On Fri, Nov 7, 2014 at 12:09 AM, Mark Rutland <mark.rutland at arm.com> wrote: > On Thu, Nov 06, 2014 at 04:13:04PM +0000, Arun Chandran wrote: >> On Thu, Nov 6, 2014 at 8:58 PM, Mark Rutland <mark.rutland at arm.com> wrote: >> > 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 > > Does this look correct to you? That doesn't match what I see in > apm-mustang.dts in mainline (where memory starts at 0x1_00000000). > >> >> get_memory_ranges_dt:659: SKIP: 0000000000000000 - 0000000000000000 >> >> get_memory_ranges_dt:659: SKIP: 0000000000000000 - 0000000000000000 >> >> get_memory_ranges_dt:659: SKIP: 0000000000000000 - 0000000000000000 > > This looks suspicious, but I haven't investigated the underlying code. > >> >> 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 > > So we'll load the kernel at this address... > > [...] > >> 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! >> Initializing cgroup subsys cpu >> Linux version 3.17.0-rc4+ (arun at arun-OptiPlex-9010) (gcc version 4.9.1 >> 20140505 (prerelease) (crosstool-NG linaro-1.13.1-4.9-2014.05 - Linaro >> GCC 4.9-2014.05) ) #12 PREEMPT Thu Nov 6 21:38:03 IST 2014 >> CPU: AArch64 Processor [500f0000] revision 0 >> Detected PIPT I-cache on CPU0 >> Ignoring memory block 0x100000000 - 0x180000000 > > ... then the kernel finds the single memory region described in > apm-mustang.dts which happens to be below PHYS_OFFSET for your board. So > the kernel ignores it because it cannot address it ... > >> Early serial console at MMIO32 0x1c020000 (options '') >> bootconsole [uart0] enabled >> efi: Getting EFI parameters from FDT: >> efi: UEFI not found. >> cma: Failed to reserve 16 MiB >> Kernel panic - not syncing: ERROR: Failed to allocate 0x1000 bytes below 0x0. > > ... and then explodes because it knows of no memory outside of the kernel > Image. Thanks for the nice explanation. Yes with the mainline dtb kexec won't work. Kexec works when I don't pass dtb to it. It will work (mainline dtb) only when it passes through the bootloader. Bootloader does a lot of modification to the dtb. For exmple. Memory node is changed from memory { device_type = "memory"; reg = < 0x1 0x00000000 0x0 0x80000000 >; /* Updated by bootloader */ }; to root at genericarmv8:~# hexdump /proc/device-tree/memory/reg 0000000 0000 4000 0000 0000 0000 0400 0000 0000 0000010 0000 0000 0000 0000 0000 0000 0000 0000 * 0000040 --Arun
