From: Yifan Wu <wuyifan50@huawei.com>
Date: Thu, 5 Mar 2026 01:36:38 +0000 (+0800)
Subject: selftests/arm64: Implement cmpbr_sigill() to hwcap test
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=74cd4e0e5399480e3fab2cd6a6cbdb17f673c335;p=thirdparty%2Fkernel%2Flinux.git

selftests/arm64: Implement cmpbr_sigill() to hwcap test

The function executes a CBEQ instruction which is valid if the CPU
supports the CMPBR extension. The CBEQ branches to skip the following
UDF instruction, and no SIGILL is generated. Otherwise, it will
generate a SIGILL.

Signed-off-by: Yifan Wu <wuyifan50@huawei.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---

diff --git a/tools/testing/selftests/arm64/abi/hwcap.c b/tools/testing/selftests/arm64/abi/hwcap.c
index c2661a312fc98..e22703d6b97c2 100644
--- a/tools/testing/selftests/arm64/abi/hwcap.c
+++ b/tools/testing/selftests/arm64/abi/hwcap.c
@@ -56,7 +56,8 @@ static void atomics_sigill(void)
 
 static void cmpbr_sigill(void)
 {
-	/* Not implemented, too complicated and unreliable anyway */
+	asm volatile(".inst 0x74C00040\n" /* CBEQ w0, w0, +8 */
+		     "udf #0" : : : "cc"); /* UDF #0 */
 }
 
 static void crc32_sigill(void)