[PATCH v3 2/2] prctl.2: Document the new PR_GET_TASK_SIZE option

[Joel Savitz]

Add a short explanation of the new PR_GET_TASK_SIZE option for the benefit
of future generations.

Suggested-by: David Laight <David.Laight@xxxxxxxxxx>
Signed-off-by: Joel Savitz <jsavitz@xxxxxxxxxx>
---
 man2/prctl.2 | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/man2/prctl.2 b/man2/prctl.2
index 06d8e13c7..cae582726 100644
--- a/man2/prctl.2
+++ b/man2/prctl.2
@@ -49,6 +49,7 @@
 .\" 2013-01-10 Kees Cook, document PR_SET_PTRACER
 .\" 2012-02-04 Michael Kerrisk, document PR_{SET,GET}_CHILD_SUBREAPER
 .\" 2014-11-10 Dave Hansen, document PR_MPX_{EN,DIS}ABLE_MANAGEMENT
+.\" 2019-05-03 Joel Savitz, document PR_GET_TASK_SIZE
 .\"
 .\"
 .TH PRCTL 2 2019-03-06 "Linux" "Linux Programmer's Manual"
@@ -1375,6 +1376,15 @@ system call on Tru64).
 for information on versions and architectures)
 Return unaligned access control bits, in the location pointed to by
 .IR "(unsigned int\ *) arg2" .
+.TP
+.B PR_GET_TASK_SIZE
+Copy the value of TASK_SIZE to the userspace address in
+.IR "(unsigned long\ *) arg2" .
+This value represents the highest virtual address available
+to the current process. Return
+.B EFAULT
+if this operation fails.
+
 .SH RETURN VALUE
 On success,
 .BR PR_GET_DUMPABLE ,
--
2.18.1