gdb/ppcobsd-nat.c

   1 /* Native-dependent code for OpenBSD/powerpc.
   2
   3    Copyright (C) 2004, 2005, 2006, 2007 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 2 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, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22 #include "defs.h"
  23 #include "gdbcore.h"
  24 #include "inferior.h"
  25 #include "regcache.h"
  26
  27 #include "gdb_assert.h"
  28 #include <stddef.h>
  29 #include <sys/types.h>
  30 #include <sys/ptrace.h>
  31 #include <sys/signal.h>
  32 #include <machine/frame.h>
  33 #include <machine/pcb.h>
  34 #include <machine/reg.h>
  35
  36 #include "ppc-tdep.h"
  37 #include "ppcobsd-tdep.h"
  38 #include "inf-ptrace.h"
  39 #include "bsd-kvm.h"
  40
  41 /* OpenBSD/powerpc didn't have PT_GETFPREGS/PT_SETFPREGS until release
  42    4.0.  On older releases the floating-point registers are handled by
  43    PT_GETREGS/PT_SETREGS, but fpscr wasn't available..  */
  44
  45 #ifdef PT_GETFPREGS
  46
  47 /* Returns true if PT_GETFPREGS fetches this register.  */
  48
  49 static int
  50 getfpregs_supplies (int regnum)
  51 {
  52   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
  53
  54   /* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
  55      point registers.  Traditionally, GDB's register set has still
  56      listed the floating point registers for such machines, so this
  57      code is harmless.  However, the new E500 port actually omits the
  58      floating point registers entirely from the register set --- they
  59      don't even have register numbers assigned to them.
  60
  61      It's not clear to me how best to update this code, so this assert
  62      will alert the first person to encounter the NetBSD/E500
  63      combination to the problem.  */
  64   gdb_assert (ppc_floating_point_unit_p (current_gdbarch));
  65
  66   return ((regnum >= tdep->ppc_fp0_regnum
  67            && regnum < tdep->ppc_fp0_regnum + ppc_num_fprs)
  68           || regnum == tdep->ppc_fpscr_regnum);
  69 }
  70
  71 #endif /* PT_GETFPREGS */
  72
  73 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  74    for all registers.  */
  75
  76 static void
  77 ppcobsd_fetch_registers (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 || getfpregs_supplies (regnum))
  94     {
  95       struct fpreg fpregs;
  96
  97       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
  98                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
  99         perror_with_name (_("Couldn't get floating point status"));
 100
 101       ppc_supply_fpregset (&ppcobsd_fpregset, regcache, -1,
 102                            &fpregs, sizeof fpregs);
 103     }
 104 #endif
 105 }
 106
 107 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 108    this for all registers.  */
 109
 110 static void
 111 ppcobsd_store_registers (struct regcache *regcache, int regnum)
 112 {
 113   struct reg regs;
 114
 115   if (ptrace (PT_GETREGS, PIDGET (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, PIDGET (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 || getfpregs_supplies (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_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache));
 154   struct switchframe sf;
 155   struct callframe cf;
 156   int i, regnum;
 157
 158   /* The following is true for OpenBSD 3.7:
 159
 160      The pcb contains %r1 (the stack pointer) at the point of the
 161      context switch in cpu_switch().  At that point we have a stack
 162      frame as described by `struct switchframe', and below that a call
 163      frame as described by `struct callframe'.  From this information
 164      we reconstruct the register state as it would look when we are in
 165      cpu_switch().  */
 166
 167   /* The stack pointer shouldn't be zero.  */
 168   if (pcb->pcb_sp == 0)
 169     return 0;
 170
 171   read_memory (pcb->pcb_sp, (gdb_byte *)&sf, sizeof sf);
 172   regcache_raw_supply (regcache, SP_REGNUM, &sf.sp);
 173   regcache_raw_supply (regcache, tdep->ppc_cr_regnum, &sf.cr);
 174   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 2, &sf.fixreg2);
 175   for (i = 0, regnum = tdep->ppc_gp0_regnum + 13; i < 19; i++, regnum++)
 176     regcache_raw_supply (regcache, regnum, &sf.fixreg[i]);
 177
 178   read_memory (sf.sp, (gdb_byte *)&cf, sizeof cf);
 179   regcache_raw_supply (regcache, PC_REGNUM, &cf.lr);
 180   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 30, &cf.r30);
 181   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 31, &cf.r31);
 182
 183   return 1;
 184 }
 185 \f
 186
 187 /* Provide a prototype to silence -Wmissing-prototypes.  */
 188 void _initialize_ppcobsd_nat (void);
 189
 190 void
 191 _initialize_ppcobsd_nat (void)
 192 {
 193   struct target_ops *t;
 194
 195   /* Add in local overrides.  */
 196   t = inf_ptrace_target ();
 197   t->to_fetch_registers = ppcobsd_fetch_registers;
 198   t->to_store_registers = ppcobsd_store_registers;
 199   add_target (t);
 200
 201   /* General-purpose registers.  */
 202   ppcobsd_reg_offsets.r0_offset = offsetof (struct reg, gpr);
 203   ppcobsd_reg_offsets.pc_offset = offsetof (struct reg, pc);
 204   ppcobsd_reg_offsets.ps_offset = offsetof (struct reg, ps);
 205   ppcobsd_reg_offsets.cr_offset = offsetof (struct reg, cnd);
 206   ppcobsd_reg_offsets.lr_offset = offsetof (struct reg, lr);
 207   ppcobsd_reg_offsets.ctr_offset = offsetof (struct reg, cnt);
 208   ppcobsd_reg_offsets.xer_offset = offsetof (struct reg, xer);
 209   ppcobsd_reg_offsets.mq_offset = offsetof (struct reg, mq);
 210
 211   /* Floating-point registers.  */
 212   ppcobsd_reg_offsets.f0_offset = offsetof (struct reg, fpr);
 213   ppcobsd_reg_offsets.fpscr_offset = -1;
 214 #ifdef PT_GETFPREGS
 215   ppcobsd_fpreg_offsets.f0_offset = offsetof (struct fpreg, fpr);
 216   ppcobsd_fpreg_offsets.fpscr_offset = offsetof (struct fpreg, fpscr);
 217 #endif
 218
 219   /* AltiVec registers.  */
 220   ppcobsd_reg_offsets.vr0_offset = offsetof (struct vreg, vreg);
 221   ppcobsd_reg_offsets.vscr_offset = offsetof (struct vreg, vscr);
 222   ppcobsd_reg_offsets.vrsave_offset = offsetof (struct vreg, vrsave);
 223
 224   /* Support debugging kernel virtual memory images.  */
 225   bsd_kvm_add_target (ppcobsd_supply_pcb);
 226 }