On Thu, Aug 13, 2020 at 06:26:53PM +0800, Peng Liang wrote: > 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.
And what if a is mutually exclusive with b? I.e. a and b can both be disabled, but only a or b may be enabled. Thanks, drew
