pkey: add test for memory protection keys

Memory Protection Keys for Userspace (PKU aka PKEYs) is a Skylake-SP server feature that provides a mechanism for enforcing page-based protections, but without requiring modification of the page tables when an application changes protection domains. It works by dedicating 4 previously ignored bits in each page table entry to a "protection key", giving 16 possible keys.

Test for Memory Protection Keys:
1. test allocates a pkey(e.g. PKEY_DISABLE_ACCESS) via pkey_alloc()
2. pkey_mprotect() apply this pkey to a piece of shared memory(buffer)
3. check if the access right of buffer has been changed and take effect
4. remove the access right(pkey) from this buffer via pkey_mprotect()
5. check if buffer area can be read or write after removing pkey
6. pkey_free() releases the pkey after using it

---
 configure.ac                               |   1 +
 runtest/syscalls                           |   2 +
 testcases/kernel/syscalls/pkeys/.gitignore |   1 +
 testcases/kernel/syscalls/pkeys/Makefile   |   8 ++
 testcases/kernel/syscalls/pkeys/pkey.h     |  50 ++++++++
 testcases/kernel/syscalls/pkeys/pkey01.c   | 126 +++++++++++++++++++++
 6 files changed, 188 insertions(+)
 create mode 100644 testcases/kernel/syscalls/pkeys/.gitignore
 create mode 100644 testcases/kernel/syscalls/pkeys/Makefile
 create mode 100644 testcases/kernel/syscalls/pkeys/pkey.h
 create mode 100644 testcases/kernel/syscalls/pkeys/pkey01.c

index 65fc2a232..5a9b74b0a 100644
@@ -74,6 +74,7 @@ AC_CHECK_FUNCS([ \
     pidfd_send_signal \
     preadv \
     preadv2 \
+    pkey_mprotect \
     profil \
     pwritev \
     pwritev2 \

index c6a064481..6ea991f12 100644
@@ -721,6 +721,8 @@ mprotect02 mprotect02
 mprotect03 mprotect03
 mprotect04 mprotect04
 
+pkey01 pkey01
+
 mq_notify01 mq_notify01
 mq_notify02 mq_notify02
 mq_open01 mq_open01

new file mode 100644
index 000000000..6fd5addb8
@@ -0,0 +1 @@
+/pkey01

new file mode 100644
index 000000000..9ee2c2ea5
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (c) 2019 Red Hat, Inc.
+
+top_srcdir		?= ../../../..
+
+include $(top_srcdir)/include/mk/testcases.mk
+
+include $(top_srcdir)/include/mk/generic_leaf_target.mk

2.20.1