gdb/ppc-fbsd-nat.c

   1 /* Native-dependent code for PowerPC's running FreeBSD, for GDB.
   2
   3    Copyright (C) 2013-2020 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 "gdbcore.h"
  22 #include "inferior.h"
  23 #include "regcache.h"
  24
  25 #include <sys/types.h>
  26 #include <sys/procfs.h>
  27 #include <sys/ptrace.h>
  28 #include <sys/signal.h>
  29 #include <machine/frame.h>
  30 #include <machine/pcb.h>
  31 #include <machine/reg.h>
  32
  33 #include "fbsd-nat.h"
  34 #include "gregset.h"
  35 #include "ppc-tdep.h"
  36 #include "ppc-fbsd-tdep.h"
  37 #include "inf-ptrace.h"
  38 #include "bsd-kvm.h"
  39
  40 struct ppc_fbsd_nat_target final : public fbsd_nat_target
  41 {
  42   void fetch_registers (struct regcache *, int) override;
  43   void store_registers (struct regcache *, int) override;
  44 };
  45
  46 static ppc_fbsd_nat_target the_ppc_fbsd_nat_target;
  47
  48 /* Fill GDB's register array with the general-purpose register values
  49    in *GREGSETP.  */
  50
  51 void
  52 supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregsetp)
  53 {
  54   const struct regset *regset = ppc_fbsd_gregset (sizeof (long));
  55
  56   ppc_supply_gregset (regset, regcache, -1, gregsetp, sizeof (*gregsetp));
  57 }
  58
  59 /* Fill register REGNO (if a gpr) in *GREGSETP with the value in GDB's
  60    register array. If REGNO is -1 do it for all registers.  */
  61
  62 void
  63 fill_gregset (const struct regcache *regcache,
  64               gdb_gregset_t *gregsetp, int regno)
  65 {
  66   const struct regset *regset = ppc_fbsd_gregset (sizeof (long));
  67
  68   if (regno == -1)
  69     memset (gregsetp, 0, sizeof (*gregsetp));
  70   ppc_collect_gregset (regset, regcache, regno, gregsetp, sizeof (*gregsetp));
  71 }
  72
  73 /* Fill GDB's register array with the floating-point register values
  74    in *FPREGSETP.  */
  75
  76 void
  77 supply_fpregset (struct regcache *regcache, const gdb_fpregset_t * fpregsetp)
  78 {
  79   const struct regset *regset = ppc_fbsd_fpregset ();
  80
  81   ppc_supply_fpregset (regset, regcache, -1,
  82                        fpregsetp, sizeof (*fpregsetp));
  83 }
  84
  85 /* Fill register REGNO in *FGREGSETP with the value in GDB's
  86    register array. If REGNO is -1 do it for all registers.  */
  87
  88 void
  89 fill_fpregset (const struct regcache *regcache,
  90                gdb_fpregset_t *fpregsetp, int regno)
  91 {
  92   const struct regset *regset = ppc_fbsd_fpregset ();
  93
  94   ppc_collect_fpregset (regset, regcache, regno,
  95                         fpregsetp, sizeof (*fpregsetp));
  96 }
  97
  98 /* Returns true if PT_GETFPREGS fetches this register.  */
  99
 100 static int
 101 getfpregs_supplies (struct gdbarch *gdbarch, int regno)
 102 {
 103   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 104
 105   /* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
 106          point registers.  Traditionally, GDB's register set has still
 107          listed the floating point registers for such machines, so this
 108          code is harmless.  However, the new E500 port actually omits the
 109          floating point registers entirely from the register set --- they
 110          don't even have register numbers assigned to them.
 111
 112          It's not clear to me how best to update this code, so this assert
 113          will alert the first person to encounter the NetBSD/E500
 114          combination to the problem.  */
 115
 116   gdb_assert (ppc_floating_point_unit_p (gdbarch));
 117
 118   return ((regno >= tdep->ppc_fp0_regnum
 119            && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)
 120           || regno == tdep->ppc_fpscr_regnum);
 121 }
 122
 123 /* Fetch register REGNO from the child process. If REGNO is -1, do it
 124    for all registers.  */
 125
 126 void
 127 ppc_fbsd_nat_target::fetch_registers (struct regcache *regcache, int regno)
 128 {
 129   gdb_gregset_t regs;
 130   pid_t pid = regcache->ptid ().lwp ();
 131
 132   if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 133     perror_with_name (_("Couldn't get registers"));
 134
 135   supply_gregset (regcache, &regs);
 136
 137   if (regno == -1 || getfpregs_supplies (regcache->arch (), regno))
 138     {
 139       const struct regset *fpregset = ppc_fbsd_fpregset ();
 140       gdb_fpregset_t fpregs;
 141
 142       if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 143         perror_with_name (_("Couldn't get FP registers"));
 144
 145       ppc_supply_fpregset (fpregset, regcache, regno, &fpregs, sizeof fpregs);
 146     }
 147 }
 148
 149 /* Store register REGNO back into the child process. If REGNO is -1,
 150    do this for all registers.  */
 151
 152 void
 153 ppc_fbsd_nat_target::store_registers (struct regcache *regcache, int regno)
 154 {
 155   gdb_gregset_t regs;
 156   pid_t pid = regcache->ptid ().lwp ();
 157
 158   if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 159     perror_with_name (_("Couldn't get registers"));
 160
 161   fill_gregset (regcache, &regs, regno);
 162
 163   if (ptrace (PT_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 164     perror_with_name (_("Couldn't write registers"));
 165
 166   if (regno == -1 || getfpregs_supplies (regcache->arch (), regno))
 167     {
 168       gdb_fpregset_t fpregs;
 169
 170       if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 171         perror_with_name (_("Couldn't get FP registers"));
 172
 173       fill_fpregset (regcache, &fpregs, regno);
 174
 175       if (ptrace (PT_SETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 176         perror_with_name (_("Couldn't set FP registers"));
 177     }
 178 }
 179
 180 /* Architecture specific function that reconstructs the
 181    register state from PCB (Process Control Block) and supplies it
 182    to REGCACHE.  */
 183
 184 static int
 185 ppcfbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 186 {
 187   struct gdbarch *gdbarch = regcache->arch ();
 188   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 189   int i, regnum;
 190
 191   /* The stack pointer shouldn't be zero.  */
 192   if (pcb->pcb_sp == 0)
 193     return 0;
 194
 195   regcache->raw_supply (gdbarch_sp_regnum (gdbarch), &pcb->pcb_sp);
 196   regcache->raw_supply (tdep->ppc_cr_regnum, &pcb->pcb_cr);
 197   regcache->raw_supply (tdep->ppc_lr_regnum, &pcb->pcb_lr);
 198   for (i = 0, regnum = tdep->ppc_gp0_regnum + 14; i < 20; i++, regnum++)
 199     regcache->raw_supply (regnum, &pcb->pcb_context[i]);
 200
 201   return 1;
 202 }
 203
 204 void _initialize_ppcfbsd_nat ();
 205 void
 206 _initialize_ppcfbsd_nat ()
 207 {
 208   add_inf_child_target (&the_ppc_fbsd_nat_target);
 209
 210   /* Support debugging kernel virtual memory images.  */
 211   bsd_kvm_add_target (ppcfbsd_supply_pcb);
 212 }