xref: /netbsd-src/external/gpl3/gdb.old/dist/gdb/ppc-fbsd-nat.c (revision dd3ee07da436799d8de85f3055253118b76bf345)
1 /* Native-dependent code for PowerPC's running FreeBSD, for GDB.
2 
3    Copyright (C) 2013-2019 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/procfs.h>
27 #include <sys/ptrace.h>
28 #include <sys/signal.h>
29 #include <machine/frame.h>
30 #include <machine/pcb.h>
31 #include <machine/reg.h>
32 
33 #include "fbsd-nat.h"
34 #include "gregset.h"
35 #include "ppc-tdep.h"
36 #include "ppc-fbsd-tdep.h"
37 #include "inf-ptrace.h"
38 #include "bsd-kvm.h"
39 
40 struct ppc_fbsd_nat_target final : public fbsd_nat_target
41 {
42   void fetch_registers (struct regcache *, int) override;
43   void store_registers (struct regcache *, int) override;
44 };
45 
46 static ppc_fbsd_nat_target the_ppc_fbsd_nat_target;
47 
48 /* Fill GDB's register array with the general-purpose register values
49    in *GREGSETP.  */
50 
51 void
52 supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregsetp)
53 {
54   const struct regset *regset = ppc_fbsd_gregset (sizeof (long));
55 
56   ppc_supply_gregset (regset, regcache, -1, gregsetp, sizeof (*gregsetp));
57 }
58 
59 /* Fill register REGNO (if a gpr) in *GREGSETP with the value in GDB's
60    register array. If REGNO is -1 do it for all registers.  */
61 
62 void
63 fill_gregset (const struct regcache *regcache,
64 	      gdb_gregset_t *gregsetp, int regno)
65 {
66   const struct regset *regset = ppc_fbsd_gregset (sizeof (long));
67 
68   if (regno == -1)
69     memset (gregsetp, 0, sizeof (*gregsetp));
70   ppc_collect_gregset (regset, regcache, regno, gregsetp, sizeof (*gregsetp));
71 }
72 
73 /* Fill GDB's register array with the floating-point register values
74    in *FPREGSETP.  */
75 
76 void
77 supply_fpregset (struct regcache *regcache, const gdb_fpregset_t * fpregsetp)
78 {
79   const struct regset *regset = ppc_fbsd_fpregset ();
80 
81   ppc_supply_fpregset (regset, regcache, -1,
82 		       fpregsetp, sizeof (*fpregsetp));
83 }
84 
85 /* Fill register REGNO in *FGREGSETP with the value in GDB's
86    register array. If REGNO is -1 do it for all registers.  */
87 
88 void
89 fill_fpregset (const struct regcache *regcache,
90 	       gdb_fpregset_t *fpregsetp, int regno)
91 {
92   const struct regset *regset = ppc_fbsd_fpregset ();
93 
94   ppc_collect_fpregset (regset, regcache, regno,
95 			fpregsetp, sizeof (*fpregsetp));
96 }
97 
98 /* Returns true if PT_GETFPREGS fetches this register.  */
99 
100 static int
101 getfpregs_supplies (struct gdbarch *gdbarch, int regno)
102 {
103   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
104 
105   /* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
106 	 point registers.  Traditionally, GDB's register set has still
107 	 listed the floating point registers for such machines, so this
108 	 code is harmless.  However, the new E500 port actually omits the
109 	 floating point registers entirely from the register set --- they
110 	 don't even have register numbers assigned to them.
111 
112 	 It's not clear to me how best to update this code, so this assert
113 	 will alert the first person to encounter the NetBSD/E500
114 	 combination to the problem.  */
115 
116   gdb_assert (ppc_floating_point_unit_p (gdbarch));
117 
118   return ((regno >= tdep->ppc_fp0_regnum
119 	   && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)
120 	  || regno == tdep->ppc_fpscr_regnum);
121 }
122 
123 /* Fetch register REGNO from the child process. If REGNO is -1, do it
124    for all registers.  */
125 
126 void
127 ppc_fbsd_nat_target::fetch_registers (struct regcache *regcache, int regno)
128 {
129   gdb_gregset_t regs;
130   pid_t pid = regcache->ptid ().lwp ();
131 
132   if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
133     perror_with_name (_("Couldn't get registers"));
134 
135   supply_gregset (regcache, &regs);
136 
137   if (regno == -1 || getfpregs_supplies (regcache->arch (), regno))
138     {
139       const struct regset *fpregset = ppc_fbsd_fpregset ();
140       gdb_fpregset_t fpregs;
141 
142       if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
143 	perror_with_name (_("Couldn't get FP registers"));
144 
145       ppc_supply_fpregset (fpregset, regcache, regno, &fpregs, sizeof fpregs);
146     }
147 }
148 
149 /* Store register REGNO back into the child process. If REGNO is -1,
150    do this for all registers.  */
151 
152 void
153 ppc_fbsd_nat_target::store_registers (struct regcache *regcache, int regno)
154 {
155   gdb_gregset_t regs;
156   pid_t pid = regcache->ptid ().lwp ();
157 
158   if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
159     perror_with_name (_("Couldn't get registers"));
160 
161   fill_gregset (regcache, &regs, regno);
162 
163   if (ptrace (PT_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
164     perror_with_name (_("Couldn't write registers"));
165 
166   if (regno == -1 || getfpregs_supplies (regcache->arch (), regno))
167     {
168       gdb_fpregset_t fpregs;
169 
170       if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
171 	perror_with_name (_("Couldn't get FP registers"));
172 
173       fill_fpregset (regcache, &fpregs, regno);
174 
175       if (ptrace (PT_SETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
176 	perror_with_name (_("Couldn't set FP registers"));
177     }
178 }
179 
180 /* Architecture specific function that reconstructs the
181    register state from PCB (Process Control Block) and supplies it
182    to REGCACHE.  */
183 
184 static int
185 ppcfbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
186 {
187   struct gdbarch *gdbarch = regcache->arch ();
188   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
189   int i, regnum;
190 
191   /* The stack pointer shouldn't be zero.  */
192   if (pcb->pcb_sp == 0)
193     return 0;
194 
195   regcache->raw_supply (gdbarch_sp_regnum (gdbarch), &pcb->pcb_sp);
196   regcache->raw_supply (tdep->ppc_cr_regnum, &pcb->pcb_cr);
197   regcache->raw_supply (tdep->ppc_lr_regnum, &pcb->pcb_lr);
198   for (i = 0, regnum = tdep->ppc_gp0_regnum + 14; i < 20; i++, regnum++)
199     regcache->raw_supply (regnum, &pcb->pcb_context[i]);
200 
201   return 1;
202 }
203 
204 void
205 _initialize_ppcfbsd_nat (void)
206 {
207   add_inf_child_target (&the_ppc_fbsd_nat_target);
208 
209   /* Support debugging kernel virtual memory images.  */
210   bsd_kvm_add_target (ppcfbsd_supply_pcb);
211 }
212