1 /*
2 * Copyright (c) 2012, 2019 SAP SE. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "asm/assembler.hpp"
26 #include "compiler/disassembler.hpp"
27 #include "loadlib_aix.hpp"
28 #include "memory/allocation.hpp"
29 #include "memory/allocation.inline.hpp"
30 #include "misc_aix.hpp"
31 #include "porting_aix.hpp"
32 #include "runtime/os.hpp"
33 #include "runtime/thread.hpp"
34 #include "utilities/align.hpp"
35 #include "utilities/debug.hpp"
36
37 // distinguish old xlc and xlclang++, where
38 // <ibmdemangle.h> is suggested but not found in GA release (might come with a fix)
39 #if defined(__clang__)
40 #define DISABLE_DEMANGLE
41 // #include <ibmdemangle.h>
42 #else
43 #include <demangle.h>
44 #endif
45
46 #include <sys/debug.h>
47 #include <pthread.h>
48 #include <ucontext.h>
49
50 //////////////////////////////////
51 // Provide implementation for dladdr based on LoadedLibraries pool and
52 // traceback table scan
53
54 // Search traceback table in stack,
55 // return procedure name from trace back table.
56 #define MAX_FUNC_SEARCH_LEN 0x10000
57
58 #define PTRDIFF_BYTES(p1,p2) (((ptrdiff_t)p1) - ((ptrdiff_t)p2))
59
60 // Typedefs for stackslots, stack pointers, pointers to op codes.
61 typedef unsigned long stackslot_t;
62 typedef stackslot_t* stackptr_t;
63 typedef unsigned int* codeptr_t;
64
65 // Unfortunately, the interface of dladdr makes the implementator
66 // responsible for maintaining memory for function name/library
67 // name. I guess this is because most OS's keep those values as part
68 // of the mapped executable image ready to use. On AIX, this doesn't
69 // work, so I have to keep the returned strings. For now, I do this in
70 // a primitive string map. Should this turn out to be a performance
71 // problem, a better hashmap has to be used.
72 class fixed_strings {
73 struct node : public CHeapObj<mtInternal> {
74 char* v;
75 node* next;
76 };
77
78 node* first;
79
80 public:
81
fixed_strings()82 fixed_strings() : first(0) {}
~fixed_strings()83 ~fixed_strings() {
84 node* n = first;
85 while (n) {
86 node* p = n;
87 n = n->next;
88 os::free(p->v);
89 delete p;
90 }
91 }
92
intern(const char * s)93 char* intern(const char* s) {
94 for (node* n = first; n; n = n->next) {
95 if (strcmp(n->v, s) == 0) {
96 return n->v;
97 }
98 }
99 node* p = new node;
100 p->v = os::strdup_check_oom(s);
101 p->next = first;
102 first = p;
103 return p->v;
104 }
105 };
106
107 static fixed_strings dladdr_fixed_strings;
108
get_function_name(address pc0,char * p_name,size_t namelen,int * p_displacement,const struct tbtable ** p_tb,bool demangle)109 bool AixSymbols::get_function_name (
110 address pc0, // [in] program counter
111 char* p_name, size_t namelen, // [out] optional: function name ("" if not available)
112 int* p_displacement, // [out] optional: displacement (-1 if not available)
113 const struct tbtable** p_tb, // [out] optional: ptr to traceback table to get further
114 // information (NULL if not available)
115 bool demangle // [in] whether to demangle the name
116 ) {
117 struct tbtable* tb = 0;
118 unsigned int searchcount = 0;
119
120 // initialize output parameters
121 if (p_name && namelen > 0) {
122 *p_name = '\0';
123 }
124 if (p_displacement) {
125 *p_displacement = -1;
126 }
127 if (p_tb) {
128 *p_tb = NULL;
129 }
130
131 codeptr_t pc = (codeptr_t)pc0;
132
133 // weed out obvious bogus states
134 if (pc < (codeptr_t)0x1000) {
135 trcVerbose("invalid program counter");
136 return false;
137 }
138
139 // We see random but frequent crashes in this function since some months mainly on shutdown
140 // (-XX:+DumpInfoAtExit). It appears the page we are reading is randomly disappearing while
141 // we read it (?).
