From: Daniel Bristot de Oliveira <bristot@redhat.com>
To: Borislav Petkov <bp@alien8.de>
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
"Steven Rostedt (VMware)" <rostedt@goodmis.org>,
Jiri Kosina <jkosina@suse.cz>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Chris von Recklinghausen <crecklin@redhat.com>,
Jason Baron <jbaron@akamai.com>, Scott Wood <swood@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Clark Williams <williams@redhat.com>,
x86@kernel.org
Subject: Re: [PATCH V4 2/9] jump_label: Add the jump_label_can_update_check() helper
Date: Tue, 5 Feb 2019 14:50:39 +0100 [thread overview]
Message-ID: <cb65e500-44dd-873c-622f-b49b9336b6a2@redhat.com> (raw)
In-Reply-To: <20190205072220.GD21801@zn.tnic>
Hi Borislav!
On 2/5/19 8:22 AM, Borislav Petkov wrote:
>> Subject: Re: [PATCH V4 2/9] jump_label: Add the jump_label_can_update_check() helper
>
> s/the/a/
ack!
> On Mon, Feb 04, 2019 at 08:58:55PM +0100, Daniel Bristot de Oliveira wrote:
>> Move the check of if a jump_entry is valid to a function.
>
> s/of //
ack!
>> diff --git a/kernel/jump_label.c b/kernel/jump_label.c
>> index 288d630da22d..456c0d7cbb5b 100644
>> --- a/kernel/jump_label.c
>> +++ b/kernel/jump_label.c
>> @@ -374,22 +374,32 @@ static enum jump_label_type jump_label_type(struct jump_entry *entry)
>> return enabled ^ branch;
>> }
>>
>> +bool jump_label_can_update_check(struct jump_entry *entry, bool init)
>
> static.
>
> Also, "jump_label_can_update" is sufficient for a name AFAICT.
sounds better indeed.
>> +{
>> + /*
>> + * An entry->code of 0 indicates an entry which has been
>> + * disabled because it was in an init text area.
>> + */
>> + if (init || !jump_entry_is_init(entry)) {
>> + if (!kernel_text_address(jump_entry_code(entry))) {
>> + WARN_ONCE(1, "can't patch jump_label at %pS",
>> + (void *)jump_entry_code(entry));
>> + return 0;
>> + }
>> + return 1;
>> + }
>> + return 0;
>
> Those should be bools which it returns, no?
>
> Also, I'd do the function this way, to make it more readable and not
> have three returns back-to-back. :)
>
> /*
> * An entry->code of 0 indicates an entry which has been disabled because it
> * was in an init text area.
> */
> bool jump_label_can_update(struct jump_entry *entry, bool init)
> {
> if (!init && jump_entry_is_init(entry))
> return false;
>
> if (WARN_ON_ONCE(!kernel_text_address(jump_entry_code(entry))),
> "can't patch jump_label at %pS", (void *)jump_entry_code(entry))
> return false;
>
> return true;
> }
>
> That second check could be even:
>
> if (WARN_ON_ONCE(!kernel_text_address(jump_entry_code(entry))),
> "can't patch jump_label at %pS", (void *)jump_entry_code(entry))
> return false;
>
> but that's not more readable than above, I'd say.
Agreed!
>
>> static void __jump_label_update(struct static_key *key,
>> struct jump_entry *entry,
>> struct jump_entry *stop,
>> bool init)
>> {
>> for_each_label_entry(key, entry, stop) {
>> - /*
>> - * An entry->code of 0 indicates an entry which has been
>> - * disabled because it was in an init text area.
>> - */
>> - if (init || !jump_entry_is_init(entry)) {
>> - if (kernel_text_address(jump_entry_code(entry)))
>> - arch_jump_label_transform(entry, jump_label_type(entry));
>> - else
>> - WARN_ONCE(1, "can't patch jump_label at %pS",
>> - (void *)jump_entry_code(entry));
>> + if (jump_label_can_update_check(entry, init)) {
>> + arch_jump_label_transform(entry,
>> + jump_label_type(entry));
>
> Yeah, let that one stick out.
I did not get this part...
Thanks!
-- Daniel
next prev parent reply other threads:[~2019-02-05 13:51 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-04 19:58 [PATCH V4 0/9] x86/jump_label: Bound IPIs sent when updating a static key Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 1/9] jump_label: Add for_each_label_entry helper Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 2/9] jump_label: Add the jump_label_can_update_check() helper Daniel Bristot de Oliveira
2019-02-05 7:22 ` Borislav Petkov
2019-02-05 13:50 ` Daniel Bristot de Oliveira [this message]
2019-02-05 21:13 ` Borislav Petkov
2019-02-07 13:21 ` Daniel Bristot de Oliveira
2019-02-07 14:08 ` Borislav Petkov
2019-02-07 17:00 ` Daniel Bristot de Oliveira
2019-02-07 17:08 ` Borislav Petkov
2019-02-04 19:58 ` [PATCH V4 3/9] x86/jump_label: Move checking code away from __jump_label_transform() Daniel Bristot de Oliveira
2019-02-05 7:33 ` Borislav Petkov
2019-02-05 15:22 ` Daniel Bristot de Oliveira
2019-02-15 10:05 ` Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 4/9] x86/jump_label: Add __jump_label_set_jump_code() helper Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 5/9] x86/alternative: Split text_poke_bp() into tree steps Daniel Bristot de Oliveira
2019-02-06 19:07 ` Borislav Petkov
2019-02-08 0:11 ` Steven Rostedt
2019-02-08 0:15 ` Steven Rostedt
2019-02-15 12:47 ` Daniel Bristot de Oliveira
2019-02-21 15:26 ` Steven Rostedt
2019-02-04 19:58 ` [PATCH V4 6/9] jump_label: Sort entries of the same key by the code Daniel Bristot de Oliveira
2019-02-04 19:59 ` [PATCH V4 7/9] x86/alternative: Batch of patch operations Daniel Bristot de Oliveira
2019-02-14 12:53 ` Borislav Petkov
2019-02-14 14:06 ` Steven Rostedt
2019-02-14 14:30 ` Borislav Petkov
2019-02-14 14:40 ` Steven Rostedt
2019-02-14 14:54 ` Borislav Petkov
2019-02-15 16:00 ` Daniel Bristot de Oliveira
2019-02-15 17:20 ` Steven Rostedt
2019-02-04 19:59 ` [PATCH V4 8/9] jump_label: Batch updates if arch supports it Daniel Bristot de Oliveira
2019-02-06 6:34 ` Masami Hiramatsu
2019-02-06 15:59 ` Daniel Bristot de Oliveira
2019-02-14 13:33 ` Borislav Petkov
2019-02-04 19:59 ` [PATCH V4 9/9] x86/jump_label: Batch jump label updates Daniel Bristot de Oliveira
2019-02-06 6:29 ` Masami Hiramatsu
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