powerpc: Select either privileged or hypervisor doorbell when sending

On book3s we have two msgsnd instructions with differing privilege
levels. This patch selects the appropriate instruction to use whenever
we send a doorbell interrupt.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Tested-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/dbell.h

@@ -37,12 +37,25 @@ enum ppc_dbell {
 #define SPRN_DOORBELL_CPUTAG		SPRN_TIR
 #define PPC_DBELL_TAG_MASK		0x7f
 
+static inline void _ppc_msgsnd(u32 msg)
+{
+	if (cpu_has_feature(CPU_FTR_HVMODE))
+		__asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
+	else
+		__asm__ __volatile__ (PPC_MSGSNDP(%0) : : "r" (msg));
+}
+
 #else /* CONFIG_PPC_BOOK3S */
 
 #define PPC_DBELL_MSGTYPE		PPC_DBELL
 #define SPRN_DOORBELL_CPUTAG		SPRN_PIR
 #define PPC_DBELL_TAG_MASK		0x3fff
 
+static inline void _ppc_msgsnd(u32 msg)
+{
+	__asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
+}
+
 #endif /* CONFIG_PPC_BOOK3S */
 
 extern void doorbell_cause_ipi(int cpu, unsigned long data);
@@ -54,7 +67,7 @@ static inline void ppc_msgsnd(enum ppc_dbell type, u32 flags, u32 tag)
 	u32 msg = PPC_DBELL_TYPE(type) | (flags & PPC_DBELL_MSG_BRDCAST) |
 			(tag & 0x07ffffff);
 
-	__asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
+	_ppc_msgsnd(msg);
 }
 
 #endif /* _ASM_POWERPC_DBELL_H */