Messages in this thread | | | Date | Fri, 24 Mar 2023 10:59:57 +0100 | Subject | Re: [PATCH v8 0/4] riscv: Use PUD/P4D/PGD pages for the linear mapping | From | Alexandre Ghiti <> |
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On 3/23/23 15:55, Anup Patel wrote: > On Thu, Mar 23, 2023 at 6:24 PM Alexandre Ghiti <alexghiti@rivosinc.com> wrote: >> Hi Anup, >> >> On Thu, Mar 23, 2023 at 1:18 PM Anup Patel <apatel@ventanamicro.com> wrote: >>> Hi Alex, >>> >>> On Thu, Mar 16, 2023 at 6:48 PM Alexandre Ghiti <alexghiti@rivosinc.com> wrote: >>>> This patchset intends to improve tlb utilization by using hugepages for >>>> the linear mapping. >>>> >>>> As reported by Anup in v6, when STRICT_KERNEL_RWX is enabled, we must >>>> take care of isolating the kernel text and rodata so that they are not >>>> mapped with a PUD mapping which would then assign wrong permissions to >>>> the whole region: it is achieved by introducing a new memblock API. >>>> >>>> Another patch makes use of this new API in arm64 which used some sort of >>>> hack to solve this issue: it was built/boot tested successfully. >>>> >>>> base-commit-tag: v6.3-rc1 >>>> >>>> v8: >>>> - Fix rv32, as reported by Anup >>>> - Do not modify memblock_isolate_range and fixes comment, as suggested by Mike >>>> - Use the new memblock API for crash kernel too in arm64, as suggested by Andrew >>>> - Fix arm64 double mapping (which to me did not work in v7), but ends up not >>>> being pretty at all, will wait for comments from arm64 reviewers, but >>>> this patch can easily be dropped if they do not want it. >>>> >>>> v7: >>>> - Fix Anup bug report by introducing memblock_isolate_memory which >>>> allows us to split the memblock mappings and then avoid to map the >>>> the PUD which contains the kernel as read only >>>> - Add a patch to arm64 to use this newly introduced API >>>> >>>> v6: >>>> - quiet LLVM warning by casting phys_ram_base into an unsigned long >>>> >>>> v5: >>>> - Fix nommu builds by getting rid of riscv_pfn_base in patch 1, thanks >>>> Conor >>>> - Add RB from Andrew >>>> >>>> v4: >>>> - Rebase on top of v6.2-rc3, as noted by Conor >>>> - Add Acked-by Rob >>>> >>>> v3: >>>> - Change the comment about initrd_start VA conversion so that it fits >>>> ARM64 and RISCV64 (and others in the future if needed), as suggested >>>> by Rob >>>> >>>> v2: >>>> - Add a comment on why RISCV64 does not need to set initrd_start/end that >>>> early in the boot process, as asked by Rob >>>> >>>> Alexandre Ghiti (4): >>>> riscv: Get rid of riscv_pfn_base variable >>>> mm: Introduce memblock_isolate_memory >>>> arm64: Make use of memblock_isolate_memory for the linear mapping >>>> riscv: Use PUD/P4D/PGD pages for the linear mapping >>> Kernel boot fine on RV64 but there is a failure which is still not >>> addressed. You can see this failure as following message in >>> kernel boot log: >>> 0.000000] Failed to add a System RAM resource at 80200000 >> Hmmm I don't get that in any of my test configs, would you mind >> sharing yours and your qemu command line? > Try alexghiti_test branch at > https://github.com/avpatel/linux.git > > I am building the kernel using defconfig and my rootfs is > based on busybox. > > My QEMU command is: > qemu-system-riscv64 -M virt -m 512M -nographic -bios > opensbi/build/platform/generic/firmware/fw_dynamic.bin -kernel > ./build-riscv64/arch/riscv/boot/Image -append "root=/dev/ram rw > console=ttyS0 earlycon" -initrd ./rootfs_riscv64.img -smp 4
So splitting memblock.memory is the culprit, it "confuses" the resources addition and I can only find hacky ways to fix that...
So given that the arm64 patch with the new API is not pretty and that the simplest solution is to re-merge the memblock regions afterwards (which is done by memblock_clear_nomap), I'll drop the new API and the arm64 patch to use the nomap API like arm64: I'll take advantage of that to clean setup_vm_final which I have wanted to do for a long time.
@Mike Thanks for you reviews!
@Anup Thanks for all your bug reports on this patchset, I have to improve my test flow (it is in the work :)).
> Regards, > Anup > >> Thanks >> >>> Regards, >>> Anup >>> >>>> arch/arm64/mm/mmu.c | 25 +++++++++++------ >>>> arch/riscv/include/asm/page.h | 19 +++++++++++-- >>>> arch/riscv/mm/init.c | 53 ++++++++++++++++++++++++++++------- >>>> arch/riscv/mm/physaddr.c | 16 +++++++++++ >>>> drivers/of/fdt.c | 11 ++++---- >>>> include/linux/memblock.h | 1 + >>>> mm/memblock.c | 20 +++++++++++++ >>>> 7 files changed, 119 insertions(+), 26 deletions(-) >>>> >>>> -- >>>> 2.37.2 >>>> > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv
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