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: Thu, 7 Feb 2019 18:00:53 +0100 [thread overview]
Message-ID: <473c03b3-c5c3-7412-e2ad-3dedb413d165@redhat.com> (raw)
In-Reply-To: <20190207140819.GF2414@zn.tnic>
On 2/7/19 3:08 PM, Borislav Petkov wrote:
> On Thu, Feb 07, 2019 at 02:21:09PM +0100, Daniel Bristot de Oliveira wrote:
>> diff --git a/kernel/jump_label.c b/kernel/jump_label.c
>> index 288d630da22d..1e6f4d27e28d 100644
>> --- a/kernel/jump_label.c
>> +++ b/kernel/jump_label.c
>> @@ -374,22 +374,29 @@ static enum jump_label_type jump_label_type(struct jump_entry *entry)
>> return enabled ^ branch;
>> }
>>
>> +static bool jump_label_can_update(struct jump_entry *entry, bool init)
>> +{
>> + /*
>> + * Cannot update code that was in an init text area.
>> + */
>> + if (!init || jump_entry_is_init(entry))
>
> Shouldn't this be &&
>
> ?
Oops! should be &&! sorry.
>> + return false;
>> +
>> + if (WARN_ONCE(!kernel_text_address(jump_entry_code(entry)),
>> + "can't patch jump_label at %pS", (void *)jump_entry_code(entry)))
>> + return false;
>
> Yeah, I think that this way of writing it is less readable than:
>
> if (!kernel_text_address(jump_entry_code(entry))) {
> WARN_ONCE(1, "can't patch jump_label at %pS", (void *)jump_entry_code(entry));
> return false;
> }
It is taking 95 characters. In this case, wouldn't be better to break?
if (!kernel_text_address(jump_entry_code(entry))) {
WARN_ONCE(1, "can't patch jump_label at %pS",
(void *)jump_entry_code(entry));
return false;
}
I agree your suggestion is better... just confirming that 95 is not too long...
>
>> + if (jump_label_can_update(entry, init)) {
>> + arch_jump_label_transform(entry, jump_label_type(entry));
>
> Yap.
>
> Thx.
>
Thanks!
-- Daniel
next prev parent reply other threads:[~2019-02-07 17:01 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
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 [this message]
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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