1 /* Target-dependent code for GNU/Linux running on PA-RISC, for GDB.
3 Copyright (C) 2004 Free Software Foundation, Inc.
5 This file is part of GDB.
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 2 of the License, or
10 (at your option) any later version.
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.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street, Fifth Floor,
20 Boston, MA 02110-1301, USA. */
27 #include "solib-svr4.h"
28 #include "glibc-tdep.h"
29 #include "frame-unwind.h"
30 #include "trad-frame.h"
31 #include "dwarf2-frame.h"
33 #include "hppa-tdep.h"
35 #include "elf/common.h"
38 /* Convert DWARF register number REG to the appropriate register
39 number used by GDB. */
41 hppa_dwarf_reg_to_regnum (int reg)
43 /* registers 0 - 31 are the same in both sets */
47 /* dwarf regs 32 to 85 are fpregs 4 - 31 */
48 if (reg >= 32 && reg <= 85)
49 return HPPA_FP4_REGNUM + (reg - 32);
51 warning (_("Unmapped DWARF Register #%d encountered."), reg);
57 hppa_linux_target_write_pc (CORE_ADDR v, ptid_t ptid)
59 /* Probably this should be done by the kernel, but it isn't. */
60 write_register_pid (HPPA_PCOQ_HEAD_REGNUM, v | 0x3, ptid);
61 write_register_pid (HPPA_PCOQ_TAIL_REGNUM, (v + 4) | 0x3, ptid);
64 /* An instruction to match. */
67 unsigned int data; /* See if it matches this.... */
68 unsigned int mask; /* ... with this mask. */
71 /* See bfd/elf32-hppa.c */
72 static struct insn_pattern hppa_long_branch_stub[] = {
74 { 0x20200000, 0xffe00000 },
75 /* be,n RR'xxx(%sr4,%r1) */
76 { 0xe0202002, 0xffe02002 },
80 static struct insn_pattern hppa_long_branch_pic_stub[] = {
82 { 0xe8200000, 0xffe00000 },
83 /* addil LR'xxx - ($PIC_pcrel$0 - 4), %r1 */
84 { 0x28200000, 0xffe00000 },
85 /* be,n RR'xxxx - ($PIC_pcrel$0 - 8)(%sr4, %r1) */
86 { 0xe0202002, 0xffe02002 },
90 static struct insn_pattern hppa_import_stub[] = {
91 /* addil LR'xxx, %dp */
92 { 0x2b600000, 0xffe00000 },
93 /* ldw RR'xxx(%r1), %r21 */
94 { 0x48350000, 0xffffb000 },
96 { 0xeaa0c000, 0xffffffff },
97 /* ldw RR'xxx+4(%r1), %r19 */
98 { 0x48330000, 0xffffb000 },
102 static struct insn_pattern hppa_import_pic_stub[] = {
103 /* addil LR'xxx,%r19 */
104 { 0x2a600000, 0xffe00000 },
105 /* ldw RR'xxx(%r1),%r21 */
106 { 0x48350000, 0xffffb000 },
108 { 0xeaa0c000, 0xffffffff },
109 /* ldw RR'xxx+4(%r1),%r19 */
110 { 0x48330000, 0xffffb000 },
114 static struct insn_pattern hppa_plt_stub[] = {
115 /* b,l 1b, %r20 - 1b is 3 insns before here */
116 { 0xea9f1fdd, 0xffffffff },
117 /* depi 0,31,2,%r20 */
118 { 0xd6801c1e, 0xffffffff },
122 static struct insn_pattern hppa_sigtramp[] = {
123 /* ldi 0, %r25 or ldi 1, %r25 */
124 { 0x34190000, 0xfffffffd },
125 /* ldi __NR_rt_sigreturn, %r20 */
126 { 0x3414015a, 0xffffffff },
127 /* be,l 0x100(%sr2, %r0), %sr0, %r31 */
128 { 0xe4008200, 0xffffffff },
130 { 0x08000240, 0xffffffff },
134 #define HPPA_MAX_INSN_PATTERN_LEN (4)
136 /* Return non-zero if the instructions at PC match the series
137 described in PATTERN, or zero otherwise. PATTERN is an array of
138 'struct insn_pattern' objects, terminated by an entry whose mask is
141 When the match is successful, fill INSN[i] with what PATTERN[i]
144 insns_match_pattern (CORE_ADDR pc,
145 struct insn_pattern *pattern,
151 for (i = 0; pattern[i].mask; i++)
155 deprecated_read_memory_nobpt (npc, buf, 4);
156 insn[i] = extract_unsigned_integer (buf, 4);
157 if ((insn[i] & pattern[i].mask) == pattern[i].data)
165 /* The relaxed version of the insn matcher allows us to match from somewhere
166 inside the pattern, by looking backwards in the instruction scheme. */
168 insns_match_pattern_relaxed (CORE_ADDR pc,
169 struct insn_pattern *pattern,
175 while (pattern[pat_len].mask)
178 for (offset = 0; offset < pat_len; offset++)
180 if (insns_match_pattern (pc - offset * 4,
189 hppa_linux_in_dyncall (CORE_ADDR pc)
191 struct unwind_table_entry *u;
192 u = find_unwind_entry (hppa_symbol_address ("$$dyncall"));
197 return pc >= u->region_start && pc <= u->region_end;
200 /* There are several kinds of "trampolines" that we need to deal with:
201 - long branch stubs: these are inserted by the linker when a branch
202 target is too far away for a branch insn to reach
203 - plt stubs: these should go into the .plt section, so are easy to find
204 - import stubs: used to call from object to shared lib or shared lib to
205 shared lib; these go in regular text sections. In fact the linker tries
206 to put them throughout the code because branches have limited reachability.
