Multithreaded locking for mmap().
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4654 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 794b1d0..c082138 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -29,6 +29,34 @@
//#define DEBUG_MMAP
+#if defined(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);
+ }
+}
+#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)
{
@@ -53,6 +81,7 @@
if (len == 0)
return 0;
+ mmap_lock();
host_start = start & qemu_host_page_mask;
host_end = HOST_PAGE_ALIGN(end);
if (start > host_start) {
@@ -69,7 +98,7 @@
}
ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS);
if (ret != 0)
- return ret;
+ goto error;
host_start += qemu_host_page_size;
}
if (end < host_end) {
@@ -80,7 +109,7 @@
ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size,
prot1 & PAGE_BITS);
if (ret != 0)
- return ret;
+ goto error;
host_end -= qemu_host_page_size;
}
@@ -88,10 +117,14 @@
if (host_start < host_end) {
ret = mprotect(g2h(host_start), host_end - host_start, prot);
if (ret != 0)
- return ret;
+ 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 */
@@ -214,6 +247,7 @@
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
@@ -243,12 +277,12 @@
if (offset & ~TARGET_PAGE_MASK) {
errno = EINVAL;
- return -1;
+ goto fail;
}
len = TARGET_PAGE_ALIGN(len);
if (len == 0)
- return start;
+ goto the_end;
real_start = start & qemu_host_page_mask;
if (!(flags & MAP_FIXED)) {
@@ -260,7 +294,7 @@
mmap_start = mmap_find_vma(real_start, host_len);
if (mmap_start == (abi_ulong)-1) {
errno = ENOMEM;
- return -1;
+ goto fail;
}
/* Note: we prefer to control the mapping address. It is
especially important if qemu_host_page_size >
@@ -268,7 +302,7 @@
p = mmap(g2h(mmap_start),
host_len, prot, flags | MAP_FIXED, fd, host_offset);
if (p == MAP_FAILED)
- return -1;
+ goto fail;
/* update start so that it points to the file position at 'offset' */
host_start = (unsigned long)p;
if (!(flags & MAP_ANONYMOUS))
@@ -280,7 +314,7 @@
if (start & ~TARGET_PAGE_MASK) {
errno = EINVAL;
- return -1;
+ goto fail;
}
end = start + len;
real_end = HOST_PAGE_ALIGN(end);
@@ -289,7 +323,7 @@
flg = page_get_flags(addr);
if (flg & PAGE_RESERVED) {
errno = ENXIO;
- return -1;
+ goto fail;
}
}
@@ -302,18 +336,20 @@
if ((flags & MAP_TYPE) == MAP_SHARED &&
(prot & PROT_WRITE)) {
errno = EINVAL;
- return -1;
+ goto fail;
}
retaddr = target_mmap(start, len, prot | PROT_WRITE,
MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
-1, 0);
if (retaddr == -1)
- return -1;
+ goto fail;
pread(fd, g2h(start), len, offset);
if (!(prot & PROT_WRITE)) {
ret = target_mprotect(start, len, prot);
- if (ret != 0)
- return ret;
+ if (ret != 0) {
+ start = ret;
+ goto the_end;
+ }
}
goto the_end;
}
@@ -325,13 +361,13 @@
ret = mmap_frag(real_start, start, end,
prot, flags, fd, offset);
if (ret == -1)
- return ret;
+ goto fail;
goto the_end1;
}
ret = mmap_frag(real_start, start, real_start + qemu_host_page_size,
prot, flags, fd, offset);
if (ret == -1)
- return ret;
+ goto fail;
real_start += qemu_host_page_size;
}
/* handle the end of the mapping */
@@ -341,7 +377,7 @@
prot, flags, fd,
offset + real_end - qemu_host_page_size - start);
if (ret == -1)
- return -1;
+ goto fail;
real_end -= qemu_host_page_size;
}
@@ -356,7 +392,7 @@
p = mmap(g2h(real_start), real_end - real_start,
prot, flags, fd, offset1);
if (p == MAP_FAILED)
- return -1;
+ goto fail;
}
}
the_end1:
@@ -367,7 +403,11 @@
page_dump(stdout);
printf("\n");
#endif
+ mmap_unlock();
return start;
+fail:
+ mmap_unlock();
+ return -1;
}
int target_munmap(abi_ulong start, abi_ulong len)
@@ -383,6 +423,7 @@
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);
@@ -411,15 +452,16 @@
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)
- return ret;
}
- page_set_flags(start, start + len, 0);
- return 0;
+ if (ret == 0)
+ page_set_flags(start, start + len, 0);
+ mmap_unlock();
+ return ret;
}
/* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
@@ -431,14 +473,18 @@
int prot;
unsigned long host_addr;
+ mmap_lock();
/* XXX: use 5 args syscall */
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);
+ if (host_addr == -1) {
+ new_addr = -1;
+ } else {
+ 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);
+ }
+ mmap_unlock();
return new_addr;
}
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 093b8ff..7a38bfe 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -233,6 +233,8 @@
abi_ulong new_addr);
int target_msync(abi_ulong start, abi_ulong len, int flags);
extern unsigned long last_brk;
+void mmap_lock(void);
+void mmap_unlock(void);
/* user access */
@@ -423,4 +425,8 @@
#define unlock_user_struct(host_ptr, guest_addr, copy) \
unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0)
+#if defined(USE_NPTL)
+#include <pthread.h>
+#endif
+
#endif /* QEMU_H */
