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authorMohan Kumar M <mohan@in.ibm.com>2007-03-21 08:51:32 +0300
committerPaul Mackerras <paulus@samba.org>2007-03-22 07:01:43 +0300
commitb4aea36b7956eeebfc56314ce0944db1441255ce (patch)
treea0c84f25e1f5a2ef0af624871e8f892654fd79a4 /arch/powerpc/platforms/pseries/hvCall.S
parentf144e7c7272bf527c380bffaa5e789dc28a09d8d (diff)
downloadlinux-b4aea36b7956eeebfc56314ce0944db1441255ce.tar.xz
[POWERPC] Avoid hypervisor statistics calculation in real mode
kexec invokes plpar_hcall hypervisor call in real mode. plpar_hcall refers to per cpu variables for accounting hypervisor statistics. These variables may not be in the RMO region, so accesses to them in real mode may result in a data storage exception. This fixes this problem by using a new plpar_hcall_raw function which does not update the hypervisor call statistics. Thanks to Anton for suggesting this idea. Signed-off-by: Mohan Kumar M <mohan@in.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/platforms/pseries/hvCall.S')
-rw-r--r--arch/powerpc/platforms/pseries/hvCall.S34
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/hvCall.S b/arch/powerpc/platforms/pseries/hvCall.S
index 5c7e38789897..1501b0a9e749 100644
--- a/arch/powerpc/platforms/pseries/hvCall.S
+++ b/arch/powerpc/platforms/pseries/hvCall.S
@@ -123,6 +123,40 @@ _GLOBAL(plpar_hcall)
blr /* return r3 = status */
+/*
+ * plpar_hcall_raw can be called in real mode. kexec/kdump need some
+ * hypervisor calls to be executed in real mode. So plpar_hcall_raw
+ * does not access the per cpu hypervisor call statistics variables,
+ * since these variables may not be present in the RMO region.
+ */
+_GLOBAL(plpar_hcall_raw)
+ HMT_MEDIUM
+
+ mfcr r0
+ stw r0,8(r1)
+
+ std r4,STK_PARM(r4)(r1) /* Save ret buffer */
+
+ mr r4,r5
+ mr r5,r6
+ mr r6,r7
+ mr r7,r8
+ mr r8,r9
+ mr r9,r10
+
+ HVSC /* invoke the hypervisor */
+
+ ld r12,STK_PARM(r4)(r1)
+ std r4, 0(r12)
+ std r5, 8(r12)
+ std r6, 16(r12)
+ std r7, 24(r12)
+
+ lwz r0,8(r1)
+ mtcrf 0xff,r0
+
+ blr /* return r3 = status */
+
_GLOBAL(plpar_hcall9)
HMT_MEDIUM