142 // As the pc cannot be trusted to be anything sensible lets make all reads via SafeFetch. Also
143 // bail if this is not a text address right now.
144 if (!LoadedLibraries::find_for_text_address(pc, NULL)) {
145 trcVerbose("not a text address");
146 return false;
147 }
148
149 // .. (Note that is_readable_pointer returns true if safefetch stubs are not there yet;
150 // in that case I try reading the traceback table unsafe - I rather risk secondary crashes in
151 // error files than not having a callstack.)
152 #define CHECK_POINTER_READABLE(p) \
153 if (!os::is_readable_pointer(p)) { \
154 trcVerbose("pc not readable"); \
155 return false; \
156 }
157
158 codeptr_t pc2 = (codeptr_t) pc;
159
160 // Make sure the pointer is word aligned.
161 pc2 = (codeptr_t) align_up((char*)pc2, 4);
162 CHECK_POINTER_READABLE(pc2)
163
164 // Find start of traceback table.
165 // (starts after code, is marked by word-aligned (32bit) zeros)
166 while ((*pc2 != NULL) && (searchcount++ < MAX_FUNC_SEARCH_LEN)) {
167 CHECK_POINTER_READABLE(pc2)
168 pc2++;
169 }
170 if (*pc2 != 0) {
171 trcVerbose("no traceback table found");
172 return false;
173 }
174 //
175 // Set up addressability to the traceback table
176 //
177 tb = (struct tbtable*) (pc2 + 1);
178
179 // Is this really a traceback table? No way to be sure but
180 // some indicators we can check.
181 if (tb->tb.lang >= 0xf && tb->tb.lang <= 0xfb) {
182 // Language specifiers, go from 0 (C) to 14 (Objective C).
183 // According to spec, 0xf-0xfa reserved, 0xfb-0xff reserved for ibm.
184 trcVerbose("no traceback table found");
185 return false;
186 }
187
188 // Existence of fields in the tbtable extension are contingent upon
189 // specific fields in the base table. Check for their existence so
190 // that we can address the function name if it exists.
191 pc2 = (codeptr_t) tb +
192 sizeof(struct tbtable_short)/sizeof(int);
193 if (tb->tb.fixedparms != 0 || tb->tb.floatparms != 0)
194 pc2++;
195
196 CHECK_POINTER_READABLE(pc2)
197
198 if (tb->tb.has_tboff == TRUE) {
199
200 // I want to know the displacement
201 const unsigned int tb_offset = *pc2;
202 codeptr_t start_of_procedure =
203 (codeptr_t)(((char*)tb) - 4 - tb_offset); // (-4 to omit leading 0000)
204
205 // Weed out the cases where we did find the wrong traceback table.
206 if (pc < start_of_procedure) {
207 trcVerbose("no traceback table found");
208 return false;
209 }
210
211 // return the displacement
212 if (p_displacement) {
213 (*p_displacement) = (int) PTRDIFF_BYTES(pc, start_of_procedure);
214 }
215
216 pc2++;
217 } else {
218 // return -1 for displacement
219 if (p_displacement) {
220 (*p_displacement) = -1;
221 }
222 }
223
224 if (tb->tb.int_hndl == TRUE)
225 pc2++;
226
227 if (tb->tb.has_ctl == TRUE)
228 pc2 += (*pc2) + 1; // don't care
229
230 CHECK_POINTER_READABLE(pc2)
231
232 //
233 // return function name if it exists.
234 //
235 if (p_name && namelen > 0) {
236 if (tb->tb.name_present) {
237 // Copy name from text because it may not be zero terminated.
238 const short l = MIN2<short>(*((short*)pc2), namelen - 1);
239 // Be very careful.
