| /* Target-dependent code for GNU/Linux running on PA-RISC, for GDB. |
| |
| Copyright 2004 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| |
| #include "defs.h" |
| #include "gdbcore.h" |
| #include "osabi.h" |
| #include "target.h" |
| #include "objfiles.h" |
| #include "solib-svr4.h" |
| #include "glibc-tdep.h" |
| #include "frame-unwind.h" |
| #include "trad-frame.h" |
| #include "dwarf2-frame.h" |
| #include "value.h" |
| #include "hppa-tdep.h" |
| |
| #include "elf/common.h" |
| |
| #if 0 |
| /* Convert DWARF register number REG to the appropriate register |
| number used by GDB. */ |
| static int |
| hppa_dwarf_reg_to_regnum (int reg) |
| { |
| /* registers 0 - 31 are the same in both sets */ |
| if (reg < 32) |
| return reg; |
| |
| /* dwarf regs 32 to 85 are fpregs 4 - 31 */ |
| if (reg >= 32 && reg <= 85) |
| return HPPA_FP4_REGNUM + (reg - 32); |
| |
| warning (_("Unmapped DWARF Register #%d encountered."), reg); |
| return -1; |
| } |
| #endif |
| |
| static void |
| hppa_linux_target_write_pc (CORE_ADDR v, ptid_t ptid) |
| { |
| /* Probably this should be done by the kernel, but it isn't. */ |
| write_register_pid (HPPA_PCOQ_HEAD_REGNUM, v | 0x3, ptid); |
| write_register_pid (HPPA_PCOQ_TAIL_REGNUM, (v + 4) | 0x3, ptid); |
| } |
| |
| /* An instruction to match. */ |
| struct insn_pattern |
| { |
| unsigned int data; /* See if it matches this.... */ |
| unsigned int mask; /* ... with this mask. */ |
| }; |
| |
| /* See bfd/elf32-hppa.c */ |
| static struct insn_pattern hppa_long_branch_stub[] = { |
| /* ldil LR'xxx,%r1 */ |
| { 0x20200000, 0xffe00000 }, |
| /* be,n RR'xxx(%sr4,%r1) */ |
| { 0xe0202002, 0xffe02002 }, |
| { 0, 0 } |
| }; |
| |
| static struct insn_pattern hppa_long_branch_pic_stub[] = { |
| /* b,l .+8, %r1 */ |
| { 0xe8200000, 0xffe00000 }, |
| /* addil LR'xxx - ($PIC_pcrel$0 - 4), %r1 */ |
| { 0x28200000, 0xffe00000 }, |
| /* be,n RR'xxxx - ($PIC_pcrel$0 - 8)(%sr4, %r1) */ |
| { 0xe0202002, 0xffe02002 }, |
| { 0, 0 } |
| }; |
| |
| static struct insn_pattern hppa_import_stub[] = { |
| /* addil LR'xxx, %dp */ |
| { 0x2b600000, 0xffe00000 }, |
| /* ldw RR'xxx(%r1), %r21 */ |
| { 0x48350000, 0xffffb000 }, |
| /* bv %r0(%r21) */ |
| { 0xeaa0c000, 0xffffffff }, |
| /* ldw RR'xxx+4(%r1), %r19 */ |
| { 0x48330000, 0xffffb000 }, |
| { 0, 0 } |
| }; |
| |
| static struct insn_pattern hppa_import_pic_stub[] = { |
| /* addil LR'xxx,%r19 */ |
| { 0x2a600000, 0xffe00000 }, |
| /* ldw RR'xxx(%r1),%r21 */ |
| { 0x48350000, 0xffffb000 }, |
| /* bv %r0(%r21) */ |
| { 0xeaa0c000, 0xffffffff }, |
| /* ldw RR'xxx+4(%r1),%r19 */ |
| { 0x48330000, 0xffffb000 }, |
| { 0, 0 }, |
| }; |
| |
| static struct insn_pattern hppa_plt_stub[] = { |
| /* b,l 1b, %r20 - 1b is 3 insns before here */ |
| { 0xea9f1fdd, 0xffffffff }, |
| /* depi 0,31,2,%r20 */ |
| { 0xd6801c1e, 0xffffffff }, |
| { 0, 0 } |
| }; |
| |
| static struct insn_pattern hppa_sigtramp[] = { |
| /* ldi 0, %r25 or ldi 1, %r25 */ |
| { 0x34190000, 0xfffffffd }, |
| /* ldi __NR_rt_sigreturn, %r20 */ |
| { 0x3414015a, 0xffffffff }, |
