kernel parameter 'memmap ' is failing to ioremap with error "Malformed early option memmap"

[Mehul Wagle]

Hello,

I am on SUSE 11 (Patch 1) and trying to boot the kernel with param
‘memmap’ (i.e. memmap=<SizeInG>$<StartAddrInG>). The intention is to
reserve <SizeInG> GB portion of the memory starting at address
<StartAddrInG>.


Example:
=========
Added the parameter “memmap=100G\$4G” to kernel boot commandline via yast
(NOTE: Escape character is needed for Grub2 loader)


Effect:
======
$ cat /proc/cmdline

root=/dev/disk/by-id/scsi-3600605b000f5ae5014d40a7c099e544c-part2
resume=/dev/disk/by-id/scsi-3600605b000f5ae5014d40a7c099e544c-part1
splash=silent memmap=100G\$4G


Error faced during kernel boot (snippet from dmesg):
========================================
[    0.000000] Malformed early option 'memmap
…
[ 1109.873280] ioremap of the image failed(1)


Question:
========
Is this a bug with kexec or some other known problem? Would appreciate
any help from the forum.

Regards,
Mehul Wagle