240 int i = 0; char* const p = (char*)pc2 + sizeof(short);
241 while (i < l && os::is_readable_pointer(p + i)) {
242 p_name[i] = p[i];
243 i++;
244 }
245 p_name[i] = '\0';
246
247 // If it is a C++ name, try and demangle it using the Demangle interface (see demangle.h).
248 #ifndef DISABLE_DEMANGLE
249 if (demangle) {
250 char* rest;
251 Name* const name = Demangle(p_name, rest);
252 if (name) {
253 const char* const demangled_name = name->Text();
254 if (demangled_name) {
255 strncpy(p_name, demangled_name, namelen-1);
256 p_name[namelen-1] = '\0';
257 }
258 delete name;
259 }
260 }
261 #endif
262 } else {
263 strncpy(p_name, "<nameless function>", namelen-1);
264 p_name[namelen-1] = '\0';
265 }
266 }
267
268 // Return traceback table, if user wants it.
269 if (p_tb) {
270 (*p_tb) = tb;
271 }
272
273 return true;
274
275 }
276
get_module_name(address pc,char * p_name,size_t namelen)277 bool AixSymbols::get_module_name(address pc,
278 char* p_name, size_t namelen) {
279
280 if (p_name && namelen > 0) {
281 p_name[0] = '\0';
282 loaded_module_t lm;
283 if (LoadedLibraries::find_for_text_address(pc, &lm) != NULL) {
284 strncpy(p_name, lm.shortname, namelen);
285 p_name[namelen - 1] = '\0';
286 return true;
287 }
288 }
289
290 return false;
291 }
292
293 // Special implementation of dladdr for Aix based on LoadedLibraries
294 // Note: dladdr returns non-zero for ok, 0 for error!
295 // Note: dladdr is not posix, but a non-standard GNU extension. So this tries to
296 // fulfill the contract of dladdr on Linux (see http://linux.die.net/man/3/dladdr)
297 // Note: addr may be both an AIX function descriptor or a real code pointer
298 // to the entry of a function.
299 extern "C"
dladdr(void * addr,Dl_info * info)300 int dladdr(void* addr, Dl_info* info) {
301
302 if (!addr) {
303 return 0;
304 }
305
306 assert(info, "");
307
308 int rc = 0;
309
310 const char* const ZEROSTRING = "";
311
312 // Always return a string, even if a "" one. Linux dladdr manpage
313 // does not say anything about returning NULL
314 info->dli_fname = ZEROSTRING;
315 info->dli_sname = ZEROSTRING;
316 info->dli_saddr = NULL;
317
318 address p = (address) addr;
319 loaded_module_t lm;
320 bool found = false;
321
322 enum { noclue, code, data } type = noclue;
323
324 trcVerbose("dladdr(%p)...", p);
325
326 // Note: input address may be a function. I accept both a pointer to
327 // the entry of a function and a pointer to the function decriptor.
328 // (see ppc64 ABI)
329 found = LoadedLibraries::find_for_text_address(p, &lm);
330 if (found) {
331 type = code;
332 }
333
334 if (!found) {
335 // Not a pointer into any text segment. Is it a function descriptor?
336 const FunctionDescriptor* const pfd = (const FunctionDescriptor*) p;
337 p = pfd->entry();
338 if (p) {
339 found = LoadedLibraries::find_for_text_address(p, &lm);
340 if (found) {
341 type = code;
342 }
343 }
344 }
345
346 if (!found) {
347 // Neither direct code pointer nor function descriptor. A data ptr?
348 p = (address)addr;
349 found = LoadedLibraries::find_for_data_address(p, &lm);
350 if (found) {
351 type = data;
352 }
353 }
354
355 // If we did find the shared library this address belongs to (either
356 // code or data segment) resolve library path and, if possible, the
357 // symbol name.
358 if (found) {
359
360 // No need to intern the libpath, that one is already interned one layer below.
