gdb/ppc-obsd-nat.c

   1 /* Native-dependent code for OpenBSD/powerpc.
   2
   3    Copyright (C) 2004-2017 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 <sys/types.h>
  26 #include <sys/ptrace.h>
  27 #include <sys/signal.h>
  28 #include <machine/frame.h>
  29 #include <machine/pcb.h>
  30 #include <machine/reg.h>
  31
  32 #include "ppc-tdep.h"
  33 #include "ppc-obsd-tdep.h"
  34 #include "inf-ptrace.h"
  35 #include "obsd-nat.h"
  36 #include "bsd-kvm.h"
  37
  38 /* OpenBSD/powerpc didn't have PT_GETFPREGS/PT_SETFPREGS until release
  39    4.0.  On older releases the floating-point registers are handled by
  40    PT_GETREGS/PT_SETREGS, but fpscr wasn't available..  */
  41
  42 #ifdef PT_GETFPREGS
  43
  44 /* Returns true if PT_GETFPREGS fetches this register.  */
  45
  46 static int
  47 getfpregs_supplies (struct gdbarch *gdbarch, int regnum)
  48 {
  49   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  50
  51   /* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
  52      point registers.  Traditionally, GDB's register set has still
  53      listed the floating point registers for such machines, so this
  54      code is harmless.  However, the new E500 port actually omits the
  55      floating point registers entirely from the register set --- they
  56      don't even have register numbers assigned to them.
  57
  58      It's not clear to me how best to update this code, so this assert
  59      will alert the first person to encounter the NetBSD/E500
  60      combination to the problem.  */
  61   gdb_assert (ppc_floating_point_unit_p (gdbarch));
  62
  63   return ((regnum >= tdep->ppc_fp0_regnum
  64            && regnum < tdep->ppc_fp0_regnum + ppc_num_fprs)
  65           || regnum == tdep->ppc_fpscr_regnum);
  66 }
  67
  68 #endif /* PT_GETFPREGS */
  69
  70 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  71    for all registers.  */
  72
  73 static void
  74 ppcobsd_fetch_registers (struct target_ops *ops,
  75                          struct regcache *regcache, int regnum)
  76 {
  77   struct reg regs;
  78   pid_t pid = ptid_get_pid (regcache_get_ptid (regcache));
  79
  80   if (ptrace (PT_GETREGS, pid, (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, pid, (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 target_ops *ops,
 110                          struct regcache *regcache, int regnum)
 111 {
 112   struct reg regs;
 113   pid_t pid = ptid_get_pid (regcache_get_ptid (regcache));
 114
 115   if (ptrace (PT_GETREGS, pid, (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, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 126     perror_with_name (_("Couldn't write registers"));
 127
 128 #ifdef PT_GETFPREGS
 129   if (regnum == -1
 130       || getfpregs_supplies (get_regcache_arch (regcache), regnum))
 131     {
 132       struct fpreg fpregs;
 133
 134       if (ptrace (PT_GETFPREGS, pid, (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, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 141         perror_with_name (_("Couldn't write floating point status"));
 142     }
 143 #endif
 144 }
 145 \f
 146
 147 static int
 148 ppcobsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 149 {
 150   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 151   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 152   struct switchframe sf;
 153   struct callframe cf;
 154   int i, regnum;
 155
 156   /* The following is true for OpenBSD 3.7:
 157
 158      The pcb contains %r1 (the stack pointer) at the point of the
 159      context switch in cpu_switch().  At that point we have a stack
 160      frame as described by `struct switchframe', and below that a call
 161      frame as described by `struct callframe'.  From this information
 162      we reconstruct the register state as it would look when we are in
 163      cpu_switch().  */
 164
 165   /* The stack pointer shouldn't be zero.  */
 166   if (pcb->pcb_sp == 0)
 167     return 0;
 168
 169   read_memory (pcb->pcb_sp, (gdb_byte *)&sf, sizeof sf);
 170   regcache_raw_supply (regcache, gdbarch_sp_regnum (gdbarch), &sf.sp);
 171   regcache_raw_supply (regcache, tdep->ppc_cr_regnum, &sf.cr);
 172   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 2, &sf.fixreg2);
 173   for (i = 0, regnum = tdep->ppc_gp0_regnum + 13; i < 19; i++, regnum++)
 174     regcache_raw_supply (regcache, regnum, &sf.fixreg[i]);
 175
 176   read_memory (sf.sp, (gdb_byte *)&cf, sizeof cf);
 177   regcache_raw_supply (regcache, gdbarch_pc_regnum (gdbarch), &cf.lr);
 178   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 30, &cf.r30);
 179   regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 31, &cf.r31);
 180
 181   return 1;
 182 }
 183 \f
 184
 185 /* Provide a prototype to silence -Wmissing-prototypes.  */
 186 void _initialize_ppcobsd_nat (void);
 187
 188 void
 189 _initialize_ppcobsd_nat (void)
 190 {
 191   struct target_ops *t;
 192
 193   /* Add in local overrides.  */
 194   t = inf_ptrace_target ();
 195   t->to_fetch_registers = ppcobsd_fetch_registers;
 196   t->to_store_registers = ppcobsd_store_registers;
 197   obsd_add_target (t);
 198
 199   /* General-purpose registers.  */
 200   ppcobsd_reg_offsets.r0_offset = offsetof (struct reg, gpr);
 201   ppcobsd_reg_offsets.gpr_size = 4;
 202   ppcobsd_reg_offsets.xr_size = 4;
 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   ppcobsd_fpreg_offsets.fpscr_size = 4;
 218 #endif
 219
 220   /* AltiVec registers.  */
 221   ppcobsd_reg_offsets.vr0_offset = offsetof (struct vreg, vreg);
 222   ppcobsd_reg_offsets.vscr_offset = offsetof (struct vreg, vscr);
 223   ppcobsd_reg_offsets.vrsave_offset = offsetof (struct vreg, vrsave);
 224
 225   /* Support debugging kernel virtual memory images.  */
 226   bsd_kvm_add_target (ppcobsd_supply_pcb);
 227 }