tools/testing/selftests/arm64/fp/za-fork.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2022 ARM Limited.
   4  * Original author: Mark Brown <broonie@kernel.org>
   5  */
   6
   7 // SPDX-License-Identifier: GPL-2.0-only
   8
   9 #include <linux/sched.h>
  10 #include <linux/wait.h>
  11
  12 #include "kselftest.h"
  13
  14 #define EXPECTED_TESTS 1
  15
  16 int fork_test(void);
  17 int verify_fork(void);
  18
  19 /*
  20  * If we fork the value in the parent should be unchanged and the
  21  * child should start with the same value.  This is called from the
  22  * fork_test() asm function.
  23  */
  24 int fork_test_c(void)
  25 {
  26         pid_t newpid, waiting;
  27         int child_status, parent_result;
  28
  29         newpid = fork();
  30         if (newpid == 0) {
  31                 /* In child */
  32                 if (!verify_fork()) {
  33                         ksft_print_msg("ZA state invalid in child\n");
  34                         exit(0);
  35                 } else {
  36                         exit(1);
  37                 }
  38         }
  39         if (newpid < 0) {
  40                 ksft_print_msg("fork() failed: %d\n", newpid);
  41
  42                 return 0;
  43         }
  44
  45         parent_result = verify_fork();
  46         if (!parent_result)
  47                 ksft_print_msg("ZA state invalid in parent\n");
  48
  49         for (;;) {
  50                 waiting = waitpid(newpid, &child_status, 0);
  51
  52                 if (waiting < 0) {
  53                         if (errno == EINTR)
  54                                 continue;
  55                         ksft_print_msg("waitpid() failed: %d\n", errno);
  56                         return 0;
  57                 }
  58                 if (waiting != newpid) {
  59                         ksft_print_msg("waitpid() returned wrong PID\n");
  60                         return 0;
  61                 }
  62
  63                 if (!WIFEXITED(child_status)) {
  64                         ksft_print_msg("child did not exit\n");
  65                         return 0;
  66                 }
  67
  68                 return WEXITSTATUS(child_status) && parent_result;
  69         }
  70 }
  71
  72 int main(int argc, char **argv)
  73 {
  74         int ret, i;
  75
  76         ksft_print_header();
  77         ksft_set_plan(EXPECTED_TESTS);
  78
  79         ksft_print_msg("PID: %d\n", getpid());
  80
  81         /*
  82          * This test is run with nolibc which doesn't support hwcap and
  83          * it's probably disproportionate to implement so instead check
  84          * for the default vector length configuration in /proc.
  85          */
  86         ret = open("/proc/sys/abi/sme_default_vector_length", O_RDONLY, 0);
  87         if (ret >= 0) {
  88                 ksft_test_result(fork_test(), "fork_test\n");
  89
  90         } else {
  91                 ksft_print_msg("SME not supported\n");
  92                 for (i = 0; i < EXPECTED_TESTS; i++) {
  93                         ksft_test_result_skip("fork_test\n");
  94                 }
  95         }
  96
  97         ksft_finished();
  98
  99         return 0;
 100 }