Even though some of the patches in this series made an appearance in my WXN series as well, this set amounts to a v3 of $SUBJECT, with only the pieces that remain now that the groundwork has been merged into v6.0-rc1. The v2 can be found here: https://lore.kernel.org/all/20220330154205.2483167-1-ardb@xxxxxxxxxx/ The purpose of this series is to remove any explicit cache maintenance for coherency during early boot that becomes unnecessary if we simply retain the cacheable 1:1 mapping of all of system RAM provided by EFI, and use it to populate the ID map page tables. After setting up this preliminary ID map, we disable the MMU, drop to EL1, reprogram the MAIR, TCR and SCTLR registers as before, and proceed as usual, avoiding the need for any manipulations of memory while the MMU and caches are off. The only property of the firmware provided 1:1 map we rely on is that it does not require any explicit cache maintenance for coherency - all else is under control of the kernel itself, as before. Ard Biesheuvel (7): arm64: lds: reduce effective minimum image alignment to 64k arm64: kernel: move ID map out of .text mapping arm64: head: record the MMU state at primary entry arm64: head: avoid cache invalidation when entering with the MMU on arm64: head: clean the ID map page to the PoC arm64: efi/libstub: use EFI_LOADER_CODE region when moving the kernel in memory arm64: efi/libstub: enter with the MMU on arch/arm64/include/asm/efi.h | 7 -- arch/arm64/kernel/Makefile | 9 +-- arch/arm64/kernel/efi-entry.S | 69 -------------------- arch/arm64/kernel/head.S | 46 +++++++++++-- arch/arm64/kernel/image-vars.h | 6 +- arch/arm64/kernel/vmlinux.lds.S | 13 +++- arch/arm64/mm/cache.S | 5 +- arch/arm64/mm/proc.S | 2 - drivers/firmware/efi/libstub/alignedmem.c | 5 +- drivers/firmware/efi/libstub/arm64-stub.c | 26 ++++++-- drivers/firmware/efi/libstub/efistub.h | 6 +- drivers/firmware/efi/libstub/mem.c | 3 +- drivers/firmware/efi/libstub/randomalloc.c | 5 +- include/linux/efi.h | 6 +- 14 files changed, 95 insertions(+), 113 deletions(-) delete mode 100644 arch/arm64/kernel/efi-entry.S -- 2.35.1
