Commit | Line | Data |
---|---|---|
c877c8e6 | 1 | /* Target-dependent code for GDB, the GNU debugger. |
4e052eda | 2 | |
6aba47ca | 3 | Copyright (C) 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997, |
9b254dd1 | 4 | 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 |
76a9d10f | 5 | Free Software Foundation, Inc. |
c877c8e6 KB |
6 | |
7 | This file is part of GDB. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 11 | the Free Software Foundation; either version 3 of the License, or |
c877c8e6 KB |
12 | (at your option) any later version. |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
c877c8e6 KB |
21 | |
22 | #include "defs.h" | |
23 | #include "frame.h" | |
24 | #include "inferior.h" | |
25 | #include "symtab.h" | |
26 | #include "target.h" | |
27 | #include "gdbcore.h" | |
28 | #include "gdbcmd.h" | |
29 | #include "symfile.h" | |
30 | #include "objfiles.h" | |
4e052eda | 31 | #include "regcache.h" |
fd0407d6 | 32 | #include "value.h" |
4be87837 | 33 | #include "osabi.h" |
f9be684a | 34 | #include "regset.h" |
6ded7999 | 35 | #include "solib-svr4.h" |
9aa1e687 | 36 | #include "ppc-tdep.h" |
61a65099 KB |
37 | #include "trad-frame.h" |
38 | #include "frame-unwind.h" | |
a8f60bfc | 39 | #include "tramp-frame.h" |
9aa1e687 | 40 | |
6974274f | 41 | static CORE_ADDR |
52f729a7 | 42 | ppc_linux_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc) |
c877c8e6 | 43 | { |
50fd1280 | 44 | gdb_byte buf[4]; |
c877c8e6 KB |
45 | struct obj_section *sect; |
46 | struct objfile *objfile; | |
47 | unsigned long insn; | |
48 | CORE_ADDR plt_start = 0; | |
49 | CORE_ADDR symtab = 0; | |
50 | CORE_ADDR strtab = 0; | |
51 | int num_slots = -1; | |
52 | int reloc_index = -1; | |
53 | CORE_ADDR plt_table; | |
54 | CORE_ADDR reloc; | |
55 | CORE_ADDR sym; | |
56 | long symidx; | |
57 | char symname[1024]; | |
58 | struct minimal_symbol *msymbol; | |
59 | ||
82233d87 | 60 | /* Find the section pc is in; if not in .plt, try the default method. */ |
c877c8e6 KB |
61 | sect = find_pc_section (pc); |
62 | if (!sect || strcmp (sect->the_bfd_section->name, ".plt") != 0) | |
82233d87 | 63 | return find_solib_trampoline_target (frame, pc); |
c877c8e6 KB |
64 | |
65 | objfile = sect->objfile; | |
66 | ||
67 | /* Pick up the instruction at pc. It had better be of the | |
68 | form | |
69 | li r11, IDX | |
70 | ||
71 | where IDX is an index into the plt_table. */ | |
72 | ||
73 | if (target_read_memory (pc, buf, 4) != 0) | |
74 | return 0; | |
75 | insn = extract_unsigned_integer (buf, 4); | |
76 | ||
77 | if ((insn & 0xffff0000) != 0x39600000 /* li r11, VAL */ ) | |
78 | return 0; | |
79 | ||
80 | reloc_index = (insn << 16) >> 16; | |
81 | ||
82 | /* Find the objfile that pc is in and obtain the information | |
83 | necessary for finding the symbol name. */ | |
84 | for (sect = objfile->sections; sect < objfile->sections_end; ++sect) | |
85 | { | |
86 | const char *secname = sect->the_bfd_section->name; | |
87 | if (strcmp (secname, ".plt") == 0) | |
88 | plt_start = sect->addr; | |
89 | else if (strcmp (secname, ".rela.plt") == 0) | |
90 | num_slots = ((int) sect->endaddr - (int) sect->addr) / 12; | |
91 | else if (strcmp (secname, ".dynsym") == 0) | |
92 | symtab = sect->addr; | |
93 | else if (strcmp (secname, ".dynstr") == 0) | |
94 | strtab = sect->addr; | |
95 | } | |
96 | ||
97 | /* Make sure we have all the information we need. */ | |
98 | if (plt_start == 0 || num_slots == -1 || symtab == 0 || strtab == 0) | |
99 | return 0; | |
100 | ||
101 | /* Compute the value of the plt table */ | |
102 | plt_table = plt_start + 72 + 8 * num_slots; | |
103 | ||
104 | /* Get address of the relocation entry (Elf32_Rela) */ | |
105 | if (target_read_memory (plt_table + reloc_index, buf, 4) != 0) | |
106 | return 0; | |
7c0b4a20 | 107 | reloc = extract_unsigned_integer (buf, 4); |
c877c8e6 KB |
108 | |
109 | sect = find_pc_section (reloc); | |
110 | if (!sect) | |
111 | return 0; | |
112 | ||
113 | if (strcmp (sect->the_bfd_section->name, ".text") == 0) | |
114 | return reloc; | |
115 | ||
116 | /* Now get the r_info field which is the relocation type and symbol | |
117 | index. */ | |
118 | if (target_read_memory (reloc + 4, buf, 4) != 0) | |
119 | return 0; | |
120 | symidx = extract_unsigned_integer (buf, 4); | |
121 | ||
122 | /* Shift out the relocation type leaving just the symbol index */ | |
123 | /* symidx = ELF32_R_SYM(symidx); */ | |
124 | symidx = symidx >> 8; | |
125 | ||
126 | /* compute the address of the symbol */ | |
127 | sym = symtab + symidx * 4; | |
128 | ||
129 | /* Fetch the string table index */ | |
130 | if (target_read_memory (sym, buf, 4) != 0) | |
131 | return 0; | |
132 | symidx = extract_unsigned_integer (buf, 4); | |
133 | ||
134 | /* Fetch the string; we don't know how long it is. Is it possible | |
135 | that the following will fail because we're trying to fetch too | |
136 | much? */ | |
50fd1280 AC |
137 | if (target_read_memory (strtab + symidx, (gdb_byte *) symname, |
