Jeffrey Lee
authored
Detail: For a while we've known that the correct way of doing cache maintenance on ARMv6+ (e.g. when converting a page from cacheable to non-cacheable) is as follows: 1. Write new page table entry 2. Flush old entry from TLB 3. Clean cache + drain write buffer The MMU_Changing ARMops (e.g. MMU_ChangingEntry) implement the last two items, but in the wrong order. This has caused the operations to fall out of favour and cease to be used, even in pre-ARMv6 code paths where the effects of improper cache/TLB management perhaps weren't as readily visible. This change re-specifies the relevant ARMops so that they perform their sub-operations in the correct order to make them useful on modern ARMs, updates the implementations, and updates the kernel to make use of the ops whereever relevant. File changes: - Docs/HAL/ARMop_API - Re-specify all the MMU_Changing ARMops to state that they are for use just after a page table entry has been changed (as opposed to before - e.g. 5.00 kernel behaviour). Re-specify the cacheable ones to state that the TLB invalidatation comes first. - s/ARM600, s/ChangeDyn, s/HAL, s/MemInfo, s/VMSAv6, s/AMBControl/memmap - Replace MMU_ChangingUncached + Cache_CleanInvalidate pairs with equivalent MMU_Changing op - s/ARMops - Update ARMop implementations to do everything in the correct order - s/MemMap2 - Update ARMop usage, and get rid of some lingering sledgehammer logic from ShuffleDoublyMappedRegionForGrow Admin: Tested on pretty much everything currently supported Version 5.70. Tagged as 'Kernel-5_70'