361 info->dli_fname = lm.path;
362
363 if (type == code) {
364
365 // For code symbols resolve function name and displacement. Use
366 // displacement to calc start of function.
367 char funcname[256] = "";
368 int displacement = 0;
369
370 if (AixSymbols::get_function_name(p, funcname, sizeof(funcname),
371 &displacement, NULL, true)) {
372 if (funcname[0] != '\0') {
373 const char* const interned = dladdr_fixed_strings.intern(funcname);
374 info->dli_sname = interned;
375 trcVerbose("... function name: %s ...", interned);
376 }
377
378 // From the displacement calculate the start of the function.
379 if (displacement != -1) {
380 info->dli_saddr = p - displacement;
381 } else {
382 info->dli_saddr = p;
383 }
384 } else {
385
386 // No traceback table found. Just assume the pointer is it.
387 info->dli_saddr = p;
388
389 }
390
391 } else if (type == data) {
392
393 // For data symbols.
394 info->dli_saddr = p;
395
396 } else {
397 ShouldNotReachHere();
398 }
399
400 rc = 1; // success: return 1 [sic]
401
402 }
403
404 // sanity checks.
405 if (rc) {
406 assert(info->dli_fname, "");
407 assert(info->dli_sname, "");
408 assert(info->dli_saddr, "");
409 }
410
411 return rc; // error: return 0 [sic]
412
413 }
414
415 /////////////////////////////////////////////////////////////////////////////
416 // Native callstack dumping
417
418 // Print the traceback table for one stack frame.
print_tbtable(outputStream * st,const struct tbtable * p_tb)419 static void print_tbtable (outputStream* st, const struct tbtable* p_tb) {
420
421 if (p_tb == NULL) {
422 st->print("<null>");
423 return;
424 }
425
426 switch(p_tb->tb.lang) {
427 case TB_C: st->print("C"); break;
428 case TB_FORTRAN: st->print("FORTRAN"); break;
429 case TB_PASCAL: st->print("PASCAL"); break;
430 case TB_ADA: st->print("ADA"); break;
431 case TB_PL1: st->print("PL1"); break;
432 case TB_BASIC: st->print("BASIC"); break;
433 case TB_LISP: st->print("LISP"); break;
434 case TB_COBOL: st->print("COBOL"); break;
435 case TB_MODULA2: st->print("MODULA2"); break;
436 case TB_CPLUSPLUS: st->print("C++"); break;
437 case TB_RPG: st->print("RPG"); break;
438 case TB_PL8: st->print("PL8"); break;
439 case TB_ASM: st->print("ASM"); break;
440 case TB_HPJ: st->print("HPJ"); break;
441 default: st->print("unknown");
442 }
443 st->print(" ");
444
445 if (p_tb->tb.globallink) {
446 st->print("globallink ");
447 }
448 if (p_tb->tb.is_eprol) {
449 st->print("eprol ");
450 }
451 if (p_tb->tb.int_proc) {
452 st->print("int_proc ");
453 }
454 if (p_tb->tb.tocless) {
455 st->print("tocless ");
456 }
457 if (p_tb->tb.fp_present) {
458 st->print("fp_present ");
459 }
460 if (p_tb->tb.int_hndl) {
461 st->print("interrupt_handler ");
462 }
463 if (p_tb->tb.uses_alloca) {
464 st->print("uses_alloca ");
465 }
466 if (p_tb->tb.saves_cr) {
467 st->print("saves_cr ");
468 }
469 if (p_tb->tb.saves_lr) {
470 st->print("saves_lr ");
471 }
472 if (p_tb->tb.stores_bc) {
473 st->print("stores_bc ");
474 }
475 if (p_tb->tb.fixup) {
476 st->print("fixup ");
477 }
478 if (p_tb->tb.fpr_saved > 0) {
479 st->print("fpr_saved:%d ", p_tb->tb.fpr_saved);
480 }
481 if (p_tb->tb.gpr_saved > 0) {
482 st->print("gpr_saved:%d ", p_tb->tb.gpr_saved);
483 }
484 if (p_tb->tb.fixedparms > 0) {
485 st->print("fixedparms:%d ", p_tb->tb.fixedparms);
486 }
487 if (p_tb->tb.floatparms > 0) {
488 st->print("floatparms:%d ", p_tb->tb.floatparms);
489 }
490 if (p_tb->tb.parmsonstk > 0) {
491 st->print("parmsonstk:%d", p_tb->tb.parmsonstk);
492 }
493 }
494
495 // Print information for pc (module, function, displacement, traceback table)
496 // on one line.
