| /* Common target-dependent code for ppc64 GDB, the GNU debugger. |
| |
| Copyright (C) 1986-2013 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 3 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, see <http://www.gnu.org/licenses/>. */ |
| |
| #include "defs.h" |
| #include "frame.h" |
| #include "gdbcore.h" |
| #include "ppc-tdep.h" |
| #include "ppc64-tdep.h" |
| #include "elf-bfd.h" |
| |
| /* Macros for matching instructions. Note that, since all the |
| operands are masked off before they're or-ed into the instruction, |
| you can use -1 to make masks. */ |
| |
| #define insn_d(opcd, rts, ra, d) \ |
| ((((opcd) & 0x3f) << 26) \ |
| | (((rts) & 0x1f) << 21) \ |
| | (((ra) & 0x1f) << 16) \ |
| | ((d) & 0xffff)) |
| |
| #define insn_ds(opcd, rts, ra, d, xo) \ |
| ((((opcd) & 0x3f) << 26) \ |
| | (((rts) & 0x1f) << 21) \ |
| | (((ra) & 0x1f) << 16) \ |
| | ((d) & 0xfffc) \ |
| | ((xo) & 0x3)) |
| |
| #define insn_xfx(opcd, rts, spr, xo) \ |
| ((((opcd) & 0x3f) << 26) \ |
| | (((rts) & 0x1f) << 21) \ |
| | (((spr) & 0x1f) << 16) \ |
| | (((spr) & 0x3e0) << 6) \ |
| | (((xo) & 0x3ff) << 1)) |
| |
| /* If DESC is the address of a 64-bit PowerPC FreeBSD function |
| descriptor, return the descriptor's entry point. */ |
| |
| static CORE_ADDR |
| ppc64_desc_entry_point (struct gdbarch *gdbarch, CORE_ADDR desc) |
| { |
| enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| /* The first word of the descriptor is the entry point. */ |
| return (CORE_ADDR) read_memory_unsigned_integer (desc, 8, byte_order); |
| } |
| |
| /* Pattern for the standard linkage function. These are built by |
| build_plt_stub in elf64-ppc.c, whose GLINK argument is always |
| zero. */ |
| |
| static struct ppc_insn_pattern ppc64_standard_linkage1[] = |
| { |
| /* addis r12, r2, <any> */ |
| { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 }, |
| |
| /* std r2, 40(r1) */ |
| { -1, insn_ds (62, 2, 1, 40, 0), 0 }, |
| |
| /* ld r11, <any>(r12) */ |
| { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 }, |
| |
| /* addis r12, r12, 1 <optional> */ |
| { insn_d (-1, -1, -1, -1), insn_d (15, 12, 12, 1), 1 }, |
| |
| /* ld r2, <any>(r12) */ |
| { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 12, 0, 0), 0 }, |
| |
| /* addis r12, r12, 1 <optional> */ |
| { insn_d (-1, -1, -1, -1), insn_d (15, 12, 12, 1), 1 }, |
| |
| /* mtctr r11 */ |
| { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 }, |
| |
| /* ld r11, <any>(r12) <optional> */ |
| { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 1 }, |
| |
| /* bctr */ |
| { -1, 0x4e800420, 0 }, |
| |
| { 0, 0, 0 } |
| }; |
| |
| #define PPC64_STANDARD_LINKAGE1_LEN ARRAY_SIZE (ppc64_standard_linkage1) |
| |
| static struct ppc_insn_pattern ppc64_standard_linkage2[] = |
| { |
| /* addis r12, r2, <any> */ |
| { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 }, |
| |
| /* std r2, 40(r1) */ |
| { -1, insn_ds (62, 2, 1, 40, 0), 0 }, |
| |
| /* ld r11, <any>(r12) */ |
| { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 }, |
| |
| /* addi r12, r12, <any> <optional> */ |
| { insn_d (-1, -1, -1, 0), insn_d (14, 12, 12, 0), 1 }, |
| |
| /* mtctr r11 */ |
| { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 }, |
| |
| /* ld r2, <any>(r12) */ |
| { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 12, 0, 0), 0 }, |
| |
| /* ld r11, <any>(r12) <optional> */ |
| { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 1 }, |
| |
| /* bctr */ |
| { -1, 0x4e800420, 0 }, |
| |
| { 0, 0, 0 } |
| }; |
| |
| #define PPC64_STANDARD_LINKAGE2_LEN ARRAY_SIZE (ppc64_standard_linkage2) |
| |
| static struct ppc_insn_pattern ppc64_standard_linkage3[] = |
| { |
| /* std r2, 40(r1) */ |
| { -1, insn_ds (62, 2, 1, 40, 0), 0 }, |
| |
| /* ld r11, <any>(r2) */ |
| { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 2, 0, 0), 0 }, |
| |
| /* addi r2, r2, <any> <optional> */ |
| { insn_d (-1, -1, -1, 0), insn_d (14, 2, 2, 0), 1 }, |
| |
| /* mtctr r11 */ |
| { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 }, |
| |
| /* ld r11, <any>(r2) <optional> */ |
| { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 2, 0, 0), 1 }, |
| |
| /* ld r2, <any>(r2) */ |
| { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 2, 0, 0), 0 }, |
| |
| /* bctr */ |
| { -1, 0x4e800420, 0 }, |
| |
| { 0, 0, 0 } |
| }; |
| |
| #define PPC64_STANDARD_LINKAGE3_LEN ARRAY_SIZE (ppc64_standard_linkage3) |
| |
