[PATCH] m68k: sys_ptrace cleanup
Roman Zippel [Sat, 3 Sep 2005 22:57:08 +0000 (15:57 -0700)]
- create helper function singlestep_disable()
- move variable definitions to the top of the function
- use "out_eio" label as common error destination
- don't clear failure value for PTRACE_SETREGS/PTRACE_GETREGS

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/m68k/kernel/ptrace.c

index 9bb25ea..8ed1b01 100644 (file)
@@ -103,48 +103,56 @@ static inline int put_reg(struct task_struct *task, int regno,
 }
 
 /*
- * Called by kernel/ptrace.c when detaching..
- *
  * Make sure the single step bit is not set.
  */
-void ptrace_disable(struct task_struct *child)
+static inline void singlestep_disable(struct task_struct *child)
 {
-       unsigned long tmp;
-       /* make sure the single step bit is not set. */
-       tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
+       unsigned long tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
        put_reg(child, PT_SR, tmp);
        child->thread.work.delayed_trace = 0;
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ */
+void ptrace_disable(struct task_struct *child)
+{
+       singlestep_disable(child);
        child->thread.work.syscall_trace = 0;
 }
 
 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 {
        struct task_struct *child;
-       int ret;
+       unsigned long tmp;
+       int i, ret = 0;
 
        lock_kernel();
-       ret = -EPERM;
        if (request == PTRACE_TRACEME) {
                /* are we already being traced? */
-               if (current->ptrace & PT_PTRACED)
+               if (current->ptrace & PT_PTRACED) {
+                       ret = -EPERM;
                        goto out;
+               }
                /* set the ptrace bit in the process flags. */
                current->ptrace |= PT_PTRACED;
-               ret = 0;
                goto out;
        }
-       ret = -ESRCH;
        read_lock(&tasklist_lock);
        child = find_task_by_pid(pid);
        if (child)
                get_task_struct(child);
        read_unlock(&tasklist_lock);
-       if (!child)
+       if (unlikely(!child)) {
+               ret = -ESRCH;
                goto out;
+       }
 
-       ret = -EPERM;
-       if (pid == 1)           /* you may not mess with init */
+       /* you may not mess with init */
+       if (unlikely(pid == 1)) {
+               ret = -EPERM;
                goto out_tsk;
+       }
 
        if (request == PTRACE_ATTACH) {
                ret = ptrace_attach(child);
@@ -152,86 +160,62 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
        }
 
        ret = ptrace_check_attach(child, request == PTRACE_KILL);
-       if (ret < 0)
+       if (ret)
                goto out_tsk;
 
        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: {
-               unsigned long tmp;
-               int copied;
-
-               copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
-               ret = -EIO;
-               if (copied != sizeof(tmp))
-                       break;
+       case PTRACE_PEEKDATA:
+               i = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
+               if (i != sizeof(tmp))
+                       goto out_eio;
                ret = put_user(tmp, (unsigned long *)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 ||
-                   addr > sizeof(struct user) - 3)
-                       break;
+       case PTRACE_PEEKUSR:
+               if (addr & 3)
+                       goto out_eio;
+               addr >>= 2;     /* temporary hack. */
 
-               tmp = 0;  /* Default return condition */
-               addr = addr >> 2; /* temporary hack. */
-               ret = -EIO;
-               if (addr < 19) {
+               if (addr >= 0 && addr < 19) {
                        tmp = get_reg(child, addr);
                        if (addr == PT_SR)
                                tmp >>= 16;
                } else if (addr >= 21 && addr < 49) {
                        tmp = child->thread.fp[addr - 21];
-#ifdef CONFIG_M68KFPU_EMU
                        /* Convert internal fpu reg representation
                         * into long double format
                         */
                        if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
                                tmp = ((tmp & 0xffff0000) << 15) |
                                      ((tmp & 0x0000ffff) << 16);
-#endif
                } 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 = 0;
-               if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
-                       break;
-               ret = -EIO;
+               if (access_process_vm(child, addr, &data, sizeof(data), 1) != sizeof(data))
+                       goto out_eio;
                break;
 
        case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
-               ret = -EIO;
-               if ((addr & 3) || addr < 0 ||
-                   addr > sizeof(struct user) - 3)
-                       break;
-
-               addr = addr >> 2; /* temporary hack. */
+               if (addr & 3)
+                       goto out_eio;
+               addr >>= 2;     /* temporary hack. */
 
