From: Julien Thierry <julien.thierry@arm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Torsten Duwe <duwe@lst.de>, Will Deacon <will.deacon@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Ingo Molnar <mingo@redhat.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Arnd Bergmann <arnd@arndb.de>,
AKASHI Takahiro <takahiro.akashi@linaro.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, live-patching@vger.kernel.org
Subject: Re: [PATCH 1/3] arm64: implement ftrace with regs
Date: Tue, 14 Aug 2018 09:33:52 +0100 [thread overview]
Message-ID: <a19d9e23-3dfa-ba9b-a177-cdc0d1035964@arm.com> (raw)
In-Reply-To: <20180813220315.6e8dfc9c@vmware.local.home>
On 14/08/18 03:03, Steven Rostedt wrote:
> On Mon, 13 Aug 2018 11:54:06 +0100
> Julien Thierry <julien.thierry@arm.com> wrote:
>
>>> --- a/arch/arm64/Makefile
>>> +++ b/arch/arm64/Makefile
>>> @@ -78,6 +78,15 @@ ifeq ($(CONFIG_ARM64_MODULE_PLTS),y)
>>> KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/arm64/kernel/module.lds
>>> endif
>>>
>>> +ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
>>> + CC_FLAGS_FTRACE := -fpatchable-function-entry=2
>>> + KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
>>> + ifeq ($(call cc-option,-fpatchable-function-entry=2),)
>>> + $(warning Cannot use CONFIG_DYNAMIC_FTRACE_WITH_REGS: \
>>> + -fpatchable-function-entry not supported by compiler)
>>
>> Shouldn't this be an error? The option -fpatchable-function-entry has
>> been added to the CC_FLAGS_FTRACE, so any call to the compiler is gonna
>> break anyway. Or am I missing something?
>
> I'm guessing this adds a more informative message on that error. One
> will know why -fpatchable-function-entry was added to the CFLAGS. I'm
> for more informative error messages being a victim of poor error
> messages causing me to dig deep into the guts of the build
> infrastructure to figure out simple issues.
>
Yes, I agree it is better to have this message. My point was that we
could have "$error" instead of "$warning" to stop the compilation right
away since we know everything is gonna break (and on parallel builds
this warning is gonna be drowned in compiler errors).
--
Julien Thierry
next prev parent reply other threads:[~2018-08-14 8:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-10 16:00 [PATCH 0/3] arm64 live patching Torsten Duwe
2018-08-10 16:02 ` [PATCH 1/3] arm64: implement ftrace with regs Torsten Duwe
2018-08-10 19:27 ` Steven Rostedt
2018-08-13 10:54 ` Julien Thierry
2018-08-14 2:03 ` Steven Rostedt
2018-08-14 8:33 ` Julien Thierry [this message]
2018-08-14 16:04 ` Steven Rostedt
2018-08-15 13:47 ` Torsten Duwe
2018-08-10 16:03 ` [PATCH 2/3] arm64: implement live patching Torsten Duwe
2018-08-29 11:37 ` Miroslav Benes
2018-08-10 16:03 ` [PATCH 3/3] arm64: reliable stacktraces Torsten Duwe
2018-08-10 20:44 ` Josh Poimboeuf
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