| Message ID | 20210405085712.1953848-1-mick@ics.forth.gr (mailing list archive) |
|---|---|
| Headers | show |
| Series | RISC-V: Add kexec/kdump support | expand |
Hi Nick On 4/5/21 8:57 AM, Nick Kossifidis wrote: > This patch series adds kexec/kdump and crash kernel > support on RISC-V. For testing the patches a patched > version of kexec-tools is needed (still a work in > progress) which can be found at: > > https://riscv.ics.forth.gr/kexec-tools-patched.tar.xz > > v3: > * Rebase on newer kernel tree > * Minor cleanups > * Split UAPI changes to a separate patch > * Improve / cleanup init_resources > * Resolve Palmer's comments > > v2: > * Rebase on newer kernel tree > * Minor cleanups > * Properly populate the ioresources tre, so that it > can be used later on for implementing strict /dev/mem > * Use linux,usable-memory on /memory instead of a new binding > * USe a reserved-memory node for ELF core header > > Nick Kossifidis (5): > RISC-V: Add EM_RISCV to kexec UAPI header > RISC-V: Add kexec support > RISC-V: Improve init_resources > RISC-V: Add kdump support > RISC-V: Add crash kernel support > > arch/riscv/Kconfig | 25 ++++ > arch/riscv/include/asm/elf.h | 6 + > arch/riscv/include/asm/kexec.h | 54 +++++++ > arch/riscv/kernel/Makefile | 6 + > arch/riscv/kernel/crash_dump.c | 46 ++++++ > arch/riscv/kernel/crash_save_regs.S | 56 +++++++ > arch/riscv/kernel/kexec_relocate.S | 222 ++++++++++++++++++++++++++++ > arch/riscv/kernel/machine_kexec.c | 193 ++++++++++++++++++++++++ > arch/riscv/kernel/setup.c | 113 ++++++++------ > arch/riscv/mm/init.c | 110 ++++++++++++++ > include/uapi/linux/kexec.h | 1 + > 11 files changed, 787 insertions(+), 45 deletions(-) > create mode 100644 arch/riscv/include/asm/kexec.h > create mode 100644 arch/riscv/kernel/crash_dump.c > create mode 100644 arch/riscv/kernel/crash_save_regs.S > create mode 100644 arch/riscv/kernel/kexec_relocate.S > create mode 100644 arch/riscv/kernel/machine_kexec.c > Just ask out of curiosity (maybe out of topic).. Is crash analysis [1] capable of parsing RISC-V kdump image? No? Or, any plan working on it? [1] https://github.com/crash-utility/crash Yxun Lan
On Mon, Apr 05, 2021 at 11:57:07AM +0300, Nick Kossifidis wrote: > This patch series adds kexec/kdump and crash kernel > support on RISC-V. For testing the patches a patched > version of kexec-tools is needed (still a work in > progress) which can be found at: > > https://riscv.ics.forth.gr/kexec-tools-patched.tar.xz > > v3: > * Rebase on newer kernel tree > * Minor cleanups > * Split UAPI changes to a separate patch > * Improve / cleanup init_resources > * Resolve Palmer's comments > > v2: > * Rebase on newer kernel tree > * Minor cleanups > * Properly populate the ioresources tre, so that it > can be used later on for implementing strict /dev/mem > * Use linux,usable-memory on /memory instead of a new binding Where? In any case, that's not going to work well with EFI support assuming like arm64, 'memory' is passed in UEFI structures instead of DT. That's why there's now a /chosen linux,usable-memory-ranges property. Isn't the preferred kexec interface the file based interface? I'd expect a new arch to only support that. And there's common kexec DT handling for that pending for 5.13. Rob
Στις 2021-04-07 19:29, Rob Herring έγραψε: > On Mon, Apr 05, 2021 at 11:57:07AM +0300, Nick Kossifidis wrote: >> This patch series adds kexec/kdump and crash kernel >> support on RISC-V. For testing the patches a patched >> version of kexec-tools is needed (still a work in >> progress) which can be found at: >> >> https://riscv.ics.forth.gr/kexec-tools-patched.tar.xz >> >> v3: >> * Rebase on newer kernel tree >> * Minor cleanups >> * Split UAPI changes to a separate patch >> * Improve / cleanup init_resources >> * Resolve Palmer's comments >> >> v2: >> * Rebase on newer kernel tree >> * Minor cleanups >> * Properly populate the ioresources tre, so that