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 static PTRACE_TYPE_RET
  37 gdb_ptrace (PTRACE_TYPE_ARG1 request, ptid_t ptid, PTRACE_TYPE_ARG3 addr)
  38 {
  39 #ifdef __NetBSD__
  40   /* Support for NetBSD threads: unlike other ptrace implementations in this
  41      file, NetBSD requires that we pass both the pid and lwp.  */
  42   return ptrace (request, ptid.pid (), addr, ptid.lwp ());
  43 #else
  44   pid_t pid = get_ptrace_pid (ptid);
  45   return ptrace (request, pid, addr, 0);
  46 #endif
  47 }
  48
  49 #ifdef PT_GETXSTATE_INFO
  50 size_t x86bsd_xsave_len;
  51 #endif
  52
  53 /* Support for debug registers.  */
  54
  55 #ifdef HAVE_PT_GETDBREGS
  56
  57 /* Helper macro to access debug register X.  FreeBSD/amd64 and modern
  58    versions of FreeBSD/i386 provide this macro in system headers.  Define
  59    a local version for systems that do not provide it.  */
  60 #ifndef DBREG_DRX
  61 #ifdef __NetBSD__
  62 #define DBREG_DRX(d, x) ((d)->dr[x])
  63 #else
  64 #define DBREG_DRX(d, x) ((&d->dr0)[x])
  65 #endif
  66 #endif
  67
  68 static unsigned long
  69 x86bsd_dr_get (ptid_t ptid, int regnum)
  70 {
  71   struct dbreg dbregs;
  72
  73   if (gdb_ptrace (PT_GETDBREGS, ptid, (PTRACE_TYPE_ARG3) &dbregs) == -1)
  74     perror_with_name (_("Couldn't read debug registers"));
  75
  76   return DBREG_DRX ((&dbregs), regnum);
  77 }
  78
  79 static void
  80 x86bsd_dr_set (ptid_t ptid, int regnum, unsigned long value)
  81 {
  82   struct dbreg dbregs;
  83
  84   if (gdb_ptrace (PT_GETDBREGS, ptid, (PTRACE_TYPE_ARG3) &dbregs) == -1)
  85     perror_with_name (_("Couldn't get debug registers"));
  86
  87   /* For some mysterious reason, some of the reserved bits in the
  88      debug control register get set.  Mask these off, otherwise the
  89      ptrace call below will fail.  */
  90   DBREG_DRX ((&dbregs), 7) &= ~(0xffffffff0000fc00);
  91
  92   DBREG_DRX ((&dbregs), regnum) = value;
  93
  94   for (thread_info *thread : current_inferior ()->non_exited_threads ())
  95     {
  96       if (gdb_ptrace (PT_SETDBREGS, thread->ptid,
  97                       (PTRACE_TYPE_ARG3) &dbregs) == -1)
  98         perror_with_name (_("Couldn't write debug registers"));
  99     }
 100 }
 101
 102 static void
 103 x86bsd_dr_set_control (unsigned long control)
 104 {
 105   x86bsd_dr_set (inferior_ptid, 7, control);
 106 }
 107
 108 static void
 109 x86bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 110 {
 111   gdb_assert (regnum >= 0 && regnum <= 4);
 112
 113   x86bsd_dr_set (inferior_ptid, regnum, addr);
 114 }
 115
 116 static CORE_ADDR
 117 x86bsd_dr_get_addr (int regnum)
 118 {
 119   return x86bsd_dr_get (inferior_ptid, regnum);
 120 }
 121
 122 static unsigned long
 123 x86bsd_dr_get_status (void)
 124 {
 125   return x86bsd_dr_get (inferior_ptid, 6);
 126 }
 127
 128 static unsigned long
 129 x86bsd_dr_get_control (void)
 130 {
 131   return x86bsd_dr_get (inferior_ptid, 7);
 132 }
 133
 134 #endif /* PT_GETDBREGS */
 135
 136 void _initialize_x86_bsd_nat ();
 137 void
 138 _initialize_x86_bsd_nat ()
 139 {
 140 #ifdef HAVE_PT_GETDBREGS
 141   x86_dr_low.set_control = x86bsd_dr_set_control;
 142   x86_dr_low.set_addr = x86bsd_dr_set_addr;
 143   x86_dr_low.get_addr = x86bsd_dr_get_addr;
 144   x86_dr_low.get_status = x86bsd_dr_get_status;
 145   x86_dr_low.get_control = x86bsd_dr_get_control;
 146   x86_set_debug_register_length (sizeof (void *));
 147 #endif /* HAVE_PT_GETDBREGS */
 148 }