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[/] [or1k/] [trunk/] [gdb-5.3/] [gdb/] [alpha-linux-tdep.c] - Rev 1773
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/* Target-dependent code for GNU/Linux on Alpha. Copyright 2002 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "defs.h" #include "frame.h" #include "gdbcore.h" #include "value.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 the following sequence (the first instruction is quadword aligned): bis $30,$30,$16 addq $31,0x67,$0 call_pal callsys Each instruction has a unique encoding, so we simply attempt to match the instruction the pc is pointing to with any of the above instructions. If there is a hit, we know the offset to the start of the designated sequence and can then check whether we really are executing in a designated sequence. If not, -1 is returned, otherwise the offset from the start of the desingated sequence is returned. There is a slight chance of false hits: code could jump into the middle of the designated sequence, in which case there is no guarantee that we are in the middle of a sigreturn syscall. Don't think this will be a problem in praxis, though. */ LONGEST alpha_linux_sigtramp_offset (CORE_ADDR pc) { unsigned int i[3], w; long off; if (read_memory_nobpt (pc, (char *) &w, 4) != 0) return -1; off = -1; switch (w) { case 0x47de0410: off = 0; break; /* bis $30,$30,$16 */ case 0x43ecf400: off = 4; break; /* addq $31,0x67,$0 */ case 0x00000083: off = 8; break; /* call_pal callsys */ default: return -1; } pc -= off; if (pc & 0x7) { /* designated sequence is not quadword aligned */ return -1; } if (read_memory_nobpt (pc, (char *) i, sizeof (i)) != 0) return -1; if (i[0] == 0x47de0410 && i[1] == 0x43ecf400 && i[2] == 0x00000083) return off; return -1; } 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 *frame) { return (frame->frame - 0x298); /* sizeof(struct sigcontext) */ } static void alpha_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) { struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); set_gdbarch_pc_in_sigtramp (gdbarch, alpha_linux_pc_in_sigtramp); tdep->dynamic_sigtramp_offset = alpha_linux_sigtramp_offset; tdep->sigcontext_addr = alpha_linux_sigcontext_addr; tdep->jb_pc = 2; tdep->jb_elt_size = 8; } void _initialize_alpha_linux_tdep (void) { gdbarch_register_osabi (bfd_arch_alpha, GDB_OSABI_LINUX, alpha_linux_init_abi); }
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