[PATCH for-8.1 v2] linux-user: Define real MAP_FIXED_NOREPLACE value

[Akihiko Odaki]

do_brk() assumes target_mmap() emulates MAP_FIXED_NOREPLACE even when
the host does not support it. However, such emulation is not possible
if MAP_FIXED_NOREPLACE is defined as zero.

Define MAP_FIXED_NOREPLACE with the real value instead of zero if it is
not defined.

Fixes: e69e032d1a ("linux-user: Use MAP_FIXED_NOREPLACE for do_brk()")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 include/qemu/osdep.h | 8 ++++++--
 linux-user/elfload.c | 1 -
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index cc61b00ba9..6c1050afcd 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -289,8 +289,12 @@ void QEMU_ERROR("code path is reachable")
 #ifndef MAP_ANONYMOUS
 #define MAP_ANONYMOUS MAP_ANON
 #endif
-#ifndef MAP_FIXED_NOREPLACE
-#define MAP_FIXED_NOREPLACE 0
+#if defined(__linux__) && !defined(MAP_FIXED_NOREPLACE)
+#if MAP_HUGETLB == 0x100000
+#define MAP_FIXED_NOREPLACE 0x200000
+#else
+#define MAP_FIXED_NOREPLACE 0x100000
+#endif
 #endif
 #ifndef MAP_NORESERVE
 #define MAP_NORESERVE 0
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 36e4026f05..9d9c79a653 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2807,7 +2807,6 @@ static void pgb_reserved_va(const char *image_name, 
abi_ulong guest_loaddr,
     /* Widen the "image" to the entire reserved address space. */
     pgb_static(image_name, 0, reserved_va, align);
 
-    /* osdep.h defines this as 0 if it's missing */
     flags |= MAP_FIXED_NOREPLACE;
 
     /* Reserve the memory on the host. */
-- 
2.41.0