Commit 2706bcc0 authored by Kees Cook's avatar Kees Cook Committed by Zheng Zengkai
Browse files

jump_label: Provide CONFIG-driven build state defaults

mainline inclusion
from mainline-v5.13-rc1
commit 0d66ccc1
category: feature
bugzilla: 187198, https://gitee.com/openeuler/kernel/issues/I5GVFO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0d66ccc1627013c95f1e7ef10b95b8451cd7834e



--------------------------------

As shown in the comment in jump_label.h, choosing the initial state of
static branches changes the assembly layout. If the condition is expected
to be likely it's inline, and if unlikely it is out of line via a jump.

A few places in the kernel use (or could be using) a CONFIG to choose the
default state, which would give a small performance benefit to their
compile-time declared default. Provide the infrastructure to do this.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210401232347.2791257-2-keescook@chromium.org


Signed-off-by: default avatarLiu Shixin <liushixin2@huawei.com>
Reviewed-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 156e60a4
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