| @@ -0,0 +1,101 @@
+diff --git a/linux-user/mmap.c b/linux-user/mmap.c
+index 6f300a0..8cec230 100644
+--- a/linux-user/mmap.c
++++ b/linux-user/mmap.c
+@@ -275,52 +275,59 @@ abi_ulong mmap_next_start = 0x40000000;
+
+ unsigned long last_brk;
+
+-/* 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.
+-*/
+-/* page_init() marks pages used by the host as reserved to be sure not
+- to use them. */
+-abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
++/*
++ * Find and reserve a free memory area of size 'size'. The search
++ * starts at 'start'.
++ * It must be called with mmap_lock() held.
++ * Return -1 if error.
++ */
++abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
+ {
+- abi_ulong addr, addr1, addr_start;
+- int prot;
+- unsigned long new_brk;
+-
+- new_brk = (unsigned long)sbrk(0);
+- if (last_brk && last_brk < new_brk && last_brk == (target_ulong)last_brk) {
+- /* This is a hack to catch the host allocating memory with brk().
+- If it uses mmap then we loose.
+- FIXME: We really want to avoid the host allocating memory in
+- the first place, and maybe leave some slack to avoid switching
+- to mmap. */
+- page_set_flags(last_brk & TARGET_PAGE_MASK,
+- TARGET_PAGE_ALIGN(new_brk),
+- PAGE_RESERVED);
+- }
+- last_brk = new_brk;
++ void *ptr;
++ abi_ulong addr;
+
+ size = HOST_PAGE_ALIGN(size);
+- start = start & qemu_host_page_mask;
++ start &= qemu_host_page_mask;
++
++ /* If 'start' == 0, then a default start address is used. */
++ if (start == 0)
++ start = mmap_next_start;
++
+ 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)
++ /*
++ * Reserve needed memory area to avoid a race.
++ * It should be discarded using:
++ * - mmap() with MAP_FIXED flag
++ * - mremap() with MREMAP_FIXED flag
++ * - shmat() with SHM_REMAP flag
++ */
++ ptr = mmap((void *)(unsigned long)addr, size, PROT_NONE,
++ MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
++
++ /* ENOMEM, if host address space has no memory */
++ if (ptr == MAP_FAILED)
++ return (abi_ulong)-1;
++
++ /* If address fits target address space we've found what we need */
++ if ((unsigned long)ptr + size - 1 <= (abi_ulong)-1)
+ break;
++
++ /* Unmap and try again with new page */
++ munmap(ptr, size);
+ addr += qemu_host_page_size;
+- /* we found nothing */
+- if (addr == addr_start)
++
++ /* ENOMEM if we check whole of target address space */
++ if (addr == start)
+ return (abi_ulong)-1;
+ }
+- if (start == 0)
+- mmap_next_start = addr + size;
+- return addr;
++
++ /* Update default start address */
++ if (start == mmap_next_start)
++ mmap_next_start = (unsigned long)ptr + size;
++
++ return h2g(ptr);
+ }
+
+ /* NOTE: all the constants are the HOST ones */
|