| /* be,l 0x100(%sr2, %r0), %sr0, %r31 */ |
| { 0xe4008200, 0xffffffff }, |
| /* nop */ |
| { 0x08000240, 0xffffffff }, |
| { 0, 0 } |
| }; |
| |
| #define HPPA_MAX_INSN_PATTERN_LEN (4) |
| |
| /* Return non-zero if the instructions at PC match the series |
| described in PATTERN, or zero otherwise. PATTERN is an array of |
| 'struct insn_pattern' objects, terminated by an entry whose mask is |
| zero. |
| |
| When the match is successful, fill INSN[i] with what PATTERN[i] |
| matched. */ |
| static int |
| insns_match_pattern (CORE_ADDR pc, |
| struct insn_pattern *pattern, |
| unsigned int *insn) |
| { |
| int i; |
| CORE_ADDR npc = pc; |
| |
| for (i = 0; pattern[i].mask; i++) |
| { |
| char buf[4]; |
| |
| deprecated_read_memory_nobpt (npc, buf, 4); |
| insn[i] = extract_unsigned_integer (buf, 4); |
| if ((insn[i] & pattern[i].mask) == pattern[i].data) |
| npc += 4; |
| else |
| return 0; |
| } |
| return 1; |
| } |
| |
| /* The relaxed version of the insn matcher allows us to match from somewhere |
| inside the pattern, by looking backwards in the instruction scheme. */ |
| static int |
| insns_match_pattern_relaxed (CORE_ADDR pc, |
| struct insn_pattern *pattern, |
| unsigned int *insn) |
| { |
| int pat_len = 0; |
| int offset; |
| |
| while (pattern[pat_len].mask) |
| pat_len++; |
| |
| for (offset = 0; offset < pat_len; offset++) |
| { |
| if (insns_match_pattern (pc - offset * 4, |
| pattern, insn)) |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| static int |
| hppa_linux_in_dyncall (CORE_ADDR pc) |
| { |
| struct unwind_table_entry *u; |
| u = find_unwind_entry (hppa_symbol_address ("$$dyncall")); |
| |
| if (!u) |
| return 0; |
| |
| return pc >= u->region_start && pc <= u->region_end; |
| } |
| |
| /* There are several kinds of "trampolines" that we need to deal with: |
| - long branch stubs: these are inserted by the linker when a branch |
| target is too far away for a branch insn to reach |
| - plt stubs: these should go into the .plt section, so are easy to find |
| - import stubs: used to call from object to shared lib or shared lib to |
| shared lib; these go in regular text sections. In fact the linker tries |
| to put them throughout the code because branches have limited reachability. |
| We use the same mechanism as ppc64 to recognize the stub insn patterns. |
| - $$dyncall: similar to hpux, hppa-linux uses $$dyncall for indirect function |
| calls. $$dyncall is exported by libgcc.a */ |
| static int |
| hppa_linux_in_solib_call_trampoline (CORE_ADDR pc, char *name) |
| { |
| unsigned int insn[HPPA_MAX_INSN_PATTERN_LEN]; |
| int r; |
| struct unwind_table_entry *u; |
| |
| /* on hppa-linux, linker stubs have no unwind information. Since the pattern |
| matching for linker stubs can be quite slow, we try to avoid it if |
| we can. */ |
| u = find_unwind_entry (pc); |
| |
| r = in_plt_section (pc, name) |
| || hppa_linux_in_dyncall (pc) |
| || (u == NULL |
| && (insns_match_pattern_relaxed (pc, hppa_import_stub, insn) |
| || insns_match_pattern_relaxed (pc, hppa_import_pic_stub, insn) |