print_info_for_pc(outputStream * st,codeptr_t pc,char * buf,size_t buf_size,bool demangle)497 static void print_info_for_pc (outputStream* st, codeptr_t pc, char* buf,
498 size_t buf_size, bool demangle) {
499 const struct tbtable* tb = NULL;
500 int displacement = -1;
501
502 if (!os::is_readable_pointer(pc)) {
503 st->print("(invalid)");
504 return;
505 }
506
507 if (AixSymbols::get_module_name((address)pc, buf, buf_size)) {
508 st->print("%s", buf);
509 } else {
510 st->print("(unknown module)");
511 }
512 st->print("::");
513 if (AixSymbols::get_function_name((address)pc, buf, buf_size,
514 &displacement, &tb, demangle)) {
515 st->print("%s", buf);
516 } else {
517 st->print("(unknown function)");
518 }
519 if (displacement == -1) {
520 st->print("+?");
521 } else {
522 st->print("+0x%x", displacement);
523 }
524 if (tb) {
525 st->fill_to(64);
526 st->print(" (");
527 print_tbtable(st, tb);
528 st->print(")");
529 }
530 }
531
print_stackframe(outputStream * st,stackptr_t sp,char * buf,size_t buf_size,bool demangle)532 static void print_stackframe(outputStream* st, stackptr_t sp, char* buf,
533 size_t buf_size, bool demangle) {
534
535 stackptr_t sp2 = sp;
536
537 // skip backchain
538
539 sp2++;
540
541 // skip crsave
542
543 sp2++;
544
545 // retrieve lrsave. That is the only info I need to get the function/displacement
546
547 codeptr_t lrsave = (codeptr_t) *(sp2);
548 st->print (PTR64_FORMAT " - " PTR64_FORMAT " ", sp2, lrsave);
549
550 if (lrsave != NULL) {
551 print_info_for_pc(st, lrsave, buf, buf_size, demangle);
552 }
553
554 }
555
556 // Function to check a given stack pointer against given stack limits.
is_valid_stackpointer(stackptr_t sp,stackptr_t stack_base,size_t stack_size)557 static bool is_valid_stackpointer(stackptr_t sp, stackptr_t stack_base, size_t stack_size) {
558 if (((uintptr_t)sp) & 0x7) {
559 return false;
560 }
561 if (sp > stack_base) {
562 return false;
563 }
564 if (sp < (stackptr_t) ((address)stack_base - stack_size)) {
565 return false;
566 }
567 return true;
568 }
569
570 // Returns true if function is a valid codepointer.
is_valid_codepointer(codeptr_t p)571 static bool is_valid_codepointer(codeptr_t p) {
572 if (!p) {
573 return false;
574 }
575 if (((uintptr_t)p) & 0x3) {
576 return false;
577 }
578 if (LoadedLibraries::find_for_text_address(p, NULL) == NULL) {
579 return false;
580 }
581 return true;
582 }
583
584 // Function tries to guess if the given combination of stack pointer, stack base
585 // and stack size is a valid stack frame.
is_valid_frame(stackptr_t p,stackptr_t stack_base,size_t stack_size)586 static bool is_valid_frame (stackptr_t p, stackptr_t stack_base, size_t stack_size) {
587
588 if (!is_valid_stackpointer(p, stack_base, stack_size)) {
589 return false;
590 }
591
592 // First check - the occurrence of a valid backchain pointer up the stack, followed by a
593 // valid codeptr, counts as a good candidate.
