1276 lines
31 KiB
C
1276 lines
31 KiB
C
/* Low level interface to ptrace, for GDB when running on the Intel 386.
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Copyright (C) 1988, 1989 Free Software Foundation, Inc.
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This file is part of GDB.
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GDB 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 1, or (at your option)
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any later version.
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GDB 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 GDB; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include <stdio.h>
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#include "defs.h"
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#include "param.h"
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#include "frame.h"
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#include "inferior.h"
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#ifdef USG
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#include <sys/types.h>
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#endif
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#include <sys/param.h>
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#include <sys/dir.h>
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#include <signal.h>
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#include <sys/user.h>
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#include <sys/ioctl.h>
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#include <fcntl.h>
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#ifdef COFF_ENCAPSULATE
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#include "a.out.encap.h"
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#else
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#include <a.out.h>
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#endif
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#ifndef N_SET_MAGIC
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#ifdef COFF_FORMAT
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#define N_SET_MAGIC(exec, val) ((exec).magic = (val))
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#else
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#define N_SET_MAGIC(exec, val) ((exec).a_magic = (val))
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#endif
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#endif
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#include <sys/file.h>
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#include <sys/stat.h>
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#include <sys/reg.h>
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extern int errno;
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/* This function simply calls ptrace with the given arguments.
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It exists so that all calls to ptrace are isolated in this
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machine-dependent file. */
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int
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call_ptrace (request, pid, arg3, arg4)
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int request, pid, arg3, arg4;
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{
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return ptrace (request, pid, arg3, arg4);
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}
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kill_inferior ()
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{
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if (remote_debugging)
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return;
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if (inferior_pid == 0)
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return;
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ptrace (8, inferior_pid, 0, 0);
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wait (0);
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inferior_died ();
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}
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/* This is used when GDB is exiting. It gives less chance of error.*/
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kill_inferior_fast ()
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{
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if (remote_debugging)
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return;
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if (inferior_pid == 0)
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return;
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ptrace (8, inferior_pid, 0, 0);
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wait (0);
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}
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/* Resume execution of the inferior process.
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If STEP is nonzero, single-step it.
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If SIGNAL is nonzero, give it that signal. */
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void
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resume (step, signal)
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int step;
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int signal;
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{
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errno = 0;
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if (remote_debugging)
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remote_resume (step, signal);
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else
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{
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ptrace (step ? 9 : 7, inferior_pid, 1, signal);
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if (errno)
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perror_with_name ("ptrace");
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}
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}
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void
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fetch_inferior_registers ()
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{
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register int regno;
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register unsigned int regaddr;
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char buf[MAX_REGISTER_RAW_SIZE];
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register int i;
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struct user u;
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unsigned int offset = (char *) &u.u_ar0 - (char *) &u;
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offset = ptrace (3, inferior_pid, offset, 0) - KERNEL_U_ADDR;
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for (regno = 0; regno < NUM_REGS; regno++)
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{
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regaddr = register_addr (regno, offset);
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for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
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{
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*(int *) &buf[i] = ptrace (3, inferior_pid, regaddr, 0);
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regaddr += sizeof (int);
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}
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supply_register (regno, buf);
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}
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}
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/* Store our register values back into the inferior.
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If REGNO is -1, do this for all registers.
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Otherwise, REGNO specifies which register (so we can save time). */
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store_inferior_registers (regno)
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int regno;
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{
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register unsigned int regaddr;
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char buf[80];
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struct user u;
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unsigned int offset = (char *) &u.u_ar0 - (char *) &u;
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offset = ptrace (3, inferior_pid, offset, 0) - KERNEL_U_ADDR;
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if (regno >= 0)
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{
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regaddr = register_addr (regno, offset);
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errno = 0;
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ptrace (6, inferior_pid, regaddr, read_register (regno));
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if (errno != 0)
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{
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sprintf (buf, "writing register number %d", regno);
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perror_with_name (buf);
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}
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}
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else for (regno = 0; regno < NUM_REGS; regno++)
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{
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regaddr = register_addr (regno, offset);
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errno = 0;
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ptrace (6, inferior_pid, regaddr, read_register (regno));
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if (errno != 0)
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{
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sprintf (buf, "writing register number %d", regno);
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perror_with_name (buf);
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}
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}
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}
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/* Copy LEN bytes from inferior's memory starting at MEMADDR
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to debugger memory starting at MYADDR.
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On failure (cannot read from inferior, usually because address is out
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of bounds) returns the value of errno. */
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int
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read_inferior_memory (memaddr, myaddr, len)
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CORE_ADDR memaddr;
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char *myaddr;
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int len;
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{
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register int i;
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/* Round starting address down to longword boundary. */
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register CORE_ADDR addr = memaddr & - sizeof (int);
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/* Round ending address up; get number of longwords that makes. */
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register int count
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= (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
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/* Allocate buffer of that many longwords. */
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register int *buffer = (int *) alloca (count * sizeof (int));
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extern int errno;
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/* Read all the longwords */
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for (i = 0; i < count; i++, addr += sizeof (int))
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{
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errno = 0;
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if (remote_debugging)
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buffer[i] = remote_fetch_word (addr);
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else
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buffer[i] = ptrace (1, inferior_pid, addr, 0);
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if (errno)
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return errno;
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}
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/* Copy appropriate bytes out of the buffer. */
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bcopy ((char *) buffer + (memaddr & (sizeof (int) - 1)), myaddr, len);
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return 0;
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}
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/* Copy LEN bytes of data from debugger memory at MYADDR
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to inferior's memory at MEMADDR.