| || insns_match_pattern_relaxed (pc, hppa_long_branch_stub, insn) |
| || insns_match_pattern_relaxed (pc, hppa_long_branch_pic_stub, insn))); |
| |
| return r; |
| } |
| |
| static CORE_ADDR |
| hppa_linux_skip_trampoline_code (CORE_ADDR pc) |
| { |
| unsigned int insn[HPPA_MAX_INSN_PATTERN_LEN]; |
| int dp_rel, pic_rel; |
| |
| /* dyncall handles both PLABELs and direct addresses */ |
| if (hppa_linux_in_dyncall (pc)) |
| { |
| pc = (CORE_ADDR) read_register (22); |
| |
| /* PLABELs have bit 30 set; if it's a PLABEL, then dereference it */ |
| if (pc & 0x2) |
| pc = (CORE_ADDR) read_memory_integer (pc & ~0x3, TARGET_PTR_BIT / 8); |
| |
| return pc; |
| } |
| |
| dp_rel = pic_rel = 0; |
| if ((dp_rel = insns_match_pattern (pc, hppa_import_stub, insn)) |
| || (pic_rel = insns_match_pattern (pc, hppa_import_pic_stub, insn))) |
| { |
| /* Extract the target address from the addil/ldw sequence. */ |
| pc = hppa_extract_21 (insn[0]) + hppa_extract_14 (insn[1]); |
| |
| if (dp_rel) |
| pc += (CORE_ADDR) read_register (27); |
| else |
| pc += (CORE_ADDR) read_register (19); |
| |
| /* fallthrough */ |
| } |
| |
| if (in_plt_section (pc, NULL)) |
| { |
| pc = (CORE_ADDR) read_memory_integer (pc, TARGET_PTR_BIT / 8); |
| |
| /* if the plt slot has not yet been resolved, the target will |
| be the plt stub */ |
| if (in_plt_section (pc, NULL)) |
| { |
| /* Sanity check: are we pointing to the plt stub? */ |
| if (insns_match_pattern (pc, hppa_plt_stub, insn)) |
| { |
| /* this should point to the fixup routine */ |
| pc = (CORE_ADDR) read_memory_integer (pc + 8, TARGET_PTR_BIT / 8); |
| } |
| else |
| { |
| error (_("Cannot resolve plt stub at 0x%s."), |
| paddr_nz (pc)); |
| pc = 0; |
| } |
| } |
| } |
| |
| return pc; |
| } |
| |
| /* Signal frames. */ |
| |
| /* (This is derived from MD_FALLBACK_FRAME_STATE_FOR in gcc.) |
| |
| Unfortunately, because of various bugs and changes to the kernel, |
| we have several cases to deal with. |
| |
| In 2.4, the signal trampoline is 4 bytes, and pc should point directly at |
| the beginning of the trampoline and struct rt_sigframe. |
| |
| In <= 2.6.5-rc2-pa3, the signal trampoline is 9 bytes, and pc points at |
| the 4th word in the trampoline structure. This is wrong, it should point |
| at the 5th word. This is fixed in 2.6.5-rc2-pa4. |
| |
| To detect these cases, we first take pc, align it to 64-bytes |
| to get the beginning of the signal frame, and then check offsets 0, 4 |
| and 5 to see if we found the beginning of the trampoline. This will |
| tell us how to locate the sigcontext structure. |
| |
| Note that with a 2.4 64-bit kernel, the signal context is not properly |
| passed back to userspace so the unwind will not work correctly. */ |
| static CORE_ADDR |
| hppa_linux_sigtramp_find_sigcontext (CORE_ADDR pc) |
| { |
| unsigned int dummy[HPPA_MAX_INSN_PATTERN_LEN]; |
| int offs = 0; |
| int try; |
| /* offsets to try to find the trampoline */ |
| static int pcoffs[] = { 0, 4*4, 5*4 }; |
| /* offsets to the rt_sigframe structure */ |
