gdb/ppc-obsd-nat.c

   1 /* Native-dependent code for OpenBSD/powerpc.
   2
   3    Copyright (C) 2004-2020 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 struct ppc_obsd_nat_target final : public obsd_nat_target
  39 {
  40   void fetch_registers (struct regcache *, int) override;
  41   void store_registers (struct regcache *, int) override;
  42 };
  43
  44 static ppc_obsd_nat_target the_ppc_obsd_nat_target;
  45
  46 /* OpenBSD/powerpc didn't have PT_GETFPREGS/PT_SETFPREGS until release
  47    4.0.  On older releases the floating-point registers are handled by
  48    PT_GETREGS/PT_SETREGS, but fpscr wasn't available..  */
  49
  50 #ifdef PT_GETFPREGS
  51
  52 /* Returns true if PT_GETFPREGS fetches this register.  */
  53
  54 static int
  55 getfpregs_supplies (struct gdbarch *gdbarch, int regnum)
  56 {
  57   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  58
  59   /* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
  60      point registers.  Traditionally, GDB's register set has still
  61      listed the floating point registers for such machines, so this
  62      code is harmless.  However, the new E500 port actually omits the
  63      floating point registers entirely from the register set --- they
  64      don't even have register numbers assigned to them.
  65
  66      It's not clear to me how best to update this code, so this assert
  67      will alert the first person to encounter the NetBSD/E500
  68      combination to the problem.  */
  69   gdb_assert (ppc_floating_point_unit_p (gdbarch));
  70
  71   return ((regnum >= tdep->ppc_fp0_regnum
  72            && regnum < tdep->ppc_fp0_regnum + ppc_num_fprs)
  73           || regnum == tdep->ppc_fpscr_regnum);
  74 }
  75
  76 #endif /* PT_GETFPREGS */
  77
  78 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  79    for all registers.  */
  80
  81 void
  82 ppc_obsd_nat_target::fetch_registers (struct regcache *regcache, int regnum)
  83 {
  84   struct reg regs;
  85   pid_t pid = regcache->ptid ().pid ();
  86
  87   if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
  88     perror_with_name (_("Couldn't get registers"));
  89
  90   ppc_supply_gregset (&ppcobsd_gregset, regcache, -1,
  91                       &regs, sizeof regs);
  92 #ifndef PT_GETFPREGS
  93   ppc_supply_fpregset (&ppcobsd_gregset, regcache, -1,
  94                        &regs, sizeof regs);
  95 #endif
  96
  97 #ifdef PT_GETFPREGS
  98   if (regnum == -1
  99       || getfpregs_supplies (regcache->arch (), regnum))
 100     {
 101       struct fpreg fpregs;
 102
 103       if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 104         perror_with_name (_("Couldn't get floating point status"));
 105
 106       ppc_supply_fpregset (&ppcobsd_fpregset, regcache, -1,
 107                            &fpregs, sizeof fpregs);
 108     }
 109 #endif
 110 }
 111
 112 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 113    this for all registers.  */
 114
 115 void
 116 ppc_obsd_nat_target::store_registers (struct regcache *regcache, int regnum)
 117 {
 118   struct reg regs;
 119   pid_t pid = regcache->ptid ().pid ();
 120
 121   if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 122     perror_with_name (_("Couldn't get registers"));
 123
 124   ppc_collect_gregset (&ppcobsd_gregset, regcache,
 125                        regnum, &regs, sizeof regs);
 126 #ifndef PT_GETFPREGS
 127   ppc_collect_fpregset (&ppcobsd_gregset, regcache,
 128                         regnum, &regs, sizeof regs);
 129 #endif
 130
