kexec-tools: mips: Pass initrd parameter via cmdline

Under loongson platform, use command:
kexec -l vmlinux... --append="root=UUID=28e1..." --initrd=...
kexec -e
quick restart failed like this:

********************************************************************
[    3.420791] VFS: Cannot open root device "UUID=6462a8a4-02fb-49..."
[    3.431262] Please append a correct "root=" boot option; ...
...
...
...
[    3.543175]   0801         4194304 sda1 554e69cc-01
[    3.543175]
[    3.549494]   0802        62914560 sda2 554e69cc-02
[    3.549495]
[    3.555818]   0803         8388608 sda3 554e69cc-03
[    3.555819]
[    3.562139]   0804       174553229 sda4 554e69cc-04
[    3.562139]
[    3.568463] 0b00         1048575 sr0
[    3.568464]  driver: sr
[    3.574524] Kernel panic - not syncing: VFS: Unable to mount root fs...
[    3.582750] ---[ end Kernel panic - not syncing: VFS:...
*******************************************************************

The kernel cannot parse the UUID, the UUID is parsed in the initrd.
For compatibility with previous platforms, loongson platform obtain
initrd parameter through cmdline in kernel, the kernel supports use
cmdline to parse initrd. But under the mips architecture, kexec-tools
pass the initrd through DTB.

Made the following modifications:

(1) in kexec/arch/mips/kexec-elf-mips.c
    Add patch_initrd_info(), at runtime to distinguish different cpu,
    only for loongson cpu, add initrd parameter to cmdline.

(2) in kexec/arch/mips/crashdump-mips.c
    Because loongson uses a different page_offset, it should be modified
    to ensure that crashdump functionality is correct and reliable.

(3) in kexec/arch/mips/crashdump-mips.h
    Added platform-specific page_offset macro definition.

Signed-off-by: Hui Li <lihui@loongson.cn>
Signed-off-by: Simon Horman <horms@kernel.org>
3 files changed