Hi Akashi, Thanks for the patchset - we have been waiting for quite some time for this fix so that crashkernel can boot on arm64 machines which support boot'ing via ACPI tables. I have tested this on my huawei-taishan arm64 board, so: Tested-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx> BTW, if possible I would suggest to use: Reported-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx> rather than: Reported-by: Bhupesh Sharma <bhupesh.linux@xxxxxxxxx> Thanks, Bhupesh On Fri, Jun 15, 2018 at 1:26 PM, AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> wrote: > # apologies for a bit late updates > > This patch series is a set of bug fixes to address kexec/kdump > failures which are sometimes observed on ACPI-only system and reported > in LAK-ML before. > > In short, the phenomena are: > 1. kexec'ed kernel can fail to boot because some ACPI table is corrupted > by a new kernel (or other data) being loaded into System RAM. Currently > kexec may possibly allocate space ignoring such "reserved" regions. > We will see no messages after "Bye!" > > 2. crash dump (kdump) kernel can fail to boot and get into panic due to > an alignment fault when accessing ACPI tables. This can happen because > those tables are not always properly aligned while they are mapped > non-cacheable (ioremap'ed) as they are not recognized as part of System > RAM under the current implementation. > > After discussing several possibilities to address those issues, > the agreed approach, in my understanding, is > * to add resource entries for every "reserved", i.e. memblock_reserve(), > regions to /proc/iomem. > (NOMAP regions, also marked as "reserved," remains at top-level for > backward compatibility.) > * For case (1), user space (kexec-tools) should rule out such regions > in searching for free space for loaded data. > * For case (2), the kernel should access ACPI tables by mapping > them with appropriate memory attributes described in UEFI memory map. > (This means that it doesn't require any changes in /proc/iomem, and > hence user space.) > > Please find past discussions about /proc/iomem in [1]. > > Patch#1 addresses kexec case, for which you are also required to update > user space. See necessary patches in [2]. If you want to review Patch#1, > please also take a look at and review [2]. > > Patch#2 and #3 addresses kdump case. This is a revised version after > Ard's comments.[3] > > [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-March/565980.html > [2] https://git.linaro.org/people/takahiro.akashi/kexec-tools.git arm64/resv_mem > [3] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-April/573655.html > > AKASHI Takahiro (2): > arm64: acpi,efi: fix alignment fault in accessing ACPI tables at kdump > init: map UEFI memory map early if on arm or arm64 > > James Morse (1): > arm64: export memblock_reserve()d regions via /proc/iomem > > arch/arm64/include/asm/acpi.h | 23 ++++++++++++------ > arch/arm64/kernel/acpi.c | 11 +++------ > arch/arm64/kernel/setup.c | 38 ++++++++++++++++++++++++++++++ > drivers/firmware/efi/arm-runtime.c | 27 ++++++++++----------- > init/main.c | 3 +++ > 5 files changed, 72 insertions(+), 30 deletions(-) > > -- > 2.17.0 > _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
