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- /* Target-dependent code for OpenBSD/powerpc.
- Copyright (C) 2004-2022 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 "arch-utils.h"
- #include "frame.h"
- #include "frame-unwind.h"
- #include "gdbtypes.h"
- #include "osabi.h"
- #include "regcache.h"
- #include "regset.h"
- #include "symtab.h"
- #include "trad-frame.h"
- #include "ppc-tdep.h"
- #include "ppc-obsd-tdep.h"
- #include "solib-svr4.h"
- /* Register offsets from <machine/reg.h>. */
- struct ppc_reg_offsets ppcobsd_reg_offsets;
- struct ppc_reg_offsets ppcobsd_fpreg_offsets;
- /* Core file support. */
- /* Supply register REGNUM in the general-purpose register set REGSET
- from the buffer specified by GREGS and LEN to register cache
- REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
- void
- ppcobsd_supply_gregset (const struct regset *regset,
- struct regcache *regcache, int regnum,
- const void *gregs, size_t len)
- {
- ppc_supply_gregset (regset, regcache, regnum, gregs, len);
- ppc_supply_fpregset (regset, regcache, regnum, gregs, len);
- }
- /* Collect register REGNUM in the general-purpose register set
- REGSET, from register cache REGCACHE into the buffer specified by
- GREGS and LEN. If REGNUM is -1, do this for all registers in
- REGSET. */
- void
- ppcobsd_collect_gregset (const struct regset *regset,
- const struct regcache *regcache, int regnum,
- void *gregs, size_t len)
- {
- ppc_collect_gregset (regset, regcache, regnum, gregs, len);
- ppc_collect_fpregset (regset, regcache, regnum, gregs, len);
- }
- /* OpenBSD/powerpc register set. */
- const struct regset ppcobsd_gregset =
- {
- &ppcobsd_reg_offsets,
- ppcobsd_supply_gregset
- };
- const struct regset ppcobsd_fpregset =
- {
- &ppcobsd_fpreg_offsets,
- ppc_supply_fpregset
- };
- /* Iterate over core file register note sections. */
- static void
- ppcobsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
- iterate_over_regset_sections_cb *cb,
- void *cb_data,
- const struct regcache *regcache)
- {
- cb (".reg", 412, 412, &ppcobsd_gregset, NULL, cb_data);
- }
- /* Signal trampolines. */
- /* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
- in virtual memory. The randomness makes it somewhat tricky to
- detect it, but fortunately we can rely on the fact that the start
- of the sigtramp routine is page-aligned. We recognize the
- trampoline by looking for the code that invokes the sigreturn
- system call. The offset where we can find that code varies from
- release to release.
- By the way, the mapping mentioned above is read-only, so you cannot
- place a breakpoint in the signal trampoline. */
- /* Default page size. */
- static const int ppcobsd_page_size = 4096;
- /* Offset for sigreturn(2). */
- static const int ppcobsd_sigreturn_offset[] = {
- 0x98, /* OpenBSD 3.8 */
- 0x0c, /* OpenBSD 3.2 */
- -1
- };
- static int
- ppcobsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
- struct frame_info *this_frame,
- void **this_cache)
- {
- struct gdbarch *gdbarch = get_frame_arch (this_frame);
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- CORE_ADDR pc = get_frame_pc (this_frame);
- CORE_ADDR start_pc = (pc & ~(ppcobsd_page_size - 1));
- const int *offset;
- const char *name;
- find_pc_partial_function (pc, &name, NULL, NULL);
- if (name)
- return 0;
- for (offset = ppcobsd_sigreturn_offset; *offset != -1; offset++)
- {
- gdb_byte buf[2 * PPC_INSN_SIZE];
- unsigned long insn;
- if (!safe_frame_unwind_memory (this_frame, start_pc + *offset,
- {buf, sizeof buf}))
- continue;
- /* Check for "li r0,SYS_sigreturn". */
- insn = extract_unsigned_integer (buf, PPC_INSN_SIZE, byte_order);
- if (insn != 0x38000067)
- continue;
- /* Check for "sc". */
- insn = extract_unsigned_integer (buf + PPC_INSN_SIZE,
- PPC_INSN_SIZE, byte_order);
- if (insn != 0x44000002)
- continue;
- return 1;
- }
- return 0;
- }
- static struct trad_frame_cache *
- ppcobsd_sigtramp_frame_cache (struct frame_info *this_frame, void **this_cache)
- {
- struct gdbarch *gdbarch = get_frame_arch (this_frame);
- ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- struct trad_frame_cache *cache;
- CORE_ADDR addr, base, func;
- gdb_byte buf[PPC_INSN_SIZE];
- unsigned long insn, sigcontext_offset;
