xref: /netbsd-src/external/gpl3/gdb.old/dist/gdb/sparc64-obsd-tdep.c (revision 6881a4007f077b54e5f51159c52b9b25f57deb0d)
1 /* Target-dependent code for OpenBSD/sparc64.
2 
3    Copyright (C) 2004-2023 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 #include "frame.h"
22 #include "frame-unwind.h"
23 #include "gdbcore.h"
24 #include "osabi.h"
25 #include "regcache.h"
26 #include "regset.h"
27 #include "symtab.h"
28 #include "objfiles.h"
29 #include "trad-frame.h"
30 #include "inferior.h"
31 
32 #include "obsd-tdep.h"
33 #include "sparc64-tdep.h"
34 #include "solib-svr4.h"
35 #include "bsd-uthread.h"
36 
37 /* Older OpenBSD versions used the traditional NetBSD core file
38    format, even for ports that use ELF.  These core files don't use
39    multiple register sets.  Instead, the general-purpose and
40    floating-point registers are lumped together in a single section.
41    Unlike on NetBSD, OpenBSD uses a different layout for its
42    general-purpose registers than the layout used for ptrace(2).
43 
44    Newer OpenBSD versions use ELF core files.  Here the register sets
45    match the ptrace(2) layout.  */
46 
47 /* From <machine/reg.h>.  */
48 const struct sparc_gregmap sparc64obsd_gregmap =
49 {
50   0 * 8,			/* "tstate" */
51   1 * 8,			/* %pc */
52   2 * 8,			/* %npc */
53   3 * 8,			/* %y */
54   -1,				/* %fprs */
55   -1,
56   5 * 8,			/* %g1 */
57   20 * 8,			/* %l0 */
58   4				/* sizeof (%y) */
59 };
60 
61 const struct sparc_gregmap sparc64obsd_core_gregmap =
62 {
63   0 * 8,			/* "tstate" */
64   1 * 8,			/* %pc */
65   2 * 8,			/* %npc */
66   3 * 8,			/* %y */
67   -1,				/* %fprs */
68   -1,
69   7 * 8,			/* %g1 */
70   22 * 8,			/* %l0 */
71   4				/* sizeof (%y) */
72 };
73 
74 static void
75 sparc64obsd_supply_gregset (const struct regset *regset,
76 			    struct regcache *regcache,
77 			    int regnum, const void *gregs, size_t len)
78 {
79   const void *fpregs = (char *)gregs + 288;
80 
81   if (len < 832)
82     {
83       sparc64_supply_gregset (&sparc64obsd_gregmap, regcache, regnum, gregs);
84       return;
85     }
86 
87   sparc64_supply_gregset (&sparc64obsd_core_gregmap, regcache, regnum, gregs);
88   sparc64_supply_fpregset (&sparc64_bsd_fpregmap, regcache, regnum, fpregs);
89 }
90 
91 static void
92 sparc64obsd_supply_fpregset (const struct regset *regset,
93 			     struct regcache *regcache,
94 			     int regnum, const void *fpregs, size_t len)
95 {
96   sparc64_supply_fpregset (&sparc64_bsd_fpregmap, regcache, regnum, fpregs);
97 }
98 
99 
100 /* Signal trampolines.  */
101 
102 /* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
103    in virtual memory.  The randomness makes it somewhat tricky to
104    detect it, but fortunately we can rely on the fact that the start
105    of the sigtramp routine is page-aligned.  We recognize the
106    trampoline by looking for the code that invokes the sigreturn
107    system call.  The offset where we can find that code varies from
108    release to release.
