Hi, I rebased my series to the latest arm64 for-next/core (v4.0-rc4) and pushed it out to: git://git.kernel.org/pub/scm/linux/kernel/git/geoff/linux-kexec.git kexec-v9 -Geoff On Thu, 2015-03-19 at 20:35 +0000, Geoff Levand wrote: > Hi All, > > This series adds the core support for kexec re-boots on arm64. This v8 of the > series is mainly just a rebase to Linux-4.0-rc3, and a few very minor changes > requested for v7. > > To load a second stage kernel and execute a kexec re-boot on arm64 my patches to > kexec-tools [2], which have not yet been merged upstream, are needed. > > I have tested with the ARM VE fast model, the ARM Base model and the ARM > Foundation model with various kernel config options for both the first and > second stage kernels. Kexec on EFI systems works correctly. With the ACPI > kernel patches from [3] applied, kexec on ACPI systems seeems to work correctly. > More ACPI + kexec testing is needed. > > Patch 1 here moves the macros from proc-macros.S to asm/assembler.h so that the > dcache_line_size macro it defines can be uesd by kexec's relocate kernel > routine. > > Patches 2-4 rework the arm64 hcall mechanism to give the arm64 soft_restart() > routine the ability to switch exception levels from EL1 to EL2 for kernels that > were entered in EL2. > > Patches 5-6 add the actual kexec support. > > Please consider all patches for inclusion. > > [1] https://git.kernel.org/cgit/linux/kernel/git/geoff/linux-kexec.git > [2] https://git.kernel.org/cgit/linux/kernel/git/geoff/kexec-tools.git > [3] http://git.linaro.org/leg/acpi/acpi.git #acpi-topic-juno-fvp > > Several things are known to have problems on kexec re-boot: > > spin-table > ---------- > > PROBLEM: The spin-table enable method does not implement all the methods needed > for CPU hot-plug, so the first stage kernel cannot be shutdown properly. > > WORK-AROUND: Upgrade to system firmware that provides PSCI enable method > support, OR build the first stage kernel with CONFIG_SMP=n, OR pass 'maxcpus=1' > on the first stage kernel command line. > > FIX: Upgrade system firmware to provide PSCI enable method support or add > missing spin-table support to the kernel. > > KVM > --- > > PROBLEM: KVM acquires hypervisor resources on startup, but does not free those > resources on shutdown, so the first stage kernel cannot be shutdown properly > when using kexec. > > WORK-AROUND: Build the first stage kernel with CONFIG_KVM=n, or apply KVM bug > fix patches from [1]. > > FIX: Takahiro Akashi has preliminary patches to fix the KVM shutdown problem. I > have those in my master branch at [1]. KVM + kexec works properly with that > branch. Patches neeeded: > > arm64: kvm: add a cpu tear-down function > arm64: kexec: fix kvm issue > arm64/kvm: Remove !KEXEC Kconfig dependency > arm64/kexec: Enable kexec in the arm64 defconfig > > /memreserve/ > ---------- > > PROBLEM: Device tree /memreserve/ entries are not available in > /proc/device-tree. For systems that have /memreserve/ entries and use > /proc/device-tree during kexec, the second stage kernel will use the reserved > regions and the system will become unstable. > > WORK-AROUND: Enable the kernel config option CONFIG_SYSFS=y to expose a binary > device tree to user space at /sys/firmware/fdt that includes /memreserve/ > entries OR pass a user specified DTB using the kexec --dtb option. > > FIX: This is expected behavior. To maximize user support, rework device tree > definitions to not use /memreserve/ entries. > > -Geoff