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On failure (cannot write the inferior)
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returns the value of errno. */
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int
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write_inferior_memory (memaddr, myaddr, len)
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CORE_ADDR memaddr;
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char *myaddr;
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int len;
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{
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register int i;
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/* Round starting address down to longword boundary. */
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register CORE_ADDR addr = memaddr & - sizeof (int);
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/* Round ending address up; get number of longwords that makes. */
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register int count
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= (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
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/* Allocate buffer of that many longwords. */
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register int *buffer = (int *) alloca (count * sizeof (int));
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extern int errno;
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/* Fill start and end extra bytes of buffer with existing memory data. */
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if (remote_debugging)
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buffer[0] = remote_fetch_word (addr);
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else
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buffer[0] = ptrace (1, inferior_pid, addr, 0);
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if (count > 1)
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{
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if (remote_debugging)
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buffer[count - 1]
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= remote_fetch_word (addr + (count - 1) * sizeof (int));
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else
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buffer[count - 1]
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= ptrace (1, inferior_pid,
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addr + (count - 1) * sizeof (int), 0);
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}
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/* Copy data to be written over corresponding part of buffer */
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bcopy (myaddr, (char *) buffer + (memaddr & (sizeof (int) - 1)), len);
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/* Write the entire buffer. */
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for (i = 0; i < count; i++, addr += sizeof (int))
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{
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errno = 0;
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if (remote_debugging)
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remote_store_word (addr, buffer[i]);
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else
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ptrace (4, inferior_pid, addr, buffer[i]);
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if (errno)
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return errno;
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}
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return 0;
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}
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/* Work with core dump and executable files, for GDB.
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This code would be in core.c if it weren't machine-dependent. */
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#ifndef N_TXTADDR
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#define N_TXTADDR(hdr) 0
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#endif /* no N_TXTADDR */
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#ifndef N_DATADDR
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#define N_DATADDR(hdr) hdr.a_text
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#endif /* no N_DATADDR */
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/* Make COFF and non-COFF names for things a little more compatible
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to reduce conditionals later. */
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#ifndef COFF_FORMAT
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#ifndef AOUTHDR
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#define AOUTHDR struct exec
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#endif
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#endif
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extern char *sys_siglist[];
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/* Hook for `exec_file_command' command to call. */
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extern void (*exec_file_display_hook) ();
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/* File names of core file and executable file. */
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extern char *corefile;
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extern char *execfile;
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/* Descriptors on which core file and executable file are open.
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Note that the execchan is closed when an inferior is created
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and reopened if the inferior dies or is killed. */
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extern int corechan;
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extern int execchan;
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/* Last modification time of executable file.
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Also used in source.c to compare against mtime of a source file. */
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extern int exec_mtime;
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/* Virtual addresses of bounds of the two areas of memory in the core file. */
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extern CORE_ADDR data_start;
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extern CORE_ADDR data_end;
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extern CORE_ADDR stack_start;
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extern CORE_ADDR stack_end;
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/* Virtual addresses of bounds of two areas of memory in the exec file.
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Note that the data area in the exec file is used only when there is no core file. */
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extern CORE_ADDR text_start;
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extern CORE_ADDR text_end;
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extern CORE_ADDR exec_data_start;
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extern CORE_ADDR exec_data_end;
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/* Address in executable file of start of text area data. */
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extern int text_offset;
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/* Address in executable file of start of data area data. */
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extern int exec_data_offset;
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/* Address in core file of start of data area data. */
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extern int data_offset;
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/* Address in core file of start of stack area data. */
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extern int stack_offset;
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#ifdef COFF_FORMAT
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/* various coff data structures */
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extern FILHDR file_hdr;
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extern SCNHDR text_hdr;
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extern SCNHDR data_hdr;
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#endif /* not COFF_FORMAT */
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/* a.out header saved in core file. */
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extern AOUTHDR core_aouthdr;
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/* a.out header of exec file. */
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extern AOUTHDR exec_aouthdr;
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extern void validate_files ();
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core_file_command (filename, from_tty)
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char *filename;
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int from_tty;
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{
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int val;
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extern char registers[];
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/* Discard all vestiges of any previous core file
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and mark data and stack spaces as empty. */
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if (corefile)
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free (corefile);
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corefile = 0;
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if (corechan >= 0)
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close (corechan);
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corechan = -1;
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data_start = 0;
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data_end = 0;
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stack_start = STACK_END_ADDR;
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stack_end = STACK_END_ADDR;
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/* Now, if a new core file was specified, open it and digest it. */
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if (filename)
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{
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filename = tilde_expand (filename);
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make_cleanup (free, filename);
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if (have_inferior_p ())
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error ("To look at a core file, you must kill the inferior with \"kill\".");
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corechan = open (filename, O_RDONLY, 0);
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||
if (corechan < 0)
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perror_with_name (filename);
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||
/* 4.2-style (and perhaps also sysV-style) core dump file. */
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{
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struct user u;
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int reg_offset;
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val = myread (corechan, &u, sizeof u);
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if (val < 0)
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perror_with_name (filename);
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data_start = exec_data_start;
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data_end = data_start + NBPG * u.u_dsize;
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stack_start = stack_end - NBPG * u.u_ssize;
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data_offset = NBPG * UPAGES;
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stack_offset = NBPG * (UPAGES + u.u_dsize);
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reg_offset = (int) u.u_ar0 - KERNEL_U_ADDR;
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||
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||
/* I don't know where to find this info.
