Re: [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions

From: Andy Lutomirski
Date: Thu May 02 2019 - 16:26:27 EST

> On May 2, 2019, at 12:28 PM, Jiri Kosina <jikos@xxxxxxxxxx> wrote:
>> On Thu, 2 May 2019, Linus Torvalds wrote:
>> I forget: is #BP _only_ for the "int3" instruction?
> Hmm, according to 17.3.2 in vol 3 of SDM (and table 6-1 there), that
> indeed seems to be the case, so we should be fine.

Iâm reasonably confident that the absurd MOV SS; INT3 sequence results in #BP from user mode and then #DB inside that (as opposed to vice versa), so this should be okay.