Logo Search packages:      
Sourcecode: linux version File versions  Download package

ptrace.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * arch/sh64/kernel/ptrace.c
 *
 * Copyright (C) 2000, 2001  Paolo Alberelli
 * Copyright (C) 2003  Paul Mundt
 *
 * Started from SH3/4 version:
 *   SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
 *
 *   Original x86 implementation:
 *    By Ross Biro 1/23/92
 *    edited by Linus Torvalds
 *
 */

#include <linux/kernel.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/signal.h>
#include <linux/syscalls.h>

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>

/* This mask defines the bits of the SR which the user is not allowed to
   change, which are everything except S, Q, M, PR, SZ, FR. */
#define SR_MASK      (0xffff8cfd)

/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */

/*
 * This routine will get a word from the user area in the process kernel stack.
 */
static inline int get_stack_long(struct task_struct *task, int offset)
{
      unsigned char *stack;

      stack = (unsigned char *)(task->thread.uregs);
      stack += offset;
      return (*((int *)stack));
}

static inline unsigned long
get_fpu_long(struct task_struct *task, unsigned long addr)
{
      unsigned long tmp;
      struct pt_regs *regs;
      regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;

      if (!tsk_used_math(task)) {
            if (addr == offsetof(struct user_fpu_struct, fpscr)) {
                  tmp = FPSCR_INIT;
            } else {
                  tmp = 0xffffffffUL; /* matches initial value in fpu.c */
            }
            return tmp;
      }

      if (last_task_used_math == task) {
            grab_fpu();
            fpsave(&task->thread.fpu.hard);
            release_fpu();
            last_task_used_math = 0;
            regs->sr |= SR_FD;
      }

      tmp = ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)];
      return tmp;
}

/*
 * This routine will put a word into the user area in the process kernel stack.
 */
static inline int put_stack_long(struct task_struct *task, int offset,
                         unsigned long data)
{
      unsigned char *stack;

      stack = (unsigned char *)(task->thread.uregs);
      stack += offset;
      *(unsigned long *) stack = data;
      return 0;
}

static inline int
put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
{
      struct pt_regs *regs;

      regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;

      if (!tsk_used_math(task)) {
            fpinit(&task->thread.fpu.hard);
            set_stopped_child_used_math(task);
      } else if (last_task_used_math == task) {
            grab_fpu();
            fpsave(&task->thread.fpu.hard);
            release_fpu();
            last_task_used_math = 0;
            regs->sr |= SR_FD;
      }

      ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)] = data;
      return 0;
}


long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
      int ret;

      switch (request) {
      /* when I and D space are separate, these will need to be fixed. */
      case PTRACE_PEEKTEXT: /* read word at location addr. */
      case PTRACE_PEEKDATA:
            ret = generic_ptrace_peekdata(child, addr, data);
            break;

      /* read the word at location addr in the USER area. */
      case PTRACE_PEEKUSR: {
            unsigned long tmp;

            ret = -EIO;
            if ((addr & 3) || addr < 0)
                  break;

            if (addr < sizeof(struct pt_regs))
                  tmp = get_stack_long(child, addr);
            else if ((addr >= offsetof(struct user, fpu)) &&
                   (addr <  offsetof(struct user, u_fpvalid))) {
                  tmp = get_fpu_long(child, addr - offsetof(struct user, fpu));
            } else if (addr == offsetof(struct user, u_fpvalid)) {
                  tmp = !!tsk_used_math(child);
            } else {
                  break;
            }
            ret = put_user(tmp, (unsigned long *)data);
            break;
      }

      /* when I and D space are separate, this will have to be fixed. */
      case PTRACE_POKETEXT: /* write the word at location addr. */
      case PTRACE_POKEDATA:
            ret = generic_ptrace_pokedata(child, addr, data);
            break;

      case PTRACE_POKEUSR:
                /* write the word at location addr in the USER area. We must
                   disallow any changes to certain SR bits or u_fpvalid, since
                   this could crash the kernel or result in a security
                   loophole. */
            ret = -EIO;
            if ((addr & 3) || addr < 0)
                  break;

