kexec arm support

[Aggelis Aggelis <aggelis@gmail.com>]

I use MitySOM-5CSX dev kit (cyclone v)and i would like to boot to a
different kernel using kexec.

In my configuration:

KERNEL : https://github.com/altera-opensource/linux-socfpga/archive/socfpga-4.9.76-ltsi-rt.zip
COMPILER : https://releases.linaro.org/archive/14.04/components/toolchain/binaries/gcc-linaro-arm-linux-gnueabihf-4.8-2014.04_linux.tar.bz2

In the kernel configuration kexec is enabled

zcat /proc/config.gz |grep KEXEC
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC=y

and the default kernel cmdline is

# cat /proc/cmdline
root=/dev/mmcblk0p3 rootwait rw earlycon

First we load kernel with

#./kexec --version
kexec-tools 2.0.19

kexec  -d -l zImagebkx --dtb=socfpga_cyclone5_mitysom5csx_devkit.dtb
--command-line="root=/dev/mmcblk0p3 rootwait rw earlycon"
syscall kexec_file_load not available.
kernel: 0xb6a9d008 kernel_size: 0x4a55c8
MEMORY RANGES
0000000000000000-000000003fffffff (0)
zImage header: 0x016f2818 0x00000000 0x004a55c8
zImage size 0x4a55c8, file size 0x4a55c8
zImage requires 0x004b65c8 bytes
Kernel: address=0x00008000 size=0x0178fce8
DT    : address=0x01799000 size=0x00007cf4
kexec_load: entry = 0x8000 flags = 0x280000
nr_segments = 2
segment[0].buf   = 0xb6a9d008
segment[0].bufsz = 0x4a55cc
segment[0].mem   = 0x8000
segment[0].memsz = 0x4a6000
segment[1].buf   = 0x8e610
segment[1].bufsz = 0x7cf4
segment[1].mem   = 0x1799000
segment[1].memsz = 0x8000


and kexec  kernel with


kexec  -e
[  134.110855] kexec_core: Starting new kernel
[  134.115064] Disabling non-boot CPUs ...
[  134.176961] CPU1: shutdown
[  134.180624] Bye!
Uncompressing Linux... done, booting the kernel.

and then nothing  no messages on console. The same kernel boots
successfully with U-Boot

using kernel 4.1.22 from https://github.com/dlaut/linux-socfpga and
applying the patch described in
https://patchwork.kernel.org/patch/6504321/
i  successfully kexeced 4.9.76 kernel from 4.1.22 using the same
kexec-tools 2.0.19.

root@node1:/mnt/test#uname -a Linux node1 4.1.22-ltsi-altera #2 SMP
PREEMPT Mon Jul 29 12:38:06 EEST 2019 armv7l GNU/L


root@node1:/mnt/test# kexec -d -e
[   46.306102] kexec: Starting new kernel
[   46.309928] Disabling non-boot CPUs ...
[   46.306102] kexec: Starting new kernel
[   46.378053] CPU1: shutdown
[   46.381875] Bye!
Uncompressing Linux... done, booting the kernel.
[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 4.9.76-rt61-ltsi-altera (aggelis@corei5)
(gcc version 4.8.3 20140401 (prerelease) (crosstool-NG l9
[    0.000000] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=10c5387d
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing
instruction cache
[    0.000000] OF: fdt:Machine model: MitySOM-5CSX Altera SOCFPGA Cyclone V
[    0.000000] cma: Reserved 16 MiB at 0x3f000000
[    0.000000] Memory policy: Data cache writealloc
[    0.000000] percpu: Embedded 15 pages/cpu @ef6bf000 s29184 r8192
d24064 u61440
[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.
Total pages: 260416
[    0.000000] Kernel command line: root=/dev/mmcblk0p3 rootwait
[    0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)
[    0.000000] Dentry cache hash table entries: 131072 (order: 8, 1048576 bytes)
[    0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[    0.000000] allocated 1048576 bytes of page_ext
...
...
Angstrom v2017.12 - Kernel 4.9.76-rt61-ltsi-altera
node1 login:



The kexec patch applied on the 4.1.22 kernel (enabling kexec on
socfpga) is already present in 4.9.76 kernel.

Did something break in kexec implementation in later 4 series kernels?

Aggelis Aggelis

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