1 /* Target-dependent code for FreeBSD/arm.
2
3 Copyright (C) 2017-2024 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
21 #include "elf/common.h"
22 #include "target-descriptions.h"
23 #include "aarch32-tdep.h"
24 #include "arm-tdep.h"
25 #include "arm-fbsd-tdep.h"
26 #include "auxv.h"
27 #include "fbsd-tdep.h"
28 #include "gdbcore.h"
29 #include "inferior.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
37 static 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
47 static 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 /* Register numbers are relative to tdep->tls_regnum. */
55
56 static const struct regcache_map_entry arm_fbsd_tls_regmap[] =
57 {
58 { 1, 0, 4 }, /* tpidruro */
59 { 0 }
60 };
61
62 /* In a signal frame, sp points to a 'struct sigframe' which is
63 defined as:
64
65 struct sigframe {
66 siginfo_t sf_si;
67 ucontext_t sf_uc;
68 mcontext_vfp_t sf_vfp;
69 };
70
71 ucontext_t is defined as:
72
73 struct __ucontext {
74 sigset_t uc_sigmask;
75 mcontext_t uc_mcontext;
76 ...
77 };
78
79 mcontext_t is defined as:
80
81 struct {
82 unsigned int __gregs[17];
83 size_t mc_vfp_size;
84 void *mc_vfp_ptr;
85 ...
86 };
87
88 mcontext_vfp_t is defined as:
89
90 struct {
91 uint64_t mcv_reg[32];
92 uint32_t mcv_fpscr;
93 };
94
95 If the VFP state is valid, then mc_vfp_ptr will point to sf_vfp in
96 the sigframe, otherwise it is NULL. There is no non-VFP floating
97 point register state saved in the signal frame. */
98
99 #define ARM_SIGFRAME_UCONTEXT_OFFSET 64
100 #define ARM_UCONTEXT_MCONTEXT_OFFSET 16
101 #define ARM_MCONTEXT_VFP_PTR_OFFSET 72
102
103 /* Implement the "init" method of struct tramp_frame. */
104
105 static void
arm_fbsd_sigframe_init(const struct tramp_frame * self,const frame_info_ptr & this_frame,struct trad_frame_cache * this_cache,CORE_ADDR func)106 arm_fbsd_sigframe_init (const struct tramp_frame *self,
107 const frame_info_ptr &this_frame,
108 struct trad_frame_cache *this_cache,
109 CORE_ADDR func)
110 {
111 struct gdbarch *gdbarch = get_frame_arch (this_frame);
112 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
113 CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
114 CORE_ADDR mcontext_addr = (sp
115 + ARM_SIGFRAME_UCONTEXT_OFFSET
116 + ARM_UCONTEXT_MCONTEXT_OFFSET);
117 ULONGEST mcontext_vfp_addr;
118
119 trad_frame_set_reg_regmap (this_cache, arm_fbsd_gregmap, mcontext_addr,
120 regcache_map_entry_size (arm_fbsd_gregmap));
121
122 if (safe_read_memory_unsigned_integer (mcontext_addr
123 + ARM_MCONTEXT_VFP_PTR_OFFSET, 4,
124 byte_order,
125 &mcontext_vfp_addr)
126 && mcontext_vfp_addr != 0)
127 trad_frame_set_reg_regmap (this_cache, arm_fbsd_vfpregmap, mcontext_vfp_addr,
128 regcache_map_entry_size (arm_fbsd_vfpregmap));
129
130 trad_frame_set_id (this_cache, frame_id_build (sp, func));
131 }
132
133 static const struct tramp_frame arm_fbsd_sigframe =
134 {
135 SIGTRAMP_FRAME,
136 4,
137 {
138 {0xe1a0000d, ULONGEST_MAX}, /* mov r0, sp */
139 {0xe2800040, ULONGEST_MAX}, /* add r0, r0, #SIGF_UC */
140 {0xe59f700c, ULONGEST_MAX}, /* ldr r7, [pc, #12] */
141 {0xef0001a1, ULONGEST_MAX}, /* swi SYS_sigreturn */
142 {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
143 },
144 arm_fbsd_sigframe_init
145 };
146
147 /* Register set definitions. */
148
149 const struct regset arm_fbsd_gregset =