            if (addr < sizeof(struct pt_regs)) {
                  /* Ignore change of top 32 bits of SR */
                  if (addr == offsetof (struct pt_regs, sr)+4)
                  {
                        ret = 0;
                        break;
                  }
                  /* If lower 32 bits of SR, ignore non-user bits */
                  if (addr == offsetof (struct pt_regs, sr))
                  {
                        long cursr = get_stack_long(child, addr);
                        data &= ~(SR_MASK);
                        data |= (cursr & SR_MASK);
                  }
                  ret = put_stack_long(child, addr, data);
            }
            else if ((addr >= offsetof(struct user, fpu)) &&
                   (addr <  offsetof(struct user, u_fpvalid))) {
                  ret = put_fpu_long(child, addr - offsetof(struct user, fpu), data);
            }
            break;

      case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
      case PTRACE_CONT: { /* restart after signal. */
            ret = -EIO;
            if (!valid_signal(data))
                  break;
            if (request == PTRACE_SYSCALL)
                  set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
            else
                  clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
            child->exit_code = data;
            wake_up_process(child);
            ret = 0;
            break;
      }

/*
 * make the child exit.  Best I can do is send it a sigkill.
 * perhaps it should be put in the status that it wants to
 * exit.
 */
      case PTRACE_KILL: {
            ret = 0;
            if (child->exit_state == EXIT_ZOMBIE)     /* already dead */
                  break;
            child->exit_code = SIGKILL;
            wake_up_process(child);
            break;
      }

      case PTRACE_SINGLESTEP: {  /* set the trap flag. */
            struct pt_regs *regs;

            ret = -EIO;
            if (!valid_signal(data))
                  break;
            clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
            if ((child->ptrace & PT_DTRACE) == 0) {
                  /* Spurious delayed TF traps may occur */
                  child->ptrace |= PT_DTRACE;
            }

            regs = child->thread.uregs;

            regs->sr |= SR_SSTEP;   /* auto-resetting upon exception */

            child->exit_code = data;
            /* give it a chance to run. */
            wake_up_process(child);
            ret = 0;
            break;
      }

      default:
            ret = ptrace_request(child, request, addr, data);
            break;
      }
      return ret;
}

asmlinkage int sh64_ptrace(long request, long pid, long addr, long data)
{
      extern void poke_real_address_q(unsigned long long addr, unsigned long long data);
#define WPC_DBRMODE 0x0d104008
      static int first_call = 1;

      lock_kernel();
      if (first_call) {
            /* Set WPC.DBRMODE to 0.  This makes all debug events get
             * delivered through RESVEC, i.e. into the handlers in entry.S.
             * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
             * would normally be left set to 1, which makes debug events get
             * delivered through DBRVEC, i.e. into the remote gdb's
             * handlers.  This prevents ptrace getting them, and confuses
             * the remote gdb.) */
            printk("DBRMODE set to 0 to permit native debugging\n");
            poke_real_address_q(WPC_DBRMODE, 0);
            first_call = 0;
      }
      unlock_kernel();

      return sys_ptrace(request, pid, addr, data);
}

asmlinkage void syscall_trace(void)
{
      struct task_struct *tsk = current;

      if (!test_thread_flag(TIF_SYSCALL_TRACE))
            return;
      if (!(tsk->ptrace & PT_PTRACED))
            return;

      ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
                         ? 0x80 : 0));
      /*
       * this isn't the same as continuing with a signal, but it will do
       * for normal use.  strace only continues with a signal if the
       * stopping signal is not SIGTRAP.  -brl
       */
      if (tsk->exit_code) {
            send_sig(tsk->exit_code, tsk, 1);
            tsk->exit_code = 0;
      }
}

/* Called with interrupts disabled */
asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
{
      /* This is called after a single step exception (DEBUGSS).
         There is no need to change the PC, as it is a post-execution
         exception, as entry.S does not do anything to the PC for DEBUGSS.
         We need to clear the Single Step setting in SR to avoid
         continually stepping. */
      local_irq_enable();
      regs->sr &= ~SR_SSTEP;
      force_sig(SIGTRAP, current);
}

/* Called with interrupts disabled */
asmlinkage void do_software_break_point(unsigned long long vec,
                              struct pt_regs *regs)
{
      /* We need to forward step the PC, to counteract the backstep done
         in signal.c. */
      local_irq_enable();
      force_sig(SIGTRAP, current);
      regs->pc += 4;
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *child)
{
        /* nothing to do.. */
}

Generated by  Doxygen 1.6.0   Back to index