Messages in this thread | | | Date | Thu, 17 Aug 2023 21:27:01 +0800 | Subject | Re: [PATCH v6 0/5] riscv: Introduce KASLR | From | Song Shuai <> |
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在 2023/8/17 21:10, Alexandre Ghiti 写道: > Hi Song, > > On Tue, Aug 15, 2023 at 1:24 PM Song Shuai <songshuaishuai@tinylab.org> wrote: >> >> >> Hi, Alex: >> >> 在 2023/7/22 20:38, Alexandre Ghiti 写道: >>> The following KASLR implementation allows to randomize the kernel mapping: >>> >>> - virtually: we expect the bootloader to provide a seed in the device-tree >>> - physically: only implemented in the EFI stub, it relies on the firmware to >>> provide a seed using EFI_RNG_PROTOCOL. arm64 has a similar implementation >>> hence the patch 3 factorizes KASLR related functions for riscv to take >>> advantage. >>> >>> The new virtual kernel location is limited by the early page table that only >>> has one PUD and with the PMD alignment constraint, the kernel can only take >>> < 512 positions. >>> >> >> I have gone through the code and tested this series with RiscVVirt edk2. >> All seems good to me, you can add : >> >> Tested-by: Song Shuai <songshuaishuai@tinylab.org> >> >> And a few questions about patch 2 ("riscv: Dump out kernel offset >> information on panic"): >> >> 1. The dump_kernel_offset() function would output "Kernel Offset: 0x0 >> from 0xffffffff80000000" when booting with "nokaslr" option. >> >> How about disabling the registration of "kernel_offset_notifier" with >> "nokaslr" option? > > I'd rather keep it as it shows the "nokaslr" flag was taken into account. > >> >> 2. Inspired by patch 2, I added the Crash KASLR support based on this >> series [1]. >> So is it necessary to keep this patch if we have Crash KASLR support? > > I don't understand your question here
Crash can automatically calculate virt_offset by comparing the vmlinux and vmcore. If this patch is just intended to assist Crash in setting the "--kaslr offset," it might be deleted; if not just keep it.
> >> >> >> [1]: >> https://lore.kernel.org/linux-riscv/20230815104800.705753-1-songshuaishuai@tinylab.org/T/#u >> >>> base-commit-tag: v6.5-rc1 >>> >>> Changes in v6: >>> * Fix reintroduced build failures by compiling kaslr.c only for arm64 >>> and riscv, as suggested by Ard >>> >>> Changes in v5: >>> * Renamed efi-stub-kaslr.c into kaslr.c and fix commit log of patch 3, >>> as suggested by Ard >>> * Removed stubs since the kaslr functions were moved to their own file >>> (and then does not trigger any build failure for architectures that do >>> not call those functions since they are in their own compilation unit) >>> >>> Changes in v4: >>> * Fix efi_get_kimg macro that returned nothing >>> * Moved new kaslr functions into their own files to avoid zboot link >>> failures, as suggested by Ard >>> >>> Changes in v3: >>> * Rebase on top of 6.4-rc2 >>> * Make RANDOMIZE_BASE depend on 64bit >>> * Fix efi_icache_sync and efi_get_kimg_min_align which were undefined >>> in x86 (and certainly other archs) >>> * Add patch 4 to fix warning on rv32 >>> >>> Changes in v2: >>> * Rebase on top of 6.3-rc1 >>> * Add a riscv cache sync after memcpying the kernel >>> * Add kaslr_offset implementation for KCOV >>> * Add forward declaration to quiet LLVM >>> >>> Alexandre Ghiti (5): >>> riscv: Introduce virtual kernel mapping KASLR >>> riscv: Dump out kernel offset information on panic >>> arm64: libstub: Move KASLR handling functions to kaslr.c >>> libstub: Fix compilation warning for rv32 >>> riscv: libstub: Implement KASLR by using generic functions >>> >>> arch/arm64/include/asm/efi.h | 2 + >>> arch/riscv/Kconfig | 19 +++ >>> arch/riscv/include/asm/efi.h | 2 + >>> arch/riscv/include/asm/page.h | 3 + >>> arch/riscv/kernel/image-vars.h | 1 + >>> arch/riscv/kernel/pi/Makefile | 2 +- >>> arch/riscv/kernel/pi/cmdline_early.c | 13 ++ >>> arch/riscv/kernel/pi/fdt_early.c | 30 ++++ >>> arch/riscv/kernel/setup.c | 25 ++++ >>> arch/riscv/mm/init.c | 36 ++++- >>> drivers/firmware/efi/libstub/Makefile | 4 +- >>> drivers/firmware/efi/libstub/arm64-stub.c | 117 ++-------------- >>> drivers/firmware/efi/libstub/efistub.h | 8 ++ >>> drivers/firmware/efi/libstub/kaslr.c | 159 ++++++++++++++++++++++ >>> drivers/firmware/efi/libstub/riscv-stub.c | 33 ++--- >>> 15 files changed, 328 insertions(+), 126 deletions(-) >>> create mode 100644 arch/riscv/kernel/pi/fdt_early.c >>> create mode 100644 drivers/firmware/efi/libstub/kaslr.c >>> >> >> -- >> Thanks >> Song Shuai > > Thanks for testing this and your suggestions! > > Alex >
-- Thanks Song Shuai
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