594 stackptr_t sp2 = (stackptr_t) *p;
595 if (is_valid_stackpointer(sp2, stack_base, stack_size) && // found a valid stack pointer in the stack...
596 ((sp2 - p) > 6) && // ... pointing upwards and not into my frame...
597 is_valid_codepointer((codeptr_t)(*(sp2 + 2)))) // ... followed by a code pointer after two slots...
598 {
599 return true;
600 }
601
602 return false;
603 }
604
605 // Try to relocate a stack back chain in a given stack.
606 // Used in callstack dumping, when the backchain is broken by an overwriter
try_find_backchain(stackptr_t last_known_good_frame,stackptr_t stack_base,size_t stack_size)607 static stackptr_t try_find_backchain (stackptr_t last_known_good_frame,
608 stackptr_t stack_base, size_t stack_size)
609 {
610 if (!is_valid_stackpointer(last_known_good_frame, stack_base, stack_size)) {
611 return NULL;
612 }
613
614 stackptr_t sp = last_known_good_frame;
615
616 sp += 6; // Omit next fixed frame slots.
617 while (sp < stack_base) {
618 if (is_valid_frame(sp, stack_base, stack_size)) {
619 return sp;
620 }
621 sp ++;
622 }
623
624 return NULL;
625 }
626
decode_instructions_at_pc(const char * header,codeptr_t pc,int num_before,int num_after,outputStream * st)627 static void decode_instructions_at_pc(const char* header,
628 codeptr_t pc, int num_before,
629 int num_after, outputStream* st) {
630 // TODO: PPC port Disassembler::decode(pc, 16, 16, st);
631 }
632
633
print_callstack_for_context(outputStream * st,const ucontext_t * context,bool demangle,char * buf,size_t buf_size)634 void AixNativeCallstack::print_callstack_for_context(outputStream* st, const ucontext_t* context,
635 bool demangle, char* buf, size_t buf_size) {
636
637 #define MAX_CALLSTACK_DEPTH 50
638
639 unsigned long* sp;
640 unsigned long* sp_last;
641 int frame;
642
643 // To print the first frame, use the current value of iar:
644 // current entry indicated by iar (the current pc)
645 codeptr_t cur_iar = 0;
646 stackptr_t cur_sp = 0;
647 codeptr_t cur_rtoc = 0;
648 codeptr_t cur_lr = 0;
649
650 const ucontext_t* uc = (const ucontext_t*) context;
651
652 // fallback: use the current context
653 ucontext_t local_context;
654 if (!uc) {
655 st->print_cr("No context given, using current context.");
656 if (getcontext(&local_context) == 0) {
657 uc = &local_context;
658 } else {
659 st->print_cr("No context given and getcontext failed. ");
660 return;
661 }
662 }
663
664 cur_iar = (codeptr_t)uc->uc_mcontext.jmp_context.iar;
665 cur_sp = (stackptr_t)uc->uc_mcontext.jmp_context.gpr[1];
666 cur_rtoc = (codeptr_t)uc->uc_mcontext.jmp_context.gpr[2];
667 cur_lr = (codeptr_t)uc->uc_mcontext.jmp_context.lr;
668
669 // syntax used here:
670 // n -------------- <-- stack_base, stack_to
671 // n-1 | |
672 // ... | older |
673 // ... | frames | |
674 // | | | stack grows downward
675 // ... | younger | |
676 // ... | frames | V
677 // | |
678 // |------------| <-- cur_sp, current stack ptr
679 // | |
680 // | unsused |
681 // | stack |
682 // | |
683 // . .
684 // . .
685 // . .
686 // . .
687 // | |
688 // 0 -------------- <-- stack_from
689 //
690
691 // Retrieve current stack base, size from the current thread. If there is none,
692 // retrieve it from the OS.
