path: root/arch
diff options
authorMike Kravetz <kravetz@us.ibm.com>2006-03-27 15:20:00 -0800
committerPaul Mackerras <paulus@samba.org>2006-03-28 16:45:33 +1100
commit9fe901d124871f5781b9c4ccbb7ff93fdff9d39e (patch)
tree234931bc56432ccf06f1f9c8463501bca64d6a0b /arch
parente78b47a59026f04eb98b9d392901be13b56f444f (diff)
[PATCH] powerpc: Workaround for pSeries RTAS bug
A bug in the RTAS services incorrectly interprets some bits in the CR when called from the OS. Specifically, bits in CR4. The result could be a firmware crash that also takes down the partition. A firmware fix is in the works. We have seen this situation when performing DLPAR operations. As a temporary workaround, clear the CR in enter_rtas(). Note that enter_rtas() will not set any bits in CR4 before calling RTAS. Also note that the 32 bit version of enter_rtas() should have the same work around even though the chances of hitting the bug are much smaller due to the lack of DLPAR on 32 bit kernels. However, my assembly skills are a bit rusty and the 32 bit code doesn't seem to follow the conventions for where things should be saved. In addition, I don't have a system to test 32 bit kernels. Help creating and at least touch testing the same workaround for 32 bit would be appreciated. Signed-off-by: Mike Kravetz <kravetz@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch')
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 1060155d84c3..19ad5c6b1818 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -617,6 +617,12 @@ _GLOBAL(enter_rtas)
mfsrr1 r10
std r10,_SRR1(r1)
+ /* Temporary workaround to clear CR until RTAS can be modified to
+ * ignore all bits.
+ */
+ li r0,0
+ mtcr r0
/* There is no way it is acceptable to get here with interrupts enabled,
* check it with the asm equivalent of WARN_ON