207 We use the same mechanism as ppc64 to recognize the stub insn patterns.
208 - $$dyncall: similar to hpux, hppa-linux uses $$dyncall for indirect function
209 calls. $$dyncall is exported by libgcc.a */
211 hppa_linux_in_solib_call_trampoline (CORE_ADDR pc, char *name)
213 unsigned int insn[HPPA_MAX_INSN_PATTERN_LEN];
215 struct unwind_table_entry *u;
217 /* on hppa-linux, linker stubs have no unwind information. Since the pattern
218 matching for linker stubs can be quite slow, we try to avoid it if
220 u = find_unwind_entry (pc);
222 r = in_plt_section (pc, name)
223 || hppa_linux_in_dyncall (pc)
225 && (insns_match_pattern_relaxed (pc, hppa_import_stub, insn)
226 || insns_match_pattern_relaxed (pc, hppa_import_pic_stub, insn)
227 || insns_match_pattern_relaxed (pc, hppa_long_branch_stub, insn)
228 || insns_match_pattern_relaxed (pc, hppa_long_branch_pic_stub, insn)));
234 hppa_linux_skip_trampoline_code (CORE_ADDR pc)
236 unsigned int insn[HPPA_MAX_INSN_PATTERN_LEN];
239 /* dyncall handles both PLABELs and direct addresses */
240 if (hppa_linux_in_dyncall (pc))
242 pc = (CORE_ADDR) read_register (22);
244 /* PLABELs have bit 30 set; if it's a PLABEL, then dereference it */
246 pc = (CORE_ADDR) read_memory_integer (pc & ~0x3, TARGET_PTR_BIT / 8);
251 dp_rel = pic_rel = 0;
252 if ((dp_rel = insns_match_pattern (pc, hppa_import_stub, insn))
253 || (pic_rel = insns_match_pattern (pc, hppa_import_pic_stub, insn)))
255 /* Extract the target address from the addil/ldw sequence. */
256 pc = hppa_extract_21 (insn[0]) + hppa_extract_14 (insn[1]);
259 pc += (CORE_ADDR) read_register (27);
261 pc += (CORE_ADDR) read_register (19);
266 if (in_plt_section (pc, NULL))
268 pc = (CORE_ADDR) read_memory_integer (pc, TARGET_PTR_BIT / 8);
270 /* if the plt slot has not yet been resolved, the target will
272 if (in_plt_section (pc, NULL))
274 /* Sanity check: are we pointing to the plt stub? */
275 if (insns_match_pattern (pc, hppa_plt_stub, insn))
277 /* this should point to the fixup routine */
278 pc = (CORE_ADDR) read_memory_integer (pc + 8, TARGET_PTR_BIT / 8);
282 error (_("Cannot resolve plt stub at 0x%s."),
294 /* (This is derived from MD_FALLBACK_FRAME_STATE_FOR in gcc.)
296 Unfortunately, because of various bugs and changes to the kernel,
297 we have several cases to deal with.
299 In 2.4, the signal trampoline is 4 bytes, and pc should point directly at
300 the beginning of the trampoline and struct rt_sigframe.
302 In <= 2.6.5-rc2-pa3, the signal trampoline is 9 bytes, and pc points at
303 the 4th word in the trampoline structure. This is wrong, it should point
304 at the 5th word. This is fixed in 2.6.5-rc2-pa4.
306 To detect these cases, we first take pc, align it to 64-bytes
307 to get the beginning of the signal frame, and then check offsets 0, 4
308 and 5 to see if we found the beginning of the trampoline. This will
309 tell us how to locate the sigcontext structure.
