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Commit 4dc316c6 authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

uprobes/x86: Cleanup the single-stepping code 



No functional changes.

Now that default arch_uprobe_enable/disable_step() helpers do nothing,
x86 has no reason to reimplement them. Change arch_uprobe_*_xol() hooks
to do the necessary work and remove the x86-specific hooks.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
parent 65b2c8f0

arch/x86/kernel/uprobes.c

+19 −35
Original line number Diff line number Diff line
@@ -478,6 +478,11 @@ int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) 
	regs->ip = current->utask->xol_vaddr;

	pre_xol_rip_insn(auprobe, regs, autask);



	autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);

	regs->flags |= X86_EFLAGS_TF;

	if (test_tsk_thread_flag(current, TIF_BLOCKSTEP))

		set_task_blockstep(current, false);



	return 0;

}
@@ -603,6 +608,16 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) 
	if (auprobe->fixups & UPROBE_FIX_CALL)

		result = adjust_ret_addr(regs->sp, correction);



	/*

	 * arch_uprobe_pre_xol() doesn't save the state of TIF_BLOCKSTEP

	 * so we can get an extra SIGTRAP if we do not clear TF. We need

	 * to examine the opcode to make it right.

	 */

	if (utask->autask.saved_tf)

		send_sig(SIGTRAP, current, 0);

	else if (!(auprobe->fixups & UPROBE_FIX_SETF))

		regs->flags &= ~X86_EFLAGS_TF;



	return result;

}
@@ -647,6 +662,10 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) 
	current->thread.trap_nr = utask->autask.saved_trap_nr;

	handle_riprel_post_xol(auprobe, regs, NULL);

	instruction_pointer_set(regs, utask->vaddr);



	/* clear TF if it was set by us in arch_uprobe_pre_xol() */

	if (!utask->autask.saved_tf)

		regs->flags &= ~X86_EFLAGS_TF;

}



/*
@@ -676,38 +695,3 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) 
		send_sig(SIGTRAP, current, 0);

	return ret;

}
 


void arch_uprobe_enable_step(struct arch_uprobe *auprobe)

{

	struct task_struct *task = current;

	struct arch_uprobe_task	*autask	= &task->utask->autask;

	struct pt_regs *regs = task_pt_regs(task);



	autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);



	regs->flags |= X86_EFLAGS_TF;

	if (test_tsk_thread_flag(task, TIF_BLOCKSTEP))

		set_task_blockstep(task, false);

}



void arch_uprobe_disable_step(struct arch_uprobe *auprobe)

{

	struct task_struct *task = current;

	struct arch_uprobe_task	*autask	= &task->utask->autask;

	bool trapped = (task->utask->state == UTASK_SSTEP_TRAPPED);

	struct pt_regs *regs = task_pt_regs(task);

	/*

	 * The state of TIF_BLOCKSTEP was not saved so we can get an extra

	 * SIGTRAP if we do not clear TF. We need to examine the opcode to

	 * make it right.

	 */

	if (unlikely(trapped)) {

		if (!autask->saved_tf)

			regs->flags &= ~X86_EFLAGS_TF;

	} else {

		if (autask->saved_tf)

			send_sig(SIGTRAP, task, 0);

		else if (!(auprobe->fixups & UPROBE_FIX_SETF))

			regs->flags &= ~X86_EFLAGS_TF;

	}

}