From: Florent Revest <revest@chromium.org>
To: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
bpf@vger.kernel.org
Cc: catalin.marinas@arm.com, will@kernel.org, rostedt@goodmis.org,
mhiramat@kernel.org, mark.rutland@arm.com, ast@kernel.org,
daniel@iogearbox.net, andrii@kernel.org, kpsingh@kernel.org,
jolsa@kernel.org, xukuohai@huaweicloud.com, lihuafei1@huawei.com,
Florent Revest <revest@chromium.org>
Subject: [PATCH v3 0/4] Add ftrace direct call for arm64
Date: Fri, 24 Mar 2023 18:14:47 +0100 [thread overview]
Message-ID: <20230324171451.2752302-1-revest@chromium.org> (raw)
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 v2 [3]:
- Dropped the first 6 patches which got merged separately in the tracing tree
- Minor rebase changes when switching to v6.3-rc3
- Fixed a typo in a comment (trmapoline -> trampoline)
1: https://lore.kernel.org/all/ZB2Nl7fzpHoq5V20@FVFF77S0Q05N/
2: https://lore.kernel.org/all/20220913162732.163631-1-xukuohai@huaweicloud.com/
3: https://lore.kernel.org/all/20230207182135.2671106-1-revest@chromium.org/
Florent Revest (4):
arm64: ftrace: Add direct call support
arm64: ftrace: Simplify get_ftrace_plt
arm64: ftrace: Add direct call trampoline samples support
selftests/bpf: Update the tests deny list on aarch64
arch/arm64/Kconfig | 6 ++
arch/arm64/include/asm/ftrace.h | 22 +++++
arch/arm64/kernel/asm-offsets.c | 6 ++
arch/arm64/kernel/entry-ftrace.S | 90 ++++++++++++++++----
arch/arm64/kernel/ftrace.c | 46 +++++++---
samples/ftrace/ftrace-direct-modify.c | 32 +++++++
samples/ftrace/ftrace-direct-multi-modify.c | 36 ++++++++
samples/ftrace/ftrace-direct-multi.c | 22 +++++
samples/ftrace/ftrace-direct-too.c | 25 ++++++
samples/ftrace/ftrace-direct.c | 23 +++++
tools/testing/selftests/bpf/DENYLIST.aarch64 | 82 ++----------------
11 files changed, 288 insertions(+), 102 deletions(-)
--
2.40.0.348.gf938b09366-goog
next reply other threads:[~2023-03-24 17:15 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-24 17:14 Florent Revest [this message]
2023-03-24 17:14 ` [PATCH v3 1/4] arm64: ftrace: Add direct call support Florent Revest
2023-03-24 17:14 ` [PATCH v3 2/4] arm64: ftrace: Simplify get_ftrace_plt Florent Revest
2023-03-24 18:01 ` Mark Rutland
2023-03-24 17:14 ` [PATCH v3 3/4] arm64: ftrace: Add direct call trampoline samples support Florent Revest
2023-03-27 13:45 ` Florent Revest
2023-03-24 17:14 ` [PATCH v3 4/4] selftests/bpf: Update the tests deny list on aarch64 Florent Revest
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