150 {
151 arm_fbsd_gregmap,
152 regcache_supply_regset, regcache_collect_regset
153 };
154
155 const struct regset arm_fbsd_vfpregset =
156 {
157 arm_fbsd_vfpregmap,
158 regcache_supply_regset, regcache_collect_regset
159 };
160
161 static void
arm_fbsd_supply_tls_regset(const struct regset * regset,struct regcache * regcache,int regnum,const void * buf,size_t size)162 arm_fbsd_supply_tls_regset (const struct regset *regset,
163 struct regcache *regcache,
164 int regnum, const void *buf, size_t size)
165 {
166 struct gdbarch *gdbarch = regcache->arch ();
167 arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
168
169 regcache->supply_regset (regset, tdep->tls_regnum, regnum, buf, size);
170 }
171
172 static void
arm_fbsd_collect_tls_regset(const struct regset * regset,const struct regcache * regcache,int regnum,void * buf,size_t size)173 arm_fbsd_collect_tls_regset (const struct regset *regset,
174 const struct regcache *regcache,
175 int regnum, void *buf, size_t size)
176 {
177 struct gdbarch *gdbarch = regcache->arch ();
178 arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
179
180 regcache->collect_regset (regset, tdep->tls_regnum, regnum, buf, size);
181 }
182
183 const struct regset arm_fbsd_tls_regset =
184 {
185 arm_fbsd_tls_regmap,
186 arm_fbsd_supply_tls_regset, arm_fbsd_collect_tls_regset
187 };
188
189 /* Implement the "iterate_over_regset_sections" gdbarch method. */
190
191 static void
arm_fbsd_iterate_over_regset_sections(struct gdbarch * gdbarch,iterate_over_regset_sections_cb * cb,void * cb_data,const struct regcache * regcache)192 arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
193 iterate_over_regset_sections_cb *cb,
194 void *cb_data,
195 const struct regcache *regcache)
196 {
197 arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
198
199 cb (".reg", ARM_FBSD_SIZEOF_GREGSET, ARM_FBSD_SIZEOF_GREGSET,
200 &arm_fbsd_gregset, NULL, cb_data);
201
202 if (tdep->tls_regnum > 0)
203 cb (".reg-aarch-tls", ARM_FBSD_SIZEOF_TLSREGSET, ARM_FBSD_SIZEOF_TLSREGSET,
204 &arm_fbsd_tls_regset, NULL, cb_data);
205
206 /* While FreeBSD/arm cores do contain a NT_FPREGSET / ".reg2"
207 register set, it is not populated with register values by the
208 kernel but just contains all zeroes. */
209 if (tdep->vfp_register_count > 0)
210 cb (".reg-arm-vfp", ARM_FBSD_SIZEOF_VFPREGSET, ARM_FBSD_SIZEOF_VFPREGSET,
211 &arm_fbsd_vfpregset, "VFP floating-point", cb_data);
212 }
213
214 /* See arm-fbsd-tdep.h. */
215
216 const struct target_desc *
arm_fbsd_read_description_auxv(const std::optional<gdb::byte_vector> & auxv,target_ops * target,gdbarch * gdbarch,bool tls)217 arm_fbsd_read_description_auxv (const std::optional<gdb::byte_vector> &auxv,
218 target_ops *target, gdbarch *gdbarch, bool tls)
219 {
220 CORE_ADDR arm_hwcap = 0;
221
222 if (!auxv.has_value ()
223 || target_auxv_search (*auxv, target, gdbarch, AT_FREEBSD_HWCAP,
224 &arm_hwcap) != 1)
225 return arm_read_description (ARM_FP_TYPE_NONE, tls);
226
227 if (arm_hwcap & HWCAP_VFP)
228 {
229 if (arm_hwcap & HWCAP_NEON)
230 return aarch32_read_description (tls);
231 else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPD32))
232 == (HWCAP_VFPv3 | HWCAP_VFPD32))
233 return arm_read_description (ARM_FP_TYPE_VFPV3, tls);
234 else
