1/* Target-dependent code for FreeBSD/arm.
2
3   Copyright (C) 2017-2020 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
22#include "elf/common.h"
23#include "target-descriptions.h"
24#include "aarch32-tdep.h"
25#include "arm-tdep.h"
26#include "arm-fbsd-tdep.h"
27#include "auxv.h"
28#include "fbsd-tdep.h"
29#include "gdbcore.h"
30#include "osabi.h"
31#include "solib-svr4.h"
32#include "trad-frame.h"
33#include "tramp-frame.h"
34
35/* Register maps.  */
36
37static const struct regcache_map_entry arm_fbsd_gregmap[] =
38  {
39    { 13, ARM_A1_REGNUM, 4 }, /* r0 ... r12 */
40    { 1, ARM_SP_REGNUM, 4 },
41    { 1, ARM_LR_REGNUM, 4 },
42    { 1, ARM_PC_REGNUM, 4 },
43    { 1, ARM_PS_REGNUM, 4 },
44    { 0 }
45  };
46
47static const struct regcache_map_entry arm_fbsd_vfpregmap[] =
48  {
49    { 32, ARM_D0_REGNUM, 8 }, /* d0 ... d31 */
50    { 1, ARM_FPSCR_REGNUM, 4 },
51    { 0 }
52  };
53
54/* In a signal frame, sp points to a 'struct sigframe' which is
55   defined as:
56
57   struct sigframe {
58	   siginfo_t	sf_si;
59	   ucontext_t	sf_uc;
60	   mcontext_vfp_t sf_vfp;
61   };
62
63   ucontext_t is defined as:
64
65   struct __ucontext {
66	   sigset_t	uc_sigmask;
67	   mcontext_t	uc_mcontext;
68	   ...
69   };
70
71   mcontext_t is defined as:
72
73   struct {
74	   unsigned int __gregs[17];
75	   size_t       mc_vfp_size;
76	   void         *mc_vfp_ptr;
77	   ...
78   };
79
80   mcontext_vfp_t is defined as:
81
82   struct {
83	  uint64_t      mcv_reg[32];
84	  uint32_t      mcv_fpscr;
85   };
86
87   If the VFP state is valid, then mc_vfp_ptr will point to sf_vfp in
88   the sigframe, otherwise it is NULL.  There is no non-VFP floating
89   point register state saved in the signal frame.  */
90
91#define ARM_SIGFRAME_UCONTEXT_OFFSET	64
92#define ARM_UCONTEXT_MCONTEXT_OFFSET	16
93#define ARM_MCONTEXT_VFP_PTR_OFFSET	72
94
95/* Implement the "init" method of struct tramp_frame.  */
96
97static void
98arm_fbsd_sigframe_init (const struct tramp_frame *self,
99			struct frame_info *this_frame,
100			struct trad_frame_cache *this_cache,
101			CORE_ADDR func)
102{
103  struct gdbarch *gdbarch = get_frame_arch (this_frame);
104  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
105  CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
106  CORE_ADDR mcontext_addr = (sp
107			     + ARM_SIGFRAME_UCONTEXT_OFFSET
108			     + ARM_UCONTEXT_MCONTEXT_OFFSET);
109  ULONGEST mcontext_vfp_addr;
110
111  trad_frame_set_reg_regmap (this_cache, arm_fbsd_gregmap, mcontext_addr,
112			     regcache_map_entry_size (arm_fbsd_gregmap));
113
114  if (safe_read_memory_unsigned_integer (mcontext_addr
115					 + ARM_MCONTEXT_VFP_PTR_OFFSET, 4,
116					 byte_order,
117					 &mcontext_vfp_addr)
118      && mcontext_vfp_addr != 0)
119    trad_frame_set_reg_regmap (this_cache, arm_fbsd_vfpregmap, mcontext_vfp_addr,
120			       regcache_map_entry_size (arm_fbsd_vfpregmap));
121
122  trad_frame_set_id (this_cache, frame_id_build (sp, func));
123}
124
125static const struct tramp_frame arm_fbsd_sigframe =
126{
127  SIGTRAMP_FRAME,
128  4,
129  {
130    {0xe1a0000d, ULONGEST_MAX},		/* mov  r0, sp  */
131    {0xe2800040, ULONGEST_MAX},		/* add  r0, r0, #SIGF_UC  */
132    {0xe59f700c, ULONGEST_MAX},		/* ldr  r7, [pc, #12]  */
133    {0xef0001a1, ULONGEST_MAX},		/* swi  SYS_sigreturn  */
