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authorMohan Kumar M <mohan@in.ibm.com>2007-03-21 01:51:32 -0400
committerPaul Mackerras <paulus@samba.org>2007-03-22 00:01:43 -0400
commitb4aea36b7956eeebfc56314ce0944db1441255ce (patch)
treea0c84f25e1f5a2ef0af624871e8f892654fd79a4 /arch/powerpc/platforms/pseries/hvCall.S
parentf144e7c7272bf527c380bffaa5e789dc28a09d8d (diff)
[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)
123 123
124 blr /* return r3 = status */ 124 blr /* return r3 = status */
125 125
126/*
127 * plpar_hcall_raw can be called in real mode. kexec/kdump need some
128 * hypervisor calls to be executed in real mode. So plpar_hcall_raw
129 * does not access the per cpu hypervisor call statistics variables,
130 * since these variables may not be present in the RMO region.
131 */
132_GLOBAL(plpar_hcall_raw)
133 HMT_MEDIUM
134
135 mfcr r0
136 stw r0,8(r1)
137
138 std r4,STK_PARM(r4)(r1) /* Save ret buffer */
139
140 mr r4,r5
141 mr r5,r6
142 mr r6,r7
143 mr r7,r8
144 mr r8,r9
145 mr r9,r10
146
147 HVSC /* invoke the hypervisor */
148
149 ld r12,STK_PARM(r4)(r1)
150 std r4, 0(r12)
151 std r5, 8(r12)
152 std r6, 16(r12)
153 std r7, 24(r12)
154
155 lwz r0,8(r1)
156 mtcrf 0xff,r0
157
158 blr /* return r3 = status */
159
126_GLOBAL(plpar_hcall9) 160_GLOBAL(plpar_hcall9)
127 HMT_MEDIUM 161 HMT_MEDIUM
128 162