it >> can be used later on for implementing strict /dev/mem >> * Use linux,usable-memory on /memory instead of a new binding > > Where? In any case, that's not going to work well with EFI support > assuming like arm64, 'memory' is passed in UEFI structures instead of > DT. That's why there's now a /chosen linux,usable-memory-ranges > property. > Here: https://elixir.bootlin.com/linux/v5.12-rc5/source/drivers/of/fdt.c#L1001 The "linux,usable-memory" binding is already defined and is part of early_init_dt_scan_memory() which we call on mm/init.c to determine system's memory layout. It's simple, clean and I don't see a reason to use another binding on /chosen and add extra code for this, when we already handle it on early_init_dt_scan_memory() anyway. As for EFI, even when enabled, we still use DT to determine system memory layout, not EFI structures, plus I don't see how EFI is relevant here, the bootloader in kexec's case is Linux, not EFI. BTW the /memory node is mandatory in any case, it should exist on DT regardless of EFI, /chosen node on the other hand is -in general- optional, and we can still boot a riscv system without /chosen node present (we only require it for the built-in cmdline to work). Also a simple grep for "linux,usable-memory-ranges" on the latest kernel sources didn't return anything, there is also nothing on chosen.txt, where is that binding documented/implemented ? > Isn't the preferred kexec interface the file based interface? I'd > expect a new arch to only support that. And there's common kexec DT > handling for that pending for 5.13. > Both approaches have their pros an cons, that's why both are available, in no way CONFIG_KEXEC is deprecated in favor of CONFIG_KEXEC_FILE, at least not as far as I know. The main point for the file-based syscall is to support secure boot, since the image is loaded by the kernel directly without any processing by the userspace tools, so it can be pre-signed by the kernel's "vendor". On the other hand, the kernel part is more complicated and you can't pass a new device tree, the kernel needs to re-use the existing one (or modify it in-kernel), you can only override the cmdline. This doesn't work for our use cases in FORTH, where we use kexec not only to re-boot our systems, but also to boot to a system with different hw layout (e.g. FPGA prototypes or systems with FPGAs on the side), device tree overlays also don't cover our use cases. To give you an idea we can add/remove/modify devices, move them to another region etc and still use kexec to avoid going through the full boot cycle. We just unload their drivers, perform a full or partial re-programming of the FPGA from within Linux, and kexec to the new system with the new device tree. The file-based syscall can't cover this scenario, in general it's less flexible and it's only there for secure boot, not for using custom-built kernels, nor custom device tree images. Security-wise the file load syscall provides guarantees for integrity and authenticity, but depending on the kernel "vendor"'s infrastructure and signing process this may allow e.g. to load an older/vulnerable kernel through kexec and get away with it, there is no check as far as I know to make sure the loaded kernel is at least as old as the running kernel, the assumption is that the "vendor" will use a different signing key/cert for each kernel and that you'll kexec to a kernel/crash kernel that's the same version as the running one. Until we have clear guidelines on how this is meant to be used and have a discussion on secure boot within RISC-V (we have something on the TEE TG but we'll probably switch to a SIG committee for this), I don't see how this feature is a priority compared to the more generic CONFIG_KEXEC. Regards, Nick