| static int sfoffs[] = { 4*4, 10*4, 10*4 }; |
| CORE_ADDR sp; |
| |
| /* Most of the time, this will be correct. The one case when this will |
| fail is if the user defined an alternate stack, in which case the |
| beginning of the stack will not be align_down (pc, 64). */ |
| sp = align_down (pc, 64); |
| |
| /* rt_sigreturn trampoline: |
| 3419000x ldi 0, %r25 or ldi 1, %r25 (x = 0 or 2) |
| 3414015a ldi __NR_rt_sigreturn, %r20 |
| e4008200 be,l 0x100(%sr2, %r0), %sr0, %r31 |
| 08000240 nop */ |
| |
| for (try = 0; try < ARRAY_SIZE (pcoffs); try++) |
| { |
| if (insns_match_pattern (sp + pcoffs[try], hppa_sigtramp, dummy)) |
| { |
| offs = sfoffs[try]; |
| break; |
| } |
| } |
| |
| if (offs == 0) |
| { |
| if (insns_match_pattern (pc, hppa_sigtramp, dummy)) |
| { |
| /* sigaltstack case: we have no way of knowing which offset to |
| use in this case; default to new kernel handling. If this is |
| wrong the unwinding will fail. */ |
| try = 2; |
| sp = pc - pcoffs[try]; |
| } |
| else |
| { |
| return 0; |
| } |
| } |
| |
| /* sp + sfoffs[try] points to a struct rt_sigframe, which contains |
| a struct siginfo and a struct ucontext. struct ucontext contains |
| a struct sigcontext. Return an offset to this sigcontext here. Too |
| bad we cannot include system specific headers :-(. |
| sizeof(struct siginfo) == 128 |
| offsetof(struct ucontext, uc_mcontext) == 24. */ |
| return sp + sfoffs[try] + 128 + 24; |
| } |
| |
| struct hppa_linux_sigtramp_unwind_cache |
| { |
| CORE_ADDR base; |
| struct trad_frame_saved_reg *saved_regs; |
| }; |
| |
| static struct hppa_linux_sigtramp_unwind_cache * |
| hppa_linux_sigtramp_frame_unwind_cache (struct frame_info *next_frame, |
| void **this_cache) |
| { |
| struct gdbarch *gdbarch = get_frame_arch (next_frame); |
| struct hppa_linux_sigtramp_unwind_cache *info; |
| CORE_ADDR pc, scptr; |
| int i; |
| |
| if (*this_cache) |
| return *this_cache; |
| |
| info = FRAME_OBSTACK_ZALLOC (struct hppa_linux_sigtramp_unwind_cache); |
| *this_cache = info; |
| info->saved_regs = trad_frame_alloc_saved_regs (next_frame); |
| |
| pc = frame_pc_unwind (next_frame); |
| scptr = hppa_linux_sigtramp_find_sigcontext (pc); |
| |
| /* structure of struct sigcontext: |
| |
| struct sigcontext { |
| unsigned long sc_flags; |
| unsigned long sc_gr[32]; |
| unsigned long long sc_fr[32]; |
| unsigned long sc_iasq[2]; |
| unsigned long sc_iaoq[2]; |
| unsigned long sc_sar; */ |
| |
| /* Skip sc_flags. */ |
| scptr += 4; |
| |
| /* GR[0] is the psw, we don't restore that. */ |
| scptr += 4; |
| |
| /* General registers. */ |
| for (i = 1; i < 32; i++) |
| { |
| info->saved_regs[HPPA_R0_REGNUM + i].addr = scptr; |
| scptr += 4; |
| } |
| |
| /* Pad. */ |
| scptr += 4; |
| |
| /* FP regs; FP0-3 are not restored. */ |
| scptr += (8 * 4); |
| |
| for (i = 4; i < 32; i++) |
| { |
| info->saved_regs[HPPA_FP0_REGNUM + (i * 2)].addr = scptr; |
| scptr += 4; |
| info->saved_regs[HPPA_FP0_REGNUM + (i * 2) + 1].addr = scptr; |
| scptr += 4; |
| } |
| |
| /* IASQ/IAOQ. */ |
| info->saved_regs[HPPA_PCSQ_HEAD_REGNUM].addr = scptr; |
