |
| } |
| |
| if (prot1 == 0) { |
| /* no page was there, so we allocate one */ |
| void *p = mmap(host_start, qemu_host_page_size, prot, |
| flags | MAP_ANON, -1, 0); |
| if (p == MAP_FAILED) |
| return -1; |
| prot1 = prot; |
| } |
| prot1 &= PAGE_BITS; |
| |
| prot_new = prot | prot1; |
| if (!(flags & MAP_ANON)) { |
| /* msync() won't work here, so we return an error if write is |
| possible while it is a shared mapping */ |
| if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && |
| (prot & PROT_WRITE)) |
| return -1; |
| |
| /* adjust protection to be able to read */ |
| if (!(prot1 & PROT_WRITE)) |
| mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE); |
| |
| /* read the corresponding file data */ |
| pread(fd, g2h(start), end - start, offset); |
| |
| /* put final protection */ |
| if (prot_new != (prot1 | PROT_WRITE)) |
| mprotect(host_start, qemu_host_page_size, prot_new); |
| } else { |
| /* just update the protection */ |
| if (prot_new != prot1) { |
| mprotect(host_start, qemu_host_page_size, prot_new); |
| } |
| } |
| return 0; |
| } |
| |
| static abi_ulong mmap_next_start = 0x40000000; |
| |
| unsigned long last_brk; |
| |
| /* find a free memory area of size 'size'. The search starts at |
| 'start'. If 'start' == 0, then a default start address is used. |
| Return -1 if error. |
| */ |
| /* page_init() marks pages used by the host as reserved to be sure not |
| to use them. */ |
| static abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size) |
| { |
| abi_ulong addr, addr1, addr_start; |
| int prot; |
| unsigned long new_brk; |
| |
| new_brk = (unsigned long)sbrk(0); |
| if (last_brk && last_brk < new_brk && last_brk == (target_ulong)last_brk) { |
| /* This is a hack to catch the host allocating memory with brk(). |
| If it uses mmap then we loose. |
| FIXME: We really want to avoid the host allocating memory in |
| the first place, and maybe leave some slack to avoid switching |
| to mmap. */ |
| page_set_flags(last_brk & TARGET_PAGE_MASK, |
| TARGET_PAGE_ALIGN(new_brk), |
| PAGE_RESERVED); |
| } |
| last_brk = new_brk; |
| |
| size = HOST_PAGE_ALIGN(size); |
| start = start & qemu_host_page_mask; |
| addr = start; |
| if (addr == 0) |
| addr = mmap_next_start; |
| addr_start = addr; |
| for(;;) { |
| prot = 0; |
| for(addr1 = addr; addr1 < (addr + size); addr1 += TARGET_PAGE_SIZE) { |
| prot |= page_get_flags(addr1); |
| } |
| if (prot == 0) |
| break; |
| addr += qemu_host_page_size; |
| /* we found nothing */ |
| if (addr == addr_start) |
| return (abi_ulong)-1; |
| } |
| if (start == 0) |
| mmap_next_start = addr + size; |
| return addr; |
| } |
| |
| /* NOTE: all the constants are the HOST ones */ |
| abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, |
| int flags, int fd, abi_ulong offset) |
| { |
| abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; |
| unsigned long host_start; |
| |
| mmap_lock(); |
| #ifdef DEBUG_MMAP |
| { |
| printf("mmap: start=0x" TARGET_FMT_lx |
| " len=0x" TARGET_FMT_lx " prot=%c%c%c flags=", |
| start, len, |
| prot & PROT_READ ? 'r' : '-', |
| prot & PROT_WRITE ? 'w' : '-', |
| prot & PROT_EXEC ? 'x' : '-'); |
| if (flags & MAP_FIXED) |
| printf("MAP_FIXED "); |
| if (flags & MAP_ANON) |
| printf("MAP_ANON "); |
| switch(flags & TARGET_BSD_MAP_FLAGMASK) { |
| case MAP_PRIVATE: |
| printf("MAP_PRIVATE "); |
| break; |
| case MAP_SHARED: |
| printf("MAP_SHARED "); |
| break; |
| default: |
| printf("[MAP_FLAGMASK=0x%x] ", flags & TARGET_BSD_MAP_FLAGMASK); |
| break; |
| } |
| printf("fd=%d offset=" TARGET_FMT_lx "\n", fd, offset); |
| } |
| #endif |
| |
| if (offset & ~TARGET_PAGE_MASK) { |
| errno = EINVAL; |
| goto fail; |
| } |
| |
| len = TARGET_PAGE_ALIGN(len); |
| if (len == 0) |
| goto the_end; |
| real_start = start & qemu_host_page_mask; |
| |
| if (!(flags & MAP_FIXED)) { |
| abi_ulong mmap_start; |
| void *p; |
| host_offset = offset & qemu_host_page_mask; |
| host_len = len + offset - host_offset; |
| host_len = HOST_PAGE_ALIGN(host_len); |
| mmap_start = mmap_find_vma(real_start, host_len); |
| if (mmap_start == (abi_ulong)-1) { |
| errno = ENOMEM; |
| goto fail; |
| } |
| /* Note: we prefer to control the mapping address. It is |
| especially important if qemu_host_page_size > |
| qemu_real_host_page_size */ |
| p = mmap(g2h(mmap_start), |
| host_len, prot, flags | MAP_FIXED, fd, host_offset); |
| if (p == MAP_FAILED) |
| goto fail; |
| /* update start so that it points to the file position at 'offset' */ |
