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- /* Target-dependent code for OpenBSD/alpha.
- Copyright (C) 2006-2022 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 "frame.h"
- #include "gdbcore.h"
- #include "osabi.h"
- #include "obsd-tdep.h"
- #include "alpha-tdep.h"
- #include "alpha-bsd-tdep.h"
- #include "solib-svr4.h"
- /* Signal trampolines. */
- /* The OpenBSD kernel maps the signal trampoline at some random
- location in user space, which means that the traditional BSD way of
- detecting it won't work.
- The signal trampoline will be mapped at an address that is page
- aligned. We recognize the signal trampoline by looking for the
- sigreturn system call. */
- static const int alphaobsd_page_size = 8192;
- static LONGEST
- alphaobsd_sigtramp_offset (struct gdbarch *gdbarch, CORE_ADDR pc)
- {
- return (pc & (alphaobsd_page_size - 1));
- }
- static int
- alphaobsd_pc_in_sigtramp (struct gdbarch *gdbarch,
- CORE_ADDR pc, const char *name)
- {
- CORE_ADDR start_pc = (pc & ~(alphaobsd_page_size - 1));
- unsigned insn;
- if (name)
- return 0;
- /* Check for "". */
- insn = alpha_read_insn (gdbarch, start_pc + 5 * ALPHA_INSN_SIZE);
- if (insn != 0x201f0067)
- return 0;
- /* Check for "". */
- insn = alpha_read_insn (gdbarch, start_pc + 6 * ALPHA_INSN_SIZE);
- if (insn != 0x00000083)
- return 0;
- return 1;
- }
- static CORE_ADDR
- alphaobsd_sigcontext_addr (struct frame_info *this_frame)
- {
- struct gdbarch *gdbarch = get_frame_arch (this_frame);
- CORE_ADDR pc = get_frame_pc (this_frame);
- if (alphaobsd_sigtramp_offset (gdbarch, pc) < 3 * ALPHA_INSN_SIZE)
- {
- /* On entry, a pointer the `struct sigcontext' is passed in %a2. */
- return get_frame_register_unsigned (this_frame, ALPHA_A0_REGNUM + 2);
- }
- else if (alphaobsd_sigtramp_offset (gdbarch, pc) < 4 * ALPHA_INSN_SIZE)
- {
- /* It is stored on the stack Before calling the signal handler. */
- CORE_ADDR sp;
- sp = get_frame_register_unsigned (this_frame, ALPHA_SP_REGNUM);
- return get_frame_memory_unsigned (this_frame, sp, 8);
- }
- else
- {
- /* It is reloaded into %a0 for the sigreturn(2) call. */
- return get_frame_register_unsigned (this_frame, ALPHA_A0_REGNUM);
- }
- }
- static void
- alphaobsd_init_abi(struct gdbarch_info info, struct gdbarch *gdbarch)
- {
- alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
- /* Hook into the DWARF CFI frame unwinder. */
- alpha_dwarf2_init_abi (info, gdbarch);
- /* Hook into the MDEBUG frame unwinder. */
- alpha_mdebug_init_abi (info, gdbarch);
- /* OpenBSD/alpha 3.0 and earlier does not provide single step
- support via ptrace(2); use software single-stepping for now. */
- set_gdbarch_software_single_step (gdbarch, alpha_software_single_step);
- /* OpenBSD/alpha has SVR4-style shared libraries. */
- set_solib_svr4_fetch_link_map_offsets
- (gdbarch, svr4_lp64_fetch_link_map_offsets);
- set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
- tdep->dynamic_sigtramp_offset = alphaobsd_sigtramp_offset;
- tdep->pc_in_sigtramp = alphaobsd_pc_in_sigtramp;
- tdep->sigcontext_addr = alphaobsd_sigcontext_addr;
- tdep->jb_pc = 2;
- tdep->jb_elt_size = 8;
- set_gdbarch_iterate_over_regset_sections
- (gdbarch, alphanbsd_iterate_over_regset_sections);
- }
- void _initialize_alphaobsd_tdep ();
- void
- _initialize_alphaobsd_tdep ()
- {
- gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_OPENBSD,
- alphaobsd_init_abi);
- }
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