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ptrace.c

/*
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Derived from "arch/m68k/kernel/ptrace.c"
 *  Copyright (C) 1994 by Hamish Macdonald
 *  Taken from linux/kernel/ptrace.c and modified for M680x0.
 *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
 *
 * Modified by Cort Dougan (cort@hq.fsmlabs.com)
 * and Paul Mackerras (paulus@samba.org).
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License.  See the file README.legal in the main directory of
 * this archive for more details.
 */

#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/seccomp.h>
#include <linux/audit.h>
#ifdef CONFIG_PPC32
#include <linux/module.h>
#endif

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

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

/*
 * Set of msr bits that gdb can change on behalf of a process.
 */
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
#define MSR_DEBUGCHANGE 0
#else
#define MSR_DEBUGCHANGE (MSR_SE | MSR_BE)
#endif

/*
 * Max register writeable via put_reg
 */
#ifdef CONFIG_PPC32
#define PT_MAX_PUT_REG  PT_MQ
#else
#define PT_MAX_PUT_REG  PT_CCR
#endif

/*
 * Get contents of register REGNO in task TASK.
 */
unsigned long ptrace_get_reg(struct task_struct *task, int regno)
{
      unsigned long tmp = 0;

      if (task->thread.regs == NULL)
            return -EIO;

      if (regno == PT_MSR) {
            tmp = ((unsigned long *)task->thread.regs)[PT_MSR];
            return tmp | task->thread.fpexc_mode;
      }

      if (regno < (sizeof(struct pt_regs) / sizeof(unsigned long)))
            return ((unsigned long *)task->thread.regs)[regno];

      return -EIO;
}

/*
 * Write contents of register REGNO in task TASK.
 */
int ptrace_put_reg(struct task_struct *task, int regno, unsigned long data)
{
      if (task->thread.regs == NULL)
            return -EIO;

      if (regno <= PT_MAX_PUT_REG || regno == PT_TRAP) {
            if (regno == PT_MSR)
                  data = (data & MSR_DEBUGCHANGE)
                        | (task->thread.regs->msr & ~MSR_DEBUGCHANGE);
            /* We prevent mucking around with the reserved area of trap
             * which are used internally by the kernel
             */
            if (regno == PT_TRAP)
                  data &= 0xfff0;
            ((unsigned long *)task->thread.regs)[regno] = data;
            return 0;
      }
      return -EIO;
}


static int get_fpregs(void __user *data, struct task_struct *task,
                  int has_fpscr)
{
      unsigned int count = has_fpscr ? 33 : 32;

      if (copy_to_user(data, task->thread.fpr, count * sizeof(double)))
            return -EFAULT;
      return 0;
}

static int set_fpregs(void __user *data, struct task_struct *task,
                  int has_fpscr)
{
      unsigned int count = has_fpscr ? 33 : 32;

      if (copy_from_user(task->thread.fpr, data, count * sizeof(double)))
            return -EFAULT;
      return 0;
}


#ifdef CONFIG_ALTIVEC
/*
 * Get/set all the altivec registers vr0..vr31, vscr, vrsave, in one go.
 * The transfer totals 34 quadword.  Quadwords 0-31 contain the
 * corresponding vector registers.  Quadword 32 contains the vscr as the
 * last word (offset 12) within that quadword.  Quadword 33 contains the
 * vrsave as the first word (offset 0) within the quadword.
 *
 * This definition of the VMX state is compatible with the current PPC32
 * ptrace interface.  This allows signal handling and ptrace to use the
 * same structures.  This also simplifies the implementation of a bi-arch
 * (combined (32- and 64-bit) gdb.
 */

/*
 * Get contents of AltiVec register state in task TASK
 */
static int get_vrregs(unsigned long __user *data, struct task_struct *task)
{
      unsigned long regsize;

      /* copy AltiVec registers VR[0] .. VR[31] */
      regsize = 32 * sizeof(vector128);
      if (copy_to_user(data, task->thread.vr, regsize))
            return -EFAULT;
      data += (regsize / sizeof(unsigned long));

      /* copy VSCR */
      regsize = 1 * sizeof(vector128);
      if (copy_to_user(data, &task->thread.vscr, regsize))
            return -EFAULT;
      data += (regsize / sizeof(unsigned long));