311 Note that with a 2.4 64-bit kernel, the signal context is not properly
312 passed back to userspace so the unwind will not work correctly. */
314 hppa_linux_sigtramp_find_sigcontext (CORE_ADDR pc)
316 unsigned int dummy[HPPA_MAX_INSN_PATTERN_LEN];
319 /* offsets to try to find the trampoline */
320 static int pcoffs[] = { 0, 4*4, 5*4 };
321 /* offsets to the rt_sigframe structure */
322 static int sfoffs[] = { 4*4, 10*4, 10*4 };
325 /* Most of the time, this will be correct. The one case when this will
326 fail is if the user defined an alternate stack, in which case the
327 beginning of the stack will not be align_down (pc, 64). */
328 sp = align_down (pc, 64);
330 /* rt_sigreturn trampoline:
331 3419000x ldi 0, %r25 or ldi 1, %r25 (x = 0 or 2)
332 3414015a ldi __NR_rt_sigreturn, %r20
333 e4008200 be,l 0x100(%sr2, %r0), %sr0, %r31
336 for (try = 0; try < ARRAY_SIZE (pcoffs); try++)
338 if (insns_match_pattern (sp + pcoffs[try], hppa_sigtramp, dummy))
347 if (insns_match_pattern (pc, hppa_sigtramp, dummy))
349 /* sigaltstack case: we have no way of knowing which offset to
350 use in this case; default to new kernel handling. If this is
351 wrong the unwinding will fail. */
353 sp = pc - pcoffs[try];
361 /* sp + sfoffs[try] points to a struct rt_sigframe, which contains
362 a struct siginfo and a struct ucontext. struct ucontext contains
363 a struct sigcontext. Return an offset to this sigcontext here. Too
364 bad we cannot include system specific headers :-(.
365 sizeof(struct siginfo) == 128
366 offsetof(struct ucontext, uc_mcontext) == 24. */
367 return sp + sfoffs[try] + 128 + 24;
370 struct hppa_linux_sigtramp_unwind_cache
373 struct trad_frame_saved_reg *saved_regs;
376 static struct hppa_linux_sigtramp_unwind_cache *
377 hppa_linux_sigtramp_frame_unwind_cache (struct frame_info *next_frame,
380 struct gdbarch *gdbarch = get_frame_arch (next_frame);
381 struct hppa_linux_sigtramp_unwind_cache *info;
388 info = FRAME_OBSTACK_ZALLOC (struct hppa_linux_sigtramp_unwind_cache);
390 info->saved_regs = trad_frame_alloc_saved_regs (next_frame);
392 pc = frame_pc_unwind (next_frame);
393 scptr = hppa_linux_sigtramp_find_sigcontext (pc);
395 /* structure of struct sigcontext:
398 unsigned long sc_flags;
399 unsigned long sc_gr[32];
400 unsigned long long sc_fr[32];
401 unsigned long sc_iasq[2];
402 unsigned long sc_iaoq[2];
403 unsigned long sc_sar; */
408 /* GR[0] is the psw, we don't restore that. */
411 /* General registers. */
412 for (i = 1; i < 32; i++)
414 info->saved_regs[HPPA_R0_REGNUM + i].addr = scptr;
421 /* FP regs; FP0-3 are not restored. */
424 for (i = 4; i < 32; i++)
426 info->saved_regs[HPPA_FP0_REGNUM + (i * 2)].addr = scptr;
428 info->saved_regs[HPPA_FP0_REGNUM + (i * 2) + 1].addr = scptr;
433 info->saved_regs[HPPA_PCSQ_HEAD_REGNUM].addr = scptr;
435 info->saved_regs[HPPA_PCSQ_TAIL_REGNUM].addr = scptr;
438 info->saved_regs[HPPA_PCOQ_HEAD_REGNUM].addr = scptr;
440 info->saved_regs[HPPA_PCOQ_TAIL_REGNUM].addr = scptr;
443 info->base = frame_unwind_register_unsigned (next_frame, HPPA_SP_REGNUM);
449 hppa_linux_sigtramp_frame_this_id (struct frame_info *next_frame,
450 void **this_prologue_cache,
451 struct frame_id *this_id)
453 struct hppa_linux_sigtramp_unwind_cache *info
454 = hppa_linux_sigtramp_frame_unwind_cache (next_frame, this_prologue_cache);
455 *this_id = frame_id_build (info->base, frame_pc_unwind (next_frame));
459 hppa_linux_sigtramp_frame_prev_register (struct frame_info *next_frame,
460 void **this_prologue_cache,
461 int regnum, int *optimizedp,
462 enum lval_type *lvalp,
464 int *realnump, void *valuep)
466 struct hppa_linux_sigtramp_unwind_cache *info
467 = hppa_linux_sigtramp_frame_unwind_cache (next_frame, this_prologue_cache);
468 hppa_frame_prev_register_helper (next_frame, info->saved_regs, regnum,
469 optimizedp, lvalp, addrp, realnump, valuep);
472 static const struct frame_unwind hppa_linux_sigtramp_frame_unwind = {
474 hppa_linux_sigtramp_frame_this_id,
475 hppa_linux_sigtramp_frame_prev_register
