| /* Target-dependent code for GNU/Linux on Alpha. |
| Copyright (C) 2002, 2003, 2007 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., 51 Franklin Street, Fifth Floor, |
| Boston, MA 02110-1301, USA. */ |
| |
| #include "defs.h" |
| #include "frame.h" |
| #include "gdb_assert.h" |
| #include "osabi.h" |
| #include "solib-svr4.h" |
| #include "symtab.h" |
| |
| #include "alpha-tdep.h" |
| |
| /* Under GNU/Linux, signal handler invocations can be identified by |
| the designated code sequence that is used to return from a signal |
| handler. In particular, the return address of a signal handler |
| points to a sequence that copies $sp to $16, loads $0 with the |
| appropriate syscall number, and finally enters the kernel. |
| |
| This is somewhat complicated in that: |
| (1) the expansion of the "mov" assembler macro has changed over |
| time, from "bis src,src,dst" to "bis zero,src,dst", |
| (2) the kernel has changed from using "addq" to "lda" to load the |
| syscall number, |
| (3) there is a "normal" sigreturn and an "rt" sigreturn which |
| has a different stack layout. |
| */ |
| |
| static long |
| alpha_linux_sigtramp_offset_1 (CORE_ADDR pc) |
| { |
| switch (alpha_read_insn (pc)) |
| { |
| case 0x47de0410: /* bis $30,$30,$16 */ |
| case 0x47fe0410: /* bis $31,$30,$16 */ |
| return 0; |
| |
| case 0x43ecf400: /* addq $31,103,$0 */ |
| case 0x201f0067: /* lda $0,103($31) */ |
| case 0x201f015f: /* lda $0,351($31) */ |
| return 4; |
| |
| case 0x00000083: /* call_pal callsys */ |
| return 8; |
| |
| default: |
| return -1; |
| } |
| } |
| |
| static LONGEST |
| alpha_linux_sigtramp_offset (CORE_ADDR pc) |
| { |
| long i, off; |
| |
| if (pc & 3) |
| return -1; |
| |
| /* Guess where we might be in the sequence. */ |
| off = alpha_linux_sigtramp_offset_1 (pc); |
| if (off < 0) |
| return -1; |
| |
| /* Verify that the other two insns of the sequence are as we expect. */ |
| pc -= off; |
| for (i = 0; i < 12; i += 4) |
| { |
| if (i == off) |
| continue; |
| if (alpha_linux_sigtramp_offset_1 (pc + i) != i) |
| return -1; |
| } |
| |
| return off; |
| } |
| |
| static int |
| alpha_linux_pc_in_sigtramp (CORE_ADDR pc, char *func_name) |
| { |
| return alpha_linux_sigtramp_offset (pc) >= 0; |
| } |
| |
| static CORE_ADDR |
| alpha_linux_sigcontext_addr (struct frame_info *next_frame) |
| { |
| CORE_ADDR pc; |
| ULONGEST sp; |
| long off; |
| |
| pc = frame_pc_unwind (next_frame); |
| frame_unwind_unsigned_register (next_frame, ALPHA_SP_REGNUM, &sp); |
| |
| off = alpha_linux_sigtramp_offset (pc); |
| gdb_assert (off >= 0); |
| |
| /* __NR_rt_sigreturn has a couple of structures on the stack. This is: |
| |
| struct rt_sigframe { |
| struct siginfo info; |
| struct ucontext uc; |
| }; |
| |
| offsetof (struct rt_sigframe, uc.uc_mcontext); |
| */ |
| if (alpha_read_insn (pc - off + 4) == 0x201f015f) |
| return sp + 176; |
| |
| /* __NR_sigreturn has the sigcontext structure at the top of the stack. */ |
| return sp; |
| } |
| |
| static void |
| alpha_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| { |
| struct gdbarch_tdep *tdep; |
| |
| /* 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); |
| |
| tdep = gdbarch_tdep (gdbarch); |
| tdep->dynamic_sigtramp_offset = alpha_linux_sigtramp_offset; |
| tdep->sigcontext_addr = alpha_linux_sigcontext_addr; |
| tdep->pc_in_sigtramp = alpha_linux_pc_in_sigtramp; |
| tdep->jb_pc = 2; |
| tdep->jb_elt_size = 8; |
| |
| set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); |
| |
| /* Enable TLS support. */ |
| set_gdbarch_fetch_tls_load_module_address (gdbarch, |
| svr4_fetch_objfile_link_map); |
| } |
| |
| void |
| _initialize_alpha_linux_tdep (void) |
| { |
| gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_LINUX, |
| alpha_linux_init_abi); |
| } |