[PATCH v12 18/22] selftests/vm: associate key on a mapped page and detect write violation

From: Ram Pai
Date: Wed Feb 21 2018 - 20:59:09 EST


detect write-violation on a page to which write-disabled
key is associated much after the page is mapped.

cc: Dave Hansen <dave.hansen@xxxxxxxxx>
cc: Florian Weimer <fweimer@xxxxxxxxxx>
Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
---
tools/testing/selftests/vm/protection_keys.c | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index dba9162..b685e26 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -1034,6 +1034,17 @@ void test_read_of_access_disabled_region_with_page_already_mapped(int *ptr,
expected_pkey_fault(pkey);
}

+void test_write_of_write_disabled_region_with_page_already_mapped(int *ptr,
+ u16 pkey)
+{
+ *ptr = __LINE__;
+ dprintf1("disabling write access; after accessing the page, "
+ "to PKEY[%02d], doing write\n", pkey);
+ pkey_write_deny(pkey);
+ *ptr = __LINE__;
+ expected_pkey_fault(pkey);
+}
+
void test_write_of_write_disabled_region(int *ptr, u16 pkey)
{
dprintf1("disabling write access to PKEY[%02d], doing write\n", pkey);
@@ -1330,6 +1341,7 @@ void test_mprotect_pkey_on_unsupported_cpu(int *ptr, u16 pkey)
test_read_of_access_disabled_region,
test_read_of_access_disabled_region_with_page_already_mapped,
test_write_of_write_disabled_region,
+ test_write_of_write_disabled_region_with_page_already_mapped,
test_write_of_access_disabled_region,
test_kernel_write_of_access_disabled_region,
test_kernel_write_of_write_disabled_region,
--
1.7.1