/* Motorola m68k target-dependent support for GNU/Linux. Copyright 1996, 1998, 2000, 2001, 2002, 2003 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" #include "gdb_string.h" #include "gdbtypes.h" #include "osabi.h" #include "m68k-tdep.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) & 0xffffffff) | (insn1 >> 16); insn1 = ((insn1 << 16) & 0xffffffff) | (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 . */ #define SIGCONTEXT_PC_OFFSET 26 /* Offset to saved PC in ucontext, from . */ #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 (get_next_frame (frame)) sigcontext_addr = read_memory_unsigned_integer (get_frame_base (get_next_frame (frame)) + 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 (get_frame_pc (frame)) == 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. */ static 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 (get_frame_base (frame) + 4, 4); } /* The following definitions are appropriate when using the ELF format, where floating point values are returned in fp0, pointer values in a0 and other values in d0. */ /* Extract from an array REGBUF containing the (raw) register state a function return value of type TYPE, and copy that, in virtual format, into VALBUF. */ static void m68k_linux_extract_return_value (struct type *type, char *regbuf, char *valbuf) { if (TYPE_CODE (type) == TYPE_CODE_FLT) { REGISTER_CONVERT_TO_VIRTUAL (FP0_REGNUM, type, regbuf + REGISTER_BYTE (FP0_REGNUM), valbuf); } else if (TYPE_CODE (type) == TYPE_CODE_PTR) memcpy (valbuf, regbuf + REGISTER_BYTE (M68K_A0_REGNUM), TYPE_LENGTH (type)); else memcpy (valbuf, regbuf + (TYPE_LENGTH (type) >= 4 ? 0 : 4 - TYPE_LENGTH (type)), TYPE_LENGTH (type)); } /* Write into appropriate registers a function return value of type TYPE, given in virtual format. */ static void m68k_linux_store_return_value (struct type *type, char *valbuf) { if (TYPE_CODE (type) == TYPE_CODE_FLT) { char raw_buffer[REGISTER_RAW_SIZE (FP0_REGNUM)]; REGISTER_CONVERT_TO_RAW (type, FP0_REGNUM, valbuf, raw_buffer); deprecated_write_register_bytes (REGISTER_BYTE (FP0_REGNUM), raw_buffer, TYPE_LENGTH (type)); } else { if (TYPE_CODE (type) == TYPE_CODE_PTR) deprecated_write_register_bytes (REGISTER_BYTE (M68K_A0_REGNUM), valbuf, TYPE_LENGTH (type)); deprecated_write_register_bytes (0, valbuf, TYPE_LENGTH (type)); } } /* Extract from an array REGBUF containing the (raw) register state the address in which a function should return its structure value, as a CORE_ADDR. */ static CORE_ADDR m68k_linux_extract_struct_value_address (char *regbuf) { return *(CORE_ADDR *) (regbuf + REGISTER_BYTE (M68K_A0_REGNUM)); } static void m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) { set_gdbarch_deprecated_frame_saved_pc (gdbarch, m68k_linux_frame_saved_pc); set_gdbarch_deprecated_extract_return_value (gdbarch, m68k_linux_extract_return_value); set_gdbarch_deprecated_store_return_value (gdbarch, m68k_linux_store_return_value); set_gdbarch_deprecated_extract_struct_value_address (gdbarch, m68k_linux_extract_struct_value_address); } void _initialize_m68k_linux_tdep (void) { gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX, m68k_linux_init_abi); }