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||
So, for now, mark it as not available. */
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||
/* N_SET_MAGIC (core_aouthdr, 0); */
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bzero ((char *) &core_aouthdr, sizeof core_aouthdr);
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||
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||
/* Read the register values out of the core file and store
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||
them where `read_register' will find them. */
|
||
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||
{
|
||
register int regno;
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||
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||
for (regno = 0; regno < NUM_REGS; regno++)
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||
{
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||
char buf[MAX_REGISTER_RAW_SIZE];
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||
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||
val = lseek (corechan, register_addr (regno, reg_offset), 0);
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||
if (val < 0)
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||
perror_with_name (filename);
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||
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||
val = myread (corechan, buf, sizeof buf);
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||
if (val < 0)
|
||
perror_with_name (filename);
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||
supply_register (regno, buf);
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||
}
|
||
}
|
||
}
|
||
if (filename[0] == '/')
|
||
corefile = savestring (filename, strlen (filename));
|
||
else
|
||
{
|
||
corefile = concat (current_directory, "/", filename);
|
||
}
|
||
|
||
set_current_frame ( create_new_frame (read_register (FP_REGNUM),
|
||
read_pc ()));
|
||
select_frame (get_current_frame (), 0);
|
||
validate_files ();
|
||
}
|
||
else if (from_tty)
|
||
printf ("No core file now.\n");
|
||
}
|
||
|
||
exec_file_command (filename, from_tty)
|
||
char *filename;
|
||
int from_tty;
|
||
{
|
||
int val;
|
||
|
||
/* Eliminate all traces of old exec file.
|
||
Mark text segment as empty. */
|
||
|
||
if (execfile)
|
||
free (execfile);
|
||
execfile = 0;
|
||
data_start = 0;
|
||
data_end -= exec_data_start;
|
||
text_start = 0;
|
||
text_end = 0;
|
||
exec_data_start = 0;
|
||
exec_data_end = 0;
|
||
if (execchan >= 0)
|
||
close (execchan);
|
||
execchan = -1;
|
||
|
||
/* Now open and digest the file the user requested, if any. */
|
||
|
||
if (filename)
|
||
{
|
||
filename = tilde_expand (filename);
|
||
make_cleanup (free, filename);
|
||
|
||
execchan = openp (getenv ("PATH"), 1, filename, O_RDONLY, 0,
|
||
&execfile);
|
||
if (execchan < 0)
|
||
perror_with_name (filename);
|
||
|
||
#ifdef COFF_FORMAT
|
||
{
|
||
int aout_hdrsize;
|
||
int num_sections;
|
||
|
||
if (read_file_hdr (execchan, &file_hdr) < 0)
|
||
error ("\"%s\": not in executable format.", execfile);
|
||
|
||
aout_hdrsize = file_hdr.f_opthdr;
|
||
num_sections = file_hdr.f_nscns;
|
||
|
||
if (read_aout_hdr (execchan, &exec_aouthdr, aout_hdrsize) < 0)
|
||
error ("\"%s\": can't read optional aouthdr", execfile);
|
||
|
||
if (read_section_hdr (execchan, _TEXT, &text_hdr, num_sections,
|
||
aout_hdrsize) < 0)
|
||
error ("\"%s\": can't read text section header", execfile);
|
||
|
||
if (read_section_hdr (execchan, _DATA, &data_hdr, num_sections,
|
||
aout_hdrsize) < 0)
|
||
error ("\"%s\": can't read data section header", execfile);
|
||
|
||
text_start = exec_aouthdr.text_start;
|
||
text_end = text_start + exec_aouthdr.tsize;
|
||
text_offset = text_hdr.s_scnptr;
|
||
exec_data_start = exec_aouthdr.data_start;
|
||
exec_data_end = exec_data_start + exec_aouthdr.dsize;
|
||
exec_data_offset = data_hdr.s_scnptr;
|
||
data_start = exec_data_start;
|
||
data_end += exec_data_start;
|
||
exec_mtime = file_hdr.f_timdat;
|
||
}
|
||
#else /* not COFF_FORMAT */
|
||
{
|
||
struct stat st_exec;
|
||
|
||
#ifdef HEADER_SEEK_FD
|
||
HEADER_SEEK_FD (execchan);
|
||
#endif
|
||
|
||
val = myread (execchan, &exec_aouthdr, sizeof (AOUTHDR));
|
||
|
||
if (val < 0)
|
||
perror_with_name (filename);
|
||
|
||