109 
110    By the way, the mapping mentioned above is read-only, so you cannot
111    place a breakpoint in the signal trampoline.  */
112 
113 /* Default page size.  */
114 static const int sparc64obsd_page_size = 8192;
115 
116 /* Offset for sigreturn(2).  */
117 static const int sparc64obsd_sigreturn_offset[] = {
118   0xf0,				/* OpenBSD 3.8 */
119   0xec,				/* OpenBSD 3.6 */
120   0xe8,				/* OpenBSD 3.2 */
121   -1
122 };
123 
124 static int
125 sparc64obsd_pc_in_sigtramp (CORE_ADDR pc, const char *name)
126 {
127   CORE_ADDR start_pc = (pc & ~(sparc64obsd_page_size - 1));
128   unsigned long insn;
129   const int *offset;
130 
131   if (name)
132     return 0;
133 
134   for (offset = sparc64obsd_sigreturn_offset; *offset != -1; offset++)
135     {
136       /* Check for "restore %g0, SYS_sigreturn, %g1".  */
137       insn = sparc_fetch_instruction (start_pc + *offset);
138       if (insn != 0x83e82067)
139 	continue;
140 
141       /* Check for "t ST_SYSCALL".  */
142       insn = sparc_fetch_instruction (start_pc + *offset + 8);
143       if (insn != 0x91d02000)
144 	continue;
145 
146       return 1;
147     }
148 
149   return 0;
150 }
151 
152 static struct sparc_frame_cache *
153 sparc64obsd_frame_cache (frame_info_ptr this_frame, void **this_cache)
154 {
155   struct sparc_frame_cache *cache;
156   CORE_ADDR addr;
157 
158   if (*this_cache)
159     return (struct sparc_frame_cache *) *this_cache;
160 
161   cache = sparc_frame_cache (this_frame, this_cache);
162   gdb_assert (cache == *this_cache);
163 
164   /* If we couldn't find the frame's function, we're probably dealing
165      with an on-stack signal trampoline.  */
166   if (cache->pc == 0)
167     {
168       cache->pc = get_frame_pc (this_frame);
169       cache->pc &= ~(sparc64obsd_page_size - 1);
170 
171       /* Since we couldn't find the frame's function, the cache was
172 	 initialized under the assumption that we're frameless.  */
173       sparc_record_save_insn (cache);
174       addr = get_frame_register_unsigned (this_frame, SPARC_FP_REGNUM);
175       if (addr & 1)
176 	addr += BIAS;
177       cache->base = addr;
178     }
179 
180   /* We find the appropriate instance of `struct sigcontext' at a
181      fixed offset in the signal frame.  */
182   addr = cache->base + 128 + 16;
183   cache->saved_regs = sparc64nbsd_sigcontext_saved_regs (addr, this_frame);
184 
185   return cache;
186 }
187 
188 static void
189 sparc64obsd_frame_this_id (frame_info_ptr this_frame, void **this_cache,
190 			   struct frame_id *this_id)
191 {
192   struct sparc_frame_cache *cache =
193     sparc64obsd_frame_cache (this_frame, this_cache);
194 
195   (*this_id) = frame_id_build (cache->base, cache->pc);
196 }
197 
198 static struct value *
199 sparc64obsd_frame_prev_register (frame_info_ptr this_frame,
200 				 void **this_cache, int regnum)
201 {
202   struct sparc_frame_cache *cache =
203     sparc64obsd_frame_cache (this_frame, this_cache);
204 
205   return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum);
206 }
207 
208 static int
209 sparc64obsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
210 				    frame_info_ptr this_frame,
211 				    void **this_cache)
212 {
213   CORE_ADDR pc = get_frame_pc (this_frame);
214   const char *name;
215 
216   find_pc_partial_function (pc, &name, NULL, NULL);
217   if (sparc64obsd_pc_in_sigtramp (pc, name))
218     return 1;
219 
220   return 0;
221 }
222 
223 static const struct frame_unwind sparc64obsd_frame_unwind =
224 {
225   "sparc64 openbsd sigtramp",
226   SIGTRAMP_FRAME,
227   default_frame_unwind_stop_reason,
228   sparc64obsd_frame_this_id,
229   sparc64obsd_frame_prev_register,
230   NULL,
231   sparc64obsd_sigtramp_frame_sniffer
