gdb/ppc-obsd-nat.c

   1 /* Native-dependent code for OpenBSD/powerpc.
   2
   3    Copyright (C) 2004-2016 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/ptrace.h>
  27 #include <sys/signal.h>
  28 #include <machine/frame.h>
  29 #include <machine/pcb.h>
  30 #include <machine/reg.h>
  31
  32 #include "ppc-tdep.h"
  33 #include "ppc-obsd-tdep.h"
  34 #include "inf-ptrace.h"
  35 #include "obsd-nat.h"
  36 #include "bsd-kvm.h"
  37
  38 /* OpenBSD/powerpc didn't have PT_GETFPREGS/PT_SETFPREGS until release
  39    4.0.  On older releases the floating-point registers are handled by
  40    PT_GETREGS/PT_SETREGS, but fpscr wasn't available..  */
  41
  42 #ifdef PT_GETFPREGS
  43
  44 /* Returns true if PT_GETFPREGS fetches this register.  */
  45
  46 static int
  47 getfpregs_supplies (struct gdbarch *gdbarch, int regnum)
  48 {
  49   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  50
  51   /* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
  52      point registers.  Traditionally, GDB's register set has still
  53      listed the floating point registers for such machines, so this
  54      code is harmless.  However, the new E500 port actually omits the
  55      floating point registers entirely from the register set --- they
  56      don't even have register numbers assigned to them.
  57
  58      It's not clear to me how best to update this code, so this assert
  59      will alert the first person to encounter the NetBSD/E500
  60      combination to the problem.  */
  61   gdb_assert (ppc_floating_point_unit_p (gdbarch));
  62
  63   return ((regnum >= tdep->ppc_fp0_regnum
  64            && regnum < tdep->ppc_fp0_regnum + ppc_num_fprs)
  65           || regnum == tdep->ppc_fpscr_regnum);
  66 }
  67
  68 #endif /* PT_GETFPREGS */
  69
  70 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  71    for all registers.  */
  72
  73 static void
  74 ppcobsd_fetch_registers (struct target_ops *ops,
  75                          struct regcache *regcache, int regnum)
  76 {
  77   struct reg regs;
  78
  79   if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
  80               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
  81     perror_with_name (_("Couldn't get registers"));
  82
  83   ppc_supply_gregset (&ppcobsd_gregset, regcache, -1,
  84                       &regs, sizeof regs);
  85 #ifndef PT_GETFPREGS
  86   ppc_supply_fpregset (&ppcobsd_gregset, regcache, -1,
  87                        &regs, sizeof regs);
  88 #endif
  89
  90 #ifdef PT_GETFPREGS
  91   if (regnum == -1
  92       || getfpregs_supplies (get_regcache_arch (regcache), regnum))
  93     {
  94       struct fpreg fpregs;
  95
  96       if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
  97                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
  98         perror_with_name (_("Couldn't get floating point status"));
  99
 100       ppc_supply_fpregset (&ppcobsd_fpregset, regcache, -1,
 101                            &fpregs, sizeof fpregs);
 102     }
 103 #endif
 104 }
 105
 106 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 107    this for all registers.  */
 108
 109 static void
 110 ppcobsd_store_registers (struct target_ops *ops,
 111                          struct regcache *regcache, int regnum)
 112 {
 113   struct reg regs;
 114
 115   if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
 116               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 117     perror_with_name (_("Couldn't get registers"));
 118
 119   ppc_collect_gregset (&ppcobsd_gregset, regcache,
 120                        regnum, &regs, sizeof regs);
 121 #ifndef PT_GETFPREGS
 122   ppc_collect_fpregset (&ppcobsd_gregset, regcache,
 123                         regnum, &regs, sizeof regs);
 124 #endif
 125
 126   if (ptrace (PT_SETREGS, ptid_get_pid (inferior_ptid),
 127               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 128     perror_with_name (_("Couldn't write registers"));
 129
 130 #ifdef PT_GETFPREGS
 131   if (regnum == -1
 132       || getfpregs_supplies (get_regcache_arch (regcache), regnum))
