1 /* Target-dependent code for GNU/Linux on Alpha.
2 Copyright (C) 2002, 2003 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 51 Franklin Street, Fifth Floor,
19 Boston, MA 02110-1301, USA. */
23 #include "gdb_assert.h"
25 #include "solib-svr4.h"
28 #include "alpha-tdep.h"
30 /* Under GNU/Linux, signal handler invocations can be identified by
31 the designated code sequence that is used to return from a signal
32 handler. In particular, the return address of a signal handler
33 points to a sequence that copies $sp to $16, loads $0 with the
34 appropriate syscall number, and finally enters the kernel.
36 This is somewhat complicated in that:
37 (1) the expansion of the "mov" assembler macro has changed over
38 time, from "bis src,src,dst" to "bis zero,src,dst",
39 (2) the kernel has changed from using "addq" to "lda" to load the
41 (3) there is a "normal" sigreturn and an "rt" sigreturn which
42 has a different stack layout.
46 alpha_linux_sigtramp_offset_1 (CORE_ADDR pc)
48 switch (alpha_read_insn (pc))
50 case 0x47de0410: /* bis $30,$30,$16 */
51 case 0x47fe0410: /* bis $31,$30,$16 */
54 case 0x43ecf400: /* addq $31,103,$0 */
55 case 0x201f0067: /* lda $0,103($31) */
56 case 0x201f015f: /* lda $0,351($31) */
59 case 0x00000083: /* call_pal callsys */
68 alpha_linux_sigtramp_offset (CORE_ADDR pc)
75 /* Guess where we might be in the sequence. */
76 off = alpha_linux_sigtramp_offset_1 (pc);
80 /* Verify that the other two insns of the sequence are as we expect. */
82 for (i = 0; i < 12; i += 4)
86 if (alpha_linux_sigtramp_offset_1 (pc + i) != i)
94 alpha_linux_pc_in_sigtramp (CORE_ADDR pc, char *func_name)
96 return alpha_linux_sigtramp_offset (pc) >= 0;
100 alpha_linux_sigcontext_addr (struct frame_info *next_frame)
106 pc = frame_pc_unwind (next_frame);
107 frame_unwind_unsigned_register (next_frame, ALPHA_SP_REGNUM, &sp);
109 off = alpha_linux_sigtramp_offset (pc);
110 gdb_assert (off >= 0);
112 /* __NR_rt_sigreturn has a couple of structures on the stack. This is:
119 offsetof (struct rt_sigframe, uc.uc_mcontext);
121 if (alpha_read_insn (pc - off + 4) == 0x201f015f)
124 /* __NR_sigreturn has the sigcontext structure at the top of the stack. */
129 alpha_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
131 struct gdbarch_tdep *tdep;
133 /* Hook into the DWARF CFI frame unwinder. */
134 alpha_dwarf2_init_abi (info, gdbarch);
136 /* Hook into the MDEBUG frame unwinder. */
137 alpha_mdebug_init_abi (info, gdbarch);
139 tdep = gdbarch_tdep (gdbarch);
140 tdep->dynamic_sigtramp_offset = alpha_linux_sigtramp_offset;
141 tdep->sigcontext_addr = alpha_linux_sigcontext_addr;
142 tdep->pc_in_sigtramp = alpha_linux_pc_in_sigtramp;
144 tdep->jb_elt_size = 8;
146 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
148 /* Enable TLS support. */
149 set_gdbarch_fetch_tls_load_module_address (gdbarch,
150 svr4_fetch_objfile_link_map);
154 _initialize_alpha_linux_tdep (void)
156 gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_LINUX,
157 alpha_linux_init_abi);