[PATCH 0/3] arm64: kexec, kdump: fix boot failures on acpi-only system
bhsharma at redhat.com
Fri Jun 15 05:52:02 PDT 2018
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 at redhat.com>
BTW, if possible I would suggest to use:
Reported-by: Bhupesh Sharma <bhsharma at redhat.com>
Reported-by: Bhupesh Sharma <bhupesh.linux at gmail.com>
On Fri, Jun 15, 2018 at 1:26 PM, AKASHI Takahiro
<takahiro.akashi at linaro.org> 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 .
> Patch#1 addresses kexec case, for which you are also required to update
> user space. See necessary patches in . If you want to review Patch#1,
> please also take a look at and review .
> Patch#2 and #3 addresses kdump case. This is a revised version after
> Ard's comments.
>  http://lists.infradead.org/pipermail/linux-arm-kernel/2018-March/565980.html
>  https://git.linaro.org/people/takahiro.akashi/kexec-tools.git arm64/resv_mem
>  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(-)
More information about the kexec