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 (int regnum)
  49 {
  50   struct gdbarch_tdep *tdep = gdbarch_tdep (current_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 (current_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 || getfpregs_supplies (regnum))
  92     {
  93       struct fpreg fpregs;
  94
  95       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
  96                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
  97         perror_with_name (_("Couldn't get floating point status"));
  98
  99       ppc_supply_fpregset (&ppcobsd_fpregset, regcache, -1,
 100                            &fpregs, sizeof fpregs);
 101     }
 102 #endif
 103 }
 104
 105 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 106    this for all registers.  */
 107
 108 static void
 109 ppcobsd_store_registers (struct regcache *regcache, int regnum)
 110 {
 111   struct reg regs;
 112
 113   if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 114               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 115     perror_with_name (_("Couldn't get registers"));
 116
 117   ppc_collect_gregset (&ppcobsd_gregset, regcache,
 118                        regnum, &regs, sizeof regs);
 119 #ifndef PT_GETFPREGS
 120   ppc_collect_fpregset (&ppcobsd_gregset, regcache,
 121                         regnum, &regs, sizeof regs);
 122 #endif
 123
 124   if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
 125               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 126     perror_with_name (_("Couldn't write registers"));
 127
 128 #ifdef PT_GETFPREGS
 129   if (regnum == -1 || getfpregs_supplies (regnum))
 130     {
 131       struct fpreg fpregs;
 132
 133       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 134                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 135         perror_with_name (_("Couldn't get floating point status"));
 136
 137       ppc_collect_fpregset (&ppcobsd_fpregset, regcache,
 138                             regnum, &fpregs, sizeof fpregs);
 139
 140       if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
 141                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 142         perror_with_name (_("Couldn't write floating point status"));
 143     }
 144 #endif
 145 }
 146 \f
 147
 148 static int
 149 ppcobsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 150 {
 151   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 152   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 153   struct switchframe sf;
 154   struct callframe cf;
 155   int i, regnum;
 156
 157   /* The following is true for OpenBSD 3.7:
 158
 159      The pcb contains %r1 (the stack pointer) at the point of the
 160      context switch in cpu_switch().  At that point we have a stack
 161      frame as described by `struct switchframe', and below that a call
 162      frame as described by `struct callframe'.  From this information
 163      we reconstruct the register state as it would look when we are in
 164      cpu_switch().  */
 165
 166   /* The stack pointer shouldn't be zero.  */
 167   if (pcb->pcb_sp == 0)
 168     return 0;
 169
 170   read_memory (pcb->pcb_sp, (gdb_byte *)&sf, sizeof sf);
 171   regcache_raw_supply (regcache, gdbarch_sp_regnum (gdbarch), &sf.sp);
 172   regcache_raw_supply (regcache, tdep->ppc_cr_regnum, &sf.cr);
 173   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 2, &sf.fixreg2);
 174   for (i = 0, regnum = tdep->ppc_gp0_regnum + 13; i < 19; i++, regnum++)
 175     regcache_raw_supply (regcache, regnum, &sf.fixreg[i]);
 176
 177   read_memory (sf.sp, (gdb_byte *)&cf, sizeof cf);
 178   regcache_raw_supply (regcache, gdbarch_pc_regnum (gdbarch), &cf.lr);
 179   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 30, &cf.r30);
 180   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 31, &cf.r31);
 181
 182   return 1;
 183 }
 184 \f
 185
 186 /* Provide a prototype to silence -Wmissing-prototypes.  */
 187 void _initialize_ppcobsd_nat (void);
 188
 189 void
 190 _initialize_ppcobsd_nat (void)
 191 {
 192   struct target_ops *t;
 193
 194   /* Add in local overrides.  */
 195   t = inf_ptrace_target ();
 196   t->to_fetch_registers = ppcobsd_fetch_registers;
 197   t->to_store_registers = ppcobsd_store_registers;
 198   add_target (t);
 199
 200   /* General-purpose registers.  */
 201   ppcobsd_reg_offsets.r0_offset = offsetof (struct reg, gpr);
 202   ppcobsd_reg_offsets.gpr_size = 4;
 203   ppcobsd_reg_offsets.xr_size = 4;
 204   ppcobsd_reg_offsets.pc_offset = offsetof (struct reg, pc);
 205   ppcobsd_reg_offsets.ps_offset = offsetof (struct reg, ps);
 206   ppcobsd_reg_offsets.cr_offset = offsetof (struct reg, cnd);
 207   ppcobsd_reg_offsets.lr_offset = offsetof (struct reg, lr);
 208   ppcobsd_reg_offsets.ctr_offset = offsetof (struct reg, cnt);
 209   ppcobsd_reg_offsets.xer_offset = offsetof (struct reg, xer);
 210   ppcobsd_reg_offsets.mq_offset = offsetof (struct reg, mq);
 211
 212   /* Floating-point registers.  */
 213   ppcobsd_reg_offsets.f0_offset = offsetof (struct reg, fpr);
 214   ppcobsd_reg_offsets.fpscr_offset = -1;
 215 #ifdef PT_GETFPREGS
 216   ppcobsd_fpreg_offsets.f0_offset = offsetof (struct fpreg, fpr);
 217   ppcobsd_fpreg_offsets.fpscr_offset = offsetof (struct fpreg, fpscr);
 218   ppcobsd_fpreg_offsets.fpscr_size = 4;
 219 #endif
 220
 221   /* AltiVec registers.  */
 222   ppcobsd_reg_offsets.vr0_offset = offsetof (struct vreg, vreg);
 223   ppcobsd_reg_offsets.vscr_offset = offsetof (struct vreg, vscr);
 224   ppcobsd_reg_offsets.vrsave_offset = offsetof (struct vreg, vrsave);
 225
 226   /* Support debugging kernel virtual memory images.  */
 227   bsd_kvm_add_target (ppcobsd_supply_pcb);
 228 }