kexec-tools: arm64: Enable D-cache in purgatory

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.

Changes since V2:
- typo in name create_block_entry() fixed
- moved shared definition between kexec and purgatory to a common file.
- MT_NORMAL as 0
- PTRS_PER_* and other calculation around pmd_index() etc have been defined like in kernel
- page table size has been kept for 5 tables, with comment about expansion
- Pass only virt address to create_block_entry() now
- Addresses in kexec and purgatory domain have been defined as host_addr_t and guest_addr_t respectively for clear code reading

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         | 119 +++++++++++++++
 kexec/arch/arm64/kexec-mmu.h           |  76 ++++++++++
 purgatory/arch/arm64/Makefile          |   1 +
 purgatory/arch/arm64/cache.S           | 264 +++++++++++++++++++++++++++++++++
 purgatory/arch/arm64/purgatory-arm64.c |   5 +
 5 files changed, 465 insertions(+)
 create mode 100644 kexec/arch/arm64/kexec-mmu.h
 create mode 100644 purgatory/arch/arm64/cache.S

2.9.3