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

Commit 74e59dfc authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

uprobes: Change handle_swbp() to expose bp_vaddr to handler_chain() 



Change handle_swbp() to set regs->ip = bp_vaddr in advance, this is
what consumer->handler() needs but uprobe_get_swbp_addr() is not
exported.

This also simplifies the code and makes it more consistent across
the supported architectures. handle_swbp() becomes the only caller
of uprobe_get_swbp_addr().

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
parent cf31ec3f

arch/x86/kernel/uprobes.c

+0 −1
Original line number Diff line number Diff line
@@ -681,7 +681,6 @@ static bool __skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) 
			continue;



		if (auprobe->insn[i] == 0x90) {

			regs->ip = uprobe_get_swbp_addr(regs);

			regs->ip += i + 1;

			return true;

		}

kernel/events/uprobes.c

+7 −8
Original line number Diff line number Diff line
@@ -1504,6 +1504,10 @@ static void handle_swbp(struct pt_regs *regs) 
		}

		return;

	}



	/* change it in advance for ->handler() and restart */

	instruction_pointer_set(regs, bp_vaddr);



	/*

	 * TODO: move copy_insn/etc into _register and remove this hack.

	 * After we hit the bp, _unregister + _register can install the
@@ -1511,14 +1515,14 @@ static void handle_swbp(struct pt_regs *regs) 
	 */

	smp_rmb(); /* pairs with wmb() in install_breakpoint() */

	if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags)))

		goto restart;

		goto out;



	utask = current->utask;

	if (!utask) {

		utask = add_utask();

		/* Cannot allocate; re-execute the instruction. */

		if (!utask)

			goto restart;

			goto out;

	}



	handler_chain(uprobe, regs);
@@ -1531,12 +1535,7 @@ static void handle_swbp(struct pt_regs *regs) 
		return;

	}



restart:

	/*

	 * cannot singlestep; cannot skip instruction;

	 * re-execute the instruction.

	 */

	instruction_pointer_set(regs, bp_vaddr);

	/* can_skip_sstep() succeeded, or restart if can't singlestep */

out:

	put_uprobe(uprobe);

}

kernel/trace/trace_uprobe.c

+2 −2
Original line number Diff line number Diff line
@@ -492,7 +492,7 @@ static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs) 
		return;



	entry = ring_buffer_event_data(event);

	entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));

	entry->ip = instruction_pointer(task_pt_regs(current));

	data = (u8 *)&entry[1];

	for (i = 0; i < tu->nr_args; i++)

		call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
@@ -667,7 +667,7 @@ static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs) 
	if (!entry)

		goto out;



	entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));

	entry->ip = instruction_pointer(task_pt_regs(current));

	data = (u8 *)&entry[1];

	for (i = 0; i < tu->nr_args; i++)

		call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);