text_start = N_TXTADDR (exec_aouthdr);
|
||
exec_data_start = N_DATADDR (exec_aouthdr);
|
||
|
||
text_offset = N_TXTOFF (exec_aouthdr);
|
||
exec_data_offset = N_TXTOFF (exec_aouthdr) + exec_aouthdr.a_text;
|
||
|
||
text_end = text_start + exec_aouthdr.a_text;
|
||
exec_data_end = exec_data_start + exec_aouthdr.a_data;
|
||
data_start = exec_data_start;
|
||
data_end += exec_data_start;
|
||
|
||
fstat (execchan, &st_exec);
|
||
exec_mtime = st_exec.st_mtime;
|
||
}
|
||
#endif /* not COFF_FORMAT */
|
||
|
||
validate_files ();
|
||
}
|
||
else if (from_tty)
|
||
printf ("No exec file now.\n");
|
||
|
||
/* Tell display code (if any) about the changed file name. */
|
||
if (exec_file_display_hook)
|
||
(*exec_file_display_hook) (filename);
|
||
}
|
||
|
||
/* helper functions for m-i386.h */
|
||
|
||
/* stdio style buffering to minimize calls to ptrace */
|
||
static CORE_ADDR codestream_next_addr;
|
||
static CORE_ADDR codestream_addr;
|
||
static unsigned char codestream_buf[sizeof (int)];
|
||
static int codestream_off;
|
||
static int codestream_cnt;
|
||
|
||
#define codestream_tell() (codestream_addr + codestream_off)
|
||
#define codestream_peek() (codestream_cnt == 0 ? \
|
||
codestream_fill(1): codestream_buf[codestream_off])
|
||
#define codestream_get() (codestream_cnt-- == 0 ? \
|
||
codestream_fill(0) : codestream_buf[codestream_off++])
|
||
|
||
static unsigned char
|
||
codestream_fill (peek_flag)
|
||
{
|
||
codestream_addr = codestream_next_addr;
|
||
codestream_next_addr += sizeof (int);
|
||
codestream_off = 0;
|
||
codestream_cnt = sizeof (int);
|
||
read_memory (codestream_addr,
|
||
(unsigned char *)codestream_buf,
|
||
sizeof (int));
|
||
|
||
if (peek_flag)
|
||
return (codestream_peek());
|
||
else
|
||
return (codestream_get());
|
||
}
|
||
|
||
static void
|
||
codestream_seek (place)
|
||
{
|
||
codestream_next_addr = place & -sizeof (int);
|
||
codestream_cnt = 0;
|
||
codestream_fill (1);
|
||
while (codestream_tell() != place)
|
||
codestream_get ();
|
||
}
|
||
|
||
static void
|
||
codestream_read (buf, count)
|
||
unsigned char *buf;
|
||
{
|
||
unsigned char *p;
|
||
int i;
|
||
p = buf;
|
||
for (i = 0; i < count; i++)
|
||
*p++ = codestream_get ();
|
||
}
|
||
|
||
/* next instruction is a jump, move to target */
|
||
static
|
||
i386_follow_jump ()
|
||
{
|
||
int long_delta;
|
||
short short_delta;
|
||
char byte_delta;
|
||
int data16;
|
||
int pos;
|
||
|
||
pos = codestream_tell ();
|
||
|
||
data16 = 0;
|
||
if (codestream_peek () == 0x66)
|
||
{
|
||
codestream_get ();
|
||
data16 = 1;
|
||
}
|
||
|
||
switch (codestream_get ())
|
||
{
|
||
case 0xe9:
|
||
/* relative jump: if data16 == 0, disp32, else disp16 */
|
||
if (data16)
|
||
{
|
||
codestream_read ((unsigned char *)&short_delta, 2);
|
||
pos += short_delta + 3; /* include size of jmp inst */
|
||
}
|
||
else
|
||
{
|
||
codestream_read ((unsigned char *)&long_delta, 4);
|
||
pos += long_delta + 5;
|
||
}
|
||
break;
|
||
case 0xeb:
|
||
/* relative jump, disp8 (ignore data16) */
|
||
codestream_read ((unsigned char *)&byte_delta, 1);
|
||
pos += byte_delta + 2;
|
||
break;
|
||
}
|
||
codestream_seek (pos + data16);
|
||
}
|
||
|
||
/*
|
||
* find & return amound a local space allocated, and advance codestream to
|
||
* first register push (if any)
|
||
*
|
||
* if entry sequence doesn't make sense, return -1, and leave
|
||
* codestream pointer random
|
||
*/
|
||
static long
|
||
i386_get_frame_setup (pc)
|
||
{
|
||
unsigned char op;
|
||
|
||
codestream_seek (pc);
|
||
|
||
i386_follow_jump ();
|
||
|
||
op = codestream_get ();
|
||
|
||
if (op == 0x58) /* popl %eax */
|
||
{
|
||
/*
|
||
* this function must start with
|
||
*
|
||
* popl %eax 0x58
|
||
* xchgl %eax, (%esp) 0x87 0x04 0x24
|
||
* or xchgl %eax, 0(%esp) 0x87 0x44 0x24 0x00
|
||
*
|
||
* (the system 5 compiler puts out the second xchg
|
||
* inst, and the assembler doesn't try to optimize it,
|
||
* so the 'sib' form gets generated)
|
||
*
|
||
* this sequence is used to get the address of the return
|
||
* buffer for a function that returns a structure
|
||
*/
|
||
int pos;
|
||
unsigned char buf[4];
|
||
static unsigned char proto1[3] = { 0x87,0x04,0x24 };
|
||
static unsigned char proto2[4] = { 0x87,0x44,0x24,0x00 };
|
||
pos = codestream_tell ();
|
||
codestream_read (buf, 4);
