xref: /netbsd-src/external/gpl3/gdb.old/dist/gdb/aarch64-fbsd-tdep.c (revision 6881a4007f077b54e5f51159c52b9b25f57deb0d)
1 /* Target-dependent code for FreeBSD/aarch64.
2 
3    Copyright (C) 2017-2023 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 "gdbarch.h"
23 #include "fbsd-tdep.h"
24 #include "aarch64-tdep.h"
25 #include "aarch64-fbsd-tdep.h"
26 #include "inferior.h"
27 #include "osabi.h"
28 #include "solib-svr4.h"
29 #include "target.h"
30 #include "tramp-frame.h"
31 #include "trad-frame.h"
32 
33 /* Register maps.  */
34 
35 static const struct regcache_map_entry aarch64_fbsd_gregmap[] =
36   {
37     { 30, AARCH64_X0_REGNUM, 8 }, /* x0 ... x29 */
38     { 1, AARCH64_LR_REGNUM, 8 },
39     { 1, AARCH64_SP_REGNUM, 8 },
40     { 1, AARCH64_PC_REGNUM, 8 },
41     { 1, AARCH64_CPSR_REGNUM, 4 },
42     { 0 }
43   };
44 
45 static const struct regcache_map_entry aarch64_fbsd_fpregmap[] =
46   {
47     { 32, AARCH64_V0_REGNUM, 16 }, /* v0 ... v31 */
48     { 1, AARCH64_FPSR_REGNUM, 4 },
49     { 1, AARCH64_FPCR_REGNUM, 4 },
50     { 0 }
51   };
52 
53 /* Register numbers are relative to tdep->tls_regnum_base.  */
54 
55 static const struct regcache_map_entry aarch64_fbsd_tls_regmap[] =
56   {
57     { 1, 0, 8 },	/* tpidr */
58     { 0 }
59   };
60 
61 /* In a signal frame, sp points to a 'struct sigframe' which is
62    defined as:
63 
64    struct sigframe {
65 	   siginfo_t	sf_si;
66 	   ucontext_t	sf_uc;
67    };
68 
69    ucontext_t is defined as:
70 
71    struct __ucontext {
72 	   sigset_t	uc_sigmask;
73 	   mcontext_t	uc_mcontext;
74 	   ...
75    };
76 
77    The mcontext_t contains the general purpose register set followed
78    by the floating point register set.  The floating point register
79    set is only valid if the _MC_FP_VALID flag is set in mc_flags.  */
80 
81 #define AARCH64_SIGFRAME_UCONTEXT_OFFSET	80
82 #define AARCH64_UCONTEXT_MCONTEXT_OFFSET	16
83 #define	AARCH64_MCONTEXT_FPREGS_OFFSET		272
84 #define	AARCH64_MCONTEXT_FLAGS_OFFSET		800
85 #define AARCH64_MCONTEXT_FLAG_FP_VALID		0x1
86 
87 /* Implement the "init" method of struct tramp_frame.  */
88 
89 static void
90 aarch64_fbsd_sigframe_init (const struct tramp_frame *self,
91 			     frame_info_ptr this_frame,
92 			     struct trad_frame_cache *this_cache,
93 			     CORE_ADDR func)
94 {
95   struct gdbarch *gdbarch = get_frame_arch (this_frame);
96   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
97   CORE_ADDR sp = get_frame_register_unsigned (this_frame, AARCH64_SP_REGNUM);
98   CORE_ADDR mcontext_addr
99     = (sp
100        + AARCH64_SIGFRAME_UCONTEXT_OFFSET
101        + AARCH64_UCONTEXT_MCONTEXT_OFFSET);
102   gdb_byte buf[4];
103 
104   trad_frame_set_reg_regmap (this_cache, aarch64_fbsd_gregmap, mcontext_addr,
105 			     regcache_map_entry_size (aarch64_fbsd_gregmap));
106 
107   if (target_read_memory (mcontext_addr + AARCH64_MCONTEXT_FLAGS_OFFSET, buf,
108 			  4) == 0
109       && (extract_unsigned_integer (buf, 4, byte_order)
110 	  & AARCH64_MCONTEXT_FLAG_FP_VALID))
111     trad_frame_set_reg_regmap (this_cache, aarch64_fbsd_fpregmap,
112 			       mcontext_addr + AARCH64_MCONTEXT_FPREGS_OFFSET,
113 			       regcache_map_entry_size (aarch64_fbsd_fpregmap));
114 
115   trad_frame_set_id (this_cache, frame_id_build (sp, func));
116 }
117 
118 static const struct tramp_frame aarch64_fbsd_sigframe =
119 {
120   SIGTRAMP_FRAME,
121   4,
122   {
123     {0x910003e0, ULONGEST_MAX},		/* mov  x0, sp  */
124     {0x91014000, ULONGEST_MAX},		/* add  x0, x0, #SF_UC  */
125     {0xd2803428, ULONGEST_MAX},		/* mov  x8, #SYS_sigreturn  */
126     {0xd4000001, ULONGEST_MAX},		/* svc  0x0  */
127     {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
128   },
129   aarch64_fbsd_sigframe_init
130 };
131 
132 /* Register set definitions.  */
133 
134 const struct regset aarch64_fbsd_gregset =
135   {
136     aarch64_fbsd_gregmap,
137     regcache_supply_regset, regcache_collect_regset
138   };
139 
140 const struct regset aarch64_fbsd_fpregset =
141   {
142     aarch64_fbsd_fpregmap,
143     regcache_supply_regset, regcache_collect_regset
144   };
145 
146 static void
147 aarch64_fbsd_supply_tls_regset (const struct regset *regset,
148 				struct regcache *regcache,
