gdb/x86-bsd-nat.c

   1 /* Native-dependent code for X86 BSD's.
   2
   3    Copyright (C) 2003-2024 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 "inferior.h"
  21 #include "gdbthread.h"
  22
  23 /* We include <signal.h> to make sure `struct fxsave64' is defined on
  24    NetBSD, since NetBSD's <machine/reg.h> needs it.  */
  25 #include <signal.h>
  26 #include <sys/types.h>
  27 #include <sys/ptrace.h>
  28 #include <machine/reg.h>
  29
  30 #include "x86-nat.h"
  31 #include "x86-bsd-nat.h"
  32 #include "inf-ptrace.h"
  33 \f
  34
  35 /* Support for debug registers.  */
  36
  37 #ifdef HAVE_PT_GETDBREGS
  38
  39 static PTRACE_TYPE_RET
  40 gdb_ptrace (PTRACE_TYPE_ARG1 request, ptid_t ptid, PTRACE_TYPE_ARG3 addr)
  41 {
  42 #ifdef __NetBSD__
  43   /* Support for NetBSD threads: unlike other ptrace implementations in this
  44      file, NetBSD requires that we pass both the pid and lwp.  */
  45   return ptrace (request, ptid.pid (), addr, ptid.lwp ());
  46 #else
  47   pid_t pid = get_ptrace_pid (ptid);
  48   return ptrace (request, pid, addr, 0);
  49 #endif
  50 }
  51
  52 /* Helper macro to access debug register X.  FreeBSD/amd64 and modern
  53    versions of FreeBSD/i386 provide this macro in system headers.  Define
  54    a local version for systems that do not provide it.  */
  55 #ifndef DBREG_DRX
  56 #ifdef __NetBSD__
  57 #define DBREG_DRX(d, x) ((d)->dr[x])
  58 #else
  59 #define DBREG_DRX(d, x) ((&d->dr0)[x])
  60 #endif
  61 #endif
  62
  63 static unsigned long
  64 x86bsd_dr_get (ptid_t ptid, int regnum)
  65 {
  66   struct dbreg dbregs;
  67
  68   if (gdb_ptrace (PT_GETDBREGS, ptid, (PTRACE_TYPE_ARG3) &dbregs) == -1)
  69     perror_with_name (_("Couldn't read debug registers"));
  70
  71   return DBREG_DRX ((&dbregs), regnum);
  72 }
  73
  74 static void
  75 x86bsd_dr_set (ptid_t ptid, int regnum, unsigned long value)
  76 {
  77   struct dbreg dbregs;
  78
  79   if (gdb_ptrace (PT_GETDBREGS, ptid, (PTRACE_TYPE_ARG3) &dbregs) == -1)
  80     perror_with_name (_("Couldn't get debug registers"));
  81
  82   /* For some mysterious reason, some of the reserved bits in the
  83      debug control register get set.  Mask these off, otherwise the
  84      ptrace call below will fail.  */
  85   DBREG_DRX ((&dbregs), 7) &= ~(0xffffffff0000fc00);
  86
  87   DBREG_DRX ((&dbregs), regnum) = value;
  88
  89   for (thread_info *thread : current_inferior ()->non_exited_threads ())
  90     {
  91       if (gdb_ptrace (PT_SETDBREGS, thread->ptid,
  92                       (PTRACE_TYPE_ARG3) &dbregs) == -1)
  93         perror_with_name (_("Couldn't write debug registers"));
  94     }
  95 }
  96
  97 static void
  98 x86bsd_dr_set_control (unsigned long control)
  99 {
 100   x86bsd_dr_set (inferior_ptid, 7, control);
 101 }
 102
 103 static void
 104 x86bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 105 {
 106   gdb_assert (regnum >= 0 && regnum <= 4);
 107
 108   x86bsd_dr_set (inferior_ptid, regnum, addr);
 109 }
 110
 111 static CORE_ADDR
 112 x86bsd_dr_get_addr (int regnum)
 113 {
 114   return x86bsd_dr_get (inferior_ptid, regnum);
 115 }
 116
 117 static unsigned long
 118 x86bsd_dr_get_status (void)
 119 {
 120   return x86bsd_dr_get (inferior_ptid, 6);
 121 }
 122
 123 static unsigned long
 124 x86bsd_dr_get_control (void)
 125 {
 126   return x86bsd_dr_get (inferior_ptid, 7);
 127 }
 128
 129 #endif /* PT_GETDBREGS */
 130
 131 void _initialize_x86_bsd_nat ();
 132 void
 133 _initialize_x86_bsd_nat ()
 134 {
 135 #ifdef HAVE_PT_GETDBREGS
 136   x86_dr_low.set_control = x86bsd_dr_set_control;
 137   x86_dr_low.set_addr = x86bsd_dr_set_addr;
 138   x86_dr_low.get_addr = x86bsd_dr_get_addr;
 139   x86_dr_low.get_status = x86bsd_dr_get_status;
 140   x86_dr_low.get_control = x86bsd_dr_get_control;
 141   x86_set_debug_register_length (sizeof (void *));
 142 #endif /* HAVE_PT_GETDBREGS */
 143 }