linux-kernel - Re: [PATCH v4 0/4] Add ftrace direct call for arm64

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CABRcYm+p-_z0i7TyyA16NPY3GkR37mFxN1SKiV6RBS1pGEoa1Q@mail.gmail.com>
Date:   Mon, 3 Apr 2023 13:25:56 +0200
From:   Florent Revest <revest@...omium.org>
To:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-trace-kernel@...r.kernel.org, bpf@...r.kernel.org
Cc:     catalin.marinas@....com, will@...nel.org, rostedt@...dmis.org,
        mhiramat@...nel.org, mark.rutland@....com, ast@...nel.org,
        daniel@...earbox.net, andrii@...nel.org, kpsingh@...nel.org,
        jolsa@...nel.org, xukuohai@...weicloud.com, lihuafei1@...wei.com
Subject: Re: [PATCH v4 0/4] Add ftrace direct call for arm64

On Mon, Apr 3, 2023 at 1:21 PM Florent Revest <revest@...omium.org> wrote:
>
> This series adds ftrace direct call support to arm64.
> This makes BPF tracing programs (fentry/fexit/fmod_ret/lsm) work on arm64.
>
> It is meant to be taken by the arm64 tree but it depends on the
> trace-direct-v6.3-rc3 tag of the linux-trace tree:
>   git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
> That tag was created by Steven Rostedt so the arm64 tree can pull the prior work
> this depends on. [1]
>
> Thanks to the ftrace refactoring under that tag, an ftrace_ops backing a ftrace
> direct call will only ever point to *one* direct call. This means we can look up
> the direct called trampoline address stored in the ops from the ftrace_caller
> trampoline in the case when the destination would be out of reach of a BL
> instruction at the ftrace callsite. This fixes limitations of previous attempts
> such as [2].
>
> This series has been tested on arm64 with:
> 1- CONFIG_FTRACE_SELFTEST
> 2- samples/ftrace/*.ko (cf: patch 3)
> 3- tools/testing/selftests/bpf/test_progs (cf: patch 4)
>
> Changes since v3 [3]:
> - Added "BTI C" instructions at the beginning of each ftrace direct call sample

Ugh, I am an idiot (let's just blame Mondays!) and didn't actually
amend this change, I'm sending the series again as a v5 and this time
with the change actually folded in... Please ignore this v4, sorry for
the noise! :|