From: Vlastimil Babka <vbabka@suse.cz>
To: Stafford Horne <shorne@gmail.com>, Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Kees Cook <keescook@chromium.org>, Jessica Yu <jeyu@redhat.com>,
Petr Mladek <pmladek@suse.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Yang Shi <yang.shi@linaro.org>, Tejun Heo <tj@kernel.org>,
Prarit Bhargava <prarit@redhat.com>,
Yaowei Bai <baiyaowei@cmss.chinamobile.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>
Subject: Re: [PATCH -next] init/main: Init jump_labels before they are used to build zonelists
Date: Tue, 17 Jan 2017 17:11:32 +0100 [thread overview]
Message-ID: <8c4e1c37-1a8e-9e5e-c276-f7bd3cfb248b@suse.cz> (raw)
In-Reply-To: <20170117143043.GA7836@lianli.shorne-pla.net>
On 01/17/2017 03:30 PM, Stafford Horne wrote:
> On Tue, Jan 17, 2017 at 02:44:54PM +0100, Peter Zijlstra wrote:
>> On Tue, Jan 17, 2017 at 02:07:36PM +0100, Vlastimil Babka wrote:
>>
>>> Anyway I'm not sure if this patch is safe. Hopefully Peter can judge
>>> this better...
>>>
>>>> Cc: Vlastimil Babka <vbabka@suse.cz>
>>>> Signed-off-by: Stafford Horne <shorne@gmail.com>
>>>> ---
>>>> init/main.c | 3 +--
>>>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>>>
>>>> diff --git a/init/main.c b/init/main.c
>>>> index 8b1adb6e..d1ca7cb 100644
>>>> --- a/init/main.c
>>>> +++ b/init/main.c
>>>> @@ -513,6 +513,7 @@ asmlinkage __visible void __init start_kernel(void)
>>>> boot_cpu_state_init();
>>>> smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
>>>>
>>>> + jump_label_init();
>>>> build_all_zonelists(NULL, NULL);
>>>> page_alloc_init();
>>>>
>>>> @@ -526,8 +527,6 @@ asmlinkage __visible void __init start_kernel(void)
>>>> parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
>>>> NULL, set_init_arg);
>>>>
>>>> - jump_label_init();
>>>> -
>>
>> Urgh, that means auditing all archs that implement this. The thing
>> you're looking for is if the self-modifying code cruft can be done that
>> early.
>>
>> x86 looks to be fine, because this is after setup_arch() which is
>> required for ideal_nops[] to be initialied and we use text_poke_early()
>> which doesn't really need anything else.
>>
>> I've not gone through the other arches...
>
> Vlastimil,
>
> Will you be able to look into that? Openrisc doesnt have jump_label
> support, so its no issue at the moment.
>
> Archs that do have it:
>
> arch/arm64/Kconfig: select HAVE_ARCH_JUMP_LABEL
> arch/mips/Kconfig: select HAVE_ARCH_JUMP_LABEL
> arch/s390/Kconfig: select HAVE_ARCH_JUMP_LABEL
> arch/sparc/Kconfig: select HAVE_ARCH_JUMP_LABEL if SPARC64
> arch/tile/Kconfig: select HAVE_ARCH_JUMP_LABEL
> arch/x86/Kconfig: select HAVE_ARCH_JUMP_LABEL
> arch/arm/Kconfig: select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
> arch/powerpc/Kconfig: select HAVE_ARCH_JUMP_LABEL
>
> I looked at a few (arm, tile) and I dont see their arch_jump_label_transform*
> implementations depending on global state like ideal_nops from x86. They
> should be ok.
Thanks, I'll try.
> If no time, Should you change your patch to not use static keys for
> build_all_zonelists at least?
Yes that would be uglier but possible if I find issues or I'm not
confident enough with the auditing...
next prev parent reply other threads:[~2017-01-17 16:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-17 12:56 [PATCH -next] init/main: Init jump_labels before they are used to build zonelists Stafford Horne
2017-01-17 13:07 ` Vlastimil Babka
2017-01-17 13:44 ` Peter Zijlstra
2017-01-17 14:30 ` Stafford Horne
2017-01-17 16:11 ` Vlastimil Babka [this message]
2017-01-17 20:34 ` Andrew Morton
2017-01-17 20:49 ` Vlastimil Babka
2017-01-19 8:28 ` Vlastimil Babka
2017-01-19 9:56 ` Mel Gorman
2017-01-23 5:54 ` Michael Ellerman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=8c4e1c37-1a8e-9e5e-c276-f7bd3cfb248b@suse.cz \
--to=vbabka@suse.cz \
--cc=akpm@linux-foundation.org \
--cc=aryabinin@virtuozzo.com \
--cc=baiyaowei@cmss.chinamobile.com \
--cc=jeyu@redhat.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
--cc=peterz@infradead.org \
--cc=pmladek@suse.com \
--cc=prarit@redhat.com \
--cc=shorne@gmail.com \
--cc=tglx@linutronix.de \
--cc=tj@kernel.org \
--cc=yang.shi@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).