From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Date: Tue, 10 May 2011 15:13:39 +0000 (+0200)
Subject: [S390] kernel: Initialize register 14 when starting new CPU
X-Git-Tag: v2.6.39~48^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8eb4bd666ffdca7171cd8118138a91842012b028;p=pandora-kernel.git

[S390] kernel: Initialize register 14 when starting new CPU

When starting a new CPU we currently jump to start_secondary() without
setting register 14 (the return address) correctly. Therefore on the stack
frame for start_secondary an invalid return address is stored. This leads
to wrong stack back traces in kernel dumps.

Example:

 #00 [1f33fe48] cpu_idle at 10614a
 #01 [1f33fe90] start_secondary at 54fa88
 #02 [1f33feb8] (null) at 0                 <--- invalid

To fix this start_secondary() is called now with basr/brasl that sets
register 14 correctly. The output of the stack backtrace looks then
like the following:

 #00 [1f33fe48] cpu_idle at 10614a
 #01 [1f33fe90] start_secondary at 54fa88
 #02 [1f33feb8] restart_base at 54f41e      <--- correct

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

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