powerpc: Always use SPRN_SPRG_HSCRATCH0 when running in HV mode

This uses feature sections to arrange that we always use HSPRG1
as the scratch register in the interrupt entry code rather than
SPRG2 when we're running in hypervisor mode on POWER7.  This will
ensure that we don't trash the guest's SPRG2 when we are running
KVM guests.  To simplify the code, we define GET_SCRATCH0() and
SET_SCRATCH0() macros like the GET_PACA/SET_PACA macros.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

2 files changed, 4 insertions, 4 deletions

diff --git a/arch/powerpc/kvm/book3s_rmhandlers.S b/arch/powerpc/kvm/book3s_rmhandlers.S
index 046e1f3d4432..ae99af66ca34 100644
--- a/arch/powerpc/kvm/book3s_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_rmhandlers.S
@@ -70,7 +70,7 @@
 .global kvmppc_trampoline_\intno
 kvmppc_trampoline_\intno:
 
-        mtspr   SPRN_SPRG_SCRATCH0, r13         /* Save r13 */
+        SET_SCRATCH0(r13)               /* Save r13 */
 
         /*
          * First thing to do is to find out if we're coming
@@ -89,7 +89,7 @@ kvmppc_trampoline_\intno:
         lwz     r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH1)(r13)
         mtcr    r12
         PPC_LL  r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH0)(r13)
-        mfspr   r13, SPRN_SPRG_SCRATCH0         /* r13 = original r13 */
+        GET_SCRATCH0(r13)                       /* r13 = original r13 */
         b       kvmppc_resume_\intno            /* Get back original handler */
 
         /* Now we know we're handling a KVM guest */
@@ -157,7 +157,7 @@ kvmppc_handler_skip_ins:
         lwz     r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH1)(r13)
         mtcr    r12
         PPC_LL  r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH0)(r13)
-        mfspr   r13, SPRN_SPRG_SCRATCH0
+        GET_SCRATCH0(r13)
 
         /* And get back into the code */
         RFI
diff --git a/arch/powerpc/kvm/book3s_segment.S b/arch/powerpc/kvm/book3s_segment.S
index d842795d0f23..451264274b8c 100644
--- a/arch/powerpc/kvm/book3s_segment.S
+++ b/arch/powerpc/kvm/book3s_segment.S
@@ -168,7 +168,7 @@ kvmppc_handler_trampoline_exit:
         PPC_STL r4, (SHADOW_VCPU_OFF + SVCPU_SHADOW_SRR1)(r13)
 
         /* Get scratch'ed off registers */
-        mfspr   r9, SPRN_SPRG_SCRATCH0
+        GET_SCRATCH0(r9)
         PPC_LL  r8, (SHADOW_VCPU_OFF + SVCPU_SCRATCH0)(r13)
         lwz     r7, (SHADOW_VCPU_OFF + SVCPU_SCRATCH1)(r13)