Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit aa85b9af authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

[PATCH] x86_64: clean up ptrace single-stepping 



Ported from i386 (originally from Linus)

clean up ptrace single-stepping, make PT_DTRACE exact.
  
  (This makes the naming of "DTRACE" purely historical, since
  on x86 it now means "single step in progress").

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent b6d9a5d8

arch/x86_64/kernel/ptrace.c

+50 −29
Original line number Diff line number Diff line
@@ -63,6 +63,12 @@ static inline unsigned long get_stack_long(struct task_struct *task, int offset) 
	return (*((unsigned long *)stack));

}



static inline struct pt_regs *get_child_regs(struct task_struct *task)

{

	struct pt_regs *regs = (void *)task->thread.rsp0;

	return regs - 1;

}



/*

 * this routine will put a word on the processes privileged stack. 

 * the offset is how far from the base addr as stored in the TSS.
@@ -80,6 +86,42 @@ static inline long put_stack_long(struct task_struct *task, int offset, 
	return 0;

}



static void set_singlestep(struct task_struct *child)

{

	struct pt_regs *regs = get_child_regs(child);



	/*

	 * Always set TIF_SINGLESTEP - this guarantees that

	 * we single-step system calls etc..  This will also

	 * cause us to set TF when returning to user mode.

	 */

	set_tsk_thread_flag(child, TIF_SINGLESTEP);



	/*

	 * If TF was already set, don't do anything else

	 */

	if (regs->eflags & TRAP_FLAG)

		return;



	/* Set TF on the kernel stack.. */

	regs->eflags |= TRAP_FLAG;



	child->ptrace |= PT_DTRACE;

}



static void clear_singlestep(struct task_struct *child)

{

	/* Always clear TIF_SINGLESTEP... */

	clear_tsk_thread_flag(child, TIF_SINGLESTEP);



	/* But touch TF only if it was set by us.. */

	if (child->ptrace & PT_DTRACE) {

		struct pt_regs *regs = get_child_regs(child);

		regs->eflags &= ~TRAP_FLAG;

		child->ptrace &= ~PT_DTRACE;

	}

}



/*

 * Called by kernel/ptrace.c when detaching..

 *
@@ -87,11 +129,7 @@ static inline long put_stack_long(struct task_struct *task, int offset, 
 */

void ptrace_disable(struct task_struct *child)

{ 

	long tmp;



	clear_tsk_thread_flag(child, TIF_SINGLESTEP);

	tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;

	put_stack_long(child, EFL_OFFSET, tmp);

	clear_singlestep(child);

}



static int putreg(struct task_struct *child,
@@ -338,8 +376,7 @@ asmlinkage long sys_ptrace(long request, long pid, unsigned long addr, long data 
		}

		break;

	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */

	case PTRACE_CONT: { /* restart after signal. */

		long tmp;

	case PTRACE_CONT:    /* restart after signal. */



		ret = -EIO;

		if ((unsigned long) data > _NSIG)
@@ -351,13 +388,10 @@ asmlinkage long sys_ptrace(long request, long pid, unsigned long addr, long data 
		clear_tsk_thread_flag(child, TIF_SINGLESTEP);

		child->exit_code = data;

		/* make sure the single step bit is not set. */

		tmp = get_stack_long(child, EFL_OFFSET);

		tmp &= ~TRAP_FLAG;

		put_stack_long(child, EFL_OFFSET,tmp);

		clear_singlestep(child);

		wake_up_process(child);

		ret = 0;

		break;

	}



#ifdef CONFIG_IA32_EMULATION

		/* This makes only sense with 32bit programs. Allow a
@@ -394,41 +428,28 @@ asmlinkage long sys_ptrace(long request, long pid, unsigned long addr, long data 
 * perhaps it should be put in the status that it wants to 

 * exit.

 */

	case PTRACE_KILL: {

		long tmp;



	case PTRACE_KILL:

		ret = 0;

		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */

			break;

		clear_tsk_thread_flag(child, TIF_SINGLESTEP);

		child->exit_code = SIGKILL;

		/* make sure the single step bit is not set. */

		tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;

		put_stack_long(child, EFL_OFFSET, tmp);

		clear_singlestep(child);

		wake_up_process(child);

		break;

	}



	case PTRACE_SINGLESTEP: {  /* set the trap flag. */

		long tmp;



	case PTRACE_SINGLESTEP:    /* set the trap flag. */

		ret = -EIO;

		if ((unsigned long) data > _NSIG)

			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;

		}

		tmp = get_stack_long(child, EFL_OFFSET) | TRAP_FLAG;

		put_stack_long(child, EFL_OFFSET, tmp);

		set_tsk_thread_flag(child, TIF_SINGLESTEP);

		set_singlestep(child);

		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. */