Hi Palmer, On Thu, Jan 20, 2022 at 11:05 AM Alexandre Ghiti <alexandre.ghiti@xxxxxxxxxxxxx> wrote: > > On Thu, Jan 20, 2022 at 8:30 AM Alexandre Ghiti > <alexandre.ghiti@xxxxxxxxxxxxx> wrote: > > > > On Thu, Jan 20, 2022 at 5:18 AM Palmer Dabbelt <palmer@xxxxxxxxxxx> wrote: > > > > > > On Mon, 06 Dec 2021 02:46:44 PST (-0800), alexandre.ghiti@xxxxxxxxxxxxx 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(-) > > > > > > Sorry this took a while. This is on for-next, with a bit of juggling: a > > > handful of trivial fixes for configs that were failing to build/boot and > > > some merge issues. I also pulled out that MAXPHYSMEM fix to the top, so > > > it'd be easier to backport. This is bigger than something I'd normally like to > > > take late in the cycle, but given there's a lot of cleanups, likely some fixes, > > > and it looks like folks have been testing this I'm just going to go with it. > > > > > > > Yes yes yes! That's fantastic news :) > > > > > Let me know if there's any issues with the merge, it was a bit hairy. > > > Probably best to just send along a fixup patch at this point. > > > > I'm going to take a look at that now, and I'll fix anything that comes > > up quickly :) > > I see in for-next that you did not take the following patches: > > 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 > > I'm not sure this was your intention. If it was, I believe that at > least the first 2 patches are needed in this series, the 3rd one is a > useful fix and we can discuss the 4th if that's an issue for you. Can you confirm that this was intentional and maybe explain the motivation behind it? Because I see value in those patches. Thanks, Alex > > I tested for-next on both sv39 and sv48 successfully, I took a glance > at the code and noticed you fixed the PTRS_PER_PGD error, thanks for > that. Otherwise nothing obvious has popped. > > Thanks again, > > Alex > > > > > Thanks! > > > > Alex > > > > > > > > Thanks!
