On 4/1/22 4:10 PM, Chang S. Bae wrote:

The test assumes an insufficient altstack is allowed. Then it raises a signal to test the delivery failure due to an altstack overflow.

The kernel now provides an option to tweak sigaltstack()'s sanity check to prevent an insufficient altstack. ENOMEM is returned on the check failure.

Adjust the code to skip the test when this option is on.

Mention the option name here and in the Skip message.

Signed-off-by: Chang S. Bae chang.seok.bae@intel.com Cc: linux-kselftest@vger.kernel.org Cc: linux-kernel@vger.kernel.org

---

tools/testing/selftests/x86/sigaltstack.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/x86/sigaltstack.c b/tools/testing/selftests/x86/sigaltstack.c index f689af75e979..22a88b764a8e 100644 --- a/tools/testing/selftests/x86/sigaltstack.c +++ b/tools/testing/selftests/x86/sigaltstack.c @@ -88,8 +88,18 @@ static void sigalrm(int sig, siginfo_t *info, void *ctx_void) static void test_sigaltstack(void *altstack, unsigned long size) {

• if (setup_altstack(altstack, size))

• if (setup_altstack(altstack, size)) {

• /*
  

•  * The kernel may return ENOMEM when the altstack size
  

•  * is insufficient. Skip the test in this case.
  

•  */
  

• if (errno == ENOMEM && size < at_minstack_size) {
  

• 	printf("[SKIP]\tThe running kernel disallows an insufficient size.\n");
  

Please improve this message to clearly why it is okay to skip the test. Mention that the option to disallowing insufficient is enabled and that the test can't be run.

• 	return;
  

• }
  

• err(1, "sigaltstack()");
• }

sigalrm_expected = (size > at_minstack_size) ? true : false;

With these changes:

Reviewed-by: Shuah Khan skhan@linuxfoundation.org

thanks, -- Shuah

On 4/1/22 4:10 PM, Chang S. Bae wrote:

When a CPU does not have AMX, the test fails. But this is wrong as it should be runnable regardless. Skip the test instead.

Reported-by: Thomas Gleixner tglx@linutronix.de Fixes: 6a3e0651b4a ("selftests/x86/amx: Add test cases for AMX state management") Signed-off-by: Chang S. Bae chang.seok.bae@intel.com Cc: linux-kselftest@vger.kernel.org Cc: linux-kernel@vger.kernel.org

---

tools/testing/selftests/x86/amx.c | 42 +++++++++++++++++++++++-------- 1 file changed, 31 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c index 3615ef4a48bb..14abb6072a7d 100644 --- a/tools/testing/selftests/x86/amx.c +++ b/tools/testing/selftests/x86/amx.c @@ -106,6 +106,12 @@ static void clearhandler(int sig) #define CPUID_LEAF1_ECX_XSAVE_MASK (1 << 26) #define CPUID_LEAF1_ECX_OSXSAVE_MASK (1 << 27)

+static struct {

• unsigned xsave: 1;
• unsigned osxsave: 1;

+} cpuinfo;

Why is this needed? Also naming this cpuinfo is confuing.

static inline void check_cpuid_xsave(void) { uint32_t eax, ebx, ecx, edx; @@ -118,10 +124,8 @@ static inline void check_cpuid_xsave(void) eax = 1; ecx = 0; cpuid(&eax, &ebx, &ecx, &edx);

• if (!(ecx & CPUID_LEAF1_ECX_XSAVE_MASK))

• fatal_error("cpuid: no CPU xsave support");
  

• if (!(ecx & CPUID_LEAF1_ECX_OSXSAVE_MASK))

• fatal_error("cpuid: no OS xsave support");
  

• cpuinfo.xsave = !!(ecx & CPUID_LEAF1_ECX_XSAVE_MASK);
• cpuinfo.osxsave = !!(ecx & CPUID_LEAF1_ECX_OSXSAVE_MASK);

Why add this complexity. Why not just Skip here?

} static uint32_t xbuf_size; @@ -161,14 +165,31 @@ static void check_cpuid_xtiledata(void) * eax: XTILEDATA state component size * ebx: XTILEDATA state component offset in user buffer */

• if (!eax || !ebx)

• fatal_error("xstate cpuid: invalid tile data size/offset: %d/%d",
  

• 		eax, ebx);
  

• xtiledata.size = eax; xtiledata.xbuf_offset = ebx; }

+static bool amx_available(void) +{

• check_cpuid_xsave();
• if (!cpuinfo.xsave) {

• printf("[SKIP]\tcpuid: no CPU xsave support\n");
  

• return false;
  

• } else if (!cpuinfo.osxsave) {

• printf("[SKIP]\tcpuid: no OS xsave support\n");
  

• return false;
  

• }
• check_cpuid_xtiledata();
• if (!xtiledata.size || !xtiledata.xbuf_offset) {

• printf("[SKIP]\txstate cpuid: no tile data (size/offset: %d/%d)\n",
  

•        xtiledata.size, xtiledata.xbuf_offset);
  

• return false;
  

• }
• return true;

+}

I am not seeing any value in adding this layer of abstraction. Keep it simple and do the handling in main()

/* The helpers for managing XSAVE buffer and tile states: */ struct xsave_buffer *alloc_xbuf(void) @@ -826,9 +847,8 @@ static void test_context_switch(void) int main(void) {

• /* Check hardware availability at first */
• check_cpuid_xsave();
• check_cpuid_xtiledata();

• if (!amx_available())

• return 0;
  

This should KSFT_SKIP for this to be reported as a skip. Returning 0 will be reported as a Pass.

init_stashed_xsave(); sethandler(SIGILL, handle_noperm, 0);

thanks, -- Shuah