diff options
Diffstat (limited to 'linux-user/mmap.c')
| -rw-r--r-- | linux-user/mmap.c | 417 |
1 files changed, 417 insertions, 0 deletions
diff --git a/linux-user/mmap.c b/linux-user/mmap.c new file mode 100644 index 0000000..0c90625 --- /dev/null +++ b/linux-user/mmap.c @@ -0,0 +1,417 @@ +/* + * mmap support for qemu + * + * Copyright (c) 2003 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, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ +#include <stdlib.h> +#include <stdio.h> +#include <stdarg.h> +#include <string.h> +#include <unistd.h> +#include <errno.h> +#include <sys/mman.h> + +#include "qemu.h" + +//#define DEBUG_MMAP + +/* NOTE: all the constants are the HOST ones, but addresses are target. */ +int target_mprotect(target_ulong start, target_ulong len, int prot) +{ + target_ulong end, host_start, host_end, addr; + int prot1, ret; + +#ifdef DEBUG_MMAP + printf("mprotect: start=0x%lx len=0x%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; + if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC)) + return -EINVAL; + if (len == 0) + return 0; + + 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) + return ret; + 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) + return ret; + 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) + return ret; + } + page_set_flags(start, start + len, prot | PAGE_VALID); + return 0; +} + +/* map an incomplete host page */ +static int mmap_frag(target_ulong real_start, + target_ulong start, target_ulong end, + int prot, int flags, int fd, target_ulong offset) +{ + target_ulong real_end, ret, 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 */ + ret = (long)mmap(host_start, qemu_host_page_size, prot, + flags | MAP_ANONYMOUS, -1, 0); + if (ret == -1) + return ret; + prot1 = prot; + } + prot1 &= PAGE_BITS; + + prot_new = prot | prot1; + if (!(flags & MAP_ANONYMOUS)) { + /* msync() won't work here, so we return an error if write is + possible while it is a shared mapping */ + if ((flags & MAP_TYPE) == MAP_SHARED && + (prot & PROT_WRITE)) + return -EINVAL; + + /* 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; +} + +/* NOTE: all the constants are the HOST ones */ +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; +#if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \ + defined(__ia64) + static target_ulong last_start = 0x40000000; +#elif defined(__CYGWIN__) + /* Cygwin doesn't have a whole lot of address space. */ + static target_ulong last_start = 0x18000000; +#endif + +#ifdef DEBUG_MMAP + { + printf("mmap: start=0x%lx len=0x%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_ANONYMOUS) + printf("MAP_ANON "); + switch(flags & MAP_TYPE) { + case MAP_PRIVATE: + printf("MAP_PRIVATE "); + break; + case MAP_SHARED: + printf("MAP_SHARED "); + break; + default: + printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE); + break; + } + printf("fd=%d offset=%lx\n", fd, offset); + } +#endif + + if (offset & ~TARGET_PAGE_MASK) { + errno = EINVAL; + return -1; + } + + len = TARGET_PAGE_ALIGN(len); + if (len == 0) + return start; + real_start = start & qemu_host_page_mask; + + if (!(flags & MAP_FIXED)) { +#if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \ + defined(__ia64) || defined(__CYGWIN__) + /* tell the kenel to search at the same place as i386 */ + if (real_start == 0) { + real_start = last_start; + last_start += HOST_PAGE_ALIGN(len); + } +#endif + if (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 *)real_start, start - real_start); + if (end < real_end) + munmap((void *)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; + host_start = (long)mmap(real_start ? g2h(real_start) : NULL, + host_len, prot, flags, fd, host_offset); + if (host_start == -1) + return host_start; + /* update start so that it points to the file position at 'offset' */ + if (!(flags & MAP_ANONYMOUS)) + host_start += offset - host_offset; + start = h2g(host_start); + goto the_end1; + } + } + + if (start & ~TARGET_PAGE_MASK) { + errno = EINVAL; + return -1; + } + end = start + len; + real_end = HOST_PAGE_ALIGN(end); + + /* worst case: we cannot map the file because the offset is not + aligned, so we read it */ + if (!(flags & MAP_ANONYMOUS) && + (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 & MAP_TYPE) == MAP_SHARED && + (prot & PROT_WRITE)) { + errno = EINVAL; + return -1; + } + retaddr = target_mmap(start, len, prot | PROT_WRITE, + MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, + -1, 0); + if (retaddr == -1) + return retaddr; + pread(fd, g2h(start), len, offset); + if (!(prot & PROT_WRITE)) { + ret = target_mprotect(start, len, prot); + if (ret != 0) + return ret; + } + 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) + return ret; + goto the_end1; + } + ret = mmap_frag(real_start, start, real_start + qemu_host_page_size, + prot, flags, fd, offset); + if (ret == -1) + return ret; + 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) + return ret; + real_end -= qemu_host_page_size; + } + + /* map the middle (easier) */ + if (real_start < real_end) { + unsigned long offset1; + if (flags & MAP_ANONYMOUS) + offset1 = 0; + else + offset1 = offset + real_start - start; + ret = (long)mmap(g2h(real_start), real_end - real_start, + prot, flags, fd, offset1); + if (ret == -1) + return ret; + } + the_end1: + page_set_flags(start, start + len, prot | PAGE_VALID); + the_end: +#ifdef DEBUG_MMAP + printf("ret=0x%lx\n", (long)start); + page_dump(stdout); + printf("\n"); +#endif + return start; +} + +int target_munmap(target_ulong start, target_ulong len) +{ + target_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; + 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; + } + + /* unmap what we can */ + if (real_start < real_end) { + ret = munmap((void *)real_start, real_end - real_start); + if (ret != 0) + return ret; + } + + page_set_flags(start, start + len, 0); + return 0; +} + +/* 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_ulong new_size, unsigned long flags, + target_ulong new_addr) +{ + int prot; + + /* 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); + 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); + return new_addr; +} + +int target_msync(target_ulong start, target_ulong len, int flags) +{ + target_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); +} + |