138 | sizeof (symname)) != 0) | |
c877c8e6 KB |
139 | return 0; |
140 | ||
141 | /* This might not work right if we have multiple symbols with the | |
142 | same name; the only way to really get it right is to perform | |
143 | the same sort of lookup as the dynamic linker. */ | |
5520a790 | 144 | msymbol = lookup_minimal_symbol_text (symname, NULL); |
c877c8e6 KB |
145 | if (!msymbol) |
146 | return 0; | |
147 | ||
148 | return SYMBOL_VALUE_ADDRESS (msymbol); | |
149 | } | |
150 | ||
122a33de KB |
151 | /* ppc_linux_memory_remove_breakpoints attempts to remove a breakpoint |
152 | in much the same fashion as memory_remove_breakpoint in mem-break.c, | |
153 | but is careful not to write back the previous contents if the code | |
154 | in question has changed in between inserting the breakpoint and | |
155 | removing it. | |
156 | ||
157 | Here is the problem that we're trying to solve... | |
158 | ||
159 | Once upon a time, before introducing this function to remove | |
160 | breakpoints from the inferior, setting a breakpoint on a shared | |
161 | library function prior to running the program would not work | |
162 | properly. In order to understand the problem, it is first | |
163 | necessary to understand a little bit about dynamic linking on | |
164 | this platform. | |
165 | ||
166 | A call to a shared library function is accomplished via a bl | |
167 | (branch-and-link) instruction whose branch target is an entry | |
168 | in the procedure linkage table (PLT). The PLT in the object | |
169 | file is uninitialized. To gdb, prior to running the program, the | |
170 | entries in the PLT are all zeros. | |
171 | ||
172 | Once the program starts running, the shared libraries are loaded | |
173 | and the procedure linkage table is initialized, but the entries in | |
174 | the table are not (necessarily) resolved. Once a function is | |
175 | actually called, the code in the PLT is hit and the function is | |
176 | resolved. In order to better illustrate this, an example is in | |
177 | order; the following example is from the gdb testsuite. | |
178 | ||
179 | We start the program shmain. | |
180 | ||
181 | [kev@arroyo testsuite]$ ../gdb gdb.base/shmain | |
182 | [...] | |
183 | ||
184 | We place two breakpoints, one on shr1 and the other on main. | |
185 | ||
186 | (gdb) b shr1 | |
187 | Breakpoint 1 at 0x100409d4 | |
188 | (gdb) b main | |
189 | Breakpoint 2 at 0x100006a0: file gdb.base/shmain.c, line 44. | |
190 | ||
191 | Examine the instruction (and the immediatly following instruction) | |
192 | upon which the breakpoint was placed. Note that the PLT entry | |
193 | for shr1 contains zeros. | |
194 | ||
195 | (gdb) x/2i 0x100409d4 | |
196 | 0x100409d4 <shr1>: .long 0x0 | |
197 | 0x100409d8 <shr1+4>: .long 0x0 | |
198 | ||
199 | Now run 'til main. | |
200 | ||
201 | (gdb) r | |
202 | Starting program: gdb.base/shmain | |
203 | Breakpoint 1 at 0xffaf790: file gdb.base/shr1.c, line 19. | |
204 | ||
205 | Breakpoint 2, main () | |
206 | at gdb.base/shmain.c:44 | |
207 | 44 g = 1; | |
208 | ||
209 | Examine the PLT again. Note that the loading of the shared | |
210 | library has initialized the PLT to code which loads a constant | |
211 | (which I think is an index into the GOT) into r11 and then | |
212 | branchs a short distance to the code which actually does the | |
213 | resolving. | |
214 | ||
215 | (gdb) x/2i 0x100409d4 | |
216 | 0x100409d4 <shr1>: li r11,4 | |
217 | 0x100409d8 <shr1+4>: b 0x10040984 <sg+4> | |
218 | (gdb) c | |
219 | Continuing. | |
220 | ||
221 | Breakpoint 1, shr1 (x=1) | |
222 | at gdb.base/shr1.c:19 | |
223 | 19 l = 1; | |
224 | ||
225 | Now we've hit the breakpoint at shr1. (The breakpoint was | |
226 | reset from the PLT entry to the actual shr1 function after the | |
227 | shared library was loaded.) Note that the PLT entry has been | |
228 | resolved to contain a branch that takes us directly to shr1. | |
229 | (The real one, not the PLT entry.) | |
230 | ||
231 | (gdb) x/2i 0x100409d4 | |
232 | 0x100409d4 <shr1>: b 0xffaf76c <shr1> | |
233 | 0x100409d8 <shr1+4>: b 0x10040984 <sg+4> | |
234 | ||
235 | The thing to note here is that the PLT entry for shr1 has been | |
236 | changed twice. | |
237 | ||
238 | Now the problem should be obvious. GDB places a breakpoint (a | |
239 | trap instruction) on the zero value of the PLT entry for shr1. | |
240 | Later on, after the shared library had been loaded and the PLT | |
241 | initialized, GDB gets a signal indicating this fact and attempts | |
242 | (as it always does when it stops) to remove all the breakpoints. | |
243 | ||
244 | The breakpoint removal was causing the former contents (a zero | |
245 | word) to be written back to the now initialized PLT entry thus | |
246 | destroying a portion of the initialization that had occurred only a | |
247 | short time ago. When execution continued, the zero word would be | |
