gdb/ppcobsd-nat.c

   1 /* Native-dependent code for OpenBSD/powerpc.
   2
   3    Copyright (C) 2004-2012 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 target_ops *ops,
  76                          struct regcache *regcache, int regnum)
  77 {
  78   struct reg regs;
  79
  80   if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
  81               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
  82     perror_with_name (_("Couldn't get registers"));
  83
  84   ppc_supply_gregset (&ppcobsd_gregset, regcache, -1,
  85                       &regs, sizeof regs);
  86 #ifndef PT_GETFPREGS
  87   ppc_supply_fpregset (&ppcobsd_gregset, regcache, -1,
  88                        &regs, sizeof regs);
  89 #endif
  90
  91 #ifdef PT_GETFPREGS
  92   if (regnum == -1
  93       || getfpregs_supplies (get_regcache_arch (regcache), 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 target_ops *ops,
 112                          struct regcache *regcache, int regnum)
 113 {
 114   struct reg regs;
 115
 116   if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 117               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 118     perror_with_name (_("Couldn't get registers"));
 119
 120   ppc_collect_gregset (&ppcobsd_gregset, regcache,
 121                        regnum, &regs, sizeof regs);
 122 #ifndef PT_GETFPREGS
 123   ppc_collect_fpregset (&ppcobsd_gregset, regcache,
 124                         regnum, &regs, sizeof regs);
 125 #endif
 126
 127   if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
 128               (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 129     perror_with_name (_("Couldn't write registers"));
 130
 131 #ifdef PT_GETFPREGS
 132   if (regnum == -1
 133       || getfpregs_supplies (get_regcache_arch (regcache), regnum))
 134     {
 135       struct fpreg fpregs;
 136
 137       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 138                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 139         perror_with_name (_("Couldn't get floating point status"));
 140
 141       ppc_collect_fpregset (&ppcobsd_fpregset, regcache,
 142                             regnum, &fpregs, sizeof fpregs);
 143
 144       if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
 145                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 146         perror_with_name (_("Couldn't write floating point status"));
 147     }
 148 #endif
 149 }
 150 \f
 151
 152 static int
 153 ppcobsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 154 {
 155   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 156   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 157   struct switchframe sf;
 158   struct callframe cf;
 159   int i, regnum;
 160
 161   /* The following is true for OpenBSD 3.7:
 162
 163      The pcb contains %r1 (the stack pointer) at the point of the
 164      context switch in cpu_switch().  At that point we have a stack
 165      frame as described by `struct switchframe', and below that a call
 166      frame as described by `struct callframe'.  From this information
 167      we reconstruct the register state as it would look when we are in
 168      cpu_switch().  */
 169
 170   /* The stack pointer shouldn't be zero.  */
 171   if (pcb->pcb_sp == 0)
 172     return 0;
 173
 174   read_memory (pcb->pcb_sp, (gdb_byte *)&sf, sizeof sf);
 175   regcache_raw_supply (regcache, gdbarch_sp_regnum (gdbarch), &sf.sp);
 176   regcache_raw_supply (regcache, tdep->ppc_cr_regnum, &sf.cr);
 177   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 2, &sf.fixreg2);
 178   for (i = 0, regnum = tdep->ppc_gp0_regnum + 13; i < 19; i++, regnum++)
 179     regcache_raw_supply (regcache, regnum, &sf.fixreg[i]);
 180
 181   read_memory (sf.sp, (gdb_byte *)&cf, sizeof cf);
 182   regcache_raw_supply (regcache, gdbarch_pc_regnum (gdbarch), &cf.lr);
 183   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 30, &cf.r30);
 184   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 31, &cf.r31);
 185
 186   return 1;
 187 }
 188 \f
 189
 190 /* Provide a prototype to silence -Wmissing-prototypes.  */
 191 void _initialize_ppcobsd_nat (void);
 192
 193 void
 194 _initialize_ppcobsd_nat (void)
 195 {
 196   struct target_ops *t;
 197
 198   /* Add in local overrides.  */
 199   t = inf_ptrace_target ();
 200   t->to_fetch_registers = ppcobsd_fetch_registers;
 201   t->to_store_registers = ppcobsd_store_registers;
 202   add_target (t);
 203
 204   /* General-purpose registers.  */
 205   ppcobsd_reg_offsets.r0_offset = offsetof (struct reg, gpr);
 206   ppcobsd_reg_offsets.gpr_size = 4;
 207   ppcobsd_reg_offsets.xr_size = 4;
 208   ppcobsd_reg_offsets.pc_offset = offsetof (struct reg, pc);
 209   ppcobsd_reg_offsets.ps_offset = offsetof (struct reg, ps);
 210   ppcobsd_reg_offsets.cr_offset = offsetof (struct reg, cnd);
 211   ppcobsd_reg_offsets.lr_offset = offsetof (struct reg, lr);
 212   ppcobsd_reg_offsets.ctr_offset = offsetof (struct reg, cnt);
 213   ppcobsd_reg_offsets.xer_offset = offsetof (struct reg, xer);
 214   ppcobsd_reg_offsets.mq_offset = offsetof (struct reg, mq);
 215
 216   /* Floating-point registers.  */
 217   ppcobsd_reg_offsets.f0_offset = offsetof (struct reg, fpr);
 218   ppcobsd_reg_offsets.fpscr_offset = -1;
 219 #ifdef PT_GETFPREGS
 220   ppcobsd_fpreg_offsets.f0_offset = offsetof (struct fpreg, fpr);
 221   ppcobsd_fpreg_offsets.fpscr_offset = offsetof (struct fpreg, fpscr);
 222   ppcobsd_fpreg_offsets.fpscr_size = 4;
 223 #endif
 224
 225   /* AltiVec registers.  */
 226   ppcobsd_reg_offsets.vr0_offset = offsetof (struct vreg, vreg);
 227   ppcobsd_reg_offsets.vscr_offset = offsetof (struct vreg, vscr);
 228   ppcobsd_reg_offsets.vrsave_offset = offsetof (struct vreg, vrsave);
 229
 230   /* Support debugging kernel virtual memory images.  */
 231   bsd_kvm_add_target (ppcobsd_supply_pcb);
 232 }