478 /* hppa-linux always uses "new-style" rt-signals. The signal handler's return
479 address should point to a signal trampoline on the stack. The signal
480 trampoline is embedded in a rt_sigframe structure that is aligned on
481 the stack. We take advantage of the fact that sp must be 64-byte aligned,
482 and the trampoline is small, so by rounding down the trampoline address
483 we can find the beginning of the struct rt_sigframe. */
484 static const struct frame_unwind *
485 hppa_linux_sigtramp_unwind_sniffer (struct frame_info *next_frame)
487 CORE_ADDR pc = frame_pc_unwind (next_frame);
489 if (hppa_linux_sigtramp_find_sigcontext (pc))
490 return &hppa_linux_sigtramp_frame_unwind;
495 /* Attempt to find (and return) the global pointer for the given
498 This is a rather nasty bit of code searchs for the .dynamic section
499 in the objfile corresponding to the pc of the function we're trying
500 to call. Once it finds the addresses at which the .dynamic section
501 lives in the child process, it scans the Elf32_Dyn entries for a
502 DT_PLTGOT tag. If it finds one of these, the corresponding
503 d_un.d_ptr value is the global pointer. */
506 hppa_linux_find_global_pointer (struct value *function)
508 struct obj_section *faddr_sect;
511 faddr = value_as_address (function);
513 /* Is this a plabel? If so, dereference it to get the gp value. */
521 status = target_read_memory (faddr + 4, buf, sizeof (buf));
523 return extract_unsigned_integer (buf, sizeof (buf));
526 /* If the address is in the plt section, then the real function hasn't
527 yet been fixed up by the linker so we cannot determine the gp of
529 if (in_plt_section (faddr, NULL))
532 faddr_sect = find_pc_section (faddr);
533 if (faddr_sect != NULL)
535 struct obj_section *osect;
537 ALL_OBJFILE_OSECTIONS (faddr_sect->objfile, osect)
539 if (strcmp (osect->the_bfd_section->name, ".dynamic") == 0)
543 if (osect < faddr_sect->objfile->sections_end)
548 while (addr < osect->endaddr)
554 status = target_read_memory (addr, buf, sizeof (buf));
557 tag = extract_signed_integer (buf, sizeof (buf));
559 if (tag == DT_PLTGOT)
561 CORE_ADDR global_pointer;
563 status = target_read_memory (addr + 4, buf, sizeof (buf));
566 global_pointer = extract_unsigned_integer (buf, sizeof (buf));
569 return global_pointer;
582 /* Forward declarations. */
583 extern initialize_file_ftype _initialize_hppa_linux_tdep;
586 hppa_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
588 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
590 /* GNU/Linux is always ELF. */
593 tdep->find_global_pointer = hppa_linux_find_global_pointer;
595 set_gdbarch_write_pc (gdbarch, hppa_linux_target_write_pc);
597 frame_unwind_append_sniffer (gdbarch, hppa_linux_sigtramp_unwind_sniffer);
599 /* GNU/Linux uses SVR4-style shared libraries. */
600 set_solib_svr4_fetch_link_map_offsets
601 (gdbarch, svr4_ilp32_fetch_link_map_offsets);
603 tdep->in_solib_call_trampoline = hppa_linux_in_solib_call_trampoline;
604 set_gdbarch_skip_trampoline_code
605 (gdbarch, hppa_linux_skip_trampoline_code);
607 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */
608 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
610 /* On hppa-linux, currently, sizeof(long double) == 8. There has been
611 some discussions to support 128-bit long double, but it requires some
612 more work in gcc and glibc first. */
613 set_gdbarch_long_double_bit (gdbarch, 64);
616 /* Dwarf-2 unwinding support. Not yet working. */
617 set_gdbarch_dwarf_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum);
618 set_gdbarch_dwarf2_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum);
619 frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer);
620 frame_base_append_sniffer (gdbarch, dwarf2_frame_base_sniffer);
623 /* Enable TLS support. */
624 set_gdbarch_fetch_tls_load_module_address (gdbarch,
625 svr4_fetch_objfile_link_map);
629 _initialize_hppa_linux_tdep (void)
631 gdbarch_register_osabi (bfd_arch_hppa, 0, GDB_OSABI_LINUX, hppa_linux_init_abi);