ARK-OS/arkos/kernel/glibc/sysdeps/x86/tst-string-rtm.h

/* Test string function in a transactionally executing RTM region.
   Copyright (C) 2021-2026 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <string.h>
#include <x86intrin.h>
#include <sys/platform/x86.h>
#include <support/check.h>
#include <support/test-driver.h>

static int
do_test_1 (const char *name, unsigned int loop, int (*prepare) (void),
	   int (*function) (void))
{
  if (!CPU_FEATURE_ACTIVE (RTM))
    return EXIT_UNSUPPORTED;

  int status = prepare ();
  if (status != EXIT_SUCCESS)
    return status;

  unsigned int i;
  unsigned int naborts = 0;
  unsigned int failed = 0;

  /* Iterate LOOP number of times, calling the same function over
     and over again in an attempt to detect the following failure
     modes:

     1. Aborting instruction on the hot path.
     2. Number of instructions executed exceeds maximum.
     3. Memory reads or writes exceed maximum.

     The function getting bigger may increase the abort rate due
     to external events, despite not triggering #2 above, and may
     need adjusting the abort rate failure test below.  */
  for (i = 0; i < loop; i++)
    {
      failed |= function ();
      if (_xbegin() == _XBEGIN_STARTED)
	{
	  failed |= function ();
	  _xend();
	}
      else
	{
	  failed |= function ();
	  ++naborts;
	}
    }

  if (failed)
    FAIL_EXIT1 ("%s() failed", name);

  if (naborts)
    {
      /* Low single digit (<= 5%) noise-level aborts are normal for TSX
	 for reasons that are outside of the library's control.
	 In pre-commit CI on an E5-2698 v4 we sometimes see ~5% aborts.
	 Set the trip point to 6%.  */
      double rate = 100 * ((double) naborts) / ((double) loop);
      if (rate > 6)
	FAIL_EXIT1 ("TSX abort rate: %.2f%% (%d out of %d)",
		    rate, naborts, loop);
    }

  return EXIT_SUCCESS;
}

static int do_test (void);

#include <support/test-driver.c>