powerpc/pseries: Inform the hypervisor we are using EBB regs

On LPAR systems we need to inform the hypervisor that we are using the
EBB registers. We do this by setting a bit in the Virtual Processor Area
(VPA) - formerly known as the lppaca.

For now we do this always, ie. we do not dynamically enable/disable.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/lppaca.h

@@ -66,7 +66,8 @@ struct lppaca {
 
 	u8	reserved6[48];
 	u8	cede_latency_hint;
-	u8	reserved7[7];
+	u8	ebb_regs_in_use;
+	u8	reserved7[6];
 	u8	dtl_enable_mask;	/* Dispatch Trace Log mask */
 	u8	donate_dedicated_cpu;	/* Donate dedicated CPU cycles */
 	u8	fpregs_in_use;

arch/powerpc/platforms/pseries/lpar.c

@@ -71,6 +71,9 @@ void vpa_init(int cpu)
 	if (cpu_has_feature(CPU_FTR_ALTIVEC))
 		lppaca_of(cpu).vmxregs_in_use = 1;
 
+	if (cpu_has_feature(CPU_FTR_ARCH_207S))
+		lppaca_of(cpu).ebb_regs_in_use = 1;
+
 	addr = __pa(&lppaca_of(cpu));
 	ret = register_vpa(hwcpu, addr);