1  /* Test the implementation of __ppc_set_ppr_* functions.
       2     Copyright (C) 2017-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <inttypes.h>
      20  #include <stdio.h>
      21  #include <stdint.h>
      22  #include <sys/auxv.h>
      23  
      24  #include <sys/platform/ppc.h>
      25  
      26  #include <support/test-driver.h>
      27  
      28  #ifdef __powerpc64__
      29    typedef uint64_t ppr_t;
      30  # define MFPPR "mfppr"
      31    /* The thread priority value is obtained from bits 11:13.  */
      32  # define EXTRACT_THREAD_PRIORITY(x) ((x >> 50) & 7)
      33  #else
      34    typedef uint32_t ppr_t;
      35  # define MFPPR "mfppr32"
      36    /* For 32-bit, the upper 32 bits of the Program Priority Register (PPR)
      37       are used, so the thread priority value is obtained from bits 43:46.  */
      38  # define EXTRACT_THREAD_PRIORITY(x) ((x >> 18) & 7)
      39  #endif /* !__powerpc64__ */
      40  
      41  /* Read the thread priority value set in the PPR.  */
      42  static __inline__ ppr_t
      43  get_thread_priority (void)
      44  {
      45    /* Read the PPR.  */
      46    ppr_t ppr;
      47    asm volatile (".machine push; .machine power7; "MFPPR" %0; .machine pop"
      48  		: "=r"(ppr));
      49    /* Return the thread priority value.  */
      50    return EXTRACT_THREAD_PRIORITY (ppr);
      51  }
      52  
      53  /* Check the thread priority bits of PPR are set as expected. */
      54  uint8_t
      55  check_thread_priority (uint8_t expected)
      56  {
      57    ppr_t actual = get_thread_priority ();
      58  
      59    if (actual != expected)
      60      {
      61        printf ("FAIL: Expected %"PRIu8" got %"PRIuMAX".\n", expected,
      62  	      (uintmax_t) actual);
      63        return 1;
      64      }
      65    printf ("PASS: Thread priority set to %"PRIu8" correctly.\n", expected);
      66    return 0;
      67  }
      68  
      69  /* The Power ISA 2.06 allows the following thread priorities for any
      70     problem state program: low (2), medium low (3), and medium (4).
      71     Power ISA 2.07b added very low (1).
      72     Check whether the values set by __ppc_set_ppr_* are correct.  */
      73  static int
      74  do_test (void)
      75  {
      76    /* Check for the minimum required Power ISA to run these tests.  */
      77    if ((getauxval (AT_HWCAP) & PPC_FEATURE_ARCH_2_06) == 0)
      78      {
      79        printf ("Requires an environment that implements the Power ISA version"
      80                " 2.06 or greater.\n");
      81        return EXIT_UNSUPPORTED;
      82      }
      83  
      84    uint8_t rc = 0;
      85  
      86  #ifdef _ARCH_PWR8
      87    __ppc_set_ppr_very_low ();
      88    rc |= check_thread_priority (1);
      89  #endif /* _ARCH_PWR8 */
      90  
      91    __ppc_set_ppr_low ();
      92    rc |= check_thread_priority (2);
      93  
      94    __ppc_set_ppr_med_low ();
      95    rc |= check_thread_priority (3);
      96  
      97    __ppc_set_ppr_med ();
      98    rc |= check_thread_priority (4);
      99  
     100    return rc;
     101  }
     102  
     103  #include <support/test-driver.c>