Module Name: src
Committed By: riastradh
Date: Tue May 20 15:23:12 UTC 2014
Modified Files:
src/share/man/man9: uvm_map.9
Log Message:
Split large paragraph about uobj/uoffset into a bulleted list.
Mention that uvm_map doesn't add a reference to uobj. Evidently this
information is important, since I just wasted countless hours over
the past months investigating kernel memory corruption arising from a
failure to notice this fact.
To generate a diff of this commit:
cvs rdiff -u -r1.2 -r1.3 src/share/man/man9/uvm_map.9
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/share/man/man9/uvm_map.9
diff -u src/share/man/man9/uvm_map.9:1.2 src/share/man/man9/uvm_map.9:1.3
--- src/share/man/man9/uvm_map.9:1.2 Fri Jun 3 18:43:38 2011
+++ src/share/man/man9/uvm_map.9 Tue May 20 15:23:12 2014
@@ -1,4 +1,4 @@
-.\" $NetBSD: uvm_map.9,v 1.2 2011/06/03 18:43:38 rmind Exp $
+.\" $NetBSD: uvm_map.9,v 1.3 2014/05/20 15:23:12 riastradh Exp $
.\"
.\" Copyright (c) 1998 Matthew R. Green
.\" All rights reserved.
@@ -81,11 +81,14 @@ The new mapping has size
.Fa size ,
which must be a multiple of
.Dv PAGE_SIZE .
+.Pp
The
.Fa uobj
and
.Fa uoffset
-arguments can have four meanings.
+arguments can have four meanings:
+.Bl -bullet -offset indent -compact
+.It
When
.Fa uobj
is
@@ -98,10 +101,16 @@ is
does not use the machine-dependent
.Dv PMAP_PREFER
function.
-If
+.It
+When
+.Fa uobj
+is
+.Dv NULL
+and
.Fa uoffset
is any other value, it is used as the hint to
.Dv PMAP_PREFER .
+.It
When
.Fa uobj
is not
@@ -113,11 +122,22 @@ is
.Fn uvm_map
finds the offset based upon the virtual address, passed as
.Fa startp .
-If
+.It
+When
+.Fa uobj
+is not
+.Dv NULL
+and
.Fa uoffset
is any other value, then a regular mapping is performed at this offset.
The start address of the map will be returned in
.Fa startp .
+.El
+Note that
+.Fn uvm_map
+does not add a reference to
+.Fa uobj ;
+it is the caller's responsibility to do so.
.Pp
.Fa align
specifies alignment of mapping unless
