[PATCH] selftests: x86: skip the tests if prerequisites aren't fulfilled

[Muhammad Usama Anjum]

Skip instead of failing when prerequisite conditions aren't fulfilled,
such as invalid xstate values etc. This patch would make the tests show
as skip when run by:
  make -C tools/testing/selftest/ TARGETS=x86 run_tests

  ...
  # timeout set to 45
  # selftests: x86: amx_64
  # # xstate cpuid: invalid tile data size/offset: 0/0
  ok 42 selftests: x86: amx_64 # SKIP
  # timeout set to 45
  # selftests: x86: lam_64
  # # Unsupported LAM feature!
  ok 43 selftests: x86: lam_64 # SKIP
  ...

Signed-off-by: Muhammad Usama Anjum <usama.an...@collabora.com>
---
I'm not sure if xstate values should be correct on all the x86
processors. If the xstate is invalid on a CPU, the test should be
skipped instead of failing.
---
 tools/testing/selftests/x86/amx.c | 33 ++++++++++++++++++++-----------
 tools/testing/selftests/x86/lam.c |  2 +-
 2 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/x86/amx.c 
b/tools/testing/selftests/x86/amx.c
index d884fd69dd510..5d1ca0bbaaae7 100644
--- a/tools/testing/selftests/x86/amx.c
+++ b/tools/testing/selftests/x86/amx.c
@@ -103,9 +103,10 @@ static void clearhandler(int sig)
 
 #define CPUID_LEAF1_ECX_XSAVE_MASK     (1 << 26)
 #define CPUID_LEAF1_ECX_OSXSAVE_MASK   (1 << 27)
-static inline void check_cpuid_xsave(void)
+static inline int check_cpuid_xsave(void)
 {
        uint32_t eax, ebx, ecx, edx;
+       int ret = 0;
 
        /*
         * CPUID.1:ECX.XSAVE[bit 26] enumerates general
@@ -113,10 +114,16 @@ static inline void check_cpuid_xsave(void)
         * XGETBV.
         */
        __cpuid_count(1, 0, 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");
+       if (!(ecx & CPUID_LEAF1_ECX_XSAVE_MASK)) {
+               ksft_print_msg("cpuid: no CPU xsave support\n");
+               ret = -1;
+       }
+       if (!(ecx & CPUID_LEAF1_ECX_OSXSAVE_MASK)) {
+               ksft_print_msg("cpuid: no OS xsave support\n");
+               ret = -1;
+       }
+
+       return ret;
 }
 
 static uint32_t xbuf_size;
@@ -131,7 +138,7 @@ static struct {
 #define TILE_CPUID                     0x1d
 #define TILE_PALETTE_ID                        0x1
 
-static void check_cpuid_xtiledata(void)
+static int check_cpuid_xtiledata(void)
 {
        uint32_t eax, ebx, ecx, edx;
 
@@ -153,12 +160,16 @@ 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);
+       if (!eax || !ebx) {
+               ksft_print_msg("xstate cpuid: invalid tile data size/offset: 
%d/%d\n",
+                              eax, ebx);
+               return -1;
+       }
 
        xtiledata.size        = eax;
        xtiledata.xbuf_offset = ebx;
+
+       return 0;
 }
 
 /* The helpers for managing XSAVE buffer and tile states: */
@@ -929,8 +940,8 @@ static void test_ptrace(void)
 int main(void)
 {
        /* Check hardware availability at first */
-       check_cpuid_xsave();
-       check_cpuid_xtiledata();
+       if (check_cpuid_xsave() || check_cpuid_xtiledata())
+               return KSFT_SKIP;
 
        init_stashed_xsave();
        sethandler(SIGILL, handle_noperm, 0);
diff --git a/tools/testing/selftests/x86/lam.c 
b/tools/testing/selftests/x86/lam.c
index 215b8150b7cca..c0f016f45ee17 100644
--- a/tools/testing/selftests/x86/lam.c
+++ b/tools/testing/selftests/x86/lam.c
@@ -1183,7 +1183,7 @@ int main(int argc, char **argv)
 
        if (!cpu_has_lam()) {
                ksft_print_msg("Unsupported LAM feature!\n");
-               return -1;
+               return KSFT_SKIP;
        }
 
        while ((c = getopt(argc, argv, "ht:")) != -1) {
-- 
2.39.2