gdb/x86-bsd-nat.c

   1 /* Native-dependent code for X86 BSD's.
   2
   3    Copyright (C) 2003-2023 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 /* Support for debug registers.  */
  37
  38 #ifdef HAVE_PT_GETDBREGS
  39
  40 static PTRACE_TYPE_RET
  41 gdb_ptrace (PTRACE_TYPE_ARG1 request, ptid_t ptid, PTRACE_TYPE_ARG3 addr)
  42 {
  43 #ifdef __NetBSD__
  44   /* Support for NetBSD threads: unlike other ptrace implementations in this
  45      file, NetBSD requires that we pass both the pid and lwp.  */
  46   return ptrace (request, ptid.pid (), addr, ptid.lwp ());
  47 #else
  48   pid_t pid = get_ptrace_pid (ptid);
  49   return ptrace (request, pid, addr, 0);
  50 #endif
  51 }
  52
  53 /* Helper macro to access debug register X.  FreeBSD/amd64 and modern
  54    versions of FreeBSD/i386 provide this macro in system headers.  Define
  55    a local version for systems that do not provide it.  */
  56 #ifndef DBREG_DRX
  57 #ifdef __NetBSD__
  58 #define DBREG_DRX(d, x) ((d)->dr[x])
  59 #else
  60 #define DBREG_DRX(d, x) ((&d->dr0)[x])
  61 #endif
  62 #endif
  63
  64 static unsigned long
  65 x86bsd_dr_get (ptid_t ptid, int regnum)
  66 {
  67   struct dbreg dbregs;
  68
  69   if (gdb_ptrace (PT_GETDBREGS, ptid, (PTRACE_TYPE_ARG3) &dbregs) == -1)
  70     perror_with_name (_("Couldn't read debug registers"));
  71
  72   return DBREG_DRX ((&dbregs), regnum);
  73 }
  74
  75 static void
  76 x86bsd_dr_set (ptid_t ptid, int regnum, unsigned long value)
  77 {
  78   struct dbreg dbregs;
  79
  80   if (gdb_ptrace (PT_GETDBREGS, ptid, (PTRACE_TYPE_ARG3) &dbregs) == -1)
  81     perror_with_name (_("Couldn't get debug registers"));
  82
  83   /* For some mysterious reason, some of the reserved bits in the
  84      debug control register get set.  Mask these off, otherwise the
  85      ptrace call below will fail.  */
  86   DBREG_DRX ((&dbregs), 7) &= ~(0xffffffff0000fc00);
  87
  88   DBREG_DRX ((&dbregs), regnum) = value;
  89
  90   for (thread_info *thread : current_inferior ()->non_exited_threads ())
  91     {
  92       if (gdb_ptrace (PT_SETDBREGS, thread->ptid,
  93                       (PTRACE_TYPE_ARG3) &dbregs) == -1)
  94         perror_with_name (_("Couldn't write debug registers"));
  95     }
  96 }
  97
  98 static void
  99 x86bsd_dr_set_control (unsigned long control)
 100 {
 101   x86bsd_dr_set (inferior_ptid, 7, control);
 102 }
 103
 104 static void
 105 x86bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 106 {
 107   gdb_assert (regnum >= 0 && regnum <= 4);
 108
 109   x86bsd_dr_set (inferior_ptid, regnum, addr);
 110 }
 111
 112 static CORE_ADDR
 113 x86bsd_dr_get_addr (int regnum)
 114 {
 115   return x86bsd_dr_get (inferior_ptid, regnum);
 116 }
 117
 118 static unsigned long
 119 x86bsd_dr_get_status (void)
 120 {
 121   return x86bsd_dr_get (inferior_ptid, 6);
 122 }
 123
 124 static unsigned long
 125 x86bsd_dr_get_control (void)
 126 {
 127   return x86bsd_dr_get (inferior_ptid, 7);
 128 }
 129
 130 #endif /* PT_GETDBREGS */
 131
 132 void _initialize_x86_bsd_nat ();
 133 void
 134 _initialize_x86_bsd_nat ()
 135 {
 136 #ifdef HAVE_PT_GETDBREGS
 137   x86_dr_low.set_control = x86bsd_dr_set_control;
 138   x86_dr_low.set_addr = x86bsd_dr_set_addr;
 139   x86_dr_low.get_addr = x86bsd_dr_get_addr;
 140   x86_dr_low.get_status = x86bsd_dr_get_status;
 141   x86_dr_low.get_control = x86bsd_dr_get_control;
 142   x86_set_debug_register_length (sizeof (void *));
 143 #endif /* HAVE_PT_GETDBREGS */
 144 }