gdb/x86-bsd-nat.c

   1 /* Native-dependent code for X86 BSD's.
   2
   3    Copyright (C) 2003-2020 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "inferior.h"
  22 #include "gdbthread.h"
  23
  24 /* We include <signal.h> to make sure `struct fxsave64' is defined on
  25    NetBSD, since NetBSD's <machine/reg.h> needs it.  */
  26 #include <signal.h>
  27 #include <sys/types.h>
  28 #include <sys/ptrace.h>
  29 #include <machine/reg.h>
  30
  31 #include "x86-nat.h"
  32 #include "x86-bsd-nat.h"
  33 #include "inf-ptrace.h"
  34 \f
  35
  36 #ifdef PT_GETXSTATE_INFO
  37 size_t x86bsd_xsave_len;
  38 #endif
  39
  40 /* Support for debug registers.  */
  41
  42 #ifdef HAVE_PT_GETDBREGS
  43
  44 /* Helper macro to access debug register X.  FreeBSD/amd64 and modern
  45    versions of FreeBSD/i386 provide this macro in system headers.  Define
  46    a local version for systems that do not provide it.  */
  47 #ifndef DBREG_DRX
  48 #ifdef __NetBSD__
  49 #define DBREG_DRX(d, x) ((d)->dr[x])
  50 #else
  51 #define DBREG_DRX(d, x) ((&d->dr0)[x])
  52 #endif
  53 #endif
  54
  55 static unsigned long
  56 x86bsd_dr_get (ptid_t ptid, int regnum)
  57 {
  58   struct dbreg dbregs;
  59
  60   if (ptrace (PT_GETDBREGS, get_ptrace_pid (inferior_ptid),
  61               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
  62     perror_with_name (_("Couldn't read debug registers"));
  63
  64   return DBREG_DRX ((&dbregs), regnum);
  65 }
  66
  67 static void
  68 x86bsd_dr_set (int regnum, unsigned long value)
  69 {
  70   struct dbreg dbregs;
  71
  72   if (ptrace (PT_GETDBREGS, get_ptrace_pid (inferior_ptid),
  73               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
  74     perror_with_name (_("Couldn't get debug registers"));
  75
  76   /* For some mysterious reason, some of the reserved bits in the
  77      debug control register get set.  Mask these off, otherwise the
  78      ptrace call below will fail.  */
  79   DBREG_DRX ((&dbregs), 7) &= ~(0xffffffff0000fc00);
  80
  81   DBREG_DRX ((&dbregs), regnum) = value;
  82
  83   for (thread_info *thread : current_inferior ()->non_exited_threads ())
  84     {
  85       if (ptrace (PT_SETDBREGS, get_ptrace_pid (thread->ptid),
  86                   (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
  87         perror_with_name (_("Couldn't write debug registers"));
  88     }
  89 }
  90
  91 static void
  92 x86bsd_dr_set_control (unsigned long control)
  93 {
  94   x86bsd_dr_set (7, control);
  95 }
  96
  97 static void
  98 x86bsd_dr_set_addr (int regnum, CORE_ADDR addr)
  99 {
 100   gdb_assert (regnum >= 0 && regnum <= 4);
 101
 102   x86bsd_dr_set (regnum, addr);
 103 }
 104
 105 static CORE_ADDR
 106 x86bsd_dr_get_addr (int regnum)
 107 {
 108   return x86bsd_dr_get (inferior_ptid, regnum);
 109 }
 110
 111 static unsigned long
 112 x86bsd_dr_get_status (void)
 113 {
 114   return x86bsd_dr_get (inferior_ptid, 6);
 115 }
 116
 117 static unsigned long
 118 x86bsd_dr_get_control (void)
 119 {
 120   return x86bsd_dr_get (inferior_ptid, 7);
 121 }
 122
 123 #endif /* PT_GETDBREGS */
 124
 125 void
 126 _initialize_x86_bsd_nat ()
 127 {
 128 #ifdef HAVE_PT_GETDBREGS
 129   x86_dr_low.set_control = x86bsd_dr_set_control;
 130   x86_dr_low.set_addr = x86bsd_dr_set_addr;
 131   x86_dr_low.get_addr = x86bsd_dr_get_addr;
 132   x86_dr_low.get_status = x86bsd_dr_get_status;
 133   x86_dr_low.get_control = x86bsd_dr_get_control;
 134   x86_set_debug_register_length (sizeof (void *));
 135 #endif /* HAVE_PT_GETDBREGS */
 136 }