gdb/ppcobsd-nat.c

   1 /* Native-dependent code for OpenBSD/powerpc.
   2
   3    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "gdbcore.h"
  23 #include "inferior.h"
  24 #include "regcache.h"
  25
  26 #include "gdb_assert.h"
  27 #include <stddef.h>
  28 #include <sys/types.h>
  29 #include <sys/ptrace.h>
  30 #include <sys/signal.h>
  31 #include <machine/frame.h>
  32 #include <machine/pcb.h>
  33 #include <machine/reg.h>
  34
  35 #include "ppc-tdep.h"
  36 #include "ppcobsd-tdep.h"
  37 #include "inf-ptrace.h"
  38 #include "bsd-kvm.h"
  39
  40 /* OpenBSD/powerpc didn't have PT_GETFPREGS/PT_SETFPREGS until release
  41    4.0.  On older releases the floating-point registers are handled by
  42    PT_GETREGS/PT_SETREGS, but fpscr wasn't available..  */
  43
  44 #ifdef PT_GETFPREGS
  45
  46 /* Returns true if PT_GETFPREGS fetches this register.  */
  47
  48 static int
  49 getfpregs_supplies (struct gdbarch *gdbarch, int regnum)
  50 {
  51   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  52
  53   /* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
  54      point registers.  Traditionally, GDB's register set has still
  55      listed the floating point registers for such machines, so this
  56      code is harmless.  However, the new E500 port actually omits the
  57      floating point registers entirely from the register set --- they
  58      don't even have register numbers assigned to them.
  59
  60      It's not clear to me how best to update this code, so this assert
  61      will alert the first person to encounter the NetBSD/E500
  62      combination to the problem.  */
  63   gdb_assert (ppc_floating_point_unit_p (gdbarch));
  64
  65   return ((regnum >= tdep->ppc_fp0_regnum
  66            && regnum < tdep->ppc_fp0_regnum + ppc_num_fprs)
  67           || regnum == tdep->ppc_fpscr_regnum);
  68 }
  69
  70 #endif /* PT_GETFPREGS */
  71
  72 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  73    for all registers.  */
  74
  75 static void
  76 ppcobsd_fetch_registers (struct target_ops *ops,
  77                          struct regcache *regcache, int regnum)
  78 {
  79   struct reg regs;
  80
  81   if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
  82               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
  83     perror_with_name (_("Couldn't get registers"));
  84
  85   ppc_supply_gregset (&ppcobsd_gregset, regcache, -1,
  86                       &regs, sizeof regs);
  87 #ifndef PT_GETFPREGS
  88   ppc_supply_fpregset (&ppcobsd_gregset, regcache, -1,
  89                        &regs, sizeof regs);
  90 #endif
  91
  92 #ifdef PT_GETFPREGS
  93   if (regnum == -1
  94       || getfpregs_supplies (get_regcache_arch (regcache), regnum))
  95     {
  96       struct fpreg fpregs;
  97
  98       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
  99                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 100         perror_with_name (_("Couldn't get floating point status"));
 101
 102       ppc_supply_fpregset (&ppcobsd_fpregset, regcache, -1,
 103                            &fpregs, sizeof fpregs);
 104     }
 105 #endif
 106 }
 107
 108 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 109    this for all registers.  */
 110
 111 static void
 112 ppcobsd_store_registers (struct target_ops *ops,
 113                          struct regcache *regcache, int regnum)
 114 {
 115   struct reg regs;
 116
 117   if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 118               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 119     perror_with_name (_("Couldn't get registers"));
 120
 121   ppc_collect_gregset (&ppcobsd_gregset, regcache,
 122                        regnum, &regs, sizeof regs);
 123 #ifndef PT_GETFPREGS
 124   ppc_collect_fpregset (&ppcobsd_gregset, regcache,
 125                         regnum, &regs, sizeof regs);
 126 #endif
 127
 128   if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
 129               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 130     perror_with_name (_("Couldn't write registers"));
 131
 132 #ifdef PT_GETFPREGS
 133   if (regnum == -1
