[PATCH v2 00/19] arm64: Enable LPA2 support for 4k and 16k pages

[Ard Biesheuvel]

Enable support for LPA2 when running with 4k or 16k pages. In the former
case, this requires 5 level paging with a runtime fallback to 4 on
non-LPA2 hardware. For consistency, the same approach is adopted for 16k
pages, where we fall back to 3 level paging (47 bit virtual addressing)
on non-LPA2 configurations. (Falling back to 48 bits would involve
finding a workaround for the fact that we cannot construct a level 0
table covering 52 bits of VA space that appears aligned to its size in
memory, and has the top 2 entries that represent the 48-bit region
appearing at an alignment of 64 bytes, which is required by the
architecture for TTBR address values. Also, using an additional level of
paging to translate a single VA bit is wasteful in terms of TLB
efficiency)

This means support for falling back to 3 levels of paging at runtime
when configured for 4 is also needed.

Another thing worth to note is that the repurposed physical address bits
in the page table descriptors were not RES0 before, and so there is now
a big global switch (called TCR.DS) which controls how all page table
descriptors are interpreted. This requires some extra care in the PTE
conversion helpers, and additional handling in the boot code to ensure
that we set TCR.DS safely if supported (and not overridden)

Note that this series is mostly orthogonal to work by Anshuman done last
year: this series assumes that 52-bit physical addressing is never
needed to map the kernel image itself, and therefore that we never need
ID map range extension to cover the kernel with a 5th level when running
with 4. And given that the LPA2 architectural feature covers both the
virtual and physical range extensions, where enabling the latter is
required to enable the former, we can simplify things further by only
enabling them as a pair. (I.e., 52-bit physical addressing cannot be
enabled for 48-bit VA space or smaller)

This series applies onto some of my previous work that is still in
flight, so these patches will not apply in isolation. Complete branch
can be found here:
https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/log/?h=arm64-4k-lpa2

It supersedes the RFC v1 I sent out last week, which covered 16k pages
only. It also supersedes some related work I sent out in isolation
before:

[PATCH] arm64: mm: Enable KASAN for 16k/48-bit VA configurations
[PATCH 0/3] arm64: mm: Model LVA support as a CPU feature

Tested on QEMU with -cpu max and lpa2 both off and on, as well as using
the arm64.nolva override kernel command line parameter. Note that this
requires a QEMU built from the latest sources.

Cc: Marc Zyngier <maz at kernel.org>
Cc: Will Deacon <will at kernel.org>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Kees Cook <keescook at chromium.org>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Mark Brown <broonie at kernel.org>
Cc: Anshuman Khandual <anshuman.khandual at arm.com>
Cc: Richard Henderson <richard.henderson at linaro.org>
Cc: Ryan Roberts <ryan.roberts at arm.com>

Anshuman Khandual (3):
  arm64/mm: Simplify and document pte_to_phys() for 52 bit addresses
  arm64/mm: Add FEAT_LPA2 specific TCR_EL1.DS field
  arm64/mm: Add FEAT_LPA2 specific ID_AA64MMFR0.TGRAN[2]

Ard Biesheuvel (16):
  arm64: kaslr: Adjust randomization range dynamically
  arm64: mm: get rid of kimage_vaddr global variable
  arm64: head: remove order argument from early mapping routine
  arm64: mm: Handle LVA support as a CPU feature
  arm64: mm: Deal with potential ID map extension if VA_BITS >
    VA_BITS_MIN
  arm64: mm: Add feature override support for LVA
  arm64: mm: Wire up TCR.DS bit to PTE shareability fields
  arm64: mm: Add LPA2 support to phys<->pte conversion routines
  arm64: mm: Add definitions to support 5 levels of paging
  arm64: mm: add 5 level paging support to G-to-nG conversion routine
  arm64: Enable LPA2 at boot if supported by the system
  arm64: mm: Add 5 level paging support to fixmap and swapper handling
  arm64: kasan: Reduce minimum shadow alignment and enable 5 level
    paging
  arm64: mm: Add support for folding PUDs at runtime
  arm64: ptdump: Disregard unaddressable VA space
  arm64: Enable 52-bit virtual addressing for 4k and 16k granule configs

 arch/arm64/Kconfig                      |  23 ++-
 arch/arm64/include/asm/assembler.h      |  42 ++---
 arch/arm64/include/asm/cpufeature.h     |   2 +
 arch/arm64/include/asm/fixmap.h         |   1 +
 arch/arm64/include/asm/kernel-pgtable.h |  27 ++-
 arch/arm64/include/asm/memory.h         |  23 ++-
 arch/arm64/include/asm/pgalloc.h        |  53 +++++-
 arch/arm64/include/asm/pgtable-hwdef.h  |  34 +++-
 arch/arm64/include/asm/pgtable-prot.h   |  18 +-
 arch/arm64/include/asm/pgtable-types.h  |   6 +
 arch/arm64/include/asm/pgtable.h        | 197 ++++++++++++++++++--
 arch/arm64/include/asm/sysreg.h         |   2 +
 arch/arm64/include/asm/tlb.h            |   3 +-
 arch/arm64/kernel/cpufeature.c          |  46 ++++-
 arch/arm64/kernel/head.S                |  99 +++++-----
 arch/arm64/kernel/image-vars.h          |   4 +
 arch/arm64/kernel/pi/idreg-override.c   |  29 ++-
 arch/arm64/kernel/pi/kaslr_early.c      |  23 ++-
 arch/arm64/kernel/pi/map_kernel.c       | 115 +++++++++++-
 arch/arm64/kernel/sleep.S               |   3 -
 arch/arm64/mm/init.c                    |   2 +-
 arch/arm64/mm/kasan_init.c              | 124 ++++++++++--
 arch/arm64/mm/mmap.c                    |   4 +
 arch/arm64/mm/mmu.c                     | 138 ++++++++++----
 arch/arm64/mm/pgd.c                     |  17 +-
 arch/arm64/mm/proc.S                    |  76 +++++++-
 arch/arm64/mm/ptdump.c                  |   4 +-
 arch/arm64/tools/cpucaps                |   1 +
 28 files changed, 907 insertions(+), 209 deletions(-)

-- 
2.38.1.584.g0f3c55d4c2-goog