Some CPU features are dependent on other CPU features. For example,
ID_AA64PFR0_EL1.FP field and ID_AA64PFR0_EL1.AdvSIMD must have the same
value, which means FP and ADVSIMD are dependent on each other, FPHP and
ADVSIMDHP are dependent on each other.
This commit introduces a mechanism for CPU feature dependency in
AArch64. We build a directed graph from the CPU feature dependency
relationship, each edge from->to means the `to` CPU feature is dependent
on the `from` CPU feature. And we will automatically enable/disable CPU
feature according to the directed graph.
For example, a, b, and c CPU features are in relationship a->b->c, which
means c is dependent on b and b is dependent on a. If c is enabled by
user, then a and b is enabled automatically. And if a is disabled by
user, then b and c is disabled automatically.
Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
(cherry-picked from commit 9a16d2b2389664aa50e63c33af0ea94afb45185b)