| host_start = (unsigned long)p; |
| if (!(flags & MAP_ANON)) |
| host_start += offset - host_offset; |
| start = h2g(host_start); |
| } else { |
| int flg; |
| target_ulong addr; |
| |
| if (start & ~TARGET_PAGE_MASK) { |
| errno = EINVAL; |
| goto fail; |
| } |
| end = start + len; |
| real_end = HOST_PAGE_ALIGN(end); |
| |
| for(addr = real_start; addr < real_end; addr += TARGET_PAGE_SIZE) { |
| flg = page_get_flags(addr); |
| if (flg & PAGE_RESERVED) { |
| errno = ENXIO; |
| goto fail; |
| } |
| } |
| |
| /* worst case: we cannot map the file because the offset is not |
| aligned, so we read it */ |
| if (!(flags & MAP_ANON) && |
| (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) { |
| /* msync() won't work here, so we return an error if write is |
| possible while it is a shared mapping */ |
| if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && |
| (prot & PROT_WRITE)) { |
| errno = EINVAL; |
| goto fail; |
| } |
| retaddr = target_mmap(start, len, prot | PROT_WRITE, |
| MAP_FIXED | MAP_PRIVATE | MAP_ANON, |
| -1, 0); |
| if (retaddr == -1) |
| goto fail; |
| pread(fd, g2h(start), len, offset); |
| if (!(prot & PROT_WRITE)) { |
| ret = target_mprotect(start, len, prot); |
| if (ret != 0) { |
| start = ret; |
| goto the_end; |
| } |
| } |
| goto the_end; |
| } |
| |
| /* handle the start of the mapping */ |
| if (start > real_start) { |
| if (real_end == real_start + qemu_host_page_size) { |
| /* one single host page */ |
| ret = mmap_frag(real_start, start, end, |
| prot, flags, fd, offset); |
| if (ret == -1) |
| goto fail; |
| goto the_end1; |
| } |
| ret = mmap_frag(real_start, start, real_start + qemu_host_page_size, |
| prot, flags, fd, offset); |
| if (ret == -1) |
| goto fail; |
| real_start += qemu_host_page_size; |
| } |
| /* handle the end of the mapping */ |
| if (end < real_end) { |
| ret = mmap_frag(real_end - qemu_host_page_size, |
| real_end - qemu_host_page_size, real_end, |
| prot, flags, fd, |
| offset + real_end - qemu_host_page_size - start); |
| if (ret == -1) |
| goto fail; |
| real_end -= qemu_host_page_size; |
| } |
| |
| /* map the middle (easier) */ |
| if (real_start < real_end) { |
| void *p; |
| unsigned long offset1; |
| if (flags & MAP_ANON) |
| offset1 = 0; |
| else |
| offset1 = offset + real_start - start; |
| p = mmap(g2h(real_start), real_end - real_start, |
| prot, flags, fd, offset1); |
| if (p == MAP_FAILED) |
| goto fail; |
| } |
| } |
| the_end1: |
| page_set_flags(start, start + len, prot | PAGE_VALID); |
| the_end: |
| #ifdef DEBUG_MMAP |
| printf("ret=0x" TARGET_FMT_lx "\n", start); |
| page_dump(stdout); |
| printf("\n"); |
| #endif |
| mmap_unlock(); |
| return start; |
| fail: |
| mmap_unlock(); |
| return -1; |
| } |
| |
| int target_munmap(abi_ulong start, abi_ulong len) |
| { |
| abi_ulong end, real_start, real_end, addr; |
| int prot, ret; |
| |
| #ifdef DEBUG_MMAP |
| printf("munmap: start=0x%lx len=0x%lx\n", start, len); |
| #endif |
| if (start & ~TARGET_PAGE_MASK) |
| return -EINVAL; |
| len = TARGET_PAGE_ALIGN(len); |
| if (len == 0) |
| return -EINVAL; |
| mmap_lock(); |
| end = start + len; |
| real_start = start & qemu_host_page_mask; |
| real_end = HOST_PAGE_ALIGN(end); |
| |
| if (start > real_start) { |
| /* handle host page containing start */ |
| prot = 0; |
| for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) { |
| prot |= page_get_flags(addr); |
| } |
| if (real_end == real_start + qemu_host_page_size) { |
| for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { |
| prot |= page_get_flags(addr); |
| } |
| end = real_end; |
| } |
| if (prot != 0) |
| real_start += qemu_host_page_size; |
| } |
| if (end < real_end) { |
| prot = 0; |
| for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { |
| prot |= page_get_flags(addr); |
| } |
| if (prot != 0) |
| real_end -= qemu_host_page_size; |
| } |
| |
| ret = 0; |
| /* unmap what we can */ |
| if (real_start < real_end) { |
| ret = munmap(g2h(real_start), real_end - real_start); |
| } |
| |
| if (ret == 0) |
| page_set_flags(start, start + len, 0); |
| mmap_unlock(); |
| return ret; |
| } |
| |
| int target_msync(abi_ulong start, abi_ulong len, int flags) |
| { |
| abi_ulong end; |
| |
| if (start & ~TARGET_PAGE_MASK) |
| return -EINVAL; |
| len = TARGET_PAGE_ALIGN(len); |
| end = start + len; |
| if (end < start) |
| return -EINVAL; |
| if (end == start) |
| return 0; |
| |
| start &= qemu_host_page_mask; |
| return msync(g2h(start), end - start, flags); |
| } |
