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[93.147.243.166]) by smtp.gmail.com with ESMTPSA id n2-20020adffe02000000b002cfeffb442bsm11743267wrr.57.2023.03.21.10.06.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Mar 2023 10:06:34 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Tue, 21 Mar 2023 18:06:31 +0100 To: Florent Revest Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, mark.rutland@arm.com, ast@kernel.org, daniel@iogearbox.net, kpsingh@kernel.org Subject: Re: [PATCH v2 0/7] Refactor ftrace direct call APIs Message-ID: References: <20230321140424.345218-1-revest@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230321140424.345218-1-revest@chromium.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 21, 2023 at 03:04:17PM +0100, Florent Revest wrote: > Differences since v1 [1]: > - Use a READ_ONCE() to read the direct call address in call_direct_funcs > - Added an Acked-by from Mark > > This series refactors ftrace direct call APIs in preparation for arm64 support. > It is roughly a subset of [2] rebased on v6.3-rc2 and meant to be taken by > Steven's tree before all the arm64 specific bits. > > The first patch was suggested by Steven in a review of [1], it makes it more > obvious to the caller that filters probably need to be freed when unregistering > a direct call. > > The next three patches consolidate the two existing ftrace APIs for registering > direct calls. They are only split to make the reviewer's life easier. > 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 5) and, > in the future arm64 series, look it up from the ftrace trampoline. (in the > meantime, it makes call_direct_funcs a bit simpler too) > > Ftrace direct calls technically don't need DYNAMIC_FTRACE_WITH_REGS so this > extends its support to DYNAMIC_FTRACE_WITH_ARGS (patch 6). arm64 won't support > DYNAMIC_FTRACE_WITH_REGS. > > Finally, it fixes the ABI of the stub direct call trampoline used in ftrace > selftests. > > This has been tested on x86_64 with: > 1- CONFIG_FTRACE_SELFTEST > 2- samples/ftrace/*.ko > > 1: https://lore.kernel.org/all/20230316173811.1223508-1-revest@chromium.org/T/#t > 2: https://lore.kernel.org/all/20230207182135.2671106-1-revest@chromium.org/T/#t > > Florent Revest (6): > ftrace: Let unregister_ftrace_direct_multi() call ftrace_free_filter() > ftrace: Replace uses of _ftrace_direct APIs with _ftrace_direct_multi > ftrace: Remove the legacy _ftrace_direct API > ftrace: Rename _ftrace_direct_multi APIs to _ftrace_direct APIs > ftrace: Store direct called addresses in their ops > ftrace: Make DIRECT_CALLS work WITH_ARGS and !WITH_REGS lgtm Acked-by: Jiri Olsa jirka > > Mark Rutland (1): > ftrace: selftest: remove broken trace_direct_tramp > > arch/s390/kernel/mcount.S | 5 + > arch/x86/kernel/ftrace_32.S | 5 + > arch/x86/kernel/ftrace_64.S | 4 + > include/linux/ftrace.h | 61 +-- > kernel/bpf/trampoline.c | 12 +- > kernel/trace/Kconfig | 2 +- > kernel/trace/ftrace.c | 438 ++------------------ > kernel/trace/trace_selftest.c | 19 +- > samples/Kconfig | 2 +- > samples/ftrace/ftrace-direct-modify.c | 10 +- > samples/ftrace/ftrace-direct-multi-modify.c | 9 +- > samples/ftrace/ftrace-direct-multi.c | 5 +- > samples/ftrace/ftrace-direct-too.c | 10 +- > samples/ftrace/ftrace-direct.c | 10 +- > 14 files changed, 101 insertions(+), 491 deletions(-) > > -- > 2.40.0.rc2.332.ga46443480c-goog >