125 lines
3.8 KiB
C
125 lines
3.8 KiB
C
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/* Motorola m68k target-dependent support for GNU/Linux.
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Copyright 1996, 1998, 2000, 2001, 2002 Free Software Foundation,
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Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include "gdbcore.h"
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#include "frame.h"
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#include "target.h"
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/* Check whether insn1 and insn2 are parts of a signal trampoline. */
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#define IS_SIGTRAMP(insn1, insn2) \
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(/* addaw #20,sp; moveq #119,d0; trap #0 */ \
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(insn1 == 0xdefc0014 && insn2 == 0x70774e40) \
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/* moveq #119,d0; trap #0 */ \
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|| insn1 == 0x70774e40)
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#define IS_RT_SIGTRAMP(insn1, insn2) \
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(/* movel #173,d0; trap #0 */ \
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(insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \
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/* moveq #82,d0; notb d0; trap #0 */ \
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|| (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))
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/* Return non-zero if PC points into the signal trampoline. For the sake
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of m68k_linux_frame_saved_pc we also distinguish between non-RT and RT
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signal trampolines. */
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int
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m68k_linux_in_sigtramp (CORE_ADDR pc)
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{
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CORE_ADDR sp;
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char buf[12];
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unsigned long insn0, insn1, insn2;
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if (read_memory_nobpt (pc - 4, buf, sizeof (buf)))
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return 0;
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insn1 = extract_unsigned_integer (buf + 4, 4);
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insn2 = extract_unsigned_integer (buf + 8, 4);
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if (IS_SIGTRAMP (insn1, insn2))
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return 1;
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if (IS_RT_SIGTRAMP (insn1, insn2))
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return 2;
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insn0 = extract_unsigned_integer (buf, 4);
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if (IS_SIGTRAMP (insn0, insn1))
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return 1;
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if (IS_RT_SIGTRAMP (insn0, insn1))
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return 2;
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insn0 = (insn0 << 16) | (insn1 >> 16);
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insn1 = (insn1 << 16) | (insn2 >> 16);
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if (IS_SIGTRAMP (insn0, insn1))
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return 1;
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if (IS_RT_SIGTRAMP (insn0, insn1))
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return 2;
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return 0;
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}
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/* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */
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#define SIGCONTEXT_PC_OFFSET 26
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/* Offset to saved PC in ucontext, from <asm/ucontext.h>. */
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#define UCONTEXT_PC_OFFSET 88
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/* Get saved user PC for sigtramp from sigcontext or ucontext. */
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static CORE_ADDR
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m68k_linux_sigtramp_saved_pc (struct frame_info *frame)
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{
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CORE_ADDR sigcontext_addr;
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char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT];
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int ptrbytes = TARGET_PTR_BIT / TARGET_CHAR_BIT;
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int sigcontext_offs = (2 * TARGET_INT_BIT) / TARGET_CHAR_BIT;
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/* Get sigcontext address, it is the third parameter on the stack. */
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if (frame->next)
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sigcontext_addr = read_memory_integer (FRAME_ARGS_ADDRESS (frame->next)
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+ FRAME_ARGS_SKIP
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+ sigcontext_offs,
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ptrbytes);
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else
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sigcontext_addr = read_memory_integer (read_register (SP_REGNUM)
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+ sigcontext_offs,
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ptrbytes);
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/* Don't cause a memory_error when accessing sigcontext in case the
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stack layout has changed or the stack is corrupt. */
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if (m68k_linux_in_sigtramp (frame->pc) == 2)
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target_read_memory (sigcontext_addr + UCONTEXT_PC_OFFSET, buf, ptrbytes);
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else
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target_read_memory (sigcontext_addr + SIGCONTEXT_PC_OFFSET, buf, ptrbytes);
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return extract_unsigned_integer (buf, ptrbytes);
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}
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/* Return the saved program counter for FRAME. */
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CORE_ADDR
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m68k_linux_frame_saved_pc (struct frame_info *frame)
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{
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if (get_frame_type (frame) == SIGTRAMP_FRAME)
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return m68k_linux_sigtramp_saved_pc (frame);
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return read_memory_integer (frame->frame + 4, 4);
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}
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