|
||
if (bcmp (buf, proto1, 3) == 0)
|
||
pos += 3;
|
||
else if (bcmp (buf, proto2, 4) == 0)
|
||
pos += 4;
|
||
|
||
codestream_seek (pos);
|
||
op = codestream_get (); /* update next opcode */
|
||
}
|
||
|
||
if (op == 0x55) /* pushl %esp */
|
||
{
|
||
/* check for movl %esp, %ebp - can be written two ways */
|
||
switch (codestream_get ())
|
||
{
|
||
case 0x8b:
|
||
if (codestream_get () != 0xec)
|
||
return (-1);
|
||
break;
|
||
case 0x89:
|
||
if (codestream_get () != 0xe5)
|
||
return (-1);
|
||
break;
|
||
default:
|
||
return (-1);
|
||
}
|
||
/* check for stack adjustment
|
||
*
|
||
* subl $XXX, %esp
|
||
*
|
||
* note: you can't subtract a 16 bit immediate
|
||
* from a 32 bit reg, so we don't have to worry
|
||
* about a data16 prefix
|
||
*/
|
||
op = codestream_peek ();
|
||
if (op == 0x83)
|
||
{
|
||
/* subl with 8 bit immed */
|
||
codestream_get ();
|
||
if (codestream_get () != 0xec)
|
||
return (-1);
|
||
/* subl with signed byte immediate
|
||
* (though it wouldn't make sense to be negative)
|
||
*/
|
||
return (codestream_get());
|
||
}
|
||
else if (op == 0x81)
|
||
{
|
||
/* subl with 32 bit immed */
|
||
int locals;
|
||
codestream_get();
|
||
if (codestream_get () != 0xec)
|
||
return (-1);
|
||
/* subl with 32 bit immediate */
|
||
codestream_read ((unsigned char *)&locals, 4);
|
||
return (locals);
|
||
}
|
||
else
|
||
{
|
||
return (0);
|
||
}
|
||
}
|
||
else if (op == 0xc8)
|
||
{
|
||
/* enter instruction: arg is 16 bit unsigned immed */
|
||
unsigned short slocals;
|
||
codestream_read ((unsigned char *)&slocals, 2);
|
||
codestream_get (); /* flush final byte of enter instruction */
|
||
return (slocals);
|
||
}
|
||
return (-1);
|
||
}
|
||
|
||
/* Return number of args passed to a frame.
|
||
Can return -1, meaning no way to tell. */
|
||
|
||
/* on the 386, the instruction following the call could be:
|
||
* popl %ecx - one arg
|
||
* addl $imm, %esp - imm/4 args; imm may be 8 or 32 bits
|
||
* anything else - zero args
|
||
*/
|
||
|
||
int
|
||
i386_frame_num_args (fi)
|
||
struct frame_info fi;
|
||
{
|
||
int retpc;
|
||
unsigned char op;
|
||
struct frame_info *pfi;
|
||
|
||
pfi = get_prev_frame_info ((fi));
|
||
if (pfi == 0)
|
||
{
|
||
/* Note: this can happen if we are looking at the frame for
|
||
main, because FRAME_CHAIN_VALID won't let us go into
|
||
start. If we have debugging symbols, that's not really
|
||
a big deal; it just means it will only show as many arguments
|
||
to main as are declared. */
|
||
return -1;
|
||
}
|
||
else
|
||
{
|
||
retpc = pfi->pc;
|
||
op = read_memory_integer (retpc, 1);
|
||
if (op == 0x59)
|
||
/* pop %ecx */
|
||
return 1;
|
||
else if (op == 0x83)
|
||
{
|
||
op = read_memory_integer (retpc+1, 1);
|
||
if (op == 0xc4)
|
||
/* addl $<signed imm 8 bits>, %esp */
|
||
return (read_memory_integer (retpc+2,1)&0xff)/4;
|
||
else
|
||
return 0;
|
||
}
|
||
else if (op == 0x81)
|
||
{ /* add with 32 bit immediate */
|
||
op = read_memory_integer (retpc+1, 1);
|
||
if (op == 0xc4)
|
||
/* addl $<imm 32>, %esp */
|
||
return read_memory_integer (retpc+2, 4) / 4;
|
||
else
|
||
return 0;
|
||
}
|
||
else
|
||
{
|
||
return 0;
|
||
}
|
||
}
|
||
}
|
||
|
||
/*
|
||
* parse the first few instructions of the function to see
|
||
* what registers were stored.
|
||
*
|
||
* We handle these cases:
|
||
*
|
||
* The startup sequence can be at the start of the function,
|
||
* or the function can start with a branch to startup code at the end.
|
||
*
|
||
* %ebp can be set up with either the 'enter' instruction, or
|
||
* 'pushl %ebp, movl %esp, %ebp' (enter is too slow to be useful,
|
||
* but was once used in the sys5 compiler)
|
||
*
|
||
* Local space is allocated just below the saved %ebp by either the
|
||
* 'enter' instruction, or by 'subl $<size>, %esp'. 'enter' has
|
||
* a 16 bit unsigned argument for space to allocate, and the
|
||
* 'addl' instruction could have either a signed byte, or
|
||
* 32 bit immediate.
|
||
*
|
||
* Next, the registers used by this function are pushed. In
|
||
* the sys5 compiler they will always be in the order: %edi, %esi, %ebx
|
||
* (and sometimes a harmless bug causes it to also save but not restore %eax);
|
||
* however, the code below is willing to see the pushes in any order,
|
||
* and will handle up to 8 of them.