248 | executed as an instruction an an illegal instruction trap was | |
249 | generated instead. (0 is not a legal instruction.) | |
250 | ||
251 | The fix for this problem was fairly straightforward. The function | |
252 | memory_remove_breakpoint from mem-break.c was copied to this file, | |
253 | modified slightly, and renamed to ppc_linux_memory_remove_breakpoint. | |
254 | In tm-linux.h, MEMORY_REMOVE_BREAKPOINT is defined to call this new | |
255 | function. | |
256 | ||
257 | The differences between ppc_linux_memory_remove_breakpoint () and | |
258 | memory_remove_breakpoint () are minor. All that the former does | |
259 | that the latter does not is check to make sure that the breakpoint | |
260 | location actually contains a breakpoint (trap instruction) prior | |
261 | to attempting to write back the old contents. If it does contain | |
262 | a trap instruction, we allow the old contents to be written back. | |
263 | Otherwise, we silently do nothing. | |
264 | ||
265 | The big question is whether memory_remove_breakpoint () should be | |
266 | changed to have the same functionality. The downside is that more | |
267 | traffic is generated for remote targets since we'll have an extra | |
268 | fetch of a memory word each time a breakpoint is removed. | |
269 | ||
270 | For the time being, we'll leave this self-modifying-code-friendly | |
271 | version in ppc-linux-tdep.c, but it ought to be migrated somewhere | |
272 | else in the event that some other platform has similar needs with | |
273 | regard to removing breakpoints in some potentially self modifying | |
274 | code. */ | |
482ca3f5 | 275 | int |
ae4b2284 MD |
276 | ppc_linux_memory_remove_breakpoint (struct gdbarch *gdbarch, |
277 | struct bp_target_info *bp_tgt) | |
482ca3f5 | 278 | { |
8181d85f | 279 | CORE_ADDR addr = bp_tgt->placed_address; |
f4f9705a | 280 | const unsigned char *bp; |
482ca3f5 KB |
281 | int val; |
282 | int bplen; | |
50fd1280 | 283 | gdb_byte old_contents[BREAKPOINT_MAX]; |
482ca3f5 KB |
284 | |
285 | /* Determine appropriate breakpoint contents and size for this address. */ | |
ae4b2284 | 286 | bp = gdbarch_breakpoint_from_pc (gdbarch, &addr, &bplen); |
482ca3f5 | 287 | if (bp == NULL) |
8a3fe4f8 | 288 | error (_("Software breakpoints not implemented for this target.")); |
482ca3f5 KB |
289 | |
290 | val = target_read_memory (addr, old_contents, bplen); | |
291 | ||
292 | /* If our breakpoint is no longer at the address, this means that the | |
293 | program modified the code on us, so it is wrong to put back the | |
294 | old value */ | |
295 | if (val == 0 && memcmp (bp, old_contents, bplen) == 0) | |
8181d85f | 296 | val = target_write_memory (addr, bp_tgt->shadow_contents, bplen); |
482ca3f5 KB |
297 | |
298 | return val; | |
299 | } | |
6ded7999 | 300 | |
b9ff3018 AC |
301 | /* For historic reasons, PPC 32 GNU/Linux follows PowerOpen rather |
302 | than the 32 bit SYSV R4 ABI structure return convention - all | |
303 | structures, no matter their size, are put in memory. Vectors, | |
304 | which were added later, do get returned in a register though. */ | |
305 | ||
05580c65 AC |
306 | static enum return_value_convention |
307 | ppc_linux_return_value (struct gdbarch *gdbarch, struct type *valtype, | |
50fd1280 AC |
308 | struct regcache *regcache, gdb_byte *readbuf, |
309 | const gdb_byte *writebuf) | |
b9ff3018 | 310 | { |
05580c65 AC |
311 | if ((TYPE_CODE (valtype) == TYPE_CODE_STRUCT |
312 | || TYPE_CODE (valtype) == TYPE_CODE_UNION) | |
313 | && !((TYPE_LENGTH (valtype) == 16 || TYPE_LENGTH (valtype) == 8) | |
314 | && TYPE_VECTOR (valtype))) | |
315 | return RETURN_VALUE_STRUCT_CONVENTION; | |
316 | else | |
475b6ddd AC |
317 | return ppc_sysv_abi_return_value (gdbarch, valtype, regcache, readbuf, |
318 | writebuf); | |
b9ff3018 AC |
319 | } |
320 | ||
f470a70a JB |
321 | /* Macros for matching instructions. Note that, since all the |
322 | operands are masked off before they're or-ed into the instruction, | |
323 | you can use -1 to make masks. */ | |
324 | ||
325 | #define insn_d(opcd, rts, ra, d) \ | |
326 | ((((opcd) & 0x3f) << 26) \ | |
327 | | (((rts) & 0x1f) << 21) \ | |
328 | | (((ra) & 0x1f) << 16) \ | |
329 | | ((d) & 0xffff)) | |
330 | ||
331 | #define insn_ds(opcd, rts, ra, d, xo) \ | |
332 | ((((opcd) & 0x3f) << 26) \ | |
333 | | (((rts) & 0x1f) << 21) \ | |
334 | | (((ra) & 0x1f) << 16) \ | |
335 | | ((d) & 0xfffc) \ | |
336 | | ((xo) & 0x3)) | |
337 | ||
338 | #define insn_xfx(opcd, rts, spr, xo) \ | |
339 | ((((opcd) & 0x3f) << 26) \ | |
340 | | (((rts) & 0x1f) << 21) \ | |
341 | | (((spr) & 0x1f) << 16) \ | |
342 | | (((spr) & 0x3e0) << 6) \ | |
343 | | (((xo) & 0x3ff) << 1)) | |
344 | ||
345 | /* Read a PPC instruction from memory. PPC instructions are always | |
346 | big-endian, no matter what endianness the program is running in, so | |
347 | we can't use read_memory_integer or one of its friends here. */ | |
348 | static unsigned int | |
349 | read_insn (CORE_ADDR pc) | |
