[PATCH 00/10] arm64 kexec kernel patches V5

[Mark Rutland]

On Thu, Nov 06, 2014 at 12:16:12PM +0000, Arun Chandran wrote:
> Hi Geoff,
> 
> I am trying this on my hardware (apm-mustang.dtb)
> 
> On Fri, Oct 24, 2014 at 4:40 AM, Geoff Levand <geoff at infradead.org> wrote:
> > Hi All,
> >
> > This series adds the core support for kexec re-boots on arm64.  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.
> >
> > 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.
> >
> > Patches 1-4 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 and 6 convert the use of device tree /memreserve/ to device tree
> > reserved-memory nodes.
> >
> > Patch 7 moves proc-macros.S from arm64/mm to arm64/include/asm so that the
> > dcache_line_size macro it defines can be uesd by kexec's relocate kernel
> > routine.
> >
> > Patches 8-10 add the actual kexec support.
> >
> > Please consider all patches for inclusion.  Any comments or suggestions on how
> > to improve are welcome.
> >
> > [1]  https://git.linaro.org/people/geoff.levand/linux-kexec.git
> > [2]  https://git.linaro.org/people/geoff.levand/kexec-tools.git
> >
> > 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.
> 
> I have CONFIG_SMP=n
> 
> >
> > FIX: Upgrade system firmware to provide PSCI enable method support.
> >
> > 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.
> >
> > WORK-AROUND:  Build the first stage kernel with CONFIG_KVM=n.
> 
> KVM also disabled.
> 
> /root at genericarmv8:~# usr/local/sbin/kexec --lite -l vmlinux
> --dtb=apm-mustang.dtb --command-line=
> "root=/dev/nfs rw
> nfsroot=10.162.103.145:/nfs_root/linaro-image-lamp-genericarmv8,nfsvers=3
>  ip=:::::eth0:dhcp panic=1 console=ttyS0,115200
> earlyprintk=uart8250-32bit,0x1c020000"
> 
> kexec version: 14.10.21.16.36-ga38e0a6
> arch_process_options:85: command_line: root=/dev/nfs rw
> nfsroot=10.162.103.145:/nfs_root/linaro-image-lamp-genericarmv8,nfsvers=3
> ip=:::::eth0:dhcp panic=1 console=ttyS0,115200
> earlyprintk=uart8250-32bit,0x1
> c020000
> arch_process_options:87: initrd: (null)
> arch_process_options:88: dtb: apm-mustang.dtb
> arch_process_options:89: lite: 1
> kernel: 0x7f756e7010 kernel_size: 0x488a308
> Modified cmdline: root=/dev/nfs
> Unable to find /proc/device-tree//chosen/linux,stdout-path, printing
> from purgatory is diabled
> get_memory_ranges_dt:638: node_1516 memory
> get_memory_ranges_dt:664:  RAM: 0000004000000000 - 0000004400000000
> get_memory_ranges_dt:659: SKIP: 0000000000000000 - 0000000000000000
> get_memory_ranges_dt:659: SKIP: 0000000000000000 - 0000000000000000
> get_memory_ranges_dt:659: SKIP: 0000000000000000 - 0000000000000000
> get_memory_ranges_dt:678: Success
> elf_arm64_load: PE format: yes
> p_vaddr: ffffffc000080000
> virt_to_phys: ffffffc000080000 -> 0000004000080000
> add_segment_phys_virt: 0000007f756f7010 - 0000007f75d3cf70 (00645f60)
> -> 0000004000080000 - 00000040006fb000 (0067b000)
> elf_arm64_load: text_offset: 0000000000080000
> elf_arm64_load: image_size:  000000000067f000
> elf_arm64_load: page_offset: ffffffc000000000
> elf_arm64_load: memstart:    0000004000000000
> virt_to_phys: ffffffc000080000 -> 0000004000080000
> elf_arm64_load: e_entry:     ffffffc000080000 -> 0000004000080000
> virt_to_phys: ffffffc000080000 -> 0000004000080000
> Modified cmdline:root=/dev/nfs rw
> nfsroot=10.162.103.145:/nfs_root/linaro-image-lamp-genericarmv8,nfsvers=3
> ip=:::::eth0:dhcp panic=1 console=ttyS0,115200
> earlyprintk=uart8250-32bit,0x1c020000
> Unable to find /proc/device-tree//chosen/linux,stdout-path, printing
> from purgatory is diabled
> read_cpu_info: dtb_1 cpu-0 (/cpus/cpu at 000): hwid-0, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_1 cpu-1 (/cpus/cpu at 001): hwid-1, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_1 cpu-2 (/cpus/cpu at 100): hwid-100, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_1 cpu-3 (/cpus/cpu at 101): hwid-101, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_1 cpu-4 (/cpus/cpu at 200): hwid-200, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_1 cpu-5 (/cpus/cpu at 201): hwid-201, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_1 cpu-6 (/cpus/cpu at 300): hwid-300, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_1 cpu-7 (/cpus/cpu at 301): hwid-301, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_2 cpu-0 (/cpus/cpu at 000): hwid-0, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_2 cpu-1 (/cpus/cpu at 001): hwid-1, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_2 cpu-2 (/cpus/cpu at 100): hwid-100, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_2 cpu-3 (/cpus/cpu at 101): hwid-101, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_2 cpu-4 (/cpus/cpu at 200): hwid-200, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_2 cpu-5 (/cpus/cpu at 201): hwid-201, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_2 cpu-6 (/cpus/cpu at 300): hwid-300, 'spin-table',
> cpu-release-addr 400000fff8
> read_cpu_info: dtb_2 cpu-7 (/cpus/cpu at 301): hwid-301, 'spin-table',
> cpu-release-addr 400000fff8
> check_cpu_properties: hwid-0: OK
> check_cpu_properties: hwid-1: OK
> check_cpu_properties: hwid-100: OK
> check_cpu_properties: hwid-101: OK
> check_cpu_properties: hwid-200: OK
> check_cpu_properties: hwid-201: OK
> check_cpu_properties: hwid-300: OK
> check_cpu_properties: hwid-301: OK
> dtb:    base 4000700000, size 221ch (8732)
> add_segment_phys_virt: 0000000024c14c90 - 0000000024c16eac (0000221c)
> -> 0000004000700000 - 0000004000703000 (00003000)
> kexec_load: entry = 0x4000080000 flags = 0xb70000
> nr_segments = 2
> segment[0].buf   = 0x7f756f7010
> segment[0].bufsz = 0x645f60
> segment[0].mem   = 0x4000080000
> segment[0].memsz = 0x67b000
> segment[1].buf   = 0x24c14c90
> segment[1].bufsz = 0x221c
> segment[1].mem   = 0x4000700000
> segment[1].memsz = 0x3000
> 
> root at genericarmv8:~# /usr/local/sbin/kexec --lite -e
> kexec version: 14.10.21.16.36-ga38e0a6
> arch_process_options:85: command_line: (null)
> arch_process_options:87: initrd: (null)
> arch_process_options:88: dtb: (null)
> arch_process_options:89: lite: 1
> sd 0:0:0:0: [sda] Synchronizing SCSI cache
> kexec: Starting new kernel
> Bye!
> 
> It fails to come up.  In debugger I can see
> 
>     Core number       : 0
>     Core state        : debug (AArch64 EL1)
>     Debug entry cause : External Debug Request
>     Current PC        : 0xffffffc000083200

That's a kernel virtual address, and it looks to be somewhere early in
the boot path, given it's close to PAGE_OFFSET + TEXT_OFFSET.

Can you figure out what this corresponds to in your kernel image?

Thanks,
Mark.