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ptrace.c

/* ptrace.c: FRV specific parts of process tracing
 *
 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * - Derived from arch/m68k/kernel/ptrace.c
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <linux/regset.h>
#include <linux/elf.h>
#include <linux/tracehook.h>

#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/unistd.h>

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

/*
 * retrieve the contents of FRV userspace general registers
 */
static int genregs_get(struct task_struct *target,
                   const struct user_regset *regset,
                   unsigned int pos, unsigned int count,
                   void *kbuf, void __user *ubuf)
{
      const struct user_int_regs *iregs = &target->thread.user->i;
      int ret;

      ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                          iregs, 0, sizeof(*iregs));
      if (ret < 0)
            return ret;

      return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
                              sizeof(*iregs), -1);
}

/*
 * update the contents of the FRV userspace general registers
 */
static int genregs_set(struct task_struct *target,
                   const struct user_regset *regset,
                   unsigned int pos, unsigned int count,
                   const void *kbuf, const void __user *ubuf)
{
      struct user_int_regs *iregs = &target->thread.user->i;
      unsigned int offs_gr0, offs_gr1;
      int ret;

      /* not allowed to set PSR or __status */
      if (pos < offsetof(struct user_int_regs, psr) + sizeof(long) &&
          pos + count > offsetof(struct user_int_regs, psr))
            return -EIO;

      if (pos < offsetof(struct user_int_regs, __status) + sizeof(long) &&
          pos + count > offsetof(struct user_int_regs, __status))
            return -EIO;

      /* set the control regs */
      offs_gr0 = offsetof(struct user_int_regs, gr[0]);
      offs_gr1 = offsetof(struct user_int_regs, gr[1]);
      ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                         iregs, 0, offs_gr0);
      if (ret < 0)
            return ret;

      /* skip GR0/TBR */
      ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                              offs_gr0, offs_gr1);
      if (ret < 0)
            return ret;

      /* set the general regs */
      ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                         &iregs->gr[1], offs_gr1, sizeof(*iregs));
      if (ret < 0)
            return ret;

      return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                              sizeof(*iregs), -1);
}

/*
 * retrieve the contents of FRV userspace FP/Media registers
 */
static int fpmregs_get(struct task_struct *target,
                   const struct user_regset *regset,
                   unsigned int pos, unsigned int count,
                   void *kbuf, void __user *ubuf)
{
      const struct user_fpmedia_regs *fpregs = &target->thread.user->f;
      int ret;

      ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                          fpregs, 0, sizeof(*fpregs));
      if (ret < 0)
            return ret;

      return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
                              sizeof(*fpregs), -1);
}

/*
 * update the contents of the FRV userspace FP/Media registers
 */
static int fpmregs_set(struct task_struct *target,
                   const struct user_regset *regset,
                   unsigned int pos, unsigned int count,
                   const void *kbuf, const void __user *ubuf)
{
      struct user_fpmedia_regs *fpregs = &target->thread.user->f;
      int ret;

      ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                         fpregs, 0, sizeof(*fpregs));
      if (ret < 0)
            return ret;

      return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                              sizeof(*fpregs), -1);
}

/*
 * determine if the FP/Media registers have actually been used
 */
static int fpmregs_active(struct task_struct *target,
                    const struct user_regset *regset)
{
      return tsk_used_math(target) ? regset->n : 0;
}

/*
 * Define the register sets available on the FRV under Linux
 */
enum frv_regset {
      REGSET_GENERAL,
      REGSET_FPMEDIA,
};

static const struct user_regset frv_regsets[] = {
      /*
       * General register format is:
       *    PSR, ISR, CCR, CCCR, LR, LCR, PC, (STATUS), SYSCALLNO, ORIG_G8
       *    GNER0-1, IACC0, TBR, GR1-63
       */
      [REGSET_GENERAL] = {
            .core_note_type   = NT_PRSTATUS,
            .n          = ELF_NGREG,
            .size       = sizeof(long),
            .align            = sizeof(long),
            .get        = genregs_get,
            .set        = genregs_set,
      },
      /*
       * FPU/Media register format is:
       *    FR0-63, FNER0-1, MSR0-1, ACC0-7, ACCG0-8, FSR
       */
      [REGSET_FPMEDIA] = {
            .core_note_type   = NT_PRFPREG,
            .n          = sizeof(struct user_fpmedia_regs) / sizeof(long),
            .size       = sizeof(long),
            .align            = sizeof(long),
            .get        = fpmregs_get,
            .set        = fpmregs_set,
            .active           = fpmregs_active,
      },
};

static const struct user_regset_view user_frv_native_view = {
      .name       = "frv",
      .e_machine  = EM_FRV,
      .regsets    = frv_regsets,
      .n          = ARRAY_SIZE(frv_regsets),
};