693 stackptr_t stack_base = NULL;
694 size_t stack_size = NULL;
695 {
696 AixMisc::stackbounds_t stackbounds;
697 if (!AixMisc::query_stack_bounds_for_current_thread(&stackbounds)) {
698 st->print_cr("Cannot retrieve stack bounds.");
699 return;
700 }
701 stack_base = (stackptr_t)stackbounds.base;
702 stack_size = stackbounds.size;
703 }
704
705 st->print_cr("------ current frame:");
706 st->print("iar: " PTR64_FORMAT " ", p2i(cur_iar));
707 print_info_for_pc(st, cur_iar, buf, buf_size, demangle);
708 st->cr();
709
710 if (cur_iar && os::is_readable_pointer(cur_iar)) {
711 decode_instructions_at_pc(
712 "Decoded instructions at iar:",
713 cur_iar, 32, 16, st);
714 }
715
716 // Print out lr too, which may be interesting if we did jump to some bogus location;
717 // in those cases the new frame is not built up yet and the caller location is only
718 // preserved via lr register.
719 st->print("lr: " PTR64_FORMAT " ", p2i(cur_lr));
720 print_info_for_pc(st, cur_lr, buf, buf_size, demangle);
721 st->cr();
722
723 if (cur_lr && os::is_readable_pointer(cur_lr)) {
724 decode_instructions_at_pc(
725 "Decoded instructions at lr:",
726 cur_lr, 32, 16, st);
727 }
728
729 // Check and print sp.
730 st->print("sp: " PTR64_FORMAT " ", p2i(cur_sp));
731 if (!is_valid_stackpointer(cur_sp, stack_base, stack_size)) {
732 st->print("(invalid) ");
733 goto cleanup;
734 } else {
735 st->print("(base - 0x%X) ", PTRDIFF_BYTES(stack_base, cur_sp));
736 }
737 st->cr();
738
739 // Check and print rtoc.
740 st->print("rtoc: " PTR64_FORMAT " ", p2i(cur_rtoc));
741 if (cur_rtoc == NULL || cur_rtoc == (codeptr_t)-1 ||
742 !os::is_readable_pointer(cur_rtoc)) {
743 st->print("(invalid)");
744 } else if (((uintptr_t)cur_rtoc) & 0x7) {
745 st->print("(unaligned)");
746 }
747 st->cr();
748
749 st->print_cr("|---stackaddr----| |----lrsave------|: <function name>");
750
751 ///
752 // Walk callstack.
753 //
754 // (if no context was given, use the current stack)
755 sp = (unsigned long*)(*(unsigned long*)cur_sp); // Stack pointer
756 sp_last = cur_sp;
757
758 frame = 0;
759
760 while (frame < MAX_CALLSTACK_DEPTH) {
761
762 // Check sp.
763 bool retry = false;
764 if (sp == NULL) {
765 // The backchain pointer was NULL. This normally means the end of the chain. But the
766 // stack might be corrupted, and it may be worth looking for the stack chain.
767 if (is_valid_stackpointer(sp_last, stack_base, stack_size) && (stack_base - 0x10) > sp_last) {
768 // If we are not within <guess> 0x10 stackslots of the stack base, we assume that this
769 // is indeed not the end of the chain but that the stack was corrupted. So lets try to
770 // find the end of the chain.
771 st->print_cr("*** back chain pointer is NULL - end of stack or broken backchain ? ***");
772 retry = true;
773 } else {
774 st->print_cr("*** end of backchain ***");
775 goto end_walk_callstack;
776 }
777 } else if (!is_valid_stackpointer(sp, stack_base, stack_size)) {
778 st->print_cr("*** stack pointer invalid - backchain corrupted (" PTR_FORMAT ") ***", p2i(sp));
779 retry = true;
780 } else if (sp < sp_last) {
781 st->print_cr("invalid stack pointer: " PTR_FORMAT " (not monotone raising)", p2i(sp));
782 retry = true;
783 }
784
785 // If backchain is broken, try to recover, by manually scanning the stack for a pattern
786 // which looks like a valid stack.
