Re: [PATCH v2 00/10] Introduce sv48 support without relocatable kernel

Alexandre ghiti
2021-12-06T10:50:08Z

On 11/25/21 00:29, Heiko Stübner wrote:
> Am Mittwoch, 29. September 2021, 16:51:03 CET schrieb Alexandre Ghiti:
>> 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.
>>
>> Tested on:
>> - qemu rv64 sv39: OK
>> - qemu rv64 sv48: OK
>> - qemu rv64 sv39 + kasan: OK
>> - qemu rv64 sv48 + kasan: OK
>> - qemu rv32: OK
>> - Unmatched: OK
> On a beagleV (which supports only sv39) I've tested both the limit via
> the mmu-type in the devicetree and also that the fallback works when
> I disable the mmu-type in the dt, so
>
> Tested-by: Heiko Stuebner <heiko@sntech.de>
>

Thanks Heiko for testing this, unfortunately I could not add this tag to
the latest version as significant changes came up.

Thanks again for taking the time to test this,

Alex

>>
>>
>> Changes in v2:
>> - Rebase onto for-next
>> - Fix KASAN
>> - Fix stack canary
>> - Get completely rid of MAXPHYSMEM configs
>> - Add documentation
>>
>> Alexandre Ghiti (10):
>> 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
>>
>> Documentation/riscv/vm-layout.rst | 36 ++
>> arch/riscv/Kconfig | 35 +-
>> 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 | 2 +-
>> arch/riscv/include/asm/page.h | 10 +
>> arch/riscv/include/asm/pgalloc.h | 40 +++
>> arch/riscv/include/asm/pgtable-64.h | 108 +++++-
>> arch/riscv/include/asm/pgtable.h | 30 +-
>> 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 | 323 +++++++++++++++---
>> arch/riscv/mm/kasan_init.c | 91 +++--
>> drivers/firmware/efi/libstub/efi-stub.c | 2 +
>> include/asm-generic/pgalloc.h | 24 +-
>> include/linux/sizes.h | 1 +
>> 21 files changed, 615 insertions(+), 131 deletions(-)
>>
>>
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