350 | { | |
351 | unsigned char buf[4]; | |
352 | ||
353 | read_memory (pc, buf, 4); | |
354 | return (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3]; | |
355 | } | |
356 | ||
357 | ||
358 | /* An instruction to match. */ | |
359 | struct insn_pattern | |
360 | { | |
361 | unsigned int mask; /* mask the insn with this... */ | |
362 | unsigned int data; /* ...and see if it matches this. */ | |
363 | int optional; /* If non-zero, this insn may be absent. */ | |
364 | }; | |
365 | ||
366 | /* Return non-zero if the instructions at PC match the series | |
367 | described in PATTERN, or zero otherwise. PATTERN is an array of | |
368 | 'struct insn_pattern' objects, terminated by an entry whose mask is | |
369 | zero. | |
370 | ||
371 | When the match is successful, fill INSN[i] with what PATTERN[i] | |
372 | matched. If PATTERN[i] is optional, and the instruction wasn't | |
373 | present, set INSN[i] to 0 (which is not a valid PPC instruction). | |
374 | INSN should have as many elements as PATTERN. Note that, if | |
375 | PATTERN contains optional instructions which aren't present in | |
376 | memory, then INSN will have holes, so INSN[i] isn't necessarily the | |
377 | i'th instruction in memory. */ | |
378 | static int | |
379 | insns_match_pattern (CORE_ADDR pc, | |
380 | struct insn_pattern *pattern, | |
381 | unsigned int *insn) | |
382 | { | |
383 | int i; | |
384 | ||
385 | for (i = 0; pattern[i].mask; i++) | |
386 | { | |
387 | insn[i] = read_insn (pc); | |
388 | if ((insn[i] & pattern[i].mask) == pattern[i].data) | |
389 | pc += 4; | |
390 | else if (pattern[i].optional) | |
391 | insn[i] = 0; | |
392 | else | |
393 | return 0; | |
394 | } | |
395 | ||
396 | return 1; | |
397 | } | |
398 | ||
399 | ||
400 | /* Return the 'd' field of the d-form instruction INSN, properly | |
401 | sign-extended. */ | |
402 | static CORE_ADDR | |
403 | insn_d_field (unsigned int insn) | |
404 | { | |
405 | return ((((CORE_ADDR) insn & 0xffff) ^ 0x8000) - 0x8000); | |
406 | } | |
407 | ||
408 | ||
409 | /* Return the 'ds' field of the ds-form instruction INSN, with the two | |
410 | zero bits concatenated at the right, and properly | |
411 | sign-extended. */ | |
412 | static CORE_ADDR | |
413 | insn_ds_field (unsigned int insn) | |
414 | { | |
415 | return ((((CORE_ADDR) insn & 0xfffc) ^ 0x8000) - 0x8000); | |
416 | } | |
417 | ||
418 | ||
e538d2d7 | 419 | /* If DESC is the address of a 64-bit PowerPC GNU/Linux function |
d64558a5 JB |
420 | descriptor, return the descriptor's entry point. */ |
421 | static CORE_ADDR | |
422 | ppc64_desc_entry_point (CORE_ADDR desc) | |
423 | { | |
424 | /* The first word of the descriptor is the entry point. */ | |
425 | return (CORE_ADDR) read_memory_unsigned_integer (desc, 8); | |
426 | } | |
427 | ||
428 | ||
f470a70a JB |
429 | /* Pattern for the standard linkage function. These are built by |
430 | build_plt_stub in elf64-ppc.c, whose GLINK argument is always | |
431 | zero. */ | |
432 | static struct insn_pattern ppc64_standard_linkage[] = | |
433 | { | |
434 | /* addis r12, r2, <any> */ | |
435 | { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 }, | |
436 | ||
437 | /* std r2, 40(r1) */ | |
438 | { -1, insn_ds (62, 2, 1, 40, 0), 0 }, | |
439 | ||
440 | /* ld r11, <any>(r12) */ | |
441 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 }, | |
442 | ||
443 | /* addis r12, r12, 1 <optional> */ | |
444 | { insn_d (-1, -1, -1, -1), insn_d (15, 12, 2, 1), 1 }, | |
445 | ||
446 | /* ld r2, <any>(r12) */ | |
447 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 12, 0, 0), 0 }, | |
448 | ||
449 | /* addis r12, r12, 1 <optional> */ | |
450 | { insn_d (-1, -1, -1, -1), insn_d (15, 12, 2, 1), 1 }, | |
451 | ||
452 | /* mtctr r11 */ | |
453 | { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), | |
454 | 0 }, | |
455 | ||
456 | /* ld r11, <any>(r12) */ | |
457 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 }, | |
458 | ||
459 | /* bctr */ | |
460 | { -1, 0x4e800420, 0 }, | |
461 | ||
462 | { 0, 0, 0 } | |
463 | }; | |
464 | #define PPC64_STANDARD_LINKAGE_LEN \ | |
465 | (sizeof (ppc64_standard_linkage) / sizeof (ppc64_standard_linkage[0])) | |
466 | ||
f470a70a JB |
467 | /* When the dynamic linker is doing lazy symbol resolution, the first |
468 | call to a function in another object will go like this: | |
469 | ||
470 | - The user's function calls the linkage function: | |
471 | ||
472 | 100007c4: 4b ff fc d5 bl 10000498 | |
473 | 100007c8: e8 41 00 28 ld r2,40(r1) | |
474 | ||
475 | - The linkage function loads the entry point (and other stuff) from | |
476 | the function descriptor in the PLT, and jumps to it: | |
477 | ||
478 | 10000498: 3d 82 00 00 addis r12,r2,0 | |
479 | 1000049c: f8 41 00 28 std r2,40(r1) | |
480 | 100004a0: e9 6c 80 98 ld r11,-32616(r12) | |
481 | 100004a4: e8 4c 80 a0 ld r2,-32608(r12) | |
482 | 100004a8: 7d 69 03 a6 mtctr r11 | |
483 | 100004ac: e9 6c 80 a8 ld r11,-32600(r12) | |
