On 02/09/2010 01:26, Philip Rowlands wrote:
The RHEL 5.5 installer initrd checks for the well-known kernel params
CMSDASD and CMSCONFFILE, exposed as env vars:
linuxrc.s390:
12 # Copyright (C) IBM Corp. 2008,2009
13 # Author: Steffen Maier <[email protected]>
...
35 VERSION=1.2
...
2757 # Parse configuration
2758 if [ -n "$CMSDASD" -a -n "$CMSCONFFILE" ]; then
2759 readcmsfile $CMSDASD $CMSCONFFILE
2760 source /tmp/$CMSCONFFILE #2>/dev/null
2761 fi
documented at
http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5.5/html/Installation_Guide/s1-s390-steps-vm.html
however, I see the actual PARM being lowercased, e.g.
CP IPL 222 PARM rdinit=/bin/sh CMSDASD=234
(minidisk 222 prepared earlier with zipl)
results in an initrd shell showing:
# env
cmsdasd=234
Found the answer (I think); all parms are not created equal.
Parms from memory are not case-adjusted; these include parms from zipl
-P, zipl -p, and those punched following the kernel image if using a
virtual reader. These parms have a 896-byte limit.
Parms from registers are case-adjusted; these are parms passed with the
IPL ... PARM ...
syntax. These parms are limited to 64 bytes (or maybe 41).
RH bugzilla 475530 appears to add IPL ... PARM support, but I can't find
any documented description of case handling, just empirical tests.
As a workaround I've baked CMSDASD and CMSCONFFILE parms into the boot
minidisk with zipl, and pointed them at a temporary disk and file
created for the purpose.
Cheers,
Phil
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