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Commit 2b82cadf authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

uprobes/x86: Introduce push_ret_address() 



Extract the "push return address" code from branch_emulate_op() into
the new simple helper, push_ret_address(). It will have more users.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
parent 78d9af4c

arch/x86/kernel/uprobes.c

+12 −3
Original line number Diff line number Diff line
@@ -407,6 +407,17 @@ static int default_pre_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs) 
	return 0;

}



static int push_ret_address(struct pt_regs *regs, unsigned long ip)

{

	unsigned long new_sp = regs->sp - sizeof_long();



	if (copy_to_user((void __user *)new_sp, &ip, sizeof_long()))

		return -EFAULT;



	regs->sp = new_sp;

	return 0;

}



/*

 * Adjust the return address pushed by a call insn executed out of line.

 */
@@ -517,7 +528,6 @@ static bool branch_emulate_op(struct arch_uprobe *auprobe, struct pt_regs *regs) 
	unsigned long offs = (long)auprobe->branch.offs;



	if (branch_is_call(auprobe)) {

		unsigned long new_sp = regs->sp - sizeof_long();

		/*

		 * If it fails we execute this (mangled, see the comment in

		 * branch_clear_offset) insn out-of-line. In the likely case
@@ -527,9 +537,8 @@ static bool branch_emulate_op(struct arch_uprobe *auprobe, struct pt_regs *regs) 
		 *

		 * But there is corner case, see the comment in ->post_xol().

		 */

		if (copy_to_user((void __user *)new_sp, &new_ip, sizeof_long()))

		if (push_ret_address(regs, new_ip))

			return false;

		regs->sp = new_sp;

	} else if (!check_jmp_cond(auprobe, regs)) {

		offs = 0;

	}