|
||
*
|
||
* If the setup sequence is at the end of the function, then the
|
||
* next instruction will be a branch back to the start.
|
||
*/
|
||
|
||
i386_frame_find_saved_regs (fip, fsrp)
|
||
struct frame_info *fip;
|
||
struct frame_saved_regs *fsrp;
|
||
{
|
||
unsigned long locals;
|
||
unsigned char *p;
|
||
unsigned char op;
|
||
CORE_ADDR dummy_bottom;
|
||
CORE_ADDR adr;
|
||
int i;
|
||
|
||
bzero (fsrp, sizeof *fsrp);
|
||
|
||
/* if frame is the end of a dummy, compute where the
|
||
* beginning would be
|
||
*/
|
||
dummy_bottom = fip->frame - 4 - NUM_REGS*4 - CALL_DUMMY_LENGTH;
|
||
|
||
/* check if the PC is in the stack, in a dummy frame */
|
||
if (dummy_bottom <= fip->pc && fip->pc <= fip->frame)
|
||
{
|
||
/* all regs were saved by push_call_dummy () */
|
||
adr = fip->frame - 4;
|
||
for (i = 0; i < NUM_REGS; i++)
|
||
{
|
||
fsrp->regs[i] = adr;
|
||
adr -= 4;
|
||
}
|
||
return;
|
||
}
|
||
|
||
locals = i386_get_frame_setup (get_pc_function_start (fip->pc));
|
||
|
||
if (locals >= 0)
|
||
{
|
||
adr = fip->frame - 4 - locals;
|
||
for (i = 0; i < 8; i++)
|
||
{
|
||
op = codestream_get ();
|
||
if (op < 0x50 || op > 0x57)
|
||
break;
|
||
fsrp->regs[op - 0x50] = adr;
|
||
adr -= 4;
|
||
}
|
||
}
|
||
|
||
fsrp->regs[PC_REGNUM] = fip->frame + 4;
|
||
fsrp->regs[FP_REGNUM] = fip->frame;
|
||
}
|
||
|
||
/* return pc of first real instruction */
|
||
i386_skip_prologue (pc)
|
||
{
|
||
unsigned char op;
|
||
int i;
|
||
|
||
if (i386_get_frame_setup (pc) < 0)
|
||
return (pc);
|
||
|
||
/* found valid frame setup - codestream now points to
|
||
* start of push instructions for saving registers
|
||
*/
|
||
|
||
/* skip over register saves */
|
||
for (i = 0; i < 8; i++)
|
||
{
|
||
op = codestream_peek ();
|
||
/* break if not pushl inst */
|
||
if (op < 0x50 || op > 0x57)
|
||
break;
|
||
codestream_get ();
|
||
}
|
||
|
||
i386_follow_jump ();
|
||
|
||
return (codestream_tell ());
|
||
}
|
||
|
||
i386_push_dummy_frame ()
|
||
{
|
||
CORE_ADDR sp = read_register (SP_REGNUM);
|
||
int regnum;
|
||
|
||
sp = push_word (sp, read_register (PC_REGNUM));
|
||
sp = push_word (sp, read_register (FP_REGNUM));
|
||
write_register (FP_REGNUM, sp);
|
||
for (regnum = 0; regnum < NUM_REGS; regnum++)
|
||
sp = push_word (sp, read_register (regnum));
|
||
write_register (SP_REGNUM, sp);
|
||
}
|
||
|
||
i386_pop_frame ()
|
||
{
|
||
FRAME frame = get_current_frame ();
|
||
CORE_ADDR fp;
|
||
int regnum;
|
||
struct frame_saved_regs fsr;
|
||
struct frame_info *fi;
|
||
|
||
fi = get_frame_info (frame);
|
||
fp = fi->frame;
|
||
get_frame_saved_regs (fi, &fsr);
|
||
for (regnum = 0; regnum < NUM_REGS; regnum++)
|
||
{
|
||
CORE_ADDR adr;
|
||
adr = fsr.regs[regnum];
|
||
if (adr)
|
||
write_register (regnum, read_memory_integer (adr, 4));
|
||
}
|
||
write_register (FP_REGNUM, read_memory_integer (fp, 4));
|
||
write_register (PC_REGNUM, read_memory_integer (fp + 4, 4));
|
||
write_register (SP_REGNUM, fp + 8);
|
||
flush_cached_frames ();
|
||
set_current_frame ( create_new_frame (read_register (FP_REGNUM),
|
||
read_pc ()));
|
||
}
|
||
|
||
/* this table must line up with REGISTER_NAMES in m-i386.h */
|
||
/* symbols like 'EAX' come from <sys/reg.h> */
|
||
static int regmap[] =
|
||
{
|
||
EAX, ECX, EDX, EBX,
|
||
UESP, EBP, ESI, EDI,
|
||
EIP, EFL, CS, SS,
|
||
DS, ES, FS, GS,
|
||
};
|
||
|
||
/* blockend is the value of u.u_ar0, and points to the
|
||
* place where GS is stored
|
||
*/
|
||
i386_register_u_addr (blockend, regnum)
|
||
{
|
||
#if 0
|
||
/* this will be needed if fp registers are reinstated */
|
||
/* for now, you can look at them with 'info float'
|
||
* sys5 wont let you change them with ptrace anyway
|
||
*/
|
||
if (regnum >= FP0_REGNUM && regnum <= FP7_REGNUM)
|
||
{
