Patch "x86/pkeys/selftests: Factor out "instruction page"" has been added to the 4.16-stable tree

This is a note to let you know that I've just added the patch titled

x86/pkeys/selftests: Factor out "instruction page"

to the 4.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-pkeys-selftests-factor-out-instruction-page.patch
and it can be found in the queue-4.16 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Dave Hansen <[email protected]>
Date: Wed, 9 May 2018 10:13:47 -0700
Subject: x86/pkeys/selftests: Factor out "instruction page"

From: Dave Hansen <[email protected]>

[ Upstream commit 3fcd2b2d928904cbf30b01e2c5e4f1dd2f9ab262 ]

We currently have an execute-only test, but it is for the explicit mprotect_pkey() interface. We will soon add a test for the implicit mprotect(PROT_EXEC) enterface. We need this code in both tests.

---
 tools/testing/selftests/x86/protection_keys.c |   21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

@@ -1253,12 +1253,9 @@ void test_ptrace_of_child(int *ptr, u16
 	free(plain_ptr_unaligned);
 }
 
-void test_executing_on_unreadable_memory(int *ptr, u16 pkey)
+void *get_pointer_to_instructions(void)
 {
 	void *p1;
-	int scratch;
-	int ptr_contents;
-	int ret;
 
 	p1 = ALIGN_PTR_UP(&lots_o_noops_around_write, PAGE_SIZE);
 	dprintf3("&lots_o_noops: %p\n", &lots_o_noops_around_write);

@@ -1268,7 +1265,23 @@ void test_executing_on_unreadable_memory
 	/* Point 'p1' at the *second* page of the function: */
 	p1 += PAGE_SIZE;
 
+	/*
+	 * Try to ensure we fault this in on next touch to ensure
+	 * we get an instruction fault as opposed to a data one
+	 */
 	madvise(p1, PAGE_SIZE, MADV_DONTNEED);
+
+	return p1;
+}
+
+void test_executing_on_unreadable_memory(int *ptr, u16 pkey)
+{
+	void *p1;
+	int scratch;
+	int ptr_contents;
+	int ret;
+
+	p1 = get_pointer_to_instructions();
 	lots_o_noops_around_write(&scratch);
 	ptr_contents = read_ptr(p1);
 	dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);

Patches currently in stable-queue which might be from [email protected] are

queue-4.16/x86-pkeys-selftests-factor-out-instruction-page.patch queue-4.16/x86-pkeys-selftests-fix-pointer-math.patch queue-4.16/x86-pkeys-selftests-adjust-the-self-test-to-fresh-distros-that-export-the-pkeys-abi.patch queue-4.16/x86-pkeys-selftests-add-a-test-for-pkey-0.patch queue-4.16/x86-pkeys-selftests-stop-using-assert.patch queue-4.16/x86-pkeys-selftests-save-off-prot-for-allocations.patch queue-4.16/x86-pkeys-selftests-remove-dead-debugging-code-fix-dprint_in_signal.patch queue-4.16/x86-mpx-selftests-adjust-the-self-test-to-fresh-distros-that-export-the-mpx-abi.patch queue-4.16/x86-pkeys-selftests-add-prot_exec-test.patch queue-4.16/x86-pkeys-selftests-allow-faults-on-unknown-keys.patch queue-4.16/x86-pkeys-selftests-give-better-unexpected-fault-error-messages.patch queue-4.16/x86-pkeys-selftests-avoid-printf-in-signal-deadlocks.patch queue-4.16/x86-pkeys-selftests-fix-pkey-exhaustion-test-off-by-one.patch