This is a note to let you know that I've just added the patch titled
s390/test_unwind: use raw opcode instead of invalid instruction
to the 5.10-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:
s390-test_unwind-use-raw-opcode-instead-of-invalid-i.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8feef89bff5cf1503e15fd4e35ecc87bb7e1c621
Author: Ilie Halip <ilie.halip@xxxxxxxxx>
Date: Wed Nov 17 19:48:21 2021 +0200
s390/test_unwind: use raw opcode instead of invalid instruction
[ Upstream commit 53ae7230918154d1f4281d7aa3aae9650436eadf ]
Building with clang & LLVM_IAS=1 leads to an error:
arch/s390/lib/test_unwind.c:179:4: error: invalid register pair
" mvcl %%r1,%%r1\n"
^
The test creates an invalid instruction that would trap at runtime, but the
LLVM inline assembler tries to validate it at compile time too.
Use the raw instruction opcode instead.
Reported-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Ilie Halip <ilie.halip@xxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Suggested-by: Ulrich Weigand <Ulrich.Weigand@xxxxxxxxxx>
Link: https://github.com/ClangBuiltLinux/linux/issues/1421
Link: https://lore.kernel.org/r/20211117174822.3632412-1-ilie.halip@xxxxxxxxx
Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
[hca@xxxxxxxxxxxxx: use illegal opcode, and update comment]
Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/s390/lib/test_unwind.c b/arch/s390/lib/test_unwind.c
index 6bad84c372dcb..b0b67e6d1f6e2 100644
--- a/arch/s390/lib/test_unwind.c
+++ b/arch/s390/lib/test_unwind.c
@@ -171,10 +171,11 @@ static noinline int unwindme_func4(struct unwindme *u)
}
/*
- * trigger specification exception
+ * Trigger operation exception; use insn notation to bypass
+ * llvm's integrated assembler sanity checks.
*/
asm volatile(
- " mvcl %%r1,%%r1\n"
+ " .insn e,0x0000\n" /* illegal opcode */
"0: nopr %%r7\n"
EX_TABLE(0b, 0b)
:);