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
      return &user_frv_native_view;
}

/*
 * Get contents of register REGNO in task TASK.
 */
static inline long get_reg(struct task_struct *task, int regno)
{
      struct user_context *user = task->thread.user;

      if (regno < 0 || regno >= PT__END)
            return 0;

      return ((unsigned long *) user)[regno];
}

/*
 * Write contents of register REGNO in task TASK.
 */
static inline int put_reg(struct task_struct *task, int regno,
                    unsigned long data)
{
      struct user_context *user = task->thread.user;

      if (regno < 0 || regno >= PT__END)
            return -EIO;

      switch (regno) {
      case PT_GR(0):
            return 0;
      case PT_PSR:
      case PT__STATUS:
            return -EIO;
      default:
            ((unsigned long *) user)[regno] = data;
            return 0;
      }
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Control h/w single stepping
 */
void user_enable_single_step(struct task_struct *child)
{
      child->thread.frame0->__status |= REG__STATUS_STEP;
}

void user_disable_single_step(struct task_struct *child)
{
      child->thread.frame0->__status &= ~REG__STATUS_STEP;
}

void ptrace_disable(struct task_struct *child)
{
      user_disable_single_step(child);
}

long arch_ptrace(struct task_struct *child, long request,
             unsigned long addr, unsigned long data)
{
      unsigned long tmp;
      int ret;
      int regno = addr >> 2;
      unsigned long __user *datap = (unsigned long __user *) data;

      switch (request) {
            /* read the word at location addr in the USER area. */
      case PTRACE_PEEKUSR: {
            tmp = 0;
            ret = -EIO;
            if (addr & 3)
                  break;

            ret = 0;
            switch (regno) {
            case 0 ... PT__END - 1:
                  tmp = get_reg(child, regno);
                  break;

            case PT__END + 0:
                  tmp = child->mm->end_code - child->mm->start_code;
                  break;

            case PT__END + 1:
                  tmp = child->mm->end_data - child->mm->start_data;
                  break;

            case PT__END + 2:
                  tmp = child->mm->start_stack - child->mm->start_brk;
                  break;

            case PT__END + 3:
                  tmp = child->mm->start_code;
                  break;

            case PT__END + 4:
                  tmp = child->mm->start_stack;
                  break;

            default:
                  ret = -EIO;
                  break;
            }

            if (ret == 0)
                  ret = put_user(tmp, datap);
            break;
      }

      case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
            ret = -EIO;
            if (addr & 3)
                  break;

            switch (regno) {
            case 0 ... PT__END - 1:
                  ret = put_reg(child, regno, data);
                  break;
            }
            break;

      case PTRACE_GETREGS:    /* Get all integer regs from the child. */
            return copy_regset_to_user(child, &user_frv_native_view,
                                 REGSET_GENERAL,
                                 0, sizeof(child->thread.user->i),
                                 datap);

      case PTRACE_SETREGS:    /* Set all integer regs in the child. */
            return copy_regset_from_user(child, &user_frv_native_view,
                                   REGSET_GENERAL,
                                   0, sizeof(child->thread.user->i),
                                   datap);

      case PTRACE_GETFPREGS:  /* Get the child FP/Media state. */
            return copy_regset_to_user(child, &user_frv_native_view,
                                 REGSET_FPMEDIA,
                                 0, sizeof(child->thread.user->f),
                                 datap);

      case PTRACE_SETFPREGS:  /* Set the child FP/Media state. */
            return copy_regset_from_user(child, &user_frv_native_view,
                                   REGSET_FPMEDIA,
                                   0, sizeof(child->thread.user->f),
                                   datap);

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

/*
 * handle tracing of system call entry
 * - return the revised system call number or ULONG_MAX to cause ENOSYS
 */
asmlinkage unsigned long syscall_trace_entry(void)
{
      __frame->__status |= REG__STATUS_SYSC_ENTRY;
      if (tracehook_report_syscall_entry(__frame)) {
            /* tracing decided this syscall should not happen, so
             * We'll return a bogus call number to get an ENOSYS
             * error, but leave the original number in
             * __frame->syscallno
             */
            return ULONG_MAX;
      }

      return __frame->syscallno;
}

/*
 * handle tracing of system call exit
 */
asmlinkage void syscall_trace_exit(void)
{
      __frame->__status |= REG__STATUS_SYSC_EXIT;
      tracehook_report_syscall_exit(__frame, 0);
}

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