149 				int regnum, const void *buf, size_t size)
150 {
151   struct gdbarch *gdbarch = regcache->arch ();
152   aarch64_gdbarch_tdep *tdep = gdbarch_tdep<aarch64_gdbarch_tdep> (gdbarch);
153 
154   regcache->supply_regset (regset, tdep->tls_regnum_base, regnum, buf, size);
155 }
156 
157 static void
158 aarch64_fbsd_collect_tls_regset (const struct regset *regset,
159 				 const struct regcache *regcache,
160 				 int regnum, void *buf, size_t size)
161 {
162   struct gdbarch *gdbarch = regcache->arch ();
163   aarch64_gdbarch_tdep *tdep = gdbarch_tdep<aarch64_gdbarch_tdep> (gdbarch);
164 
165   regcache->collect_regset (regset, tdep->tls_regnum_base, regnum, buf, size);
166 }
167 
168 const struct regset aarch64_fbsd_tls_regset =
169   {
170     aarch64_fbsd_tls_regmap,
171     aarch64_fbsd_supply_tls_regset, aarch64_fbsd_collect_tls_regset
172   };
173 
174 /* Implement the "iterate_over_regset_sections" gdbarch method.  */
175 
176 static void
177 aarch64_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
178 					   iterate_over_regset_sections_cb *cb,
179 					   void *cb_data,
180 					   const struct regcache *regcache)
181 {
182   aarch64_gdbarch_tdep *tdep = gdbarch_tdep<aarch64_gdbarch_tdep> (gdbarch);
183 
184   cb (".reg", AARCH64_FBSD_SIZEOF_GREGSET, AARCH64_FBSD_SIZEOF_GREGSET,
185       &aarch64_fbsd_gregset, NULL, cb_data);
186   cb (".reg2", AARCH64_FBSD_SIZEOF_FPREGSET, AARCH64_FBSD_SIZEOF_FPREGSET,
187       &aarch64_fbsd_fpregset, NULL, cb_data);
188 
189   if (tdep->has_tls ())
190     cb (".reg-aarch-tls", AARCH64_FBSD_SIZEOF_TLSREGSET,
191 	AARCH64_FBSD_SIZEOF_TLSREGSET, &aarch64_fbsd_tls_regset,
192 	"TLS register", cb_data);
193 }
194 
195 /* Implement the "core_read_description" gdbarch method.  */
196 
197 static const struct target_desc *
198 aarch64_fbsd_core_read_description (struct gdbarch *gdbarch,
199 				    struct target_ops *target, bfd *abfd)
200 {
201   asection *tls = bfd_get_section_by_name (abfd, ".reg-aarch-tls");
202 
203   aarch64_features features;
204   features.tls = tls != nullptr? 1 : 0;
205 
206   return aarch64_read_description (features);
207 }
208 
209 /* Implement the get_thread_local_address gdbarch method.  */
210 
211 static CORE_ADDR
212 aarch64_fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
213 				       CORE_ADDR lm_addr, CORE_ADDR offset)
214 {
215   aarch64_gdbarch_tdep *tdep = gdbarch_tdep<aarch64_gdbarch_tdep> (gdbarch);
216   struct regcache *regcache;
217 
218   regcache = get_thread_arch_regcache (current_inferior ()->process_target (),
219 				       ptid, gdbarch);
220 
221   target_fetch_registers (regcache, tdep->tls_regnum_base);
222 
223   ULONGEST tpidr;
224   if (regcache->cooked_read (tdep->tls_regnum_base, &tpidr) != REG_VALID)
225     error (_("Unable to fetch %%tpidr"));
226 
227   /* %tpidr points to the TCB whose first member is the dtv
228       pointer.  */
229   CORE_ADDR dtv_addr = tpidr;
230   return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset);
231 }
232 
233 /* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
234 
235 static void
236 aarch64_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
237 {
238   aarch64_gdbarch_tdep *tdep = gdbarch_tdep<aarch64_gdbarch_tdep> (gdbarch);
239 
240   /* Generic FreeBSD support.  */
241   fbsd_init_abi (info, gdbarch);
242 
243   set_solib_svr4_fetch_link_map_offsets (gdbarch,
244 					 svr4_lp64_fetch_link_map_offsets);
245 
246   tramp_frame_prepend_unwinder (gdbarch, &aarch64_fbsd_sigframe);
247 
248   /* Enable longjmp.  */
249   tdep->jb_pc = 13;
250 
251   set_gdbarch_iterate_over_regset_sections
252     (gdbarch, aarch64_fbsd_iterate_over_regset_sections);
253   set_gdbarch_core_read_description (gdbarch,
254 				     aarch64_fbsd_core_read_description);
255 
256   if (tdep->has_tls ())
257     {
258       set_gdbarch_fetch_tls_load_module_address (gdbarch,
259 						 svr4_fetch_objfile_link_map);
260       set_gdbarch_get_thread_local_address
261 	(gdbarch, aarch64_fbsd_get_thread_local_address);
262     }
263 }
264 
265 void _initialize_aarch64_fbsd_tdep ();
266 void
267 _initialize_aarch64_fbsd_tdep ()
268 {
269   gdbarch_register_osabi (bfd_arch_aarch64, 0, GDB_OSABI_FREEBSD,
270 			  aarch64_fbsd_init_abi);
271 }
272