earlyprintk=efi,keep will cause kernel hangs while freeing initmem like
below:
VFS: Mounted root (ext4 filesystem) readonly on device 254:2.
devtmpfs: mounted
Freeing unused kernel memory: 880K (ffffffff817d4000 - ffffffff818b0000)
It is caused by efi earlyprintk use __init function which will be freed
later. Such as early_efi_write is marked as __init, also it will use
early_ioremap which is init function as well.
To fix this issue, I added early initcall early_efi_map_fb which maps
the whole efi fb for later use. OTOH, adding a wrapper function
early_efi_map which calls early_ioremap before ioremap is available.
With this patch applied efi boot ok with earlyprintk=efi,keep console=efi
Signed-off-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
34f51147d2