From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: Changbin Du <changbin.du@gmail.com>
Cc: Michal Marek <michal.lkml@markovi.net>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Russell King <linux@armlinux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Steven Rostedt <rostedt@goodmis.org>, X86 ML <x86@kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-sparse@vger.kernel.org, Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v3 4/4] kernel hacking: new config CC_OPTIMIZE_FOR_DEBUGGING to apply GCC -Og optimization
Date: Mon, 29 Oct 2018 22:16:02 +0900 [thread overview]
Message-ID: <CAK7LNAS8UPXBbOpG9Zy_aP7an2jbq5H7uQGymUAn+hv46WQ4Bw@mail.gmail.com> (raw)
In-Reply-To: <20181028130945.23581-5-changbin.du@gmail.com>
On Sun, Oct 28, 2018 at 10:11 PM Changbin Du <changbin.du@gmail.com> wrote:
>
> This will apply GCC '-Og' optimization level which is supported
> since GCC 4.8. This optimization level offers a reasonable level
> of optimization while maintaining fast compilation and a good
> debugging experience. It is similar to '-O1' while perferring
> to keep debug ability over runtime speed.
>
> If enabling this option breaks your kernel, you should either
> disable this or find a fix (mostly in the arch code). Currently
> this option has only been tested on x86_64 and arm platform.
>
> This option can satisfy people who was searching for a method
> to disable compiler optimizations so to achieve better kernel
> debugging experience with kgdb or qemu.
>
> The main problem of '-Og' is we must not use __attribute__((error(msg))).
> The compiler will report error though the call to error function
> still can be optimize out. So we must fallback to array tricky.
I removed the sentence "So we must fallback to array tricky."
Commit 81b45683487a51b0f4d3b29d37f20d6d078544e4
killed the fallback to the negative array trick.
I also resolved a conflict.
Your series is now available in the following branch.
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild kbuild
Please double check if I did it correctly.
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2018-10-29 13:16 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-28 13:09 [PATCH v3 0/4] kernel hacking: GCC optimization for better debug experience (-Og) Changbin Du
2018-10-28 13:09 ` [PATCH v3 1/4] x86/mm: declare check_la57_support() as inline Changbin Du
2018-10-28 18:09 ` Steven Rostedt
2018-10-29 13:04 ` Masahiro Yamada
2018-11-02 11:27 ` Borislav Petkov
2018-11-09 16:27 ` Masahiro Yamada
2018-11-10 1:41 ` Changbin Du
2018-10-28 13:09 ` [PATCH v3 2/4] kernel hacking: new config NO_AUTO_INLINE to disable compiler auto-inline optimizations Changbin Du
2018-10-29 13:03 ` Masahiro Yamada
2018-10-28 13:09 ` [PATCH v3 3/4] ARM: mm: fix build error in fix_to_virt with CONFIG_CC_OPTIMIZE_FOR_DEBUGGING Changbin Du
2018-10-29 13:05 ` Masahiro Yamada
2018-10-28 13:09 ` [PATCH v3 4/4] kernel hacking: new config CC_OPTIMIZE_FOR_DEBUGGING to apply GCC -Og optimization Changbin Du
2018-10-29 13:16 ` Masahiro Yamada [this message]
2018-10-29 14:54 ` Changbin Du
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