From: Mark Rutland <mark.rutland@arm.com>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>,
Will Deacon <will@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Kees Cook <keescook@chromium.org>,
Nick Desaulniers <ndesaulniers@google.com>,
clang-built-linux@googlegroups.com,
kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH v4 09/29] arm64: disable recordmcount with DYNAMIC_FTRACE_WITH_REGS
Date: Wed, 30 Sep 2020 10:58:50 +0100 [thread overview]
Message-ID: <20200930095850.GA68612@C02TD0UTHF1T.local> (raw)
In-Reply-To: <20200929214631.3516445-10-samitolvanen@google.com>
Hi Sami,
On Tue, Sep 29, 2020 at 02:46:11PM -0700, Sami Tolvanen wrote:
> Select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY to disable
> recordmcount when DYNAMIC_FTRACE_WITH_REGS is selected.
Could you please add an explanation as to /why/ this is necessary in the
commit message? I couldn't figure this out form the commit message
alone, and reading the cover letter also didn't help.
If the minimum required GCC version supports patchable-function-entry
I'd be happy to make that a requirement for dynamic ftrace on arm64, as
then we'd only need to support one mechanism, and can get rid of some
redundant code. We already default to it when present anyhow.
>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
> ---
> arch/arm64/Kconfig | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 6d232837cbee..ad522b021f35 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -155,6 +155,8 @@ config ARM64
> select HAVE_DYNAMIC_FTRACE
> select HAVE_DYNAMIC_FTRACE_WITH_REGS \
> if $(cc-option,-fpatchable-function-entry=2)
> + select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
> + if DYNAMIC_FTRACE_WITH_REGS
This doesn't look quite right to me. Presumably we shouldn't allow
DYNAMIC_FTRACE_WITH_REGS to be selected if HAVE_DYNAMIC_FTRACE_WITH_REGS
isn't.
Thanks,
Mark.
next prev parent reply other threads:[~2020-09-30 9:59 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 21:46 [PATCH v4 00/29] Add support for Clang LTO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 01/29] RAS/CEC: Fix cec_init() prototype Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 02/29] x86/asm: Replace __force_order with memory clobber Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 03/29] kbuild: preprocess module linker script Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 04/29] objtool: Add a pass for generating __mcount_loc Sami Tolvanen
2020-10-01 13:17 ` Miroslav Benes
2020-10-01 13:36 ` Peter Zijlstra
2020-10-02 14:13 ` Josh Poimboeuf
2020-10-05 7:10 ` Miroslav Benes
2020-09-29 21:46 ` [PATCH v4 05/29] objtool: Don't autodetect vmlinux.o Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 06/29] tracing: move function tracer options to Kconfig Sami Tolvanen
2020-09-30 0:12 ` Steven Rostedt
2020-09-30 16:05 ` Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 07/29] tracing: add support for objtool mcount Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 08/29] x86, build: use " Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 09/29] arm64: disable recordmcount with DYNAMIC_FTRACE_WITH_REGS Sami Tolvanen
2020-09-30 9:58 ` Mark Rutland [this message]
2020-09-30 17:10 ` Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 10/29] treewide: remove DISABLE_LTO Sami Tolvanen
2020-09-30 20:45 ` Kees Cook
2020-09-29 21:46 ` [PATCH v4 11/29] kbuild: add support for Clang LTO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 12/29] kbuild: lto: fix module versioning Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 13/29] kbuild: lto: postpone objtool Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 14/29] kbuild: lto: limit inlining Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 15/29] kbuild: lto: merge module sections Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 16/29] kbuild: lto: remove duplicate dependencies from .mod files Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 17/29] init: lto: ensure initcall ordering Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 18/29] init: lto: fix PREL32 relocations Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 19/29] PCI: Fix PREL32 relocations for LTO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 20/29] modpost: lto: strip .lto from module names Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 21/29] scripts/mod: disable LTO for empty.c Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 22/29] efi/libstub: disable LTO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 23/29] drivers/misc/lkdtm: disable LTO for rodata.o Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 24/29] arm64: vdso: disable LTO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 25/29] KVM: arm64: disable LTO for the nVHE directory Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 26/29] arm64: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 27/29] x86, vdso: disable LTO only for vDSO Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 28/29] x86, cpu: disable LTO for cpu.c Sami Tolvanen
2020-09-29 21:46 ` [PATCH v4 29/29] x86, build: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen
2020-09-30 21:10 ` [PATCH v4 00/29] Add support for Clang LTO Kees Cook
2020-09-30 21:58 ` Nick Desaulniers
2020-09-30 22:12 ` Sami Tolvanen
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