[PATCH v4 2/2] selftests/x86/amx: Update the ARCH_REQ_XCOMP_PERM test

Chang S. Bae
2022-01-29T17:44:42Z

Update the arch_prctl test to check the permission bitmap whether the
requested feature is added as expected or not.

Every non-dynamic feature that is enabled is permitted already for use.
TILECFG is not dynamic feature. Ensure the bit is always on from
ARCH_GET_XCOMP_PERM.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-kselftest@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
tools/testing/selftests/x86/amx.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c
index 3615ef4a48bb..e1e2c8f3356f 100644
--- a/tools/testing/selftests/x86/amx.c
+++ b/tools/testing/selftests/x86/amx.c
@@ -368,9 +368,16 @@ static void req_xtiledata_perm(void)

static void validate_req_xcomp_perm(enum expected_result exp)
{
- unsigned long bitmask;
+ unsigned long bitmask, expected_bitmask;
long rc;

+ rc = syscall(SYS_arch_prctl, ARCH_GET_XCOMP_PERM, &bitmask);
+ if (rc) {
+ fatal_error("prctl(ARCH_GET_XCOMP_PERM) error: %ld", rc);
+ } else if (!(bitmask & XFEATURE_MASK_XTILECFG)) {
+ fatal_error("ARCH_GET_XCOMP_PERM returns XFEATURE_XTILECFG off.");
+ }
+
rc = syscall(SYS_arch_prctl, ARCH_REQ_XCOMP_PERM, XFEATURE_XTILEDATA);
if (exp == FAIL_EXPECTED) {
if (rc) {
@@ -383,10 +390,15 @@ static void validate_req_xcomp_perm(enum expected_result exp)
fatal_error("ARCH_REQ_XCOMP_PERM saw unexpected failure.\n");
}

+ expected_bitmask = bitmask | XFEATURE_MASK_XTILEDATA;
+
rc = syscall(SYS_arch_prctl, ARCH_GET_XCOMP_PERM, &bitmask);
if (rc) {
fatal_error("prctl(ARCH_GET_XCOMP_PERM) error: %ld", rc);
- } else if (bitmask & XFEATURE_MASK_XTILE) {
+ } else if (bitmask != expected_bitmask) {
+ fatal_error("ARCH_REQ_XCOMP_PERM saw a wrong bitmask: %lx, expected: %lx.\n",
+ bitmask, expected_bitmask);
+ } else {
printf("\tARCH_REQ_XCOMP_PERM is successful.\n");
}
}
--
2.17.1