x86/pkeys/selftests: Add a test for pkey 0

[mirror_ubuntu-bionic-kernel.git] / tools / testing / selftests / x86 / protection_keys.c

diff --git a/tools/testing/selftests/x86/protection_keys.c b/tools/testing/selftests/x86/protection_keys.c
index 986ed38a2b2526a316e424f6b9456c65a4391b83..460b4bdf4c1edff9d5dfa0d451dbaa393d53b80c 100644 (file)
--- a/tools/testing/selftests/x86/protection_keys.c
+++ b/tools/testing/selftests/x86/protection_keys.c
@@ -1184,6 +1184,35 @@ void test_pkey_alloc_exhaust(int *ptr, u16 pkey)
        }
 }
 
+/*
+ * pkey 0 is special.  It is allocated by default, so you do not
+ * have to call pkey_alloc() to use it first.  Make sure that it
+ * is usable.
+ */
+void test_mprotect_with_pkey_0(int *ptr, u16 pkey)
+{
+       long size;
+       int prot;
+
+       assert(pkey_last_malloc_record);
+       size = pkey_last_malloc_record->size;
+       /*
+        * This is a bit of a hack.  But mprotect() requires
+        * huge-page-aligned sizes when operating on hugetlbfs.
+        * So, make sure that we use something that's a multiple
+        * of a huge page when we can.
+        */
+       if (size >= HPAGE_SIZE)
+               size = HPAGE_SIZE;
+       prot = pkey_last_malloc_record->prot;
+
+       /* Use pkey 0 */
+       mprotect_pkey(ptr, size, prot, 0);
+
+       /* Make sure that we can set it back to the original pkey. */
+       mprotect_pkey(ptr, size, prot, pkey);
+}
+
 void test_ptrace_of_child(int *ptr, u16 pkey)
 {
        __attribute__((__unused__)) int peek_result;
@@ -1378,6 +1407,7 @@ void (*pkey_tests[])(int *ptr, u16 pkey) = {
        test_kernel_gup_write_to_write_disabled_region,
        test_executing_on_unreadable_memory,
        test_implicit_mprotect_exec_only_memory,
+       test_mprotect_with_pkey_0,
        test_ptrace_of_child,
        test_pkey_syscalls_on_non_allocated_pkey,
        test_pkey_syscalls_bad_args,