| scptr += 4; |
| info->saved_regs[HPPA_PCSQ_TAIL_REGNUM].addr = scptr; |
| scptr += 4; |
| |
| info->saved_regs[HPPA_PCOQ_HEAD_REGNUM].addr = scptr; |
| scptr += 4; |
| info->saved_regs[HPPA_PCOQ_TAIL_REGNUM].addr = scptr; |
| scptr += 4; |
| |
| info->base = frame_unwind_register_unsigned (next_frame, HPPA_SP_REGNUM); |
| |
| return info; |
| } |
| |
| static void |
| hppa_linux_sigtramp_frame_this_id (struct frame_info *next_frame, |
| void **this_prologue_cache, |
| struct frame_id *this_id) |
| { |
| struct hppa_linux_sigtramp_unwind_cache *info |
| = hppa_linux_sigtramp_frame_unwind_cache (next_frame, this_prologue_cache); |
| *this_id = frame_id_build (info->base, frame_pc_unwind (next_frame)); |
| } |
| |
| static void |
| hppa_linux_sigtramp_frame_prev_register (struct frame_info *next_frame, |
| void **this_prologue_cache, |
| int regnum, int *optimizedp, |
| enum lval_type *lvalp, |
| CORE_ADDR *addrp, |
| int *realnump, void *valuep) |
| { |
| struct hppa_linux_sigtramp_unwind_cache *info |
| = hppa_linux_sigtramp_frame_unwind_cache (next_frame, this_prologue_cache); |
| hppa_frame_prev_register_helper (next_frame, info->saved_regs, regnum, |
| optimizedp, lvalp, addrp, realnump, valuep); |
| } |
| |
| static const struct frame_unwind hppa_linux_sigtramp_frame_unwind = { |
| SIGTRAMP_FRAME, |
| hppa_linux_sigtramp_frame_this_id, |
| hppa_linux_sigtramp_frame_prev_register |
| }; |
| |
| /* hppa-linux always uses "new-style" rt-signals. The signal handler's return |
| address should point to a signal trampoline on the stack. The signal |
| trampoline is embedded in a rt_sigframe structure that is aligned on |
| the stack. We take advantage of the fact that sp must be 64-byte aligned, |
| and the trampoline is small, so by rounding down the trampoline address |
| we can find the beginning of the struct rt_sigframe. */ |
| static const struct frame_unwind * |
| hppa_linux_sigtramp_unwind_sniffer (struct frame_info *next_frame) |
| { |
| CORE_ADDR pc = frame_pc_unwind (next_frame); |
| |
| if (hppa_linux_sigtramp_find_sigcontext (pc)) |
| return &hppa_linux_sigtramp_frame_unwind; |
| |
| return NULL; |
| } |
| |
| /* Attempt to find (and return) the global pointer for the given |
| function. |
| |
| This is a rather nasty bit of code searchs for the .dynamic section |
| in the objfile corresponding to the pc of the function we're trying |
| to call. Once it finds the addresses at which the .dynamic section |
| lives in the child process, it scans the Elf32_Dyn entries for a |
| DT_PLTGOT tag. If it finds one of these, the corresponding |
| d_un.d_ptr value is the global pointer. */ |
| |
| static CORE_ADDR |
| hppa_linux_find_global_pointer (struct value *function) |
| { |
| struct obj_section *faddr_sect; |
| CORE_ADDR faddr; |
| |
| faddr = value_as_address (function); |
| |
| /* Is this a plabel? If so, dereference it to get the gp value. */ |
| if (faddr & 2) |
| { |
| int status; |
| char buf[4]; |
| |
| faddr &= ~3; |
| |
| status = target_read_memory (faddr + 4, buf, sizeof (buf)); |