| /* When the dynamic linker is doing lazy symbol resolution, the first |
| call to a function in another object will go like this: |
| |
| - The user's function calls the linkage function: |
| |
| 100007c4: 4b ff fc d5 bl 10000498 |
| 100007c8: e8 41 00 28 ld r2,40(r1) |
| |
| - The linkage function loads the entry point (and other stuff) from |
| the function descriptor in the PLT, and jumps to it: |
| |
| 10000498: 3d 82 00 00 addis r12,r2,0 |
| 1000049c: f8 41 00 28 std r2,40(r1) |
| 100004a0: e9 6c 80 98 ld r11,-32616(r12) |
| 100004a4: e8 4c 80 a0 ld r2,-32608(r12) |
| 100004a8: 7d 69 03 a6 mtctr r11 |
| 100004ac: e9 6c 80 a8 ld r11,-32600(r12) |
| 100004b0: 4e 80 04 20 bctr |
| |
| - But since this is the first time that PLT entry has been used, it |
| sends control to its glink entry. That loads the number of the |
| PLT entry and jumps to the common glink0 code: |
| |
| 10000c98: 38 00 00 00 li r0,0 |
| 10000c9c: 4b ff ff dc b 10000c78 |
| |
| - The common glink0 code then transfers control to the dynamic |
| linker's fixup code: |
| |
| 10000c78: e8 41 00 28 ld r2,40(r1) |
| 10000c7c: 3d 82 00 00 addis r12,r2,0 |
| 10000c80: e9 6c 80 80 ld r11,-32640(r12) |
| 10000c84: e8 4c 80 88 ld r2,-32632(r12) |
| 10000c88: 7d 69 03 a6 mtctr r11 |
| 10000c8c: e9 6c 80 90 ld r11,-32624(r12) |
| 10000c90: 4e 80 04 20 bctr |
| |
| Eventually, this code will figure out how to skip all of this, |
| including the dynamic linker. At the moment, we just get through |
| the linkage function. */ |
| |
| /* If the current thread is about to execute a series of instructions |
| at PC matching the ppc64_standard_linkage pattern, and INSN is the result |
| from that pattern match, return the code address to which the |
| standard linkage function will send them. (This doesn't deal with |
| dynamic linker lazy symbol resolution stubs.) */ |
| |
| static CORE_ADDR |
| ppc64_standard_linkage1_target (struct frame_info *frame, |
| CORE_ADDR pc, unsigned int *insn) |
| { |
| struct gdbarch *gdbarch = get_frame_arch (frame); |
| struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| |
| /* The address of the function descriptor this linkage function |
| references. */ |
| CORE_ADDR desc |
| = ((CORE_ADDR) get_frame_register_unsigned (frame, |
| tdep->ppc_gp0_regnum + 2) |
| + (ppc_insn_d_field (insn[0]) << 16) |
| + ppc_insn_ds_field (insn[2])); |
| |
| /* The first word of the descriptor is the entry point. Return that. */ |
| return ppc64_desc_entry_point (gdbarch, desc); |
| } |
| |
| static CORE_ADDR |
| ppc64_standard_linkage2_target (struct frame_info *frame, |
| CORE_ADDR pc, unsigned int *insn) |
| { |
| struct gdbarch *gdbarch = get_frame_arch (frame); |
| struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| |
| /* The address of the function descriptor this linkage function |
| references. */ |
| CORE_ADDR desc |
| = ((CORE_ADDR) get_frame_register_unsigned (frame, |
| tdep->ppc_gp0_regnum + 2) |
| + (ppc_insn_d_field (insn[0]) << 16) |
| + ppc_insn_ds_field (insn[2])); |
| |
| /* The first word of the descriptor is the entry point. Return that. */ |
| return ppc64_desc_entry_point (gdbarch, desc); |
| } |
| |
| static CORE_ADDR |
| ppc64_standard_linkage3_target (struct frame_info *frame, |
| CORE_ADDR pc, unsigned int *insn) |
| { |
| struct gdbarch *gdbarch = get_frame_arch (frame); |
| struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| |
| /* The address of the function descriptor this linkage function |
| references. */ |
| CORE_ADDR desc |
| = ((CORE_ADDR) get_frame_register_unsigned (frame, |
| tdep->ppc_gp0_regnum + 2) |
| + ppc_insn_ds_field (insn[1])); |
| |
| /* The first word of the descriptor is the entry point. Return that. */ |
| return ppc64_desc_entry_point (gdbarch, desc); |
| } |
| |
| |
| /* Given that we've begun executing a call trampoline at PC, return |
| the entry point of the function the trampoline will go to. */ |
| |
| CORE_ADDR |
| ppc64_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc) |
| { |
| unsigned int ppc64_standard_linkage1_insn[PPC64_STANDARD_LINKAGE1_LEN]; |
| unsigned int ppc64_standard_linkage2_insn[PPC64_STANDARD_LINKAGE2_LEN]; |
| unsigned int ppc64_standard_linkage3_insn[PPC64_STANDARD_LINKAGE3_LEN]; |
| CORE_ADDR target; |
| |
| if (ppc_insns_match_pattern (pc, ppc64_standard_linkage1, |
| ppc64_standard_linkage1_insn)) |
| pc = ppc64_standard_linkage1_target (frame, pc, |