232 };
233 
234 /* Kernel debugging support.  */
235 
236 static struct sparc_frame_cache *
237 sparc64obsd_trapframe_cache (frame_info_ptr this_frame, void **this_cache)
238 {
239   struct sparc_frame_cache *cache;
240   CORE_ADDR sp, trapframe_addr;
241   int regnum;
242 
243   if (*this_cache)
244     return (struct sparc_frame_cache *) *this_cache;
245 
246   cache = sparc_frame_cache (this_frame, this_cache);
247   gdb_assert (cache == *this_cache);
248 
249   sp = get_frame_register_unsigned (this_frame, SPARC_SP_REGNUM);
250   trapframe_addr = sp + BIAS + 176;
251 
252   cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
253 
254   cache->saved_regs[SPARC64_STATE_REGNUM].set_addr (trapframe_addr);
255   cache->saved_regs[SPARC64_PC_REGNUM].set_addr (trapframe_addr + 8);
256   cache->saved_regs[SPARC64_NPC_REGNUM].set_addr (trapframe_addr + 16);
257 
258   for (regnum = SPARC_G0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++)
259     cache->saved_regs[regnum].set_addr (trapframe_addr + 48
260 					+ (regnum - SPARC_G0_REGNUM) * 8);
261 
262   return cache;
263 }
264 
265 static void
266 sparc64obsd_trapframe_this_id (frame_info_ptr this_frame,
267 			       void **this_cache, struct frame_id *this_id)
268 {
269   struct sparc_frame_cache *cache =
270     sparc64obsd_trapframe_cache (this_frame, this_cache);
271 
272   (*this_id) = frame_id_build (cache->base, cache->pc);
273 }
274 
275 static struct value *
276 sparc64obsd_trapframe_prev_register (frame_info_ptr this_frame,
277 				     void **this_cache, int regnum)
278 {
279   struct sparc_frame_cache *cache =
280     sparc64obsd_trapframe_cache (this_frame, this_cache);
281 
282   return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum);
283 }
284 
285 static int
286 sparc64obsd_trapframe_sniffer (const struct frame_unwind *self,
287 			       frame_info_ptr this_frame,
288 			       void **this_cache)
289 {
290   CORE_ADDR pc;
291   ULONGEST pstate;
292   const char *name;
293 
294   /* Check whether we are in privileged mode, and bail out if we're not.  */
295   pstate = get_frame_register_unsigned (this_frame, SPARC64_PSTATE_REGNUM);
296   if ((pstate & SPARC64_PSTATE_PRIV) == 0)
297     return 0;
298 
299   pc = get_frame_address_in_block (this_frame);
300   find_pc_partial_function (pc, &name, NULL, NULL);
301   if (name && strcmp (name, "Lslowtrap_reenter") == 0)
302     return 1;
303 
304   return 0;
305 }
306 
307 static const struct frame_unwind sparc64obsd_trapframe_unwind =
308 {
309   "sparc64 openbsd trap",
310   NORMAL_FRAME,
311   default_frame_unwind_stop_reason,
312   sparc64obsd_trapframe_this_id,
313   sparc64obsd_trapframe_prev_register,
314   NULL,
315   sparc64obsd_trapframe_sniffer
316 };
317 
318 
319 /* Threads support.  */
320 
321 /* Offset wthin the thread structure where we can find %fp and %i7.  */
322 #define SPARC64OBSD_UTHREAD_FP_OFFSET	232
323 #define SPARC64OBSD_UTHREAD_PC_OFFSET	240
324 
325 static void
326 sparc64obsd_supply_uthread (struct regcache *regcache,
327 			    int regnum, CORE_ADDR addr)
328 {
329   struct gdbarch *gdbarch = regcache->arch ();
330   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
331   CORE_ADDR fp, fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
332   gdb_byte buf[8];
333 
334   /* This function calls functions that depend on the global current thread.  */
335   gdb_assert (regcache->ptid () == inferior_ptid);
336 
337   gdb_assert (regnum >= -1);
338 
339   fp = read_memory_unsigned_integer (fp_addr, 8, byte_order);
340   if (regnum == SPARC_SP_REGNUM || regnum == -1)
341     {
342       store_unsigned_integer (buf, 8, byte_order, fp);
343       regcache->raw_supply (SPARC_SP_REGNUM, buf);
344 
