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 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
47static int
48getfpregs_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
74static void
75ppcobsd_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
108static void
109ppcobsd_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
147
148static int
149ppcobsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
150{
151  struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache));
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 (current_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 (current_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
184
185/* Provide a prototype to silence -Wmissing-prototypes.  */
186void _initialize_ppcobsd_nat (void);
187
188void
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  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}
228