134    {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
135  },
136  arm_fbsd_sigframe_init
137};
138
139/* Register set definitions.  */
140
141const struct regset arm_fbsd_gregset =
142  {
143    arm_fbsd_gregmap,
144    regcache_supply_regset, regcache_collect_regset
145  };
146
147const struct regset arm_fbsd_vfpregset =
148  {
149    arm_fbsd_vfpregmap,
150    regcache_supply_regset, regcache_collect_regset
151  };
152
153/* Implement the "iterate_over_regset_sections" gdbarch method.  */
154
155static void
156arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
157				       iterate_over_regset_sections_cb *cb,
158				       void *cb_data,
159				       const struct regcache *regcache)
160{
161  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
162
163  cb (".reg", ARM_FBSD_SIZEOF_GREGSET, ARM_FBSD_SIZEOF_GREGSET,
164      &arm_fbsd_gregset, NULL, cb_data);
165
166  /* While FreeBSD/arm cores do contain a NT_FPREGSET / ".reg2"
167     register set, it is not populated with register values by the
168     kernel but just contains all zeroes.  */
169  if (tdep->vfp_register_count > 0)
170    cb (".reg-arm-vfp", ARM_FBSD_SIZEOF_VFPREGSET, ARM_FBSD_SIZEOF_VFPREGSET,
171	&arm_fbsd_vfpregset, "VFP floating-point", cb_data);
172}
173
174/* Lookup a target description from a target's AT_HWCAP auxiliary
175   vector.  */
176
177const struct target_desc *
178arm_fbsd_read_description_auxv (struct target_ops *target)
179{
180  CORE_ADDR arm_hwcap = 0;
181
182  if (target_auxv_search (target, AT_FREEBSD_HWCAP, &arm_hwcap) != 1)
183    return nullptr;
184
185  if (arm_hwcap & HWCAP_VFP)
186    {
187      if (arm_hwcap & HWCAP_NEON)
188	return aarch32_read_description ();
189      else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPD32))
190	  == (HWCAP_VFPv3 | HWCAP_VFPD32))
191	return arm_read_description (ARM_FP_TYPE_VFPV3);
192      else
193      return arm_read_description (ARM_FP_TYPE_VFPV2);
194    }
195
196  return nullptr;
197}
198
199/* Implement the "core_read_description" gdbarch method.  */
200
201static const struct target_desc *
202arm_fbsd_core_read_description (struct gdbarch *gdbarch,
203				struct target_ops *target,
204				bfd *abfd)
205{
206  return arm_fbsd_read_description_auxv (target);
207}
208
209/* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
210
211static void
212arm_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
213{
214  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
215
216  /* Generic FreeBSD support.  */
217  fbsd_init_abi (info, gdbarch);
218
219  if (tdep->fp_model == ARM_FLOAT_AUTO)
220    tdep->fp_model = ARM_FLOAT_SOFT_VFP;
221
222  tramp_frame_prepend_unwinder (gdbarch, &arm_fbsd_sigframe);
223
224  set_solib_svr4_fetch_link_map_offsets
225    (gdbarch, svr4_ilp32_fetch_link_map_offsets);
226
227  tdep->jb_pc = 24;
228  tdep->jb_elt_size = 4;
229
230  set_gdbarch_iterate_over_regset_sections
231    (gdbarch, arm_fbsd_iterate_over_regset_sections);
232  set_gdbarch_core_read_description (gdbarch, arm_fbsd_core_read_description);
233
234  /* Single stepping.  */
235  set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
236}
237
238void _initialize_arm_fbsd_tdep ();
239void
240_initialize_arm_fbsd_tdep ()
241{
242  gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_FREEBSD,
243			  arm_fbsd_init_abi);
244}
245