484 | 100004b0: 4e 80 04 20 bctr | |
485 | ||
486 | - But since this is the first time that PLT entry has been used, it | |
487 | sends control to its glink entry. That loads the number of the | |
488 | PLT entry and jumps to the common glink0 code: | |
489 | ||
490 | 10000c98: 38 00 00 00 li r0,0 | |
491 | 10000c9c: 4b ff ff dc b 10000c78 | |
492 | ||
493 | - The common glink0 code then transfers control to the dynamic | |
494 | linker's fixup code: | |
495 | ||
496 | 10000c78: e8 41 00 28 ld r2,40(r1) | |
497 | 10000c7c: 3d 82 00 00 addis r12,r2,0 | |
498 | 10000c80: e9 6c 80 80 ld r11,-32640(r12) | |
499 | 10000c84: e8 4c 80 88 ld r2,-32632(r12) | |
500 | 10000c88: 7d 69 03 a6 mtctr r11 | |
501 | 10000c8c: e9 6c 80 90 ld r11,-32624(r12) | |
502 | 10000c90: 4e 80 04 20 bctr | |
503 | ||
504 | Eventually, this code will figure out how to skip all of this, | |
505 | including the dynamic linker. At the moment, we just get through | |
506 | the linkage function. */ | |
507 | ||
508 | /* If the current thread is about to execute a series of instructions | |
509 | at PC matching the ppc64_standard_linkage pattern, and INSN is the result | |
510 | from that pattern match, return the code address to which the | |
511 | standard linkage function will send them. (This doesn't deal with | |
512 | dynamic linker lazy symbol resolution stubs.) */ | |
513 | static CORE_ADDR | |
52f729a7 UW |
514 | ppc64_standard_linkage_target (struct frame_info *frame, |
515 | CORE_ADDR pc, unsigned int *insn) | |
f470a70a | 516 | { |
52f729a7 | 517 | struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (frame)); |
f470a70a JB |
518 | |
519 | /* The address of the function descriptor this linkage function | |
520 | references. */ | |
521 | CORE_ADDR desc | |
52f729a7 UW |
522 | = ((CORE_ADDR) get_frame_register_unsigned (frame, |
523 | tdep->ppc_gp0_regnum + 2) | |
f470a70a JB |
524 | + (insn_d_field (insn[0]) << 16) |
525 | + insn_ds_field (insn[2])); | |
526 | ||
527 | /* The first word of the descriptor is the entry point. Return that. */ | |
d64558a5 | 528 | return ppc64_desc_entry_point (desc); |
f470a70a JB |
529 | } |
530 | ||
531 | ||
532 | /* Given that we've begun executing a call trampoline at PC, return | |
533 | the entry point of the function the trampoline will go to. */ | |
534 | static CORE_ADDR | |
52f729a7 | 535 | ppc64_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc) |
f470a70a JB |
536 | { |
537 | unsigned int ppc64_standard_linkage_insn[PPC64_STANDARD_LINKAGE_LEN]; | |
538 | ||
539 | if (insns_match_pattern (pc, ppc64_standard_linkage, | |
540 | ppc64_standard_linkage_insn)) | |
52f729a7 UW |
541 | return ppc64_standard_linkage_target (frame, pc, |
542 | ppc64_standard_linkage_insn); | |
f470a70a JB |
543 | else |
544 | return 0; | |
545 | } | |
546 | ||
547 | ||
2bbe3cc1 | 548 | /* Support for convert_from_func_ptr_addr (ARCH, ADDR, TARG) on PPC |
e2d0e7eb | 549 | GNU/Linux. |
02631ec0 JB |
550 | |
551 | Usually a function pointer's representation is simply the address | |
2bbe3cc1 DJ |
552 | of the function. On GNU/Linux on the PowerPC however, a function |
553 | pointer may be a pointer to a function descriptor. | |
554 | ||
555 | For PPC64, a function descriptor is a TOC entry, in a data section, | |
556 | which contains three words: the first word is the address of the | |
557 | function, the second word is the TOC pointer (r2), and the third word | |
558 | is the static chain value. | |
559 | ||
560 | For PPC32, there are two kinds of function pointers: non-secure and | |
561 | secure. Non-secure function pointers point directly to the | |
562 | function in a code section and thus need no translation. Secure | |
563 | ones (from GCC's -msecure-plt option) are in a data section and | |
564 | contain one word: the address of the function. | |
565 | ||
566 | Throughout GDB it is currently assumed that a function pointer contains | |
567 | the address of the function, which is not easy to fix. In addition, the | |
e538d2d7 JB |
568 | conversion of a function address to a function pointer would |
569 | require allocation of a TOC entry in the inferior's memory space, | |
570 | with all its drawbacks. To be able to call C++ virtual methods in | |
571 | the inferior (which are called via function pointers), | |
572 | find_function_addr uses this function to get the function address | |
2bbe3cc1 | 573 | from a function pointer. |
02631ec0 | 574 | |
2bbe3cc1 DJ |
575 | If ADDR points at what is clearly a function descriptor, transform |
576 | it into the address of the corresponding function, if needed. Be | |
577 | conservative, otherwise GDB will do the transformation on any | |
578 | random addresses such as occur when there is no symbol table. */ | |
02631ec0 JB |
579 | |
580 | static CORE_ADDR | |
2bbe3cc1 DJ |
581 | ppc_linux_convert_from_func_ptr_addr (struct gdbarch *gdbarch, |
582 | CORE_ADDR addr, | |
583 | struct target_ops *targ) | |
02631ec0 | 584 | { |