      /* copy VRSAVE */
      if (put_user(task->thread.vrsave, (u32 __user *)data))
            return -EFAULT;

      return 0;
}

/*
 * Write contents of AltiVec register state into task TASK.
 */
static int set_vrregs(struct task_struct *task, unsigned long __user *data)
{
      unsigned long regsize;

      /* copy AltiVec registers VR[0] .. VR[31] */
      regsize = 32 * sizeof(vector128);
      if (copy_from_user(task->thread.vr, data, regsize))
            return -EFAULT;
      data += (regsize / sizeof(unsigned long));

      /* copy VSCR */
      regsize = 1 * sizeof(vector128);
      if (copy_from_user(&task->thread.vscr, data, regsize))
            return -EFAULT;
      data += (regsize / sizeof(unsigned long));

      /* copy VRSAVE */
      if (get_user(task->thread.vrsave, (u32 __user *)data))
            return -EFAULT;

      return 0;
}
#endif /* CONFIG_ALTIVEC */

#ifdef CONFIG_SPE

/*
 * For get_evrregs/set_evrregs functions 'data' has the following layout:
 *
 * struct {
 *   u32 evr[32];
 *   u64 acc;
 *   u32 spefscr;
 * }
 */

/*
 * Get contents of SPE register state in task TASK.
 */
static int get_evrregs(unsigned long *data, struct task_struct *task)
{
      int i;

      if (!access_ok(VERIFY_WRITE, data, 35 * sizeof(unsigned long)))
            return -EFAULT;

      /* copy SPEFSCR */
      if (__put_user(task->thread.spefscr, &data[34]))
            return -EFAULT;

      /* copy SPE registers EVR[0] .. EVR[31] */
      for (i = 0; i < 32; i++, data++)
            if (__put_user(task->thread.evr[i], data))
                  return -EFAULT;

      /* copy ACC */
      if (__put_user64(task->thread.acc, (unsigned long long *)data))
            return -EFAULT;

      return 0;
}

/*
 * Write contents of SPE register state into task TASK.
 */
static int set_evrregs(struct task_struct *task, unsigned long *data)
{
      int i;

      if (!access_ok(VERIFY_READ, data, 35 * sizeof(unsigned long)))
            return -EFAULT;

      /* copy SPEFSCR */
      if (__get_user(task->thread.spefscr, &data[34]))
            return -EFAULT;

      /* copy SPE registers EVR[0] .. EVR[31] */
      for (i = 0; i < 32; i++, data++)
            if (__get_user(task->thread.evr[i], data))
                  return -EFAULT;
      /* copy ACC */
      if (__get_user64(task->thread.acc, (unsigned long long*)data))
            return -EFAULT;

      return 0;
}
#endif /* CONFIG_SPE */


static void set_single_step(struct task_struct *task)
{
      struct pt_regs *regs = task->thread.regs;

      if (regs != NULL) {
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
            task->thread.dbcr0 = DBCR0_IDM | DBCR0_IC;
            regs->msr |= MSR_DE;
#else
            regs->msr |= MSR_SE;
#endif
      }
      set_tsk_thread_flag(task, TIF_SINGLESTEP);
}

static void clear_single_step(struct task_struct *task)
{
      struct pt_regs *regs = task->thread.regs;

      if (regs != NULL) {
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
            task->thread.dbcr0 = 0;
            regs->msr &= ~MSR_DE;
#else
            regs->msr &= ~MSR_SE;
#endif
      }
      clear_tsk_thread_flag(task, TIF_SINGLESTEP);
}

static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
                         unsigned long data)
{
      /* We only support one DABR and no IABRS at the moment */
      if (addr > 0)
            return -EINVAL;

      /* The bottom 3 bits are flags */
      if ((data & ~0x7UL) >= TASK_SIZE)
            return -EIO;

      /* Ensure translation is on */
      if (data && !(data & DABR_TRANSLATION))
            return -EIO;

      task->thread.dabr = data;
      return 0;
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *child)
{
      /* make sure the single step bit is not set. */
      clear_single_step(child);
}