| ppc64_standard_linkage1_insn); |
| else if (ppc_insns_match_pattern (pc, ppc64_standard_linkage2, |
| ppc64_standard_linkage2_insn)) |
| pc = ppc64_standard_linkage2_target (frame, pc, |
| ppc64_standard_linkage2_insn); |
| else if (ppc_insns_match_pattern (pc, ppc64_standard_linkage3, |
| ppc64_standard_linkage3_insn)) |
| pc = ppc64_standard_linkage3_target (frame, pc, |
| ppc64_standard_linkage3_insn); |
| else |
| return 0; |
| |
| /* The PLT descriptor will either point to the already resolved target |
| address, or else to a glink stub. As the latter carry synthetic @plt |
| symbols, find_solib_trampoline_target should be able to resolve them. */ |
| target = find_solib_trampoline_target (frame, pc); |
| return target ? target : pc; |
| } |
| |
| /* Support for convert_from_func_ptr_addr (ARCH, ADDR, TARG) on PPC64 |
| GNU/Linux. |
| |
| Usually a function pointer's representation is simply the address |
| of the function. On GNU/Linux on the PowerPC however, a function |
| pointer may be a pointer to a function descriptor. |
| |
| For PPC64, a function descriptor is a TOC entry, in a data section, |
| which contains three words: the first word is the address of the |
| function, the second word is the TOC pointer (r2), and the third word |
| is the static chain value. |
| |
| Throughout GDB it is currently assumed that a function pointer contains |
| the address of the function, which is not easy to fix. In addition, the |
| conversion of a function address to a function pointer would |
| require allocation of a TOC entry in the inferior's memory space, |
| with all its drawbacks. To be able to call C++ virtual methods in |
| the inferior (which are called via function pointers), |
| find_function_addr uses this function to get the function address |
| from a function pointer. |
| |
| If ADDR points at what is clearly a function descriptor, transform |
| it into the address of the corresponding function, if needed. Be |
| conservative, otherwise GDB will do the transformation on any |
| random addresses such as occur when there is no symbol table. */ |
| |
| CORE_ADDR |
| ppc64_convert_from_func_ptr_addr (struct gdbarch *gdbarch, |
| CORE_ADDR addr, |
| struct target_ops *targ) |
| { |
| enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| struct target_section *s = target_section_by_addr (targ, addr); |
| |
| /* Check if ADDR points to a function descriptor. */ |
| if (s && strcmp (s->the_bfd_section->name, ".opd") == 0) |
| { |
| /* There may be relocations that need to be applied to the .opd |
| section. Unfortunately, this function may be called at a time |
| where these relocations have not yet been performed -- this can |
| happen for example shortly after a library has been loaded with |
| dlopen, but ld.so has not yet applied the relocations. |
| |
| To cope with both the case where the relocation has been applied, |
| and the case where it has not yet been applied, we do *not* read |
| the (maybe) relocated value from target memory, but we instead |
| read the non-relocated value from the BFD, and apply the relocation |
| offset manually. |
| |
| This makes the assumption that all .opd entries are always relocated |
| by the same offset the section itself was relocated. This should |
| always be the case for GNU/Linux executables and shared libraries. |
| Note that other kind of object files (e.g. those added via |
| add-symbol-files) will currently never end up here anyway, as this |
| function accesses *target* sections only; only the main exec and |
| shared libraries are ever added to the target. */ |
| |
| gdb_byte buf[8]; |
| int res; |
| |
| res = bfd_get_section_contents (s->bfd, s->the_bfd_section, |
| &buf, addr - s->addr, 8); |
| if (res != 0) |
| return extract_unsigned_integer (buf, 8, byte_order) |
| - bfd_section_vma (s->bfd, s->the_bfd_section) + s->addr; |
| } |
| |
| return addr; |
| } |
| |
| /* A synthetic 'dot' symbols on ppc64 has the udata.p entry pointing |
| back to the original ELF symbol it was derived from. Get the size |
| from that symbol. */ |
| |
| void |
| ppc64_elf_make_msymbol_special (asymbol *sym, struct minimal_symbol *msym) |
| { |
| if ((sym->flags & BSF_SYNTHETIC) != 0 && sym->udata.p != NULL) |
| { |
| elf_symbol_type *elf_sym = (elf_symbol_type *) sym->udata.p; |
| SET_MSYMBOL_SIZE (msym, elf_sym->internal_elf_sym.st_size); |
| } |
| } |