On Mon, 05 Apr 2021 01:57:07 PDT (-0700), mick@ics.forth.gr wrote: > This patch series adds kexec/kdump and crash kernel > support on RISC-V. For testing the patches a patched > version of kexec-tools is needed (still a work in > progress) which can be found at: > > https://riscv.ics.forth.gr/kexec-tools-patched.tar.xz > > v3: > * Rebase on newer kernel tree > * Minor cleanups > * Split UAPI changes to a separate patch > * Improve / cleanup init_resources > * Resolve Palmer's comments > > v2: > * Rebase on newer kernel tree > * Minor cleanups > * Properly populate the ioresources tre, so that it > can be used later on for implementing strict /dev/mem > * Use linux,usable-memory on /memory instead of a new binding > * USe a reserved-memory node for ELF core header > > Nick Kossifidis (5): > RISC-V: Add EM_RISCV to kexec UAPI header > RISC-V: Add kexec support > RISC-V: Improve init_resources > RISC-V: Add kdump support > RISC-V: Add crash kernel support > > arch/riscv/Kconfig | 25 ++++ > arch/riscv/include/asm/elf.h | 6 + > arch/riscv/include/asm/kexec.h | 54 +++++++ > arch/riscv/kernel/Makefile | 6 + > arch/riscv/kernel/crash_dump.c | 46 ++++++ > arch/riscv/kernel/crash_save_regs.S | 56 +++++++ > arch/riscv/kernel/kexec_relocate.S | 222 ++++++++++++++++++++++++++++ > arch/riscv/kernel/machine_kexec.c | 193 ++++++++++++++++++++++++ > arch/riscv/kernel/setup.c | 113 ++++++++------ > arch/riscv/mm/init.c | 110 ++++++++++++++ > include/uapi/linux/kexec.h | 1 + > 11 files changed, 787 insertions(+), 45 deletions(-) > create mode 100644 arch/riscv/include/asm/kexec.h > create mode 100644 arch/riscv/kernel/crash_dump.c > create mode 100644 arch/riscv/kernel/crash_save_regs.S > create mode 100644 arch/riscv/kernel/kexec_relocate.S > create mode 100644 arch/riscv/kernel/machine_kexec.c Thanks. There were some minor issues and some merge conflicts, I put this on for-next with some fixups.
Στις 2021-04-23 06:30, Palmer Dabbelt έγραψε: > On Mon, 05 Apr 2021 01:57:07 PDT (-0700), mick@ics.forth.gr wrote: >> This patch series adds kexec/kdump and crash kernel >> support on RISC-V. For testing the patches a patched >> version of kexec-tools is needed (still a work in >> progress) which can be found at: >> >> https://riscv.ics.forth.gr/kexec-tools-patched.tar.xz >> >> v3: >> * Rebase on newer kernel tree >> * Minor cleanups >> * Split UAPI changes to a separate patch >> * Improve / cleanup init_resources >> * Resolve Palmer's comments >> >> v2: >> * Rebase on newer kernel tree >> * Minor cleanups >> * Properly populate the ioresources tre, so that it >> can be used later on for implementing strict /dev/mem >> * Use linux,usable-memory on /memory instead of a new binding >> * USe a reserved-memory node for ELF core header >> >> Nick Kossifidis (5): >> RISC-V: Add EM_RISCV to kexec UAPI header >> RISC-V: Add kexec support >> RISC-V: Improve init_resources >> RISC-V: Add kdump support >> RISC-V: Add crash kernel support >> >> arch/riscv/Kconfig | 25 ++++ >> arch/riscv/include/asm/elf.h | 6 + >> arch/riscv/include/asm/kexec.h | 54 +++++++ >> arch/riscv/kernel/Makefile | 6 + >> arch/riscv/kernel/crash_dump.c | 46 ++++++ >> arch/riscv/kernel/crash_save_regs.S | 56 +++++++ >> arch/riscv/kernel/kexec_relocate.S | 222 >> ++++++++++++++++++++++++++++ >> arch/riscv/kernel/machine_kexec.c | 193 ++++++++++++++++++++++++ >> arch/riscv/kernel/setup.c | 113 ++++++++------ >> arch/riscv/mm/init.c | 110 ++++++++++++++ >> include/uapi/linux/kexec.h | 1 + >> 11 files changed, 787 insertions(+), 45 deletions(-) >> create mode 100644 arch/riscv/include/asm/kexec.h >> create mode 100644 arch/riscv/kernel/crash_dump.c >> create mode 100644 arch/riscv/kernel/crash_save_regs.S >> create mode 100644 arch/riscv/kernel/kexec_relocate.S >> create mode 100644 arch/riscv/kernel/machine_kexec.c > > Thanks. There were some minor issues and some merge conflicts, I put > this on for-next with some fixups. I've sent a v4 that shouldn't have merge conflicts, addressing some comments from Alex as well, could you use that instead or is it too late ?