 131   if (ptrace (PT_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 132     perror_with_name (_("Couldn't write registers"));
 133
 134 #ifdef PT_GETFPREGS
 135   if (regnum == -1
 136       || getfpregs_supplies (regcache->arch (), regnum))
 137     {
 138       struct fpreg fpregs;
 139
 140       if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 141         perror_with_name (_("Couldn't get floating point status"));
 142
 143       ppc_collect_fpregset (&ppcobsd_fpregset, regcache,
 144                             regnum, &fpregs, sizeof fpregs);
 145
 146       if (ptrace (PT_SETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 147         perror_with_name (_("Couldn't write floating point status"));
 148     }
 149 #endif
 150 }
 151 \f
 152
 153 static int
 154 ppcobsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 155 {
 156   struct gdbarch *gdbarch = regcache->arch ();
 157   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 158   struct switchframe sf;
 159   struct callframe cf;
 160   int i, regnum;
 161
 162   /* The following is true for OpenBSD 3.7:
 163
 164      The pcb contains %r1 (the stack pointer) at the point of the
 165      context switch in cpu_switch().  At that point we have a stack
 166      frame as described by `struct switchframe', and below that a call
 167      frame as described by `struct callframe'.  From this information
 168      we reconstruct the register state as it would look when we are in
 169      cpu_switch().  */
 170
 171   /* The stack pointer shouldn't be zero.  */
 172   if (pcb->pcb_sp == 0)
 173     return 0;
 174
 175   read_memory (pcb->pcb_sp, (gdb_byte *)&sf, sizeof sf);
 176   regcache->raw_supply (gdbarch_sp_regnum (gdbarch), &sf.sp);
 177   regcache->raw_supply (tdep->ppc_cr_regnum, &sf.cr);
 178   regcache->raw_supply (tdep->ppc_gp0_regnum + 2, &sf.fixreg2);
 179   for (i = 0, regnum = tdep->ppc_gp0_regnum + 13; i < 19; i++, regnum++)
 180     regcache->raw_supply (regnum, &sf.fixreg[i]);
 181
 182   read_memory (sf.sp, (gdb_byte *)&cf, sizeof cf);
 183   regcache->raw_supply (gdbarch_pc_regnum (gdbarch), &cf.lr);
 184   regcache->raw_supply (tdep->ppc_gp0_regnum + 30, &cf.r30);
 185   regcache->raw_supply (tdep->ppc_gp0_regnum + 31, &cf.r31);
 186
 187   return 1;
 188 }
 189
 190 void _initialize_ppcobsd_nat ();
 191 void
 192 _initialize_ppcobsd_nat ()
 193 {
 194   add_inf_child_target (&the_ppc_obsd_nat_target);
 195
 196   /* General-purpose registers.  */
 197   ppcobsd_reg_offsets.r0_offset = offsetof (struct reg, gpr);
 198   ppcobsd_reg_offsets.gpr_size = 4;
 199   ppcobsd_reg_offsets.xr_size = 4;
 200   ppcobsd_reg_offsets.pc_offset = offsetof (struct reg, pc);
 201   ppcobsd_reg_offsets.ps_offset = offsetof (struct reg, ps);
 202   ppcobsd_reg_offsets.cr_offset = offsetof (struct reg, cnd);
 203   ppcobsd_reg_offsets.lr_offset = offsetof (struct reg, lr);
 204   ppcobsd_reg_offsets.ctr_offset = offsetof (struct reg, cnt);
 205   ppcobsd_reg_offsets.xer_offset = offsetof (struct reg, xer);
 206   ppcobsd_reg_offsets.mq_offset = offsetof (struct reg, mq);
 207
 208   /* Floating-point registers.  */
 209   ppcobsd_reg_offsets.f0_offset = offsetof (struct reg, fpr);
 210   ppcobsd_reg_offsets.fpscr_offset = -1;
 211 #ifdef PT_GETFPREGS
 212   ppcobsd_fpreg_offsets.f0_offset = offsetof (struct fpreg, fpr);
 213   ppcobsd_fpreg_offsets.fpscr_offset = offsetof (struct fpreg, fpscr);
 214   ppcobsd_fpreg_offsets.fpscr_size = 4;
 215 #endif
 216
 217   /* Support debugging kernel virtual memory images.  */
 218   bsd_kvm_add_target (ppcobsd_supply_pcb);
 219 }