345       if (regnum == SPARC_SP_REGNUM)
346 	return;
347     }
348 
349   if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM
350       || regnum == -1)
351     {
352       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
353 
354       i7 = read_memory_unsigned_integer (i7_addr, 8, byte_order);
355       if (regnum == SPARC64_PC_REGNUM || regnum == -1)
356 	{
357 	  store_unsigned_integer (buf, 8, byte_order, i7 + 8);
358 	  regcache->raw_supply (SPARC64_PC_REGNUM, buf);
359 	}
360       if (regnum == SPARC64_NPC_REGNUM || regnum == -1)
361 	{
362 	  store_unsigned_integer (buf, 8, byte_order, i7 + 12);
363 	  regcache->raw_supply (SPARC64_NPC_REGNUM, buf);
364 	}
365 
366       if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM)
367 	return;
368     }
369 
370   sparc_supply_rwindow (regcache, fp, regnum);
371 }
372 
373 static void
374 sparc64obsd_collect_uthread(const struct regcache *regcache,
375 			    int regnum, CORE_ADDR addr)
376 {
377   struct gdbarch *gdbarch = regcache->arch ();
378   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
379   CORE_ADDR sp;
380   gdb_byte buf[8];
381 
382   /* This function calls functions that depend on the global current thread.  */
383   gdb_assert (regcache->ptid () == inferior_ptid);
384 
385   gdb_assert (regnum >= -1);
386 
387   if (regnum == SPARC_SP_REGNUM || regnum == -1)
388     {
389       CORE_ADDR fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
390 
391       regcache->raw_collect (SPARC_SP_REGNUM, buf);
392       write_memory (fp_addr,buf, 8);
393     }
394 
395   if (regnum == SPARC64_PC_REGNUM || regnum == -1)
396     {
397       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
398 
399       regcache->raw_collect (SPARC64_PC_REGNUM, buf);
400       i7 = extract_unsigned_integer (buf, 8, byte_order) - 8;
401       write_memory_unsigned_integer (i7_addr, 8, byte_order, i7);
402 
403       if (regnum == SPARC64_PC_REGNUM)
404 	return;
405     }
406 
407   regcache->raw_collect (SPARC_SP_REGNUM, buf);
408   sp = extract_unsigned_integer (buf, 8, byte_order);
409   sparc_collect_rwindow (regcache, sp, regnum);
410 }
411 
412 
413 static const struct regset sparc64obsd_gregset =
414   {
415     NULL, sparc64obsd_supply_gregset, NULL
416   };
417 
418 static const struct regset sparc64obsd_fpregset =
419   {
420     NULL, sparc64obsd_supply_fpregset, NULL
421   };
422 
423 static void
424 sparc64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
425 {
426   sparc_gdbarch_tdep *tdep = gdbarch_tdep<sparc_gdbarch_tdep> (gdbarch);
427 
428   tdep->gregset = &sparc64obsd_gregset;
429   tdep->sizeof_gregset = 288;
430   tdep->fpregset = &sparc64obsd_fpregset;
431   tdep->sizeof_fpregset = 272;
432 
433   /* Make sure we can single-step "new" syscalls.  */
434   tdep->step_trap = sparcnbsd_step_trap;
435 
436   frame_unwind_append_unwinder (gdbarch, &sparc64obsd_frame_unwind);
437   frame_unwind_append_unwinder (gdbarch, &sparc64obsd_trapframe_unwind);
438 
439   sparc64_init_abi (info, gdbarch);
440   obsd_init_abi (info, gdbarch);
441 
442   /* OpenBSD/sparc64 has SVR4-style shared libraries.  */
443   set_solib_svr4_fetch_link_map_offsets
444     (gdbarch, svr4_lp64_fetch_link_map_offsets);
445   set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
446 
447   /* OpenBSD provides a user-level threads implementation.  */
448   bsd_uthread_set_supply_uthread (gdbarch, sparc64obsd_supply_uthread);
449   bsd_uthread_set_collect_uthread (gdbarch, sparc64obsd_collect_uthread);
450 }
451 
452 void _initialize_sparc64obsd_tdep ();
453 void
454 _initialize_sparc64obsd_tdep ()
455 {
456   gdbarch_register_osabi (bfd_arch_sparc, bfd_mach_sparc_v9,
457 			  GDB_OSABI_OPENBSD, sparc64obsd_init_abi);
458 }
459