On Thu, 22 Apr 2021 20:36:56 PDT (-0700), mick@ics.forth.gr wrote: > Στις 2021-04-23 06:30, Palmer Dabbelt έγραψε: >> On Mon, 05 Apr 2021 01:57:07 PDT (-0700), mick@ics.forth.gr wrote: >>> This patch series adds kexec/kdump and crash kernel >>> support on RISC-V. For testing the patches a patched >>> version of kexec-tools is needed (still a work in >>> progress) which can be found at: >>> >>> https://riscv.ics.forth.gr/kexec-tools-patched.tar.xz >>> >>> v3: >>> * Rebase on newer kernel tree >>> * Minor cleanups >>> * Split UAPI changes to a separate patch >>> * Improve / cleanup init_resources >>> * Resolve Palmer's comments >>> >>> v2: >>> * Rebase on newer kernel tree >>> * Minor cleanups >>> * Properly populate the ioresources tre, so that it >>> can be used later on for implementing strict /dev/mem >>> * Use linux,usable-memory on /memory instead of a new binding >>> * USe a reserved-memory node for ELF core header >>> >>> Nick Kossifidis (5): >>> RISC-V: Add EM_RISCV to kexec UAPI header >>> RISC-V: Add kexec support >>> RISC-V: Improve init_resources >>> RISC-V: Add kdump support >>> RISC-V: Add crash kernel support >>> >>> arch/riscv/Kconfig | 25 ++++ >>> arch/riscv/include/asm/elf.h | 6 + >>> arch/riscv/include/asm/kexec.h | 54 +++++++ >>> arch/riscv/kernel/Makefile | 6 + >>> arch/riscv/kernel/crash_dump.c | 46 ++++++ >>> arch/riscv/kernel/crash_save_regs.S | 56 +++++++ >>> arch/riscv/kernel/kexec_relocate.S | 222 >>> ++++++++++++++++++++++++++++ >>> arch/riscv/kernel/machine_kexec.c | 193 ++++++++++++++++++++++++ >>> arch/riscv/kernel/setup.c | 113 ++++++++------ >>> arch/riscv/mm/init.c | 110 ++++++++++++++ >>> include/uapi/linux/kexec.h | 1 + >>> 11 files changed, 787 insertions(+), 45 deletions(-) >>> create mode 100644 arch/riscv/include/asm/kexec.h >>> create mode 100644 arch/riscv/kernel/crash_dump.c >>> create mode 100644 arch/riscv/kernel/crash_save_regs.S >>> create mode 100644 arch/riscv/kernel/kexec_relocate.S >>> create mode 100644 arch/riscv/kernel/machine_kexec.c >> >> Thanks. There were some minor issues and some merge conflicts, I put >> this on for-next with some fixups. > > I've sent a v4 that shouldn't have merge conflicts, addressing some > comments from Alex as well, could you use that instead or is it too late > ? Thanks, for some reason I didn't see it when poking around. There was still that one init_resources() merge conflict and I fixed up some of the commit texts, it's now on for-next as b94394119804 (HEAD -> for-next, riscv/for-next) RISC-V: Add crash kernel support 6e8451782c90 RISC-V: Add kdump support 0a0652429bdb RISC-V: Improve init_resources() d9a8897d6b5d RISC-V: Add kexec support f59938095b94 RISC-V: Add EM_RISCV to kexec UAPI header
