From a5b85f7959378bc038803e51918e0f64461eb9b6 Mon Sep 17 00:00:00 2001 From: ths Date: Sun, 30 Sep 2007 14:32:45 +0000 Subject: [PATCH] Fix mmap to handle differing host/target page sizes, by Edgar E. Iglesias. git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3291 c046a42c-6fe2-441c-8c8c-71466251a162 --- linux-user/mmap.c | 102 +++++++++++++++++++++++++++++----------------- linux-user/qemu.h | 4 +- 2 files changed, 67 insertions(+), 39 deletions(-) diff --git a/linux-user/mmap.c b/linux-user/mmap.c index 29f1d9625..ea916b80a 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -36,7 +36,8 @@ int target_mprotect(target_ulong start, target_ulong len, int prot) int prot1, ret; #ifdef DEBUG_MMAP - printf("mprotect: start=0x%lx len=0x%lx prot=%c%c%c\n", start, len, + 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' : '-'); @@ -151,11 +152,11 @@ static int mmap_frag(target_ulong real_start, } /* NOTE: all the constants are the HOST ones */ -long target_mmap(target_ulong start, target_ulong len, int prot, +target_long target_mmap(target_ulong start, target_ulong len, int prot, int flags, int fd, target_ulong offset) { target_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; - long host_start; + unsigned long host_start; #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \ defined(__ia64) || defined(__mips__) static target_ulong last_start = 0x40000000; @@ -166,7 +167,8 @@ long target_mmap(target_ulong start, target_ulong len, int prot, #ifdef DEBUG_MMAP { - printf("mmap: start=0x%lx len=0x%lx prot=%c%c%c flags=", + 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' : '-', @@ -186,7 +188,7 @@ long target_mmap(target_ulong start, target_ulong len, int prot, printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE); break; } - printf("fd=%d offset=%lx\n", fd, offset); + printf("fd=%d offset=" TARGET_FMT_lx "\n", fd, offset); } #endif @@ -209,34 +211,59 @@ long target_mmap(target_ulong start, target_ulong len, int prot, last_start += HOST_PAGE_ALIGN(len); } #endif - if (0 && qemu_host_page_size != qemu_real_host_page_size) { - /* NOTE: this code is only for debugging with '-p' option */ - /* ??? Can also occur when TARGET_PAGE_SIZE > host page size. */ - /* reserve a memory area */ - /* ??? This needs fixing for remapping. */ -abort(); - host_len = HOST_PAGE_ALIGN(len) + qemu_host_page_size - TARGET_PAGE_SIZE; - real_start = (long)mmap(g2h(real_start), host_len, PROT_NONE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - if (real_start == -1) - return real_start; - real_end = real_start + host_len; - start = HOST_PAGE_ALIGN(real_start); - end = start + HOST_PAGE_ALIGN(len); - if (start > real_start) - munmap((void *)g2h(real_start), start - real_start); - if (end < real_end) - munmap((void *)g2h(end), real_end - end); - /* use it as a fixed mapping */ - flags |= MAP_FIXED; - } else { - /* if not fixed, no need to do anything */ host_offset = offset & qemu_host_page_mask; host_len = len + offset - host_offset; + + if (qemu_host_page_size > qemu_real_host_page_size) { + /* + * The guest expects to see mmapped areas aligned to it's pagesize. + * If the host's real page size is smaller than the guest's, we need + * to fixup the maps. It is done by allocating a larger area, + * displacing the map (if needed) and finally chopping off the spare + * room at the edges. + */ + + /* + * We assume qemu_host_page_size is always the same as + * TARGET_PAGE_SIZE, see exec.c. qemu_real_host_page_size is the + * hosts real page size. + */ + target_ulong host_end; + unsigned long host_aligned_start; + + host_len = HOST_PAGE_ALIGN(host_len + qemu_host_page_size + - qemu_real_host_page_size); + host_start = (unsigned long) mmap(real_start ? + g2h(real_start) : NULL, + host_len, prot, flags, + fd, host_offset); + if (host_start == -1) + return -1; + + host_end = host_start + host_len; + + /* Find start and end, aligned to the targets pagesize with-in the + large mmaped area. */ + host_aligned_start = TARGET_PAGE_ALIGN(host_start); + if (!(flags & MAP_ANONYMOUS)) + host_aligned_start += offset - host_offset; + + start = h2g(host_aligned_start); + end = start + TARGET_PAGE_ALIGN(len); + + /* Chop off the leftovers, if any. */ + if (host_aligned_start > host_start) + munmap((void *)host_start, host_aligned_start - host_start); + if (end < host_end) + munmap((void *)g2h(end), host_end - end); + + goto the_end1; + } else { + /* if not fixed, no need to do anything */ host_start = (long)mmap(real_start ? g2h(real_start) : NULL, host_len, prot, flags, fd, host_offset); if (host_start == -1) - return host_start; + return -1; /* update start so that it points to the file position at 'offset' */ if (!(flags & MAP_ANONYMOUS)) host_start += offset - host_offset; @@ -267,7 +294,7 @@ abort(); MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (retaddr == -1) - return retaddr; + return -1; pread(fd, g2h(start), len, offset); if (!(prot & PROT_WRITE)) { ret = target_mprotect(start, len, prot); @@ -300,7 +327,7 @@ abort(); prot, flags, fd, offset + real_end - qemu_host_page_size - start); if (ret == -1) - return ret; + return -1; real_end -= qemu_host_page_size; } @@ -314,13 +341,13 @@ abort(); ret = (long)mmap(g2h(real_start), real_end - real_start, prot, flags, fd, offset1); if (ret == -1) - return ret; + return -1; } the_end1: page_set_flags(start, start + len, prot | PAGE_VALID); the_end: #ifdef DEBUG_MMAP - printf("ret=0x%lx\n", (long)start); + printf("ret=0x%llx\n", start); page_dump(stdout); printf("\n"); #endif @@ -381,17 +408,18 @@ int target_munmap(target_ulong start, target_ulong len) /* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED blocks which have been allocated starting on a host page */ -long target_mremap(target_ulong old_addr, target_ulong old_size, +target_long target_mremap(target_ulong old_addr, target_ulong old_size, target_ulong new_size, unsigned long flags, target_ulong new_addr) { int prot; + unsigned long host_addr; /* XXX: use 5 args syscall */ - new_addr = (long)mremap(g2h(old_addr), old_size, new_size, flags); - if (new_addr == -1) - return new_addr; - new_addr = h2g(new_addr); + host_addr = (long)mremap(g2h(old_addr), old_size, new_size, flags); + if (host_addr == -1) + return -1; + new_addr = h2g(host_addr); prot = page_get_flags(old_addr); page_set_flags(old_addr, old_addr + old_size, 0); page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID); diff --git a/linux-user/qemu.h b/linux-user/qemu.h index 78e9ab34f..e07ac7b4d 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -164,10 +164,10 @@ int do_vm86(CPUX86State *env, long subfunction, target_ulong v86_addr); /* mmap.c */ int target_mprotect(target_ulong start, target_ulong len, int prot); -long target_mmap(target_ulong start, target_ulong len, int prot, +target_long target_mmap(target_ulong start, target_ulong len, int prot, int flags, int fd, target_ulong offset); int target_munmap(target_ulong start, target_ulong len); -long target_mremap(target_ulong old_addr, target_ulong old_size, +target_long target_mremap(target_ulong old_addr, target_ulong old_size, target_ulong new_size, unsigned long flags, target_ulong new_addr); int target_msync(target_ulong start, target_ulong len, int flags);