787 if (retry) {
788 st->print_cr("trying to recover and find backchain...");
789 sp = try_find_backchain(sp_last, stack_base, stack_size);
790 if (sp) {
791 st->print_cr("found something which looks like a backchain at " PTR64_FORMAT ", after 0x%x bytes... ",
792 p2i(sp), PTRDIFF_BYTES(sp, sp_last));
793 } else {
794 st->print_cr("did not find a backchain, giving up.");
795 goto end_walk_callstack;
796 }
797 }
798
799 // Print stackframe.
800 print_stackframe(st, sp, buf, buf_size, demangle);
801 st->cr();
802 frame ++;
803
804 // Next stack frame and link area.
805 sp_last = sp;
806 sp = (unsigned long*)(*sp);
807 }
808
809 // Prevent endless loops in case of invalid callstacks.
810 if (frame == MAX_CALLSTACK_DEPTH) {
811 st->print_cr("...(stopping after %d frames.", MAX_CALLSTACK_DEPTH);
812 }
813
814 end_walk_callstack:
815
816 st->print_cr("-----------------------");
817
818 cleanup:
819
820 return;
821
822 }
823
824
query_stack_bounds_for_current_thread(stackbounds_t * out)825 bool AixMisc::query_stack_bounds_for_current_thread(stackbounds_t* out) {
826
827 // Information about this api can be found (a) in the pthread.h header and
828 // (b) in http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf1/pthread_getthrds_np.htm
829 //
830 // The use of this API to find out the current stack is kind of undefined.
831 // But after a lot of tries and asking IBM about it, I concluded that it is safe
832 // enough for cases where I let the pthread library create its stacks. For cases
833 // where I create an own stack and pass this to pthread_create, it seems not to
834 // work (the returned stack size in that case is 0).
835
836 pthread_t tid = pthread_self();
837 struct __pthrdsinfo pinfo;
838 char dummy[1]; // Just needed to satisfy pthread_getthrds_np.
839 int dummy_size = sizeof(dummy);
840
841 memset(&pinfo, 0, sizeof(pinfo));
842
843 const int rc = pthread_getthrds_np(&tid, PTHRDSINFO_QUERY_ALL, &pinfo,
844 sizeof(pinfo), dummy, &dummy_size);
845
846 if (rc != 0) {
847 fprintf(stderr, "pthread_getthrds_np failed (%d)\n", rc);
848 fflush(stdout);
849 return false;
850 }
851
852 // The following may happen when invoking pthread_getthrds_np on a pthread
853 // running on a user provided stack (when handing down a stack to pthread
854 // create, see pthread_attr_setstackaddr).
855 // Not sure what to do then.
856 if (pinfo.__pi_stackend == NULL || pinfo.__pi_stackaddr == NULL) {
857 fprintf(stderr, "pthread_getthrds_np - invalid values\n");
858 fflush(stdout);
859 return false;
860 }
861
862 // Note: we get three values from pthread_getthrds_np:
863 // __pi_stackaddr, __pi_stacksize, __pi_stackend
864 //
865 // high addr --------------------- base, high
866 //
867 // | pthread internal data, like ~2K
868 // |
869 // | --------------------- __pi_stackend (usually not page aligned, (xxxxF890))
870 // |
871 // |
872 // |
873 // |
874 // |
875 // |
876 // | --------------------- (__pi_stackend - __pi_stacksize)
877 // |
878 // | padding to align the following AIX guard pages, if enabled.
879 // |
880 // V --------------------- __pi_stackaddr low, base - size
881 //
882 // low addr AIX guard pages, if enabled (AIXTHREAD_GUARDPAGES > 0)
883 //
884
885 out->base = (address)pinfo.__pi_stackend;
886 address low = (address)pinfo.__pi_stackaddr;
887 out->size = out->base - low;
888 return true;
889
890 }
891
892
893
894
895