 134       || getfpregs_supplies (get_regcache_arch (regcache), regnum))
 135     {
 136       struct fpreg fpregs;
 137
 138       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 139                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 140         perror_with_name (_("Couldn't get floating point status"));
 141
 142       ppc_collect_fpregset (&ppcobsd_fpregset, regcache,
 143                             regnum, &fpregs, sizeof fpregs);
 144
 145       if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
 146                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 147         perror_with_name (_("Couldn't write floating point status"));
 148     }
 149 #endif
 150 }
 151 \f
 152
 153 static int
 154 ppcobsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 155 {
 156   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 157   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 158   struct switchframe sf;
 159   struct callframe cf;
 160   int i, regnum;
 161
 162   /* The following is true for OpenBSD 3.7:
 163
 164      The pcb contains %r1 (the stack pointer) at the point of the
 165      context switch in cpu_switch().  At that point we have a stack
 166      frame as described by `struct switchframe', and below that a call
 167      frame as described by `struct callframe'.  From this information
 168      we reconstruct the register state as it would look when we are in
 169      cpu_switch().  */
 170
 171   /* The stack pointer shouldn't be zero.  */
 172   if (pcb->pcb_sp == 0)
 173     return 0;
 174
 175   read_memory (pcb->pcb_sp, (gdb_byte *)&sf, sizeof sf);
 176   regcache_raw_supply (regcache, gdbarch_sp_regnum (gdbarch), &sf.sp);
 177   regcache_raw_supply (regcache, tdep->ppc_cr_regnum, &sf.cr);
 178   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 2, &sf.fixreg2);
 179   for (i = 0, regnum = tdep->ppc_gp0_regnum + 13; i < 19; i++, regnum++)
 180     regcache_raw_supply (regcache, regnum, &sf.fixreg[i]);
 181
 182   read_memory (sf.sp, (gdb_byte *)&cf, sizeof cf);
 183   regcache_raw_supply (regcache, gdbarch_pc_regnum (gdbarch), &cf.lr);
 184   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 30, &cf.r30);
 185   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 31, &cf.r31);
 186
 187   return 1;
 188 }
 189 \f
 190
 191 /* Provide a prototype to silence -Wmissing-prototypes.  */
 192 void _initialize_ppcobsd_nat (void);
 193
 194 void
 195 _initialize_ppcobsd_nat (void)
 196 {
 197   struct target_ops *t;
 198
 199   /* Add in local overrides.  */
 200   t = inf_ptrace_target ();
 201   t->to_fetch_registers = ppcobsd_fetch_registers;
 202   t->to_store_registers = ppcobsd_store_registers;
 203   add_target (t);
 204
 205   /* General-purpose registers.  */
 206   ppcobsd_reg_offsets.r0_offset = offsetof (struct reg, gpr);
 207   ppcobsd_reg_offsets.gpr_size = 4;
 208   ppcobsd_reg_offsets.xr_size = 4;
 209   ppcobsd_reg_offsets.pc_offset = offsetof (struct reg, pc);
 210   ppcobsd_reg_offsets.ps_offset = offsetof (struct reg, ps);
 211   ppcobsd_reg_offsets.cr_offset = offsetof (struct reg, cnd);
 212   ppcobsd_reg_offsets.lr_offset = offsetof (struct reg, lr);
 213   ppcobsd_reg_offsets.ctr_offset = offsetof (struct reg, cnt);
 214   ppcobsd_reg_offsets.xer_offset = offsetof (struct reg, xer);
 215   ppcobsd_reg_offsets.mq_offset = offsetof (struct reg, mq);
 216
 217   /* Floating-point registers.  */
 218   ppcobsd_reg_offsets.f0_offset = offsetof (struct reg, fpr);
 219   ppcobsd_reg_offsets.fpscr_offset = -1;
 220 #ifdef PT_GETFPREGS
 221   ppcobsd_fpreg_offsets.f0_offset = offsetof (struct fpreg, fpr);
 222   ppcobsd_fpreg_offsets.fpscr_offset = offsetof (struct fpreg, fpscr);
 223   ppcobsd_fpreg_offsets.fpscr_size = 4;
 224 #endif
 225
 226   /* AltiVec registers.  */
 227   ppcobsd_reg_offsets.vr0_offset = offsetof (struct vreg, vreg);
 228   ppcobsd_reg_offsets.vscr_offset = offsetof (struct vreg, vscr);
 229   ppcobsd_reg_offsets.vrsave_offset = offsetof (struct vreg, vrsave);
 230
 231   /* Support debugging kernel virtual memory images.  */
 232   bsd_kvm_add_target (ppcobsd_supply_pcb);
 233 }