|
||
int ubase, fpstate;
|
||
struct user u;
|
||
ubase = blockend + 4 * (SS + 1) - KSTKSZ;
|
||
fpstate = ubase + ((char *)&u.u_fpstate - (char *)&u);
|
||
return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
|
||
}
|
||
else
|
||
#endif
|
||
return (blockend + 4 * regmap[regnum]);
|
||
|
||
}
|
||
|
||
i387_to_double (from, to)
|
||
char *from;
|
||
char *to;
|
||
{
|
||
long *lp;
|
||
/* push extended mode on 387 stack, then pop in double mode
|
||
*
|
||
* first, set exception masks so no error is generated -
|
||
* number will be rounded to inf or 0, if necessary
|
||
*/
|
||
asm ("pushl %eax"); /* grab a stack slot */
|
||
asm ("fstcw (%esp)"); /* get 387 control word */
|
||
asm ("movl (%esp),%eax"); /* save old value */
|
||
asm ("orl $0x3f,%eax"); /* mask all exceptions */
|
||
asm ("pushl %eax");
|
||
asm ("fldcw (%esp)"); /* load new value into 387 */
|
||
|
||
asm ("movl 8(%ebp),%eax");
|
||
asm ("fldt (%eax)"); /* push extended number on 387 stack */
|
||
asm ("fwait");
|
||
asm ("movl 12(%ebp),%eax");
|
||
asm ("fstpl (%eax)"); /* pop double */
|
||
asm ("fwait");
|
||
|
||
asm ("popl %eax"); /* flush modified control word */
|
||
asm ("fnclex"); /* clear exceptions */
|
||
asm ("fldcw (%esp)"); /* restore original control word */
|
||
asm ("popl %eax"); /* flush saved copy */
|
||
}
|
||
|
||
double_to_i387 (from, to)
|
||
char *from;
|
||
char *to;
|
||
{
|
||
/* push double mode on 387 stack, then pop in extended mode
|
||
* no errors are possible because every 64-bit pattern
|
||
* can be converted to an extended
|
||
*/
|
||
asm ("movl 8(%ebp),%eax");
|
||
asm ("fldl (%eax)");
|
||
asm ("fwait");
|
||
asm ("movl 12(%ebp),%eax");
|
||
asm ("fstpt (%eax)");
|
||
asm ("fwait");
|
||
}
|
||
|
||
struct env387
|
||
{
|
||
unsigned short control;
|
||
unsigned short r0;
|
||
unsigned short status;
|
||
unsigned short r1;
|
||
unsigned short tag;
|
||
unsigned short r2;
|
||
unsigned long eip;
|
||
unsigned short code_seg;
|
||
unsigned short opcode;
|
||
unsigned long operand;
|
||
unsigned short operand_seg;
|
||
unsigned short r3;
|
||
unsigned char regs[8][10];
|
||
};
|
||
|
||
static
|
||
print_387_control_word (control)
|
||
unsigned short control;
|
||
{
|
||
printf ("control 0x%04x: ", control);
|
||
printf ("compute to ");
|
||
switch ((control >> 8) & 3)
|
||
{
|
||
case 0: printf ("24 bits; "); break;
|
||
case 1: printf ("(bad); "); break;
|
||
case 2: printf ("53 bits; "); break;
|
||
case 3: printf ("64 bits; "); break;
|
||
}
|
||
printf ("round ");
|
||
switch ((control >> 10) & 3)
|
||
{
|
||
case 0: printf ("NEAREST; "); break;
|
||
case 1: printf ("DOWN; "); break;
|
||
case 2: printf ("UP; "); break;
|
||
case 3: printf ("CHOP; "); break;
|
||
}
|
||
if (control & 0x3f)
|
||
{
|
||
printf ("mask:");
|
||
if (control & 0x0001) printf (" INVALID");
|
||
if (control & 0x0002) printf (" DENORM");
|
||
if (control & 0x0004) printf (" DIVZ");
|
||
if (control & 0x0008) printf (" OVERF");
|
||
if (control & 0x0010) printf (" UNDERF");
|
||
if (control & 0x0020) printf (" LOS");
|
||
printf (";");
|
||
}
|
||
printf ("\n");
|
||
if (control & 0xe080) printf ("warning: reserved bits on 0x%x\n",
|
||
control & 0xe080);
|
||
}
|
||
|
||
static
|
||
print_387_status_word (status)
|
||
unsigned short status;
|
||
{
|
||
printf ("status 0x%04x: ", status);
|
||
if (status & 0xff)
|
||
{
|
||
printf ("exceptions:");
|
||
if (status & 0x0001) printf (" INVALID");
|
||
if (status & 0x0002) printf (" DENORM");
|
||
if (status & 0x0004) printf (" DIVZ");
|
||
if (status & 0x0008) printf (" OVERF");
|
||
if (status & 0x0010) printf (" UNDERF");
|
||
if (status & 0x0020) printf (" LOS");
|
||
if (status & 0x0040) printf (" FPSTACK");
|
||
printf ("; ");
|
||
}
|
||
printf ("flags: %d%d%d%d; ",
