It takes more that 2 minutes to verify SHA in purgatory when vmlinuz image is around 13MB and initramfs is around 30MB. It takes more than 20 second even when we have -O2 optimization enabled. However, if dcache is enabled during purgatory execution then, it takes just a second in SHA verification. Therefore, these patches adds support for dcache enabling facility during purgatory execution. Although I have simplified the logic a bit now, however I understand that there are reservations for introducing this complexity for gaining few seconding of execution time during kexec or crash reboot. But, I believe if d-cache enabling code is stable enough then there should not be any hindrances to accept it. So, please give it a try with your platform and let me know if you see any issue or it does not work. I am still open to improve it further if needed. Changes since V1: - Moved page table creation logic from purgatory to kexec code. - Only 4K page table is supported, with 48 bit VA and 2M block size - if platform supports a 4K page size, then D-cache is always enabled now. Pratyush Anand (2): kexec: arm64: create identity page table to be used in purgatory arm64: enable d-cache support during purgatory sha verification kexec/arch/arm64/kexec-arm64.c | 152 ++++++++++++++++++ purgatory/arch/arm64/Makefile | 1 + purgatory/arch/arm64/cache.S | 281 +++++++++++++++++++++++++++++++++ purgatory/arch/arm64/purgatory-arm64.c | 5 + 4 files changed, 439 insertions(+) create mode 100644 purgatory/arch/arm64/cache.S -- 2.7.4