2bbe3cc1 | 585 | struct gdbarch_tdep *tdep; |
b6591e8b | 586 | struct section_table *s = target_section_by_addr (targ, addr); |
2bbe3cc1 DJ |
587 | char *sect_name = NULL; |
588 | ||
589 | if (!s) | |
590 | return addr; | |
591 | ||
592 | tdep = gdbarch_tdep (gdbarch); | |
593 | ||
594 | switch (tdep->wordsize) | |
595 | { | |
596 | case 4: | |
597 | sect_name = ".plt"; | |
598 | break; | |
599 | case 8: | |
600 | sect_name = ".opd"; | |
601 | break; | |
602 | default: | |
603 | internal_error (__FILE__, __LINE__, | |
604 | _("failed internal consistency check")); | |
605 | } | |
02631ec0 | 606 | |
9b540880 | 607 | /* Check if ADDR points to a function descriptor. */ |
2bbe3cc1 DJ |
608 | |
609 | /* NOTE: this depends on the coincidence that the address of a functions | |
610 | entry point is contained in the first word of its function descriptor | |
611 | for both PPC-64 and for PPC-32 with secure PLTs. */ | |
612 | if ((strcmp (s->the_bfd_section->name, sect_name) == 0) | |
613 | && s->the_bfd_section->flags & SEC_DATA) | |
614 | return get_target_memory_unsigned (targ, addr, tdep->wordsize); | |
9b540880 AC |
615 | |
616 | return addr; | |
02631ec0 JB |
617 | } |
618 | ||
f2db237a AM |
619 | /* This wrapper clears areas in the linux gregset not written by |
620 | ppc_collect_gregset. */ | |
621 | ||
f9be684a | 622 | static void |
f2db237a AM |
623 | ppc_linux_collect_gregset (const struct regset *regset, |
624 | const struct regcache *regcache, | |
625 | int regnum, void *gregs, size_t len) | |
f9be684a | 626 | { |
f2db237a AM |
627 | if (regnum == -1) |
628 | memset (gregs, 0, len); | |
629 | ppc_collect_gregset (regset, regcache, regnum, gregs, len); | |
f9be684a AC |
630 | } |
631 | ||
f2db237a AM |
632 | /* Regset descriptions. */ |
633 | static const struct ppc_reg_offsets ppc32_linux_reg_offsets = | |
634 | { | |
635 | /* General-purpose registers. */ | |
636 | /* .r0_offset = */ 0, | |
637 | /* .gpr_size = */ 4, | |
638 | /* .xr_size = */ 4, | |
639 | /* .pc_offset = */ 128, | |
640 | /* .ps_offset = */ 132, | |
641 | /* .cr_offset = */ 152, | |
642 | /* .lr_offset = */ 144, | |
643 | /* .ctr_offset = */ 140, | |
644 | /* .xer_offset = */ 148, | |
645 | /* .mq_offset = */ 156, | |
646 | ||
647 | /* Floating-point registers. */ | |
648 | /* .f0_offset = */ 0, | |
649 | /* .fpscr_offset = */ 256, | |
650 | /* .fpscr_size = */ 8, | |
651 | ||
652 | /* AltiVec registers. */ | |
653 | /* .vr0_offset = */ 0, | |
06caf7d2 CES |
654 | /* .vscr_offset = */ 512 + 12, |
655 | /* .vrsave_offset = */ 528 | |
f2db237a | 656 | }; |
f9be684a | 657 | |
f2db237a AM |
658 | static const struct ppc_reg_offsets ppc64_linux_reg_offsets = |
659 | { | |
660 | /* General-purpose registers. */ | |
661 | /* .r0_offset = */ 0, | |
662 | /* .gpr_size = */ 8, | |
663 | /* .xr_size = */ 8, | |
664 | /* .pc_offset = */ 256, | |
665 | /* .ps_offset = */ 264, | |
666 | /* .cr_offset = */ 304, | |
667 | /* .lr_offset = */ 288, | |
668 | /* .ctr_offset = */ 280, | |
669 | /* .xer_offset = */ 296, | |
670 | /* .mq_offset = */ 312, | |
671 | ||
672 | /* Floating-point registers. */ | |
673 | /* .f0_offset = */ 0, | |
674 | /* .fpscr_offset = */ 256, | |
675 | /* .fpscr_size = */ 8, | |
676 | ||
677 | /* AltiVec registers. */ | |
678 | /* .vr0_offset = */ 0, | |
06caf7d2 CES |
679 | /* .vscr_offset = */ 512 + 12, |
680 | /* .vrsave_offset = */ 528 | |
f2db237a | 681 | }; |
2fda4977 | 682 | |
f2db237a AM |
683 | static const struct regset ppc32_linux_gregset = { |
684 | &ppc32_linux_reg_offsets, | |
685 | ppc_supply_gregset, | |
686 | ppc_linux_collect_gregset, | |
687 | NULL | |
f9be684a AC |
688 | }; |
689 | ||
f2db237a AM |
690 | static const struct regset ppc64_linux_gregset = { |
691 | &ppc64_linux_reg_offsets, | |
692 | ppc_supply_gregset, | |
693 | ppc_linux_collect_gregset, | |
694 | NULL | |
695 | }; | |
f9be684a | 696 | |
f2db237a AM |
697 | static const struct regset ppc32_linux_fpregset = { |
698 | &ppc32_linux_reg_offsets, | |
699 | ppc_supply_fpregset, | |
700 | ppc_collect_fpregset, | |
701 | NULL | |
f9be684a AC |
702 | }; |
703 | ||
06caf7d2 CES |
704 | static const struct regset ppc32_linux_vrregset = { |
705 | &ppc32_linux_reg_offsets, | |
706 | ppc_supply_vrregset, | |
707 | ppc_collect_vrregset, | |
708 | NULL | |
709 | }; | |
710 | ||
f2db237a AM |
711 | const struct regset * |
712 | ppc_linux_gregset (int wordsize) | |
2fda4977 | 713 | { |
f2db237a | 714 | return wordsize == 8 ? &ppc64_linux_gregset : &ppc32_linux_gregset; |
2fda4977 DJ |
715 | } |
716 | ||
f2db237a AM |
717 | const struct regset * |
718 | ppc_linux_fpregset (void) | |
719 | { | |
720 | return &ppc32_linux_fpregset; | |
721 | } | |
2fda4977 | 722 | |
f9be684a AC |
723 | static const struct regset * |
724 | ppc_linux_regset_from_core_section (struct gdbarch *core_arch, | |
725 | const char *sect_name, size_t sect_size) | |
2fda4977 | 726 | { |
f9be684a AC |
727 | struct gdbarch_tdep *tdep = gdbarch_tdep (core_arch); |