|
||
(status & 0x4000) != 0,
|
||
(status & 0x0400) != 0,
|
||
(status & 0x0200) != 0,
|
||
(status & 0x0100) != 0);
|
||
|
||
printf ("top %d\n", (status >> 11) & 7);
|
||
}
|
||
|
||
static
|
||
print_387_status (status, ep)
|
||
unsigned short status;
|
||
struct env387 *ep;
|
||
{
|
||
int i;
|
||
int bothstatus;
|
||
int top;
|
||
int fpreg;
|
||
unsigned char *p;
|
||
|
||
bothstatus = ((status != 0) && (ep->status != 0));
|
||
if (status != 0)
|
||
{
|
||
if (bothstatus)
|
||
printf ("u: ");
|
||
print_387_status_word (status);
|
||
}
|
||
|
||
if (ep->status != 0)
|
||
{
|
||
if (bothstatus)
|
||
printf ("e: ");
|
||
print_387_status_word (ep->status);
|
||
}
|
||
|
||
print_387_control_word (ep->control);
|
||
printf ("last exception: ");
|
||
printf ("opcode 0x%x; ", ep->opcode);
|
||
printf ("pc 0x%x:0x%x; ", ep->code_seg, ep->eip);
|
||
printf ("operand 0x%x:0x%x\n", ep->operand_seg, ep->operand);
|
||
|
||
top = (ep->status >> 11) & 7;
|
||
|
||
printf ("regno tag msb lsb value\n");
|
||
for (fpreg = 7; fpreg >= 0; fpreg--)
|
||
{
|
||
double val;
|
||
|
||
printf ("%s %d: ", fpreg == top ? "=>" : " ", fpreg);
|
||
|
||
switch ((ep->tag >> (fpreg * 2)) & 3)
|
||
{
|
||
case 0: printf ("valid "); break;
|
||
case 1: printf ("zero "); break;
|
||
case 2: printf ("trap "); break;
|
||
case 3: printf ("empty "); break;
|
||
}
|
||
for (i = 9; i >= 0; i--)
|
||
printf ("%02x", ep->regs[fpreg][i]);
|
||
|
||
i387_to_double (ep->regs[fpreg], (char *)&val);
|
||
printf (" %g\n", val);
|
||
}
|
||
if (ep->r0)
|
||
printf ("warning: reserved0 is 0x%x\n", ep->r0);
|
||
if (ep->r1)
|
||
printf ("warning: reserved1 is 0x%x\n", ep->r1);
|
||
if (ep->r2)
|
||
printf ("warning: reserved2 is 0x%x\n", ep->r2);
|
||
if (ep->r3)
|
||
printf ("warning: reserved3 is 0x%x\n", ep->r3);
|
||
}
|
||
|
||
#ifndef U_FPSTATE
|
||
#define U_FPSTATE(u) u.u_fpstate
|
||
#endif
|
||
|
||
i386_float_info ()
|
||
{
|
||
struct user u; /* just for address computations */
|
||
int i;
|
||
/* fpstate defined in <sys/user.h> */
|
||
struct fpstate *fpstatep;
|
||
char buf[sizeof (struct fpstate) + 2 * sizeof (int)];
|
||
unsigned int uaddr;
|
||
char fpvalid;
|
||
unsigned int rounded_addr;
|
||
unsigned int rounded_size;
|
||
extern int corechan;
|
||
int skip;
|
||
|
||
uaddr = (char *)&u.u_fpvalid - (char *)&u;
|
||
if (have_inferior_p())
|
||
{
|
||
unsigned int data;
|
||
unsigned int mask;
|
||
|
||
rounded_addr = uaddr & -sizeof (int);
|
||
data = ptrace (3, inferior_pid, rounded_addr, 0);
|
||
mask = 0xff << ((uaddr - rounded_addr) * 8);
|
||
|
||
fpvalid = ((data & mask) != 0);
|
||
}
|
||
else
|
||
{
|
||
if (lseek (corechan, uaddr, 0) < 0)
|
||
perror ("seek on core file");
|
||
if (myread (corechan, &fpvalid, 1) < 0)
|
||
perror ("read on core file");
|
||
|
||
}
|
||
|
||
if (fpvalid == 0)
|
||
{
|
||
printf ("no floating point status saved\n");
|
||
return;
|
||
}
|
||
|
||
uaddr = (char *)&U_FPSTATE(u) - (char *)&u;
|
||
if (have_inferior_p ())
|
||
{
|
||
int *ip;
|
||
|
||
rounded_addr = uaddr & -sizeof (int);
|
||
rounded_size = (((uaddr + sizeof (struct fpstate)) - uaddr) +
|
||
sizeof (int) - 1) / sizeof (int);
|
||
skip = uaddr - rounded_addr;
|
||
|
||
ip = (int *)buf;
|
||
for (i = 0; i < rounded_size; i++)
|
||
{
|
||
*ip++ = ptrace (3, inferior_pid, rounded_addr, 0);
|
||
rounded_addr += sizeof (int);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
if (lseek (corechan, uaddr, 0) < 0)
|
||
perror_with_name ("seek on core file");
|
||
if (myread (corechan, buf, sizeof (struct fpstate)) < 0)
|
||
perror_with_name ("read from core file");
|
||
skip = 0;
|
||
}
|
||
|
||
fpstatep = (struct fpstate *)(buf + skip);
|
||
print_387_status (fpstatep->status, (struct env387 *)fpstatep->state);
|
||
}
|
||
|