Add a mmap flag (MAP_32BIT) on 64-bit platforms to request that a mapping use

an address in the first 2GB of the process's address space.  This flag should
have the same semantics as the same flag on Linux.

To facilitate this, add a new parameter to vm_map_find() that specifies an
optional maximum virtual address.  While here, fix several callers of
vm_map_find() to use a VMFS_* constant for the findspace argument instead of
TRUE and FALSE.

Reviewed by:	alc
Approved by:	re (kib)

1 files changed, 14 insertions, 1 deletions

diff --git a/lib/libc/sys/mmap.2 b/lib/libc/sys/mmap.2
index 130f70b..01cde0e 100644
--- a/lib/libc/sys/mmap.2
+++ b/lib/libc/sys/mmap.2
@@ -28,7 +28,7 @@
 .\"	@(#)mmap.2	8.4 (Berkeley) 5/11/95
 .\" $FreeBSD$
 .\"
-.Dd August 16, 2013
+.Dd September 9, 2013
 .Dt MMAP 2
 .Os
 .Sh NAME
@@ -98,6 +98,12 @@ argument by
 .Em or Ns 'ing
 the following values:
 .Bl -tag -width MAP_PREFAULT_READ
+.It Dv MAP_32BIT
+Request a region in the first 2GB of the current process's address space.
+If a suitable region cannot be found,
+.Fn mmap
+will fail.
+This flag is only available on 64-bit platforms.
 .It Dv MAP_ALIGNED Ns Pq Fa n
 Align the region on a requested boundary.
 If a suitable region cannot be found,
@@ -362,6 +368,13 @@ was specified and the
 argument was not page aligned, or part of the desired address space
 resides out of the valid address space for a user process.
 .It Bq Er EINVAL
+Both
+.Dv MAP_FIXED
+and
+.Dv MAP_32BIT
+were specified and part of the desired address space resides outside
+of the first 2GB of user address space.
+.It Bq Er EINVAL
 The
 .Fa len
 argument