gdb/nat/ppc-linux.c

   1 /*Copyright (C) 2015-2022 Free Software Foundation, Inc.
   2
   3    This file is part of GDB.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include "gdbsupport/common-defs.h"
  19 #include "ppc-linux.h"
  20 #include "nat/gdb_ptrace.h"
  21 #include <elf.h>
  22
  23 #ifdef HAVE_GETAUXVAL
  24 #include <sys/auxv.h>
  25 #endif
  26
  27 #ifdef __powerpc64__
  28
  29 /* Get the HWCAP from the process of GDB or GDBserver.  If success,
  30    save it in *VALP.   */
  31
  32 static void
  33 ppc64_host_hwcap (unsigned long *valp)
  34 {
  35 #ifdef HAVE_GETAUXVAL
  36   *valp = getauxval (AT_HWCAP);
  37 #else
  38   unsigned long data[2];
  39   FILE *f = fopen ("/proc/self/auxv", "r");
  40
  41   if (f == NULL)
  42     return;
  43
  44   while (fread (data, sizeof (data), 1, f) > 0)
  45     {
  46       if (data[0] == AT_HWCAP)
  47         {
  48           *valp = data[1];
  49           break;
  50         }
  51     }
  52
  53   fclose (f);
  54 #endif /* HAVE_GETAUXVAL */
  55 }
  56
  57 static inline int
  58 ppc64_64bit_inferior_p (long msr)
  59 {
  60   unsigned long ppc_host_hwcap = 0;
  61
  62   /* Get host's HWCAP to check whether the machine is Book E.  */
  63   ppc64_host_hwcap (&ppc_host_hwcap);
  64
  65   /* We actually have a 64-bit inferior only if the certain bit of the
  66      MSR is set.  The PowerISA Book III-S MSR is different from the
  67      PowerISA Book III-E MSR.  The Book III-S MSR is 64 bits wide, and
  68      its MSR[SF] is the bit 0 of a 64-bit value.  Book III-E MSR is 32
  69      bits wide, and its MSR[CM] is the bit 0 of a 32-bit value.   */
  70   if (ppc_host_hwcap & PPC_FEATURE_BOOKE)
  71     return msr & 0x80000000;
  72   else
  73     return msr < 0;
  74 }
  75
  76 #endif
  77
  78 int
  79 ppc_linux_target_wordsize (int tid)
  80 {
  81   int wordsize = 4;
  82
  83   /* Check for 64-bit inferior process.  This is the case when the host is
  84      64-bit, and in addition the top bit of the MSR register is set.  */
  85 #ifdef __powerpc64__
  86   long msr;
  87
  88   errno = 0;
  89   msr = (long) ptrace (PTRACE_PEEKUSER, tid, PT_MSR * 8, 0);
  90   if (errno == 0 && ppc64_64bit_inferior_p (msr))
  91     wordsize = 8;
  92 #endif
  93
  94   return wordsize;
  95 }