selftests/vm/pkeys: associate key on a mapped page and detect access violation

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

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "Desnes A. Nunes do Rosario" <desnesn@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Suchanek <msuchanek@suse.de>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/4a19cf9252c03dd883887e9002881599e6900d06.1585646528.git.sandipan@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index 95f173049f43fabd34e42c5502805b3db835ee67..f65d384ef6a0d98d6093f9f96b2c098ec38beee6 100644 (file)
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -984,6 +984,24 @@ void test_read_of_access_disabled_region(int *ptr, u16 pkey)
        dprintf1("*ptr: %d\n", ptr_contents);
        expected_pkey_fault(pkey);
 }
+
+void test_read_of_access_disabled_region_with_page_already_mapped(int *ptr,
+               u16 pkey)
+{
+       int ptr_contents;
+
+       dprintf1("disabling access to PKEY[%02d], doing read @ %p\n",
+                               pkey, ptr);
+       ptr_contents = read_ptr(ptr);
+       dprintf1("reading ptr before disabling the read : %d\n",
+                       ptr_contents);
+       read_pkey_reg();
+       pkey_access_deny(pkey);
+       ptr_contents = read_ptr(ptr);
+       dprintf1("*ptr: %d\n", ptr_contents);
+       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);
@@ -1390,6 +1408,7 @@ void test_mprotect_pkey_on_unsupported_cpu(int *ptr, u16 pkey)
 void (*pkey_tests[])(int *ptr, u16 pkey) = {
        test_read_of_write_disabled_region,
        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_access_disabled_region,
        test_kernel_write_of_access_disabled_region,