Στις 2021-04-23 06:48, Palmer Dabbelt έγραψε: > On Thu, 22 Apr 2021 20:36:56 PDT (-0700), mick@ics.forth.gr wrote: >> Στις 2021-04-23 06:30, Palmer Dabbelt έγραψε: >>> On Mon, 05 Apr 2021 01:57:07 PDT (-0700), mick@ics.forth.gr wrote: >>>> This patch series adds kexec/kdump and crash kernel >>>> support on RISC-V. For testing the patches a patched >>>> version of kexec-tools is needed (still a work in >>>> progress) which can be found at: >>>> >>>> https://riscv.ics.forth.gr/kexec-tools-patched.tar.xz >>>> >>>> v3: >>>> * Rebase on newer kernel tree >>>> * Minor cleanups >>>> * Split UAPI changes to a separate patch >>>> * Improve / cleanup init_resources >>>> * Resolve Palmer's comments >>>> >>>> v2: >>>> * Rebase on newer kernel tree >>>> * Minor cleanups >>>> * Properly populate the ioresources tre, so that it >>>> can be used later on for implementing strict /dev/mem >>>> * Use linux,usable-memory on /memory instead of a new binding >>>> * USe a reserved-memory node for ELF core header >>>> >>>> Nick Kossifidis (5): >>>> RISC-V: Add EM_RISCV to kexec UAPI header >>>> RISC-V: Add kexec support >>>> RISC-V: Improve init_resources >>>> RISC-V: Add kdump support >>>> RISC-V: Add crash kernel support >>>> >>>> arch/riscv/Kconfig | 25 ++++ >>>> arch/riscv/include/asm/elf.h | 6 + >>>> arch/riscv/include/asm/kexec.h | 54 +++++++ >>>> arch/riscv/kernel/Makefile | 6 + >>>> arch/riscv/kernel/crash_dump.c | 46 ++++++ >>>> arch/riscv/kernel/crash_save_regs.S | 56 +++++++ >>>> arch/riscv/kernel/kexec_relocate.S | 222 >>>> ++++++++++++++++++++++++++++ >>>> arch/riscv/kernel/machine_kexec.c | 193 ++++++++++++++++++++++++ >>>> arch/riscv/kernel/setup.c | 113 ++++++++------ >>>> arch/riscv/mm/init.c | 110 ++++++++++++++ >>>> include/uapi/linux/kexec.h | 1 + >>>> 11 files changed, 787 insertions(+), 45 deletions(-) >>>> create mode 100644 arch/riscv/include/asm/kexec.h >>>> create mode 100644 arch/riscv/kernel/crash_dump.c >>>> create mode 100644 arch/riscv/kernel/crash_save_regs.S >>>> create mode 100644 arch/riscv/kernel/kexec_relocate.S >>>> create mode 100644 arch/riscv/kernel/machine_kexec.c >>> >>> Thanks. There were some minor issues and some merge conflicts, I put >>> this on for-next with some fixups. >> >> I've sent a v4 that shouldn't have merge conflicts, addressing some >> comments from Alex as well, could you use that instead or is it too >> late >> ? > > Thanks, for some reason I didn't see it when poking around. There was > still that one init_resources() merge conflict and I fixed up some of > the commit texts, it's now on for-next as > > b94394119804 (HEAD -> for-next, riscv/for-next) RISC-V: Add crash > kernel support > 6e8451782c90 RISC-V: Add kdump support > 0a0652429bdb RISC-V: Improve init_resources() > d9a8897d6b5d RISC-V: Add kexec support > f59938095b94 RISC-V: Add EM_RISCV to kexec UAPI header Thanks a lot ! I'll keep on working on the user-space part and submit it on kexec-tools later on.