linux-kernel - [PATCH v4 2/3] selftests/lam: Skip test if LAM is disabled

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <09af68980f1c32f013a9e3b39fde70647f4a8879.1732627541.git.maciej.wieczor-retman@intel.com>
Date: Tue, 26 Nov 2024 14:34:49 +0100
From: Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>
To: shuah@...nel.org,
	hpa@...or.com,
	x86@...nel.org,
	dave.hansen@...ux.intel.com,
	bp@...en8.de,
	mingo@...hat.com,
	tglx@...utronix.de
Cc: linux-kernel@...r.kernel.org,
	linux-kselftest@...r.kernel.org,
	kirill@...temov.name,
	maciej.wieczor-retman@...el.com
Subject: [PATCH v4 2/3] selftests/lam: Skip test if LAM is disabled

Until LASS is merged into the kernel [1], LAM is left disabled in the
config file. Running the LAM selftest with disabled LAM only results in
unhelpful output.

Use one of LAM syscalls() to determine whether the kernel was compiled
with LAM support (CONFIG_ADDRESS_MASKING) or not. Skip running the tests
in the latter case.

[1] https://lore.kernel.org/all/20241028160917.1380714-1-alexander.shishkin@linux.intel.com/

Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>
---
Changelog v4:
- Add this patch to the series.

 tools/testing/selftests/x86/lam.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tools/testing/selftests/x86/lam.c b/tools/testing/selftests/x86/lam.c
index 0ac805125ab2..5aee3e231a96 100644
--- a/tools/testing/selftests/x86/lam.c
+++ b/tools/testing/selftests/x86/lam.c
@@ -124,6 +124,14 @@ static inline int cpu_has_lam(void)
 	return (cpuinfo[0] & (1 << 26));
 }
 
+static inline int kernel_has_lam(void)
+{
+	unsigned long bits;
+
+	syscall(SYS_arch_prctl, ARCH_GET_MAX_TAG_BITS, &bits);
+	return !!bits;
+}
+
 static inline int cpu_has_la57(void)
 {
 	int ret = !!system("cat /proc/cpuinfo | grep -wq la57\n");
@@ -1183,6 +1191,11 @@ int main(int argc, char **argv)
 		return KSFT_SKIP;
 	}
 
+	if (!kernel_has_lam()) {
+		ksft_print_msg("LAM is disabled in the kernel!\n");
+		return KSFT_SKIP;
+	}
+
 	while ((c = getopt(argc, argv, "ht:")) != -1) {
 		switch (c) {
 		case 't':
-- 
2.47.1