| if (status == 0) |
| return extract_unsigned_integer (buf, sizeof (buf)); |
| } |
| |
| /* If the address is in the plt section, then the real function hasn't |
| yet been fixed up by the linker so we cannot determine the gp of |
| that function. */ |
| if (in_plt_section (faddr, NULL)) |
| return 0; |
| |
| faddr_sect = find_pc_section (faddr); |
| if (faddr_sect != NULL) |
| { |
| struct obj_section *osect; |
| |
| ALL_OBJFILE_OSECTIONS (faddr_sect->objfile, osect) |
| { |
| if (strcmp (osect->the_bfd_section->name, ".dynamic") == 0) |
| break; |
| } |
| |
| if (osect < faddr_sect->objfile->sections_end) |
| { |
| CORE_ADDR addr; |
| |
| addr = osect->addr; |
| while (addr < osect->endaddr) |
| { |
| int status; |
| LONGEST tag; |
| char buf[4]; |
| |
| status = target_read_memory (addr, buf, sizeof (buf)); |
| if (status != 0) |
| break; |
| tag = extract_signed_integer (buf, sizeof (buf)); |
| |
| if (tag == DT_PLTGOT) |
| { |
| CORE_ADDR global_pointer; |
| |
| status = target_read_memory (addr + 4, buf, sizeof (buf)); |
| if (status != 0) |
| break; |
| global_pointer = extract_unsigned_integer (buf, sizeof (buf)); |
| |
| /* The payoff... */ |
| return global_pointer; |
| } |
| |
| if (tag == DT_NULL) |
| break; |
| |
| addr += 8; |
| } |
| } |
| } |
| return 0; |
| } |
| |
| /* Forward declarations. */ |
| extern initialize_file_ftype _initialize_hppa_linux_tdep; |
| |
| static void |
| hppa_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| { |
| struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| |
| /* GNU/Linux is always ELF. */ |
| tdep->is_elf = 1; |
| |
| tdep->find_global_pointer = hppa_linux_find_global_pointer; |
| |
| set_gdbarch_write_pc (gdbarch, hppa_linux_target_write_pc); |
| |
| frame_unwind_append_sniffer (gdbarch, hppa_linux_sigtramp_unwind_sniffer); |
| |
| /* GNU/Linux uses SVR4-style shared libraries. */ |
| set_solib_svr4_fetch_link_map_offsets |
| (gdbarch, svr4_ilp32_fetch_link_map_offsets); |
| |
| tdep->in_solib_call_trampoline = hppa_linux_in_solib_call_trampoline; |
| set_gdbarch_skip_trampoline_code |
| (gdbarch, hppa_linux_skip_trampoline_code); |
| |
| /* GNU/Linux uses the dynamic linker included in the GNU C Library. */ |
| set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); |
| |
| /* On hppa-linux, currently, sizeof(long double) == 8. There has been |
| some discussions to support 128-bit long double, but it requires some |
| more work in gcc and glibc first. */ |
| set_gdbarch_long_double_bit (gdbarch, 64); |
| |
| #if 0 |
| /* Dwarf-2 unwinding support. Not yet working. */ |
| set_gdbarch_dwarf_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum); |
| set_gdbarch_dwarf2_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum); |
| frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer); |
| frame_base_append_sniffer (gdbarch, dwarf2_frame_base_sniffer); |
| #endif |
| } |
| |
| void |
| _initialize_hppa_linux_tdep (void) |
| { |
| gdbarch_register_osabi (bfd_arch_hppa, 0, GDB_OSABI_LINUX, hppa_linux_init_abi); |
| } |