1 files changed, 30 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/kvm_emul.S b/arch/powerpc/kernel/kvm_emul.S
index 5cfa2aeeecb0..1dac72dd6f6e 100644
--- a/arch/powerpc/kernel/kvm_emul.S
+++ b/arch/powerpc/kernel/kvm_emul.S
@@ -34,3 +34,33 @@ kvm_hypercall_start:
         blr
 
 #define KVM_MAGIC_PAGE          (-4096)
+
+#ifdef CONFIG_64BIT
+#define LL64(reg, offs, reg2)   ld      reg, (offs)(reg2)
+#define STL64(reg, offs, reg2)  std     reg, (offs)(reg2)
+#else
+#define LL64(reg, offs, reg2)   lwz     reg, (offs + 4)(reg2)
+#define STL64(reg, offs, reg2)  stw     reg, (offs + 4)(reg2)
+#endif
+
+#define SCRATCH_SAVE                                                    \
+        /* Enable critical section. We are critical if                  \
+           shared->critical == r1 */                                    \
+        STL64(r1, KVM_MAGIC_PAGE + KVM_MAGIC_CRITICAL, 0);              \
+                                                                        \
+        /* Save state */                                                \
+        PPC_STL r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH1)(0);          \
+        PPC_STL r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH2)(0);          \
+        mfcr    r31;                                                    \
+        stw     r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH3)(0);
+
+#define SCRATCH_RESTORE                                                 \
+        /* Restore state */                                             \
+        PPC_LL  r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH1)(0);          \
+        lwz     r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH3)(0);          \
+        mtcr    r30;                                                    \
+        PPC_LL  r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH2)(0);          \
+                                                                        \
+        /* Disable critical section. We are critical if                 \
+           shared->critical == r1 and r2 is always != r1 */             \
+        STL64(r2, KVM_MAGIC_PAGE + KVM_MAGIC_CRITICAL, 0);