                if (addr == PT_SR) {
                        data &= SR_MASK;
                        data <<= 16;
                        data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
-               }
-               if (addr < 19) {
+               } else if (addr >= 0 && addr < 19) {
                        if (put_reg(child, addr, data))
-                               break;
-                       ret = 0;
-                       break;
-               }
-               if (addr >= 21 && addr < 48) {
-#ifdef CONFIG_M68KFPU_EMU
+                               goto out_eio;
+               } else if (addr >= 21 && addr < 48) {
                        /* Convert long double format
                         * into internal fpu reg representation
                         */
@@ -240,60 +224,42 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
                                data = (data & 0xffff0000) |
                                       ((data & 0x0000ffff) >> 1);
                        }
-#endif
                        child->thread.fp[addr - 21] = data;
-                       ret = 0;
-               }
+               } else
+                       goto out_eio;
                break;
 
        case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
-       case PTRACE_CONT: {     /* restart after signal. */
-               long tmp;
-
-               ret = -EIO;
+       case PTRACE_CONT:       /* restart after signal. */
                if (!valid_signal(data))
-                       break;
-               if (request == PTRACE_SYSCALL) {
+                       goto out_eio;
+
+               if (request == PTRACE_SYSCALL)
                        child->thread.work.syscall_trace = ~0;
-               } else {
+               else
                        child->thread.work.syscall_trace = 0;
-               }
                child->exit_code = data;
-               /* make sure the single step bit is not set. */
-               tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
-               put_reg(child, PT_SR, tmp);
-               child->thread.work.delayed_trace = 0;
+               singlestep_disable(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: {
-               long tmp;
-
-               ret = 0;
+       case PTRACE_KILL:
                if (child->exit_state == EXIT_ZOMBIE) /* already dead */
                        break;
                child->exit_code = SIGKILL;
-               /* make sure the single step bit is not set. */
-               tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
-               put_reg(child, PT_SR, tmp);
-               child->thread.work.delayed_trace = 0;
+               singlestep_disable(child);
                wake_up_process(child);
                break;
-       }
-
-       case PTRACE_SINGLESTEP: {  /* set the trap flag. */
-               long tmp;
 
-               ret = -EIO;
+       case PTRACE_SINGLESTEP: /* set the trap flag. */
                if (!valid_signal(data))
-                       break;
+                       goto out_eio;
+
                child->thread.work.syscall_trace = 0;
                tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
                put_reg(child, PT_SR, tmp);
@@ -302,39 +268,29 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
                child->exit_code = data;
                /* give it a chance to run. */
                wake_up_process(child);
-               ret = 0;
                break;
-       }
 
        case PTRACE_DETACH:     /* detach a process that was attached. */
                ret = ptrace_detach(child, data);
                break;
 
-       case PTRACE_GETREGS: { /* Get all gp regs from the child. */
-               int i;
-               unsigned long tmp;
+       case PTRACE_GETREGS:    /* Get all gp regs from the child. */
                for (i = 0; i < 19; i++) {
                        tmp = get_reg(child, i);
                        if (i == PT_SR)
                                tmp >>= 16;
-                       if (put_user(tmp, (unsigned long *)data)) {
-                               ret = -EFAULT;
+                       ret = put_user(tmp, (unsigned long *)data);
+                       if (ret)
                                break;
-                       }
                        data += sizeof(long);
                }
-               ret = 0;
                break;
-       }
 
-       case PTRACE_SETREGS: { /* Set all gp regs in the child. */
-               int i;
-               unsigned long tmp;
+       case PTRACE_SETREGS:    /* Set all gp regs in the child. */
                for (i = 0; i < 19; i++) {
-                       if (get_user(tmp, (unsigned long *)data)) {
-                               ret = -EFAULT;
+                       ret = get_user(tmp, (unsigned long *)data);
+                       if (ret)
                                break;
-                       }
                        if (i == PT_SR) {
                                tmp &= SR_MASK;
                                tmp <<= 16;
@@ -343,25 +299,19 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
                        put_reg(child, i, tmp);
                        data += sizeof(long);
                }
-               ret = 0;
                break;
-       }
 
-       case PTRACE_GETFPREGS: { /* Get the child FPU state. */
-               ret = 0;
+       case PTRACE_GETFPREGS:  /* Get the child FPU state. */
                if (copy_to_user((void *)data, &child->thread.fp,
                                 sizeof(struct user_m68kfp_struct)))
                        ret = -EFAULT;
                break;
-       }
 
-       case PTRACE_SETFPREGS: { /* Set the child FPU state. */
-               ret = 0;
+       case PTRACE_SETFPREGS:  /* Set the child FPU state. */
                if (copy_from_user(&child->thread.fp, (void *)data,
                                   sizeof(struct user_m68kfp_struct)))
                        ret = -EFAULT;
                break;
-       }
 
        default:
                ret = ptrace_request(child, request, addr, data);
@@ -372,6 +322,9 @@ out_tsk:
 out:
        unlock_kernel();
        return ret;
+out_eio:
+       ret = -EIO;
+       goto out_tsk;
 }
 
 asmlinkage void syscall_trace(void)