 133     {
 134       struct fpreg fpregs;
 135
 136       if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
 137                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 138         perror_with_name (_("Couldn't get floating point status"));
 139
 140       ppc_collect_fpregset (&ppcobsd_fpregset, regcache,
 141                             regnum, &fpregs, sizeof fpregs);
 142
 143       if (ptrace (PT_SETFPREGS, ptid_get_pid (inferior_ptid),
 144                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 145         perror_with_name (_("Couldn't write floating point status"));
 146     }
 147 #endif
 148 }
 149 \f
 150
 151 static int
 152 ppcobsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 153 {
 154   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 155   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 156   struct switchframe sf;
 157   struct callframe cf;
 158   int i, regnum;
 159
 160   /* The following is true for OpenBSD 3.7:
 161
 162      The pcb contains %r1 (the stack pointer) at the point of the
 163      context switch in cpu_switch().  At that point we have a stack
 164      frame as described by `struct switchframe', and below that a call
 165      frame as described by `struct callframe'.  From this information
 166      we reconstruct the register state as it would look when we are in
 167      cpu_switch().  */
 168
 169   /* The stack pointer shouldn't be zero.  */
 170   if (pcb->pcb_sp == 0)
 171     return 0;
 172
 173   read_memory (pcb->pcb_sp, (gdb_byte *)&sf, sizeof sf);
 174   regcache_raw_supply (regcache, gdbarch_sp_regnum (gdbarch), &sf.sp);
 175   regcache_raw_supply (regcache, tdep->ppc_cr_regnum, &sf.cr);
 176   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 2, &sf.fixreg2);
 177   for (i = 0, regnum = tdep->ppc_gp0_regnum + 13; i < 19; i++, regnum++)
 178     regcache_raw_supply (regcache, regnum, &sf.fixreg[i]);
 179
 180   read_memory (sf.sp, (gdb_byte *)&cf, sizeof cf);
 181   regcache_raw_supply (regcache, gdbarch_pc_regnum (gdbarch), &cf.lr);
 182   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 30, &cf.r30);
 183   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 31, &cf.r31);
 184
 185   return 1;
 186 }
 187 \f
 188
 189 /* Provide a prototype to silence -Wmissing-prototypes.  */
 190 void _initialize_ppcobsd_nat (void);
 191
 192 void
 193 _initialize_ppcobsd_nat (void)
 194 {
 195   struct target_ops *t;
 196
 197   /* Add in local overrides.  */
 198   t = inf_ptrace_target ();
 199   t->to_fetch_registers = ppcobsd_fetch_registers;
 200   t->to_store_registers = ppcobsd_store_registers;
 201   obsd_add_target (t);
 202
 203   /* General-purpose registers.  */
 204   ppcobsd_reg_offsets.r0_offset = offsetof (struct reg, gpr);
 205   ppcobsd_reg_offsets.gpr_size = 4;
 206   ppcobsd_reg_offsets.xr_size = 4;
 207   ppcobsd_reg_offsets.pc_offset = offsetof (struct reg, pc);
 208   ppcobsd_reg_offsets.ps_offset = offsetof (struct reg, ps);
 209   ppcobsd_reg_offsets.cr_offset = offsetof (struct reg, cnd);
 210   ppcobsd_reg_offsets.lr_offset = offsetof (struct reg, lr);
 211   ppcobsd_reg_offsets.ctr_offset = offsetof (struct reg, cnt);
 212   ppcobsd_reg_offsets.xer_offset = offsetof (struct reg, xer);
 213   ppcobsd_reg_offsets.mq_offset = offsetof (struct reg, mq);
 214
 215   /* Floating-point registers.  */
 216   ppcobsd_reg_offsets.f0_offset = offsetof (struct reg, fpr);
 217   ppcobsd_reg_offsets.fpscr_offset = -1;
 218 #ifdef PT_GETFPREGS
 219   ppcobsd_fpreg_offsets.f0_offset = offsetof (struct fpreg, fpr);
 220   ppcobsd_fpreg_offsets.fpscr_offset = offsetof (struct fpreg, fpscr);
 221   ppcobsd_fpreg_offsets.fpscr_size = 4;
 222 #endif
 223
 224   /* AltiVec registers.  */
 225   ppcobsd_reg_offsets.vr0_offset = offsetof (struct vreg, vreg);
 226   ppcobsd_reg_offsets.vscr_offset = offsetof (struct vreg, vscr);
 227   ppcobsd_reg_offsets.vrsave_offset = offsetof (struct vreg, vrsave);
 228
 229   /* Support debugging kernel virtual memory images.  */
 230   bsd_kvm_add_target (ppcobsd_supply_pcb);
 231 }