[RFC V2 00/10] arm64/mm: Enable FEAT_LPA2 (52 bits PA support on 4K|16K pages)

From: Anshuman Khandual
Date: Mon Jul 26 2021 - 02:36:50 EST


This series enables 52 bits PA support for 4K and 16K page configs via
existing CONFIG_ARM64_PA_BITS_52, utilizing a new arch feature FEAT_LPA2
which is available from ARM v8.7. IDMAP needs changes to accommodate two
new level of page tables in certain scenarios like (4K|39VA|52PA) but the
same problem also exists for (16K|36VA|48PA) which needs fixing. I have
sent a fix for 16K case [1] and later will enable it for FEAT_LPA2 as well.

This series applies on v5.14-rc3.

Testing:

Build and boot tested (individual patches) on all existing and new
FEAT_LPA2 enabled config combinations.

Pending:

- Enable IDMAP for FEAT_LPA2
- Enable 52 bit VA range on 4K/16K page sizes
- Evaluate KVM and SMMU impacts from FEAT_LPA2

[1] https://lore.kernel.org/lkml/1627019894-14819-1-git-send-email-anshuman.khandual@xxxxxxx/

Changes in RFC V2:

- Changed FEAT_LPA2 presence qualifying criteria wrt ID_AA64MMFR0_TGRAN_LPA2
- Changed FEAT_LPA2 specific encoding which drops the additional tmp variable
- Fixed [phys|pte]_to_[pte|phys]() helpers when FEAT_LPA2 is implemented

Changes in RFC V1:

https://lore.kernel.org/lkml/1626229291-6569-1-git-send-email-anshuman.khandual@xxxxxxx/

Anshuman Khandual (10):
mm/mmap: Dynamically initialize protection_map[]
arm64/mm: Consolidate TCR_EL1 fields
arm64/mm: Add FEAT_LPA2 specific TCR_EL1.DS field
arm64/mm: Add FEAT_LPA2 specific ID_AA64MMFR0.TGRAN[2]
arm64/mm: Add CONFIG_ARM64_PA_BITS_52_[LPA|LPA2]
arm64/mm: Add FEAT_LPA2 specific encoding
arm64/mm: Detect and enable FEAT_LPA2
arm64/mm: Add FEAT_LPA2 specific PTE_SHARED and PMD_SECT_S
arm64/mm: Add FEAT_LPA2 specific fallback (48 bits PA) when not implemented
arm64/mm: Enable CONFIG_ARM64_PA_BITS_52 on CONFIG_ARM64_[4K|16K]_PAGES

arch/arm64/Kconfig | 9 ++++++-
arch/arm64/include/asm/assembler.h | 42 ++++++++++++++++++++++++++-------
arch/arm64/include/asm/kernel-pgtable.h | 4 ++--
arch/arm64/include/asm/memory.h | 1 +
arch/arm64/include/asm/pgtable-hwdef.h | 28 ++++++++++++++++++----
arch/arm64/include/asm/pgtable.h | 18 +++++++++++---
arch/arm64/include/asm/sysreg.h | 9 +++----
arch/arm64/kernel/head.S | 30 +++++++++++++++++++++++
arch/arm64/mm/mmu.c | 3 +++
arch/arm64/mm/pgd.c | 2 +-
arch/arm64/mm/proc.S | 11 ++++++++-
arch/arm64/mm/ptdump.c | 26 ++++++++++++++++++--
mm/mmap.c | 26 ++++++++++++++++----
13 files changed, 177 insertions(+), 32 deletions(-)

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2.7.4