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.
WARNING: multiple messages have this Message-ID (diff)
From: Mark Rutland <mark.rutland@arm.com> To: Sami Tolvanen <samitolvanen@google.com> Cc: linux-arch@vger.kernel.org, x86@kernel.org, Kees Cook <keescook@chromium.org>, "Paul E. McKenney" <paulmck@kernel.org>, kernel-hardening@lists.openwall.com, Peter Zijlstra <peterz@infradead.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Masahiro Yamada <masahiroy@kernel.org>, linux-kbuild@vger.kernel.org, Nick Desaulniers <ndesaulniers@google.com>, linux-kernel@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>, clang-built-linux@googlegroups.com, linux-pci@vger.kernel.org, Will Deacon <will@kernel.org>, linux-arm-kernel@lists.infradead.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. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-09-30 9:59 UTC|newest] Thread overview: 120+ 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 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 01/29] RAS/CEC: Fix cec_init() prototype Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` 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 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 03/29] kbuild: preprocess module linker script Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 04/29] objtool: Add a pass for generating __mcount_loc Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-10-01 13:17 ` Miroslav Benes 2020-10-01 13:17 ` Miroslav Benes 2020-10-01 13:17 ` Miroslav Benes 2020-10-01 13:36 ` Peter Zijlstra 2020-10-01 13:36 ` Peter Zijlstra 2020-10-02 14:13 ` Josh Poimboeuf 2020-10-02 14:13 ` Josh Poimboeuf 2020-10-05 7:10 ` Miroslav Benes 2020-10-05 7:10 ` Miroslav Benes 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 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 06/29] tracing: move function tracer options to Kconfig Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-30 0:12 ` Steven Rostedt 2020-09-30 0:12 ` Steven Rostedt 2020-09-30 16:05 ` Sami Tolvanen 2020-09-30 16:05 ` Sami Tolvanen 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 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 08/29] x86, build: use " Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 09/29] arm64: disable recordmcount with DYNAMIC_FTRACE_WITH_REGS Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-30 9:58 ` Mark Rutland [this message] 2020-09-30 9:58 ` Mark Rutland 2020-09-30 17:10 ` Sami Tolvanen 2020-09-30 17:10 ` Sami Tolvanen 2020-09-30 17:10 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 10/29] treewide: remove DISABLE_LTO Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-30 20:45 ` Kees Cook 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 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 12/29] kbuild: lto: fix module versioning Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 13/29] kbuild: lto: postpone objtool Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 14/29] kbuild: lto: limit inlining Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 15/29] kbuild: lto: merge module sections Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` 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 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 17/29] init: lto: ensure initcall ordering Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 18/29] init: lto: fix PREL32 relocations Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 19/29] PCI: Fix PREL32 relocations for LTO Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` 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 ` Sami Tolvanen 2020-09-29 21:46 ` 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 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 22/29] efi/libstub: disable LTO Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` 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 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 24/29] arm64: vdso: disable LTO Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` 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 ` Sami Tolvanen 2020-09-29 21:46 ` 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 ` Sami Tolvanen 2020-09-29 21:46 ` 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 ` Sami Tolvanen 2020-09-29 21:46 ` 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 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` [PATCH v4 29/29] x86, build: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-29 21:46 ` Sami Tolvanen 2020-09-30 21:10 ` [PATCH v4 00/29] Add support for Clang LTO Kees Cook 2020-09-30 21:10 ` Kees Cook 2020-09-30 21:58 ` Nick Desaulniers 2020-09-30 21:58 ` Nick Desaulniers 2020-09-30 21:58 ` Nick Desaulniers 2020-09-30 22:12 ` Sami Tolvanen 2020-09-30 22:12 ` Sami Tolvanen 2020-09-30 22:12 ` Sami Tolvanen
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