728 | if (strcmp (sect_name, ".reg") == 0) | |
2fda4977 | 729 | { |
f9be684a AC |
730 | if (tdep->wordsize == 4) |
731 | return &ppc32_linux_gregset; | |
2fda4977 | 732 | else |
f9be684a | 733 | return &ppc64_linux_gregset; |
2fda4977 | 734 | } |
f9be684a | 735 | if (strcmp (sect_name, ".reg2") == 0) |
f2db237a | 736 | return &ppc32_linux_fpregset; |
06caf7d2 CES |
737 | if (strcmp (sect_name, ".reg-ppc-vmx") == 0) |
738 | return &ppc32_linux_vrregset; | |
f9be684a | 739 | return NULL; |
2fda4977 DJ |
740 | } |
741 | ||
a8f60bfc AC |
742 | static void |
743 | ppc_linux_sigtramp_cache (struct frame_info *next_frame, | |
744 | struct trad_frame_cache *this_cache, | |
745 | CORE_ADDR func, LONGEST offset, | |
746 | int bias) | |
747 | { | |
748 | CORE_ADDR base; | |
749 | CORE_ADDR regs; | |
750 | CORE_ADDR gpregs; | |
751 | CORE_ADDR fpregs; | |
752 | int i; | |
753 | struct gdbarch *gdbarch = get_frame_arch (next_frame); | |
754 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
755 | ||
3e8c568d | 756 | base = frame_unwind_register_unsigned (next_frame, |
40a6adc1 | 757 | gdbarch_sp_regnum (gdbarch)); |
a8f60bfc AC |
758 | if (bias > 0 && frame_pc_unwind (next_frame) != func) |
759 | /* See below, some signal trampolines increment the stack as their | |
760 | first instruction, need to compensate for that. */ | |
761 | base -= bias; | |
762 | ||
763 | /* Find the address of the register buffer pointer. */ | |
764 | regs = base + offset; | |
765 | /* Use that to find the address of the corresponding register | |
766 | buffers. */ | |
767 | gpregs = read_memory_unsigned_integer (regs, tdep->wordsize); | |
768 | fpregs = gpregs + 48 * tdep->wordsize; | |
769 | ||
770 | /* General purpose. */ | |
771 | for (i = 0; i < 32; i++) | |
772 | { | |
773 | int regnum = i + tdep->ppc_gp0_regnum; | |
774 | trad_frame_set_reg_addr (this_cache, regnum, gpregs + i * tdep->wordsize); | |
775 | } | |
3e8c568d | 776 | trad_frame_set_reg_addr (this_cache, |
40a6adc1 | 777 | gdbarch_pc_regnum (gdbarch), |
3e8c568d | 778 | gpregs + 32 * tdep->wordsize); |
a8f60bfc AC |
779 | trad_frame_set_reg_addr (this_cache, tdep->ppc_ctr_regnum, |
780 | gpregs + 35 * tdep->wordsize); | |
781 | trad_frame_set_reg_addr (this_cache, tdep->ppc_lr_regnum, | |
782 | gpregs + 36 * tdep->wordsize); | |
783 | trad_frame_set_reg_addr (this_cache, tdep->ppc_xer_regnum, | |
784 | gpregs + 37 * tdep->wordsize); | |
785 | trad_frame_set_reg_addr (this_cache, tdep->ppc_cr_regnum, | |
786 | gpregs + 38 * tdep->wordsize); | |
787 | ||
60f140f9 PG |
788 | if (ppc_floating_point_unit_p (gdbarch)) |
789 | { | |
790 | /* Floating point registers. */ | |
791 | for (i = 0; i < 32; i++) | |
792 | { | |
40a6adc1 | 793 | int regnum = i + gdbarch_fp0_regnum (gdbarch); |
60f140f9 PG |
794 | trad_frame_set_reg_addr (this_cache, regnum, |
795 | fpregs + i * tdep->wordsize); | |
796 | } | |
797 | trad_frame_set_reg_addr (this_cache, tdep->ppc_fpscr_regnum, | |
4019046a | 798 | fpregs + 32 * tdep->wordsize); |
60f140f9 | 799 | } |
a8f60bfc AC |
800 | trad_frame_set_id (this_cache, frame_id_build (base, func)); |
801 | } | |
802 | ||
803 | static void | |
804 | ppc32_linux_sigaction_cache_init (const struct tramp_frame *self, | |
805 | struct frame_info *next_frame, | |
806 | struct trad_frame_cache *this_cache, | |
807 | CORE_ADDR func) | |
808 | { | |
809 | ppc_linux_sigtramp_cache (next_frame, this_cache, func, | |
810 | 0xd0 /* Offset to ucontext_t. */ | |
811 | + 0x30 /* Offset to .reg. */, | |
812 | 0); | |
813 | } | |
814 | ||
815 | static void | |
816 | ppc64_linux_sigaction_cache_init (const struct tramp_frame *self, | |
817 | struct frame_info *next_frame, | |
818 | struct trad_frame_cache *this_cache, | |
819 | CORE_ADDR func) | |
820 | { | |
821 | ppc_linux_sigtramp_cache (next_frame, this_cache, func, | |
822 | 0x80 /* Offset to ucontext_t. */ | |
823 | + 0xe0 /* Offset to .reg. */, | |
824 | 128); | |
825 | } | |
826 | ||
827 | static void | |
828 | ppc32_linux_sighandler_cache_init (const struct tramp_frame *self, | |
829 | struct frame_info *next_frame, | |
830 | struct trad_frame_cache *this_cache, | |
831 | CORE_ADDR func) | |
832 | { | |
833 | ppc_linux_sigtramp_cache (next_frame, this_cache, func, | |
834 | 0x40 /* Offset to ucontext_t. */ | |
835 | + 0x1c /* Offset to .reg. */, | |
836 | 0); | |
837 | } | |
838 | ||
839 | static void | |
840 | ppc64_linux_sighandler_cache_init (const struct tramp_frame *self, | |
841 | struct frame_info *next_frame, | |
842 | struct trad_frame_cache *this_cache, | |
843 | CORE_ADDR func) | |
844 | { | |
845 | ppc_linux_sigtramp_cache (next_frame, this_cache, func, | |
846 | 0x80 /* Offset to struct sigcontext. */ | |
847 | + 0x38 /* Offset to .reg. */, | |
848 | 128); | |
849 | } | |
850 | ||
851 | static struct tramp_frame ppc32_linux_sigaction_tramp_frame = { | |
852 | SIGTRAMP_FRAME, | |
853 | 4, | |
854 | { | |
855 | { 0x380000ac, -1 }, /* li r0, 172 */ | |
