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fixed target_mmap() if host page size < TARGET_PAGE_SIZE 

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3642 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
bellard 2007-11-14 11:29:07 +00:00
parent dae3270c6e
commit a03e2d421e
1 changed files with 126 additions and 138 deletions
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264
linux-user/mmap.c
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@ -151,19 +151,53 @@ static int mmap_frag(abi_ulong real_start,
return 0; return 0;
} }
#if defined(__CYGWIN__)
/* Cygwin doesn't have a whole lot of address space. */
static abi_ulong mmap_next_start = 0x18000000;
#else
static abi_ulong mmap_next_start = 0x40000000;
#endif
/* 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.
*/
/* XXX: should mark 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;
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 */ /* NOTE: all the constants are the HOST ones */
abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
int flags, int fd, abi_ulong offset) int flags, int fd, abi_ulong offset)
{ {
abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len;
unsigned long host_start; unsigned long host_start;
#if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \
defined(__ia64) || defined(__mips__)
static abi_ulong last_start = 0x40000000;
#elif defined(__CYGWIN__)
/* Cygwin doesn't have a whole lot of address space. */
static abi_ulong last_start = 0x18000000;
#endif
#ifdef DEBUG_MMAP #ifdef DEBUG_MMAP
{ {
@ -203,147 +237,101 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
real_start = start & qemu_host_page_mask; real_start = start & qemu_host_page_mask;
if (!(flags & MAP_FIXED)) { if (!(flags & MAP_FIXED)) {
#if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \ abi_ulong mmap_start;
defined(__ia64) || defined(__mips__) || defined(__CYGWIN__) void *p;
/* tell the kernel to search at the same place as i386 */ host_offset = offset & qemu_host_page_mask;
if (real_start == 0) { host_len = len + offset - host_offset;
real_start = last_start; host_len = HOST_PAGE_ALIGN(host_len);
last_start += HOST_PAGE_ALIGN(len); mmap_start = mmap_find_vma(real_start, host_len);
if (mmap_start == (abi_ulong)-1) {
errno = ENOMEM;
return -1;
} }
#endif /* Note: we prefer to control the mapping address. It is
host_offset = offset & qemu_host_page_mask; especially important if qemu_host_page_size >
host_len = len + offset - host_offset; qemu_real_host_page_size */
p = mmap(g2h(mmap_start),
if (qemu_host_page_size > qemu_real_host_page_size) { host_len, prot, flags | MAP_FIXED, fd, host_offset);
/* if (p == MAP_FAILED)
* The guest expects to see mmapped areas aligned to it's pagesize. return -1;
* If the host's real page size is smaller than the guest's, we need /* update start so that it points to the file position at 'offset' */
* to fixup the maps. It is done by allocating a larger area, host_start = (unsigned long)p;
* displacing the map (if needed) and finally chopping off the spare if (!(flags & MAP_ANONYMOUS))
* room at the edges. host_start += offset - host_offset;
*/ start = h2g(host_start);
} else {
/* if (start & ~TARGET_PAGE_MASK) {
* 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.
*/
abi_ulong host_end;
unsigned long host_aligned_start;
void *p;
host_len = HOST_PAGE_ALIGN(host_len + qemu_host_page_size
- qemu_real_host_page_size);
p = mmap(real_start ? g2h(real_start) : NULL,
host_len, prot, flags, fd, host_offset);
if (p == MAP_FAILED)
return -1;
host_start = (unsigned long)p;
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 */
void *p = mmap(real_start ? g2h(real_start) : NULL,
host_len, prot, flags, fd, host_offset);
if (p == MAP_FAILED)
return -1;
/* update start so that it points to the file position at 'offset' */
host_start = (unsigned long)p;
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; errno = EINVAL;
return -1; return -1;
} }
retaddr = target_mmap(start, len, prot | PROT_WRITE, end = start + len;
MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, real_end = HOST_PAGE_ALIGN(end);
-1, 0);
if (retaddr == -1) /* worst case: we cannot map the file because the offset is not
return -1; aligned, so we read it */
pread(fd, g2h(start), len, offset); if (!(flags & MAP_ANONYMOUS) &&
if (!(prot & PROT_WRITE)) { (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
ret = target_mprotect(start, len, prot); /* msync() won't work here, so we return an error if write is
if (ret != 0) possible while it is a shared mapping */
return ret; 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 -1;
pread(fd, g2h(start), len, offset);
if (!(prot & PROT_WRITE)) {
ret = target_mprotect(start, len, prot);
if (ret != 0)
return ret;
}
goto the_end;
} }
goto the_end;
} /* handle the start of the mapping */
if (start > real_start) {
/* handle the start of the mapping */ if (real_end == real_start + qemu_host_page_size) {
if (start > real_start) { /* one single host page */
if (real_end == real_start + qemu_host_page_size) { ret = mmap_frag(real_start, start, end,
/* one single host page */ prot, flags, fd, offset);
ret = mmap_frag(real_start, start, end, if (ret == -1)
return ret;
goto the_end1;
}
ret = mmap_frag(real_start, start, real_start + qemu_host_page_size,
prot, flags, fd, offset); prot, flags, fd, offset);
if (ret == -1) if (ret == -1)
return ret; return ret;
goto the_end1; 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 -1;
real_end -= qemu_host_page_size;
} }
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 -1;
real_end -= qemu_host_page_size;
}
/* map the middle (easier) */ /* map the middle (easier) */
if (real_start < real_end) { if (real_start < real_end) {
void *p; void *p;
unsigned long offset1; unsigned long offset1;
if (flags & MAP_ANONYMOUS) if (flags & MAP_ANONYMOUS)
offset1 = 0; offset1 = 0;
else else
offset1 = offset + real_start - start; offset1 = offset + real_start - start;
p = mmap(g2h(real_start), real_end - real_start, p = mmap(g2h(real_start), real_end - real_start,
prot, flags, fd, offset1); prot, flags, fd, offset1);
if (p == MAP_FAILED) if (p == MAP_FAILED)
return -1; return -1;
}
} }
the_end1: the_end1:
page_set_flags(start, start + len, prot | PAGE_VALID); page_set_flags(start, start + len, prot | PAGE_VALID);