diff options
| -rw-r--r-- | linux-user/mmap.c | 30 |
1 files changed, 19 insertions, 11 deletions
diff --git a/linux-user/mmap.c b/linux-user/mmap.c index d9468fea90..b412e3fe0a 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -382,7 +382,6 @@ 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 @@ -421,6 +420,19 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, if (len == 0) goto the_end; real_start = start & qemu_host_page_mask; + host_offset = offset & qemu_host_page_mask; + + /* If the user is asking for the kernel to find a location, do that + before we truncate the length for mapping files below. */ + if (!(flags & MAP_FIXED)) { + host_len = len + offset - host_offset; + host_len = HOST_PAGE_ALIGN(host_len); + start = mmap_find_vma(real_start, host_len); + if (start == (abi_ulong)-1) { + errno = ENOMEM; + goto fail; + } + } /* When mapping files into a memory area larger than the file, accesses to pages beyond the file size will cause a SIGBUS. @@ -453,27 +465,23 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, } if (!(flags & MAP_FIXED)) { - abi_ulong mmap_start; + unsigned long host_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 | MAP_ANONYMOUS, -1, 0); + p = mmap(g2h(start), host_len, prot, + flags | MAP_FIXED | MAP_ANONYMOUS, -1, 0); 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_ANONYMOUS)) { - p = mmap(g2h(mmap_start), len, prot, + p = mmap(g2h(start), len, prot, flags | MAP_FIXED, fd, host_offset); host_start += offset - host_offset; } |