gdb/ppcobsd-nat.c

   1 /* Native-dependent code for OpenBSD/powerpc.
   2
   3    Copyright (C) 2004, 2005, 2006, 2007, 2008 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 "gdb_assert.h"
  26 #include <stddef.h>
  27 #include <sys/types.h>
  28 #include <sys/ptrace.h>
  29 #include <sys/signal.h>
  30 #include <machine/frame.h>
  31 #include <machine/pcb.h>
  32 #include <machine/reg.h>
  33
  34 #include "ppc-tdep.h"
  35 #include "ppcobsd-tdep.h"
  36 #include "inf-ptrace.h"
  37 #include "bsd-kvm.h"
  38
  39 /* OpenBSD/powerpc didn't have PT_GETFPREGS/PT_SETFPREGS until release
  40    4.0.  On older releases the floating-point registers are handled by
  41    PT_GETREGS/PT_SETREGS, but fpscr wasn't available..  */
  42
  43 #ifdef PT_GETFPREGS
  44
  45 /* Returns true if PT_GETFPREGS fetches this register.  */
  46
  47 static int
  48 getfpregs_supplies (struct gdbarch *gdbarch, int regnum)
  49 {
  50   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  51
  52   /* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
  53      point registers.  Traditionally, GDB's register set has still
  54      listed the floating point registers for such machines, so this
  55      code is harmless.  However, the new E500 port actually omits the
  56      floating point registers entirely from the register set --- they
  57      don't even have register numbers assigned to them.
  58
  59      It's not clear to me how best to update this code, so this assert
  60      will alert the first person to encounter the NetBSD/E500
  61      combination to the problem.  */
  62   gdb_assert (ppc_floating_point_unit_p (gdbarch));
  63
  64   return ((regnum >= tdep->ppc_fp0_regnum
  65            && regnum < tdep->ppc_fp0_regnum + ppc_num_fprs)
  66           || regnum == tdep->ppc_fpscr_regnum);
  67 }
  68
  69 #endif /* PT_GETFPREGS */
  70
  71 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  72    for all registers.  */
  73
  74 static void
  75 ppcobsd_fetch_registers (struct regcache *regcache, int regnum)
  76 {
  77   struct reg regs;
  78
  79   if (ptrace (PT_GETREGS, PIDGET (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, PIDGET (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 regcache *regcache, int regnum)
 111 {
 112   struct reg regs;
 113
 114   if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 115               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 116     perror_with_name (_("Couldn't get registers"));
 117
 118   ppc_collect_gregset (&ppcobsd_gregset, regcache,
 119                        regnum, &regs, sizeof regs);
 120 #ifndef PT_GETFPREGS
 121   ppc_collect_fpregset (&ppcobsd_gregset, regcache,
 122                         regnum, &regs, sizeof regs);
 123 #endif
 124
 125   if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
 126               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 127     perror_with_name (_("Couldn't write registers"));
 128
 129 #ifdef PT_GETFPREGS
 130   if (regnum == -1
 131       || getfpregs_supplies (get_regcache_arch (regcache), regnum))
 132     {
 133       struct fpreg fpregs;
 134
 135       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 136                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 137         perror_with_name (_("Couldn't get floating point status"));
 138
 139       ppc_collect_fpregset (&ppcobsd_fpregset, regcache,
 140                             regnum, &fpregs, sizeof fpregs);
 141
 142       if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
 143                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 144         perror_with_name (_("Couldn't write floating point status"));
 145     }
 146 #endif
 147 }
 148 \f
 149
 150 static int
 151 ppcobsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 152 {
 153   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 154   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 155   struct switchframe sf;
 156   struct callframe cf;
 157   int i, regnum;
 158
 159   /* The following is true for OpenBSD 3.7:
 160
 161      The pcb contains %r1 (the stack pointer) at the point of the
 162      context switch in cpu_switch().  At that point we have a stack
 163      frame as described by `struct switchframe', and below that a call
 164      frame as described by `struct callframe'.  From this information
 165      we reconstruct the register state as it would look when we are in
 166      cpu_switch().  */
 167
 168   /* The stack pointer shouldn't be zero.  */
 169   if (pcb->pcb_sp == 0)
 170     return 0;
 171
 172   read_memory (pcb->pcb_sp, (gdb_byte *)&sf, sizeof sf);
 173   regcache_raw_supply (regcache, gdbarch_sp_regnum (gdbarch), &sf.sp);
 174   regcache_raw_supply (regcache, tdep->ppc_cr_regnum, &sf.cr);
 175   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 2, &sf.fixreg2);
 176   for (i = 0, regnum = tdep->ppc_gp0_regnum + 13; i < 19; i++, regnum++)
 177     regcache_raw_supply (regcache, regnum, &sf.fixreg[i]);
 178
 179   read_memory (sf.sp, (gdb_byte *)&cf, sizeof cf);
 180   regcache_raw_supply (regcache, gdbarch_pc_regnum (gdbarch), &cf.lr);
 181   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 30, &cf.r30);
 182   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 31, &cf.r31);
 183
 184   return 1;
 185 }
 186 \f
 187
 188 /* Provide a prototype to silence -Wmissing-prototypes.  */
 189 void _initialize_ppcobsd_nat (void);
 190
 191 void
 192 _initialize_ppcobsd_nat (void)
 193 {
 194   struct target_ops *t;
 195
 196   /* Add in local overrides.  */
 197   t = inf_ptrace_target ();
 198   t->to_fetch_registers = ppcobsd_fetch_registers;
 199   t->to_store_registers = ppcobsd_store_registers;
 200   add_target (t);
 201
 202   /* General-purpose registers.  */
 203   ppcobsd_reg_offsets.r0_offset = offsetof (struct reg, gpr);
 204   ppcobsd_reg_offsets.gpr_size = 4;
 205   ppcobsd_reg_offsets.xr_size = 4;
 206   ppcobsd_reg_offsets.pc_offset = offsetof (struct reg, pc);
 207   ppcobsd_reg_offsets.ps_offset = offsetof (struct reg, ps);
 208   ppcobsd_reg_offsets.cr_offset = offsetof (struct reg, cnd);
 209   ppcobsd_reg_offsets.lr_offset = offsetof (struct reg, lr);
 210   ppcobsd_reg_offsets.ctr_offset = offsetof (struct reg, cnt);
 211   ppcobsd_reg_offsets.xer_offset = offsetof (struct reg, xer);
 212   ppcobsd_reg_offsets.mq_offset = offsetof (struct reg, mq);
 213
 214   /* Floating-point registers.  */
 215   ppcobsd_reg_offsets.f0_offset = offsetof (struct reg, fpr);
 216   ppcobsd_reg_offsets.fpscr_offset = -1;
 217 #ifdef PT_GETFPREGS
 218   ppcobsd_fpreg_offsets.f0_offset = offsetof (struct fpreg, fpr);
 219   ppcobsd_fpreg_offsets.fpscr_offset = offsetof (struct fpreg, fpscr);
 220   ppcobsd_fpreg_offsets.fpscr_size = 4;
 221 #endif
 222
 223   /* AltiVec registers.  */
 224   ppcobsd_reg_offsets.vr0_offset = offsetof (struct vreg, vreg);
 225   ppcobsd_reg_offsets.vscr_offset = offsetof (struct vreg, vscr);
 226   ppcobsd_reg_offsets.vrsave_offset = offsetof (struct vreg, vrsave);
 227
 228   /* Support debugging kernel virtual memory images.  */
 229   bsd_kvm_add_target (ppcobsd_supply_pcb);
 230 }