856 | { 0x44000002, -1 }, /* sc */ | |
857 | { TRAMP_SENTINEL_INSN }, | |
858 | }, | |
859 | ppc32_linux_sigaction_cache_init | |
860 | }; | |
861 | static struct tramp_frame ppc64_linux_sigaction_tramp_frame = { | |
862 | SIGTRAMP_FRAME, | |
863 | 4, | |
864 | { | |
865 | { 0x38210080, -1 }, /* addi r1,r1,128 */ | |
866 | { 0x380000ac, -1 }, /* li r0, 172 */ | |
867 | { 0x44000002, -1 }, /* sc */ | |
868 | { TRAMP_SENTINEL_INSN }, | |
869 | }, | |
870 | ppc64_linux_sigaction_cache_init | |
871 | }; | |
872 | static struct tramp_frame ppc32_linux_sighandler_tramp_frame = { | |
873 | SIGTRAMP_FRAME, | |
874 | 4, | |
875 | { | |
876 | { 0x38000077, -1 }, /* li r0,119 */ | |
877 | { 0x44000002, -1 }, /* sc */ | |
878 | { TRAMP_SENTINEL_INSN }, | |
879 | }, | |
880 | ppc32_linux_sighandler_cache_init | |
881 | }; | |
882 | static struct tramp_frame ppc64_linux_sighandler_tramp_frame = { | |
883 | SIGTRAMP_FRAME, | |
884 | 4, | |
885 | { | |
886 | { 0x38210080, -1 }, /* addi r1,r1,128 */ | |
887 | { 0x38000077, -1 }, /* li r0,119 */ | |
888 | { 0x44000002, -1 }, /* sc */ | |
889 | { TRAMP_SENTINEL_INSN }, | |
890 | }, | |
891 | ppc64_linux_sighandler_cache_init | |
892 | }; | |
893 | ||
7b112f9c JT |
894 | static void |
895 | ppc_linux_init_abi (struct gdbarch_info info, | |
896 | struct gdbarch *gdbarch) | |
897 | { | |
898 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
899 | ||
b14d30e1 JM |
900 | /* PPC GNU/Linux uses either 64-bit or 128-bit long doubles; where |
901 | 128-bit, they are IBM long double, not IEEE quad long double as | |
902 | in the System V ABI PowerPC Processor Supplement. We can safely | |
903 | let them default to 128-bit, since the debug info will give the | |
904 | size of type actually used in each case. */ | |
905 | set_gdbarch_long_double_bit (gdbarch, 16 * TARGET_CHAR_BIT); | |
906 | set_gdbarch_long_double_format (gdbarch, floatformats_ibm_long_double); | |
0598a43c | 907 | |
2bbe3cc1 DJ |
908 | /* Handle PPC GNU/Linux 64-bit function pointers (which are really |
909 | function descriptors) and 32-bit secure PLT entries. */ | |
910 | set_gdbarch_convert_from_func_ptr_addr | |
911 | (gdbarch, ppc_linux_convert_from_func_ptr_addr); | |
912 | ||
7b112f9c JT |
913 | if (tdep->wordsize == 4) |
914 | { | |
b9ff3018 AC |
915 | /* Until November 2001, gcc did not comply with the 32 bit SysV |
916 | R4 ABI requirement that structures less than or equal to 8 | |
917 | bytes should be returned in registers. Instead GCC was using | |
918 | the the AIX/PowerOpen ABI - everything returned in memory | |
919 | (well ignoring vectors that is). When this was corrected, it | |
920 | wasn't fixed for GNU/Linux native platform. Use the | |
921 | PowerOpen struct convention. */ | |
05580c65 | 922 | set_gdbarch_return_value (gdbarch, ppc_linux_return_value); |
b9ff3018 | 923 | |
7b112f9c JT |
924 | set_gdbarch_memory_remove_breakpoint (gdbarch, |
925 | ppc_linux_memory_remove_breakpoint); | |
61a65099 | 926 | |
f470a70a | 927 | /* Shared library handling. */ |
f470a70a JB |
928 | set_gdbarch_skip_trampoline_code (gdbarch, |
929 | ppc_linux_skip_trampoline_code); | |
7b112f9c | 930 | set_solib_svr4_fetch_link_map_offsets |
76a9d10f | 931 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); |
a8f60bfc AC |
932 | |
933 | /* Trampolines. */ | |
934 | tramp_frame_prepend_unwinder (gdbarch, &ppc32_linux_sigaction_tramp_frame); | |
935 | tramp_frame_prepend_unwinder (gdbarch, &ppc32_linux_sighandler_tramp_frame); | |
7b112f9c | 936 | } |
f470a70a JB |
937 | |
938 | if (tdep->wordsize == 8) | |
939 | { | |
fb318ff7 | 940 | /* Shared library handling. */ |
2bbe3cc1 | 941 | set_gdbarch_skip_trampoline_code (gdbarch, ppc64_skip_trampoline_code); |
fb318ff7 DJ |
942 | set_solib_svr4_fetch_link_map_offsets |
943 | (gdbarch, svr4_lp64_fetch_link_map_offsets); | |
944 | ||
a8f60bfc AC |
945 | /* Trampolines. */ |
946 | tramp_frame_prepend_unwinder (gdbarch, &ppc64_linux_sigaction_tramp_frame); | |
947 | tramp_frame_prepend_unwinder (gdbarch, &ppc64_linux_sighandler_tramp_frame); | |
f470a70a | 948 | } |
f9be684a | 949 | set_gdbarch_regset_from_core_section (gdbarch, ppc_linux_regset_from_core_section); |
b2756930 KB |
950 | |
951 | /* Enable TLS support. */ | |
952 | set_gdbarch_fetch_tls_load_module_address (gdbarch, | |
953 | svr4_fetch_objfile_link_map); | |
7b112f9c JT |
954 | } |
955 | ||
956 | void | |
957 | _initialize_ppc_linux_tdep (void) | |
958 | { | |
0a0a4ac3 AC |
959 | /* Register for all sub-familes of the POWER/PowerPC: 32-bit and |
960 | 64-bit PowerPC, and the older rs6k. */ | |
961 | gdbarch_register_osabi (bfd_arch_powerpc, bfd_mach_ppc, GDB_OSABI_LINUX, | |
962 | ppc_linux_init_abi); | |
963 | gdbarch_register_osabi (bfd_arch_powerpc, bfd_mach_ppc64, GDB_OSABI_LINUX, | |
964 | ppc_linux_init_abi); | |
965 | gdbarch_register_osabi (bfd_arch_rs6000, bfd_mach_rs6k, GDB_OSABI_LINUX, | |
966 | ppc_linux_init_abi); | |
7b112f9c | 967 | } |