235 return arm_read_description (ARM_FP_TYPE_VFPV2, tls);
236 }
237
238 return arm_read_description (ARM_FP_TYPE_NONE, tls);
239 }
240
241 /* See arm-fbsd-tdep.h. */
242
243 const struct target_desc *
arm_fbsd_read_description_auxv(bool tls)244 arm_fbsd_read_description_auxv (bool tls)
245 {
246 const std::optional<gdb::byte_vector> &auxv = target_read_auxv ();
247 return arm_fbsd_read_description_auxv (auxv,
248 current_inferior ()->top_target (),
249 current_inferior ()->arch (),
250 tls);
251 }
252
253 /* Implement the "core_read_description" gdbarch method. */
254
255 static const struct target_desc *
arm_fbsd_core_read_description(struct gdbarch * gdbarch,struct target_ops * target,bfd * abfd)256 arm_fbsd_core_read_description (struct gdbarch *gdbarch,
257 struct target_ops *target,
258 bfd *abfd)
259 {
260 asection *tls = bfd_get_section_by_name (abfd, ".reg-aarch-tls");
261
262 std::optional<gdb::byte_vector> auxv = target_read_auxv_raw (target);
263 return arm_fbsd_read_description_auxv (auxv, target, gdbarch, tls != nullptr);
264 }
265
266 /* Implement the get_thread_local_address gdbarch method. */
267
268 static CORE_ADDR
arm_fbsd_get_thread_local_address(struct gdbarch * gdbarch,ptid_t ptid,CORE_ADDR lm_addr,CORE_ADDR offset)269 arm_fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
270 CORE_ADDR lm_addr, CORE_ADDR offset)
271 {
272 arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
273 regcache *regcache
274 = get_thread_arch_regcache (current_inferior (), ptid, gdbarch);
275
276 target_fetch_registers (regcache, tdep->tls_regnum);
277
278 ULONGEST tpidruro;
279 if (regcache->cooked_read (tdep->tls_regnum, &tpidruro) != REG_VALID)
280 error (_("Unable to fetch %%tpidruro"));
281
282 /* %tpidruro points to the TCB whose first member is the dtv
283 pointer. */
284 CORE_ADDR dtv_addr = tpidruro;
285 return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset);
286 }
287
288 /* Implement the 'init_osabi' method of struct gdb_osabi_handler. */
289
290 static void
arm_fbsd_init_abi(struct gdbarch_info info,struct gdbarch * gdbarch)291 arm_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
292 {
293 arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
294
295 /* Generic FreeBSD support. */
296 fbsd_init_abi (info, gdbarch);
297
298 if (tdep->fp_model == ARM_FLOAT_AUTO)
299 tdep->fp_model = ARM_FLOAT_SOFT_VFP;
300
301 tramp_frame_prepend_unwinder (gdbarch, &arm_fbsd_sigframe);
302
303 set_solib_svr4_fetch_link_map_offsets
304 (gdbarch, svr4_ilp32_fetch_link_map_offsets);
305
306 tdep->jb_pc = 24;
307 tdep->jb_elt_size = 4;
308
309 set_gdbarch_iterate_over_regset_sections
310 (gdbarch, arm_fbsd_iterate_over_regset_sections);
311 set_gdbarch_core_read_description (gdbarch, arm_fbsd_core_read_description);
312
313 if (tdep->tls_regnum > 0)
314 {
315 set_gdbarch_fetch_tls_load_module_address (gdbarch,
316 svr4_fetch_objfile_link_map);
317 set_gdbarch_get_thread_local_address (gdbarch,
318 arm_fbsd_get_thread_local_address);
319 }
320
321 /* Single stepping. */
322 set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
323 }
324
325 void _initialize_arm_fbsd_tdep ();
326 void
_initialize_arm_fbsd_tdep()327 _initialize_arm_fbsd_tdep ()
328 {
329 gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_FREEBSD,
330 arm_fbsd_init_abi);
331 }
332