| /* Motorola m68k target-dependent support for GNU/Linux. |
| |
| Copyright 1996, 1998, 2000, 2001, 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 "gdbcore.h" |
| #include "frame.h" |
| #include "target.h" |
| |
| |
| /* Check whether insn1 and insn2 are parts of a signal trampoline. */ |
| |
| #define IS_SIGTRAMP(insn1, insn2) \ |
| (/* addaw #20,sp; moveq #119,d0; trap #0 */ \ |
| (insn1 == 0xdefc0014 && insn2 == 0x70774e40) \ |
| /* moveq #119,d0; trap #0 */ \ |
| || insn1 == 0x70774e40) |
| |
| #define IS_RT_SIGTRAMP(insn1, insn2) \ |
| (/* movel #173,d0; trap #0 */ \ |
| (insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \ |
| /* moveq #82,d0; notb d0; trap #0 */ \ |
| || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40)) |
| |
| /* Return non-zero if PC points into the signal trampoline. For the sake |
| of m68k_linux_frame_saved_pc we also distinguish between non-RT and RT |
| signal trampolines. */ |
| |
| int |
| m68k_linux_in_sigtramp (CORE_ADDR pc) |
| { |
| CORE_ADDR sp; |
| char buf[12]; |
| unsigned long insn0, insn1, insn2; |
| |
| if (read_memory_nobpt (pc - 4, buf, sizeof (buf))) |
| return 0; |
| insn1 = extract_unsigned_integer (buf + 4, 4); |
| insn2 = extract_unsigned_integer (buf + 8, 4); |
| if (IS_SIGTRAMP (insn1, insn2)) |
| return 1; |
| if (IS_RT_SIGTRAMP (insn1, insn2)) |
| return 2; |
| |
| insn0 = extract_unsigned_integer (buf, 4); |
| if (IS_SIGTRAMP (insn0, insn1)) |
| return 1; |
| if (IS_RT_SIGTRAMP (insn0, insn1)) |
| return 2; |
| |
| insn0 = (insn0 << 16) | (insn1 >> 16); |
| insn1 = (insn1 << 16) | (insn2 >> 16); |
| if (IS_SIGTRAMP (insn0, insn1)) |
| return 1; |
| if (IS_RT_SIGTRAMP (insn0, insn1)) |
| return 2; |
| |
| return 0; |
| } |
| |
| /* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */ |
| #define SIGCONTEXT_PC_OFFSET 26 |
| |
| /* Offset to saved PC in ucontext, from <asm/ucontext.h>. */ |
| #define UCONTEXT_PC_OFFSET 88 |
| |
| /* Get saved user PC for sigtramp from sigcontext or ucontext. */ |
| |
| static CORE_ADDR |
| m68k_linux_sigtramp_saved_pc (struct frame_info *frame) |
| { |
| CORE_ADDR sigcontext_addr; |
| char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT]; |
| int ptrbytes = TARGET_PTR_BIT / TARGET_CHAR_BIT; |
| int sigcontext_offs = (2 * TARGET_INT_BIT) / TARGET_CHAR_BIT; |
| |
| /* Get sigcontext address, it is the third parameter on the stack. */ |
| if (frame->next) |
| sigcontext_addr |
| = read_memory_unsigned_integer (FRAME_ARGS_ADDRESS (frame->next) |
| + FRAME_ARGS_SKIP |
| + sigcontext_offs, |
| ptrbytes); |
| else |
| sigcontext_addr |
| = read_memory_unsigned_integer (read_register (SP_REGNUM) |
| + sigcontext_offs, |
| ptrbytes); |
| |
| /* Don't cause a memory_error when accessing sigcontext in case the |
| stack layout has changed or the stack is corrupt. */ |
| if (m68k_linux_in_sigtramp (frame->pc) == 2) |
| target_read_memory (sigcontext_addr + UCONTEXT_PC_OFFSET, buf, ptrbytes); |
| else |
| target_read_memory (sigcontext_addr + SIGCONTEXT_PC_OFFSET, buf, ptrbytes); |
| return extract_unsigned_integer (buf, ptrbytes); |
| } |
| |
| /* Return the saved program counter for FRAME. */ |
| |
| CORE_ADDR |
| m68k_linux_frame_saved_pc (struct frame_info *frame) |
| { |
| if (get_frame_type (frame) == SIGTRAMP_FRAME) |
| return m68k_linux_sigtramp_saved_pc (frame); |
| |
| return read_memory_unsigned_integer (frame->frame + 4, 4); |
| } |