/*
 * Here are the old "legacy" powerpc specific getregs/setregs ptrace calls,
 * we mark them as obsolete now, they will be removed in a future version
 */
static long arch_ptrace_old(struct task_struct *child, long request, long addr,
                      long data)
{
      int ret = -EPERM;

      switch(request) {
      case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
            int i;
            unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
            unsigned long __user *tmp = (unsigned long __user *)addr;

            CHECK_FULL_REGS(child->thread.regs);
            for (i = 0; i < 32; i++) {
                  ret = put_user(*reg, tmp);
                  if (ret)
                        break;
                  reg++;
                  tmp++;
            }
            break;
      }

      case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
            int i;
            unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
            unsigned long __user *tmp = (unsigned long __user *)addr;

            CHECK_FULL_REGS(child->thread.regs);
            for (i = 0; i < 32; i++) {
                  ret = get_user(*reg, tmp);
                  if (ret)
                        break;
                  reg++;
                  tmp++;
            }
            break;
      }

      case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
            flush_fp_to_thread(child);
            ret = get_fpregs((void __user *)addr, child, 0);
            break;
      }

      case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
            flush_fp_to_thread(child);
            ret = set_fpregs((void __user *)addr, child, 0);
            break;
      }

      }
      return ret;
}

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

      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 index, tmp;

            ret = -EIO;
            /* convert to index and check */
#ifdef CONFIG_PPC32
            index = (unsigned long) addr >> 2;
            if ((addr & 3) || (index > PT_FPSCR)
                || (child->thread.regs == NULL))
#else
            index = (unsigned long) addr >> 3;
            if ((addr & 7) || (index > PT_FPSCR))
#endif
                  break;

            CHECK_FULL_REGS(child->thread.regs);
            if (index < PT_FPR0) {
                  tmp = ptrace_get_reg(child, (int) index);
            } else {
                  flush_fp_to_thread(child);
                  tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
            }
            ret = put_user(tmp,(unsigned long __user *) data);
            break;
      }

      /* If 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;

      /* write the word at location addr in the USER area */
      case PTRACE_POKEUSR: {
            unsigned long index;

            ret = -EIO;
            /* convert to index and check */
#ifdef CONFIG_PPC32
            index = (unsigned long) addr >> 2;
            if ((addr & 3) || (index > PT_FPSCR)
                || (child->thread.regs == NULL))
#else
            index = (unsigned long) addr >> 3;
            if ((addr & 7) || (index > PT_FPSCR))
#endif
                  break;

            CHECK_FULL_REGS(child->thread.regs);
            if (index < PT_FPR0) {
                  ret = ptrace_put_reg(child, index, data);
            } else {
                  flush_fp_to_thread(child);
                  ((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
                  ret = 0;
            }
            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;
            /* make sure the single step bit is not set. */
            clear_single_step(child);
            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;
            /* make sure the single step bit is not set. */
            clear_single_step(child);
            wake_up_process(child);
            break;
      }

      case PTRACE_SINGLESTEP: {  /* set the trap flag. */
            ret = -EIO;
            if (!valid_signal(data))
                  break;
            clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
            set_single_step(child);
            child->exit_code = data;
            /* give it a chance to run. */
            wake_up_process(child);
            ret = 0;
            break;
      }

      case PTRACE_GET_DEBUGREG: {
            ret = -EINVAL;
            /* We only support one DABR and no IABRS at the moment */
            if (addr > 0)
                  break;
            ret = put_user(child->thread.dabr,
                         (unsigned long __user *)data);
            break;
      }

      case PTRACE_SET_DEBUGREG:
            ret = ptrace_set_debugreg(child, addr, data);
            break;

#ifdef CONFIG_PPC64
      case PTRACE_GETREGS64:
#endif
      case PTRACE_GETREGS: { /* Get all pt_regs from the child. */
            int ui;
            if (!access_ok(VERIFY_WRITE, (void __user *)data,
                         sizeof(struct pt_regs))) {
                  ret = -EIO;
                  break;
            }
            CHECK_FULL_REGS(child->thread.regs);
            ret = 0;
            for (ui = 0; ui < PT_REGS_COUNT; ui ++) {
                  ret |= __put_user(ptrace_get_reg(child, ui),
                                (unsigned long __user *) data);
                  data += sizeof(long);
            }
            break;
      }

