From: Florent Revest <revest@chromium.org>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: Xu Kuohai <xukuohai@huawei.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
bpf@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org,
rostedt@goodmis.org, mhiramat@kernel.org, mark.rutland@arm.com,
ast@kernel.org, andrii@kernel.org, kpsingh@kernel.org,
jolsa@kernel.org, xukuohai@huaweicloud.com,
Manu Bretelle <chantra@meta.com>
Subject: Re: [PATCH 0/8] Add ftrace direct call for arm64
Date: Thu, 2 Feb 2023 18:32:04 +0100 [thread overview]
Message-ID: <CABRcYmK8AP7_aL_NqJfNYgGzzpDp2x33qdzOkDxbUECxj2F-RQ@mail.gmail.com> (raw)
In-Reply-To: <eacfbd23-da92-3572-7f57-3de425117c8a@iogearbox.net>
On Thu, Feb 2, 2023 at 11:50 AM Daniel Borkmann <daniel@iogearbox.net> wrote:
>
> On 2/2/23 9:36 AM, Xu Kuohai wrote:
> > On 2/2/2023 12:34 AM, Florent Revest 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 apply on top of the arm64 tree which contains Mark Rutland's
> >> series on CALL_OPS [1] under the for-next/ftrace tag.
> >> > The first three patches consolidate the two existing ftrace APIs for registering
> >> direct calls. They are split to make the reviewers lives easier but if it'd be a
> >> preferred style, I'd be happy to squash them in the next revision.
> >> Currently, there is both a _ftrace_direct and _ftrace_direct_multi API. Apart
> >> from samples and selftests, there are no users of the _ftrace_direct API left
> >> in-tree so this deletes it and renames the _ftrace_direct_multi API to
> >> _ftrace_direct for simplicity.
> >>
> >> The main benefit of this refactoring is that, with the API that's left, an
> >> ftrace_ops backing a direct call will only ever point to one direct call. We can
> >> therefore store the direct called trampoline address in the ops (patch 4) and
> >> look it up from the ftrace trampoline on arm64 (patch 7) in the case when the
> >> destination would be out of reach of a BL instruction at the ftrace callsite.
> >> (in this case, ftrace_caller acts as a lightweight intermediary trampoline)
> >>
> >> This series has been tested on both arm64 and x86_64 with:
> >> 1- CONFIG_FTRACE_SELFTEST (cf: patch 6)
> >> 2- samples/ftrace/*.ko (cf: patch 8)
> >> 3- tools/testing/selftests/bpf/test_progs (both -t lsm and -t fentry_fexit)
>
> Thanks a ton for working on this!
>
> > so it's time to update DENYLIST.aarch64 to unblock tests that failed due to lack of direct call.
That's a good point Xu, thanks! I'll update the deny list in my next revision.
It looks like this series fixes *a lot* of these tests, so that's exciting. :)
> +1, with regards to logistics, if possible it might be nice to eventually gets
> this into a feature branch on arm64 tree, then we could pull it too from there
> for bpf-next and hash out the BPF CI bits for arm64 in the meantime.
I believe that Manu Bretelle already wired up the BPF CI for arm64, is
there more work required ?
Regarding the logistics, whatever works sgtm... :) I suppose it's up
to Catalin or Will.
next prev parent reply other threads:[~2023-02-02 17:32 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-01 16:34 [PATCH 0/8] Add ftrace direct call for arm64 Florent Revest
2023-02-01 16:34 ` [PATCH 1/8] ftrace: Replace uses of _ftrace_direct APIs with _ftrace_direct_multi Florent Revest
2023-02-02 15:01 ` Mark Rutland
2023-02-02 17:37 ` Florent Revest
2023-02-07 15:21 ` Florent Revest
2023-02-07 15:35 ` Steven Rostedt
2023-02-07 16:19 ` Florent Revest
2023-02-01 16:34 ` [PATCH 2/8] ftrace: Remove the legacy _ftrace_direct API Florent Revest
2023-02-02 15:11 ` Mark Rutland
2023-02-01 16:34 ` [PATCH 3/8] ftrace: Rename _ftrace_direct_multi APIs to _ftrace_direct APIs Florent Revest
2023-02-02 15:17 ` Mark Rutland
2023-02-01 16:34 ` [PATCH 4/8] ftrace: Store direct called addresses in their ops Florent Revest
2023-02-02 15:29 ` Mark Rutland
2023-02-02 17:41 ` Florent Revest
2023-02-01 16:34 ` [PATCH 5/8] ftrace: Make DIRECT_CALLS work WITH_ARGS and !WITH_REGS Florent Revest
2023-02-02 15:54 ` Mark Rutland
2023-02-02 16:56 ` Mark Rutland
2023-02-02 18:19 ` Florent Revest
2023-02-03 10:03 ` Mark Rutland
2023-02-03 11:01 ` Florent Revest
2023-02-02 18:18 ` Florent Revest
2023-02-01 16:34 ` [PATCH 6/8] ftrace: Fix dead loop caused by direct call in ftrace selftest Florent Revest
2023-02-02 19:03 ` Mark Rutland
2023-02-03 12:35 ` Florent Revest
2023-02-03 15:37 ` Mark Rutland
2023-02-06 16:25 ` Florent Revest
2023-02-01 16:34 ` [PATCH 7/8] arm64: ftrace: Add direct call support Florent Revest
2023-02-03 15:34 ` Mark Rutland
2023-02-06 16:25 ` Florent Revest
2023-02-01 16:34 ` [PATCH 8/8] arm64: ftrace: Add direct called trampoline samples support Florent Revest
2023-02-02 8:36 ` [PATCH 0/8] Add ftrace direct call for arm64 Xu Kuohai
2023-02-02 10:50 ` Daniel Borkmann
2023-02-02 17:32 ` Florent Revest [this message]
2023-02-02 20:06 ` Steven Rostedt
2023-02-03 9:49 ` Mark Rutland
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