- int i;
- if (*this_cache)
- return (struct trad_frame_cache *) *this_cache;
- cache = trad_frame_cache_zalloc (this_frame);
- *this_cache = cache;
- func = get_frame_pc (this_frame);
- func &= ~(ppcobsd_page_size - 1);
- if (!safe_frame_unwind_memory (this_frame, func, {buf, sizeof buf}))
- return cache;
- /* Calculate the offset where we can find `struct sigcontext'. We
- base our calculation on the amount of stack space reserved by the
- first instruction of the signal trampoline. */
- insn = extract_unsigned_integer (buf, PPC_INSN_SIZE, byte_order);
- sigcontext_offset = (0x10000 - (insn & 0x0000ffff)) + 8;
- base = get_frame_register_unsigned (this_frame, gdbarch_sp_regnum (gdbarch));
- addr = base + sigcontext_offset + 2 * tdep->wordsize;
- for (i = 0; i < ppc_num_gprs; i++, addr += tdep->wordsize)
- {
- int regnum = i + tdep->ppc_gp0_regnum;
- trad_frame_set_reg_addr (cache, regnum, addr);
- }
- trad_frame_set_reg_addr (cache, tdep->ppc_lr_regnum, addr);
- addr += tdep->wordsize;
- trad_frame_set_reg_addr (cache, tdep->ppc_cr_regnum, addr);
- addr += tdep->wordsize;
- trad_frame_set_reg_addr (cache, tdep->ppc_xer_regnum, addr);
- addr += tdep->wordsize;
- trad_frame_set_reg_addr (cache, tdep->ppc_ctr_regnum, addr);
- addr += tdep->wordsize;
- trad_frame_set_reg_addr (cache, gdbarch_pc_regnum (gdbarch), addr);
- /* SRR0? */
- addr += tdep->wordsize;
- /* Construct the frame ID using the function start. */
- trad_frame_set_id (cache, frame_id_build (base, func));
- return cache;
- }
- static void
- ppcobsd_sigtramp_frame_this_id (struct frame_info *this_frame,
- void **this_cache, struct frame_id *this_id)
- {
- struct trad_frame_cache *cache =
- ppcobsd_sigtramp_frame_cache (this_frame, this_cache);
- trad_frame_get_id (cache, this_id);
- }
- static struct value *
- ppcobsd_sigtramp_frame_prev_register (struct frame_info *this_frame,
- void **this_cache, int regnum)
- {
- struct trad_frame_cache *cache =
- ppcobsd_sigtramp_frame_cache (this_frame, this_cache);
- return trad_frame_get_register (cache, this_frame, regnum);
- }
- static const struct frame_unwind ppcobsd_sigtramp_frame_unwind = {
- "ppc openbsd sigtramp",
- SIGTRAMP_FRAME,
- default_frame_unwind_stop_reason,
- ppcobsd_sigtramp_frame_this_id,
- ppcobsd_sigtramp_frame_prev_register,
- NULL,
- ppcobsd_sigtramp_frame_sniffer
- };
- static void
- ppcobsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
- {
- /* OpenBSD doesn't support the 128-bit `long double' from the psABI. */
- set_gdbarch_long_double_bit (gdbarch, 64);
- set_gdbarch_long_double_format (gdbarch, floatformats_ieee_double);
- /* OpenBSD currently uses a broken GCC. */
- set_gdbarch_return_value (gdbarch, ppc_sysv_abi_broken_return_value);
- /* OpenBSD uses SVR4-style shared libraries. */
- set_solib_svr4_fetch_link_map_offsets
- (gdbarch, svr4_ilp32_fetch_link_map_offsets);
- set_gdbarch_iterate_over_regset_sections
- (gdbarch, ppcobsd_iterate_over_regset_sections);
- frame_unwind_append_unwinder (gdbarch, &ppcobsd_sigtramp_frame_unwind);
- }
- void _initialize_ppcobsd_tdep ();
- void
- _initialize_ppcobsd_tdep ()
- {
- gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_OPENBSD,
- ppcobsd_init_abi);
- gdbarch_register_osabi (bfd_arch_powerpc, 0, GDB_OSABI_OPENBSD,
- ppcobsd_init_abi);
- /* Avoid initializing the register offsets again if they were
- already initialized by ppcobsd-nat.c. */
- if (ppcobsd_reg_offsets.pc_offset == 0)
- {
- /* General-purpose registers. */
- ppcobsd_reg_offsets.r0_offset = 0;
- ppcobsd_reg_offsets.gpr_size = 4;
- ppcobsd_reg_offsets.xr_size = 4;
- ppcobsd_reg_offsets.pc_offset = 384;
- ppcobsd_reg_offsets.ps_offset = 388;
- ppcobsd_reg_offsets.cr_offset = 392;
- ppcobsd_reg_offsets.lr_offset = 396;
- ppcobsd_reg_offsets.ctr_offset = 400;
- ppcobsd_reg_offsets.xer_offset = 404;
- ppcobsd_reg_offsets.mq_offset = 408;
- /* Floating-point registers. */
- ppcobsd_reg_offsets.f0_offset = 128;
- ppcobsd_reg_offsets.fpscr_offset = -1;
- }
- if (ppcobsd_fpreg_offsets.fpscr_offset == 0)
- {
- /* Floating-point registers. */
- ppcobsd_reg_offsets.f0_offset = 0;
- ppcobsd_reg_offsets.fpscr_offset = 256;
- ppcobsd_reg_offsets.fpscr_size = 4;
- }
- }
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