#ifdef CONFIG_PPC64
      case PTRACE_SETREGS64:
#endif
      case PTRACE_SETREGS: { /* Set all gp regs in the child. */
            unsigned long tmp;
            int ui;
            if (!access_ok(VERIFY_READ, (void __user *)data,
                         sizeof(struct pt_regs))) {
                  ret = -EIO;
                  break;
            }
            CHECK_FULL_REGS(child->thread.regs);
            ret = 0;
            for (ui = 0; ui < PT_REGS_COUNT; ui ++) {
                  ret = __get_user(tmp, (unsigned long __user *) data);
                  if (ret)
                        break;
                  ptrace_put_reg(child, ui, tmp);
                  data += sizeof(long);
            }
            break;
      }

      case PTRACE_GETFPREGS: { /* Get the child FPU state (FPR0...31 + FPSCR) */
            flush_fp_to_thread(child);
            ret = get_fpregs((void __user *)data, child, 1);
            break;
      }

      case PTRACE_SETFPREGS: { /* Set the child FPU state (FPR0...31 + FPSCR) */
            flush_fp_to_thread(child);
            ret = set_fpregs((void __user *)data, child, 1);
            break;
      }

#ifdef CONFIG_ALTIVEC
      case PTRACE_GETVRREGS:
            /* Get the child altivec register state. */
            flush_altivec_to_thread(child);
            ret = get_vrregs((unsigned long __user *)data, child);
            break;

      case PTRACE_SETVRREGS:
            /* Set the child altivec register state. */
            flush_altivec_to_thread(child);
            ret = set_vrregs(child, (unsigned long __user *)data);
            break;
#endif
#ifdef CONFIG_SPE
      case PTRACE_GETEVRREGS:
            /* Get the child spe register state. */
            flush_spe_to_thread(child);
            ret = get_evrregs((unsigned long __user *)data, child);
            break;

      case PTRACE_SETEVRREGS:
            /* Set the child spe register state. */
            /* this is to clear the MSR_SPE bit to force a reload
             * of register state from memory */
            flush_spe_to_thread(child);
            ret = set_evrregs(child, (unsigned long __user *)data);
            break;
#endif

      /* Old reverse args ptrace callss */
      case PPC_PTRACE_GETREGS: /* Get GPRs 0 - 31. */
      case PPC_PTRACE_SETREGS: /* Set GPRs 0 - 31. */
      case PPC_PTRACE_GETFPREGS: /* Get FPRs 0 - 31. */
      case PPC_PTRACE_SETFPREGS: /* Get FPRs 0 - 31. */
            ret = arch_ptrace_old(child, request, addr, data);
            break;

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

static void do_syscall_trace(void)
{
      /* the 0x80 provides a way for the tracing parent to distinguish
         between a syscall stop and SIGTRAP delivery */
      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 (current->exit_code) {
            send_sig(current->exit_code, current, 1);
            current->exit_code = 0;
      }
}

void do_syscall_trace_enter(struct pt_regs *regs)
{
      secure_computing(regs->gpr[0]);

      if (test_thread_flag(TIF_SYSCALL_TRACE)
          && (current->ptrace & PT_PTRACED))
            do_syscall_trace();

      if (unlikely(current->audit_context)) {
#ifdef CONFIG_PPC64
            if (!test_thread_flag(TIF_32BIT))
                  audit_syscall_entry(AUDIT_ARCH_PPC64,
                                  regs->gpr[0],
                                  regs->gpr[3], regs->gpr[4],
                                  regs->gpr[5], regs->gpr[6]);
            else
#endif
                  audit_syscall_entry(AUDIT_ARCH_PPC,
                                  regs->gpr[0],
                                  regs->gpr[3] & 0xffffffff,
                                  regs->gpr[4] & 0xffffffff,
                                  regs->gpr[5] & 0xffffffff,
                                  regs->gpr[6] & 0xffffffff);
      }
}

void do_syscall_trace_leave(struct pt_regs *regs)
{
      if (unlikely(current->audit_context))
            audit_syscall_exit((regs->ccr&0x10000000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,
                           regs->result);

      if ((test_thread_flag(TIF_SYSCALL_TRACE)
           || test_thread_flag(TIF_SINGLESTEP))
          && (current->ptrace & PT_PTRACED))
            do_syscall_trace();
}

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