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From:   Joel Savitz <jsavitz@redhat.com>
To:     linux-kernel@vger.kernel.org
Cc:     Joel Savitz <jsavitz@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
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        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Kristina Martsenko <kristina.martsenko@arm.com>,
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        Kees Cook <keescook@chromium.org>,
        "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
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        Micah Morton <mortonm@chromium.org>,
        Yang Shi <yang.shi@linux.alibaba.com>,
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        Alexey Dobriyan <adobriyan@gmail.com>,
        Rafael Aquini <aquini@redhat.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Yury Norov <yury.norov@gmail.com>,
        David Laight <David.Laight@aculab.com>
Subject: [PATCH v3 2/2] prctl.2: Document the new PR_GET_TASK_SIZE option
Date:   Fri,  3 May 2019 14:10:21 -0400
Message-Id: <1556907021-29730-3-git-send-email-jsavitz@redhat.com>
In-Reply-To: <1556907021-29730-1-git-send-email-jsavitz@redhat.com>
References: <1556907021-29730-1-git-send-email-jsavitz@redhat.com>
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Add a short explanation of the new PR_GET_TASK_SIZE option for the benefit
of future generations.

Suggested-by: David Laight <David.Laight@aculab.com>
Signed-off-by: Joel Savitz <jsavitz@redhat.com>
---
 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