Re: [PATCH v3 00/13] Introduce sv48 support without relocatable kernel

[Alexandre ghiti <alex@ghiti.fr>]

And I messed Atish address, I was pretty sure I could recall it without 
checking, I guess I'm wrong :)

Sorry for the noise,

Alex

On 12/6/21 11:46, Alexandre Ghiti wrote:
> * Please note notable changes in memory layouts and kasan population *
>
> This patchset allows to have a single kernel for sv39 and sv48 without
> being relocatable.
>
> The idea comes from Arnd Bergmann who suggested to do the same as x86,
> that is mapping the kernel to the end of the address space, which allows
> the kernel to be linked at the same address for both sv39 and sv48 and
> then does not require to be relocated at runtime.
>
> This implements sv48 support at runtime. The kernel will try to
> boot with 4-level page table and will fallback to 3-level if the HW does not
> support it. Folding the 4th level into a 3-level page table has almost no
> cost at runtime.
>
> Note that kasan region had to be moved to the end of the address space
> since its location must be known at compile-time and then be valid for
> both sv39 and sv48 (and sv57 that is coming).
>
> Tested on:
>    - qemu rv64 sv39: OK
>    - qemu rv64 sv48: OK
>    - qemu rv64 sv39 + kasan: OK
>    - qemu rv64 sv48 + kasan: OK
>    - qemu rv32: OK
>
> Changes in v3:
>    - Fix SZ_1T, thanks to Atish
>    - Fix warning create_pud_mapping, thanks to Atish
>    - Fix k210 nommu build, thanks to Atish
>    - Fix wrong rebase as noted by Samuel
>    - * Downgrade to sv39 is only possible if !KASAN (see commit changelog) *
>    - * Move KASAN next to the kernel: virtual layouts changed and kasan population *
>
> Changes in v2:
>    - Rebase onto for-next
>    - Fix KASAN
>    - Fix stack canary
>    - Get completely rid of MAXPHYSMEM configs
>    - Add documentation
>
> Alexandre Ghiti (13):
>    riscv: Move KASAN mapping next to the kernel mapping
>    riscv: Split early kasan mapping to prepare sv48 introduction
>    riscv: Introduce functions to switch pt_ops
>    riscv: Allow to dynamically define VA_BITS
>    riscv: Get rid of MAXPHYSMEM configs
>    asm-generic: Prepare for riscv use of pud_alloc_one and pud_free
>    riscv: Implement sv48 support
>    riscv: Use pgtable_l4_enabled to output mmu_type in cpuinfo
>    riscv: Explicit comment about user virtual address space size
>    riscv: Improve virtual kernel memory layout dump
>    Documentation: riscv: Add sv48 description to VM layout
>    riscv: Initialize thread pointer before calling C functions
>    riscv: Allow user to downgrade to sv39 when hw supports sv48 if !KASAN
>
>   Documentation/riscv/vm-layout.rst             |  48 ++-
>   arch/riscv/Kconfig                            |  37 +-
>   arch/riscv/configs/nommu_k210_defconfig       |   1 -
>   .../riscv/configs/nommu_k210_sdcard_defconfig |   1 -
>   arch/riscv/configs/nommu_virt_defconfig       |   1 -
>   arch/riscv/include/asm/csr.h                  |   3 +-
>   arch/riscv/include/asm/fixmap.h               |   1
>   arch/riscv/include/asm/kasan.h                |  11 +-
>   arch/riscv/include/asm/page.h                 |  20 +-
>   arch/riscv/include/asm/pgalloc.h              |  40 ++
>   arch/riscv/include/asm/pgtable-64.h           | 108 ++++-
>   arch/riscv/include/asm/pgtable.h              |  47 +-
>   arch/riscv/include/asm/sparsemem.h            |   6 +-
>   arch/riscv/kernel/cpu.c                       |  23 +-
>   arch/riscv/kernel/head.S                      |   4 +-
>   arch/riscv/mm/context.c                       |   4 +-
>   arch/riscv/mm/init.c                          | 408 ++++++++++++++----
>   arch/riscv/mm/kasan_init.c                    | 250 ++++++++---
>   drivers/firmware/efi/libstub/efi-stub.c       |   2
>   drivers/pci/controller/pci-xgene.c            |   2 +-
>   include/asm-generic/pgalloc.h                 |  24 +-
>   include/linux/sizes.h                         |   1
>   22 files changed, 833 insertions(+), 209 deletions(-)
>
> --
> 2.32.0
>
>
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