I have built both a kernel from the Raspberry Pi sources and kexec-tools for arm64, and booted my kernel on a Raspberry Pi 4.
When I attempt to run kexec, it produces no output, exits with a nonzero return code, and an error message is posted to dmesg.
The debug output
While running kexec normally prints no output, running with --debug to show debug messages shows:
# kexec -s -l /media/sda1/boot/vmlinuz-rpi4barb --initrd /media/sda1/boot/initramfs-rpi4barb --reuse-cmdline --debug
arch_process_options:178: command_line: coherent_pool=1M 8250.nr_uarts=1 snd_bcm2835.enable_compat_alsa=0 snd_bcm2835.enable_hdmi=1 snd_bcm2835.enable_headphones=1 bcm2708_fb.fbwidth=1824 bcm2708_fb.fbheight=984 bcm2708_fb.fbswap=1 smsc95xx.macaddr=DC:A6:32:09:35:A1 vc_mem.mem_base=0x3eb00000 vc_mem.mem_size=0x3ff00000 modules=loop,squashfs,sd-mod,usb-storage quiet console=tty1 console=ttyS0,115200
arch_process_options:180: initrd: /media/sda1/boot/initramfs-rpi4barb
arch_process_options:182: dtb: (null)
arch_process_options:185: console: (null)
Try gzip decompression.
Try LZMA decompression.
lzma_decompress_file: read on /media/sda1/boot/vmlinuz-rpi4barb of 65536 bytes failed
elf_arm64_probe: Not an ELF executable.
# echo $?
255
My kernel did boot (so it must be some kind of executable). file claims:
# file /media/sda1/boot/vmlinuz-rpi4barb
/media/sda1/boot/vmlinuz-rpi4barb: Linux kernel ARM64 boot executable Image, little-endian, 4K pages
The dmesg output
When I run kexec, the line Can't kexec: CPUs are stuck in the kernel appears in dmesg.
What does it mean that CPUs are stuck in the kernel, and what should I do to resolve this problem? I have googled the message, and found mostly the code that generates it and a few unanswered questions.
Is this related to PSCI?
One mailing list thread which did have some replies indicated the problem may lie with something called PSCI. Running the suggested command dmesg | grep -E 'psci|started in' results in no output, indicating that PSCI is not supported in the kernel that I built.
I don't understand that answer. The kernel docs place PSCI under kvm, but my kernel is booting to physical hardware.
Am I missing something?
Any help greatly appreciated
Have I built my kernel wrong? Are there any docs or posts I've missed showing the right way to do this?
Thanks for looking.
