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From: Bill Roberts <bill.roberts@arm.com>
To: rick.p.edgecombe@intel.com, Thomas Gleixner <tglx@kernel.org>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Shuah Khan <shuah@kernel.org>
Cc: Bill Roberts <bill.roberts@arm.com>,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: [PATCH 2/2] selftest/x86: test ARCH_SHSTK_UNLOCK
Date: Mon, 15 Jun 2026 14:51:55 -0500	[thread overview]
Message-ID: <20260615195156.257950-2-bill.roberts@arm.com> (raw)
In-Reply-To: <20260615195156.257950-1-bill.roberts@arm.com>

One should not be able to use ARCH_SHSTK_UNLOCK via arch_prctl to twiddle
feature bits, test that this is the case.

Signed-off-by: Bill Roberts <bill.roberts@arm.com>
---
 tools/testing/selftests/x86/test_shadow_stack.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/testing/selftests/x86/test_shadow_stack.c b/tools/testing/selftests/x86/test_shadow_stack.c
index 21af54d5f4ea..82a5fefa9df5 100644
--- a/tools/testing/selftests/x86/test_shadow_stack.c
+++ b/tools/testing/selftests/x86/test_shadow_stack.c
@@ -979,6 +979,14 @@ int main(int argc, char *argv[])
 {
 	int ret = 0;
 
+	/* test that we can't use unlock to set shadow stack */
+	if (!ARCH_PRCTL(ARCH_SHSTK_UNLOCK, ARCH_SHSTK_SHSTK)) {
+		printf("[SKIP]\tCould enable Shadow stack via UNLOCK\n");
+		return 1;
+	}
+
+	printf("[OK]\tCouldn't enable Shadow stack via UNLOCK\n");
+
 	if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK)) {
 		printf("[SKIP]\tCould not enable Shadow stack\n");
 		return 1;
-- 
2.54.0


  reply	other threads:[~2026-06-15 19:52 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-15 19:51 [PATCH 1/2] arch/x86: do not allow unlock to set bits Bill Roberts
2026-06-15 19:51 ` Bill Roberts [this message]
2026-06-29 21:46   ` [PATCH 2/2] selftest/x86: test ARCH_SHSTK_UNLOCK Edgecombe, Rick P
2026-06-29 17:09     ` Bill Roberts
2026-06-30 17:02       ` Edgecombe, Rick P
2026-06-29 21:57   ` Edgecombe, Rick P
2026-06-29 17:13     ` Bill Roberts
2026-06-29 21:44 ` [PATCH 1/2] arch/x86: do not allow unlock to set bits Edgecombe, Rick P
2026-06-29 17:05   ` Bill Roberts

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