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authorMohan Kumar M <mohan@in.ibm.com>2007-03-21 11:21:32 +0530
committerPaul Mackerras <paulus@samba.org>2007-03-22 15:01:43 +1100
commitb4aea36b7956eeebfc56314ce0944db1441255ce (patch)
treea0c84f25e1f5a2ef0af624871e8f892654fd79a4 /arch/powerpc/platforms/pseries
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')
-rw-r--r--arch/powerpc/platforms/pseries/hvCall.S34
-rw-r--r--arch/powerpc/platforms/pseries/lpar.c2
-rw-r--r--arch/powerpc/platforms/pseries/plpar_wrappers.h16
3 files changed, 51 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/pseries/hvCall.S b/arch/powerpc/platforms/pseries/hvCall.S
index 5c7e3878989..1501b0a9e74 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
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 7496005566e..843ee964321 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -378,7 +378,7 @@ static void pSeries_lpar_hptab_clear(void)
/* TODO: Use bulk call */
for (i = 0; i < hpte_count; i++)
- plpar_pte_remove(0, i, 0, &dummy1, &dummy2);
+ plpar_pte_remove_raw(0, i, 0, &dummy1, &dummy2);
}
/*
diff --git a/arch/powerpc/platforms/pseries/plpar_wrappers.h b/arch/powerpc/platforms/pseries/plpar_wrappers.h
index 3eb7b294d92..2e4d10c9eea 100644
--- a/arch/powerpc/platforms/pseries/plpar_wrappers.h
+++ b/arch/powerpc/platforms/pseries/plpar_wrappers.h
@@ -78,6 +78,22 @@ static inline long plpar_pte_remove(unsigned long flags, unsigned long ptex,
return rc;
}
+/* plpar_pte_remove_raw can be called in real mode. It calls plpar_hcall_raw */
+static inline long plpar_pte_remove_raw(unsigned long flags, unsigned long ptex,
+ unsigned long avpn, unsigned long *old_pteh_ret,
+ unsigned long *old_ptel_ret)
+{
+ long rc;
+ unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+
+ rc = plpar_hcall_raw(H_REMOVE, retbuf, flags, ptex, avpn);
+
+ *old_pteh_ret = retbuf[0];
+ *old_ptel_ret = retbuf[1];
+
+ return rc;
+}
+
static inline long plpar_pte_read(unsigned long flags, unsigned long ptex,
unsigned long *old_pteh_ret, unsigned long *old_ptel_ret)
{