powerpc: Add book3s privileged doorbell exception vectors

Directed Privileged Doorbell Interrupts come in at 0xa00 (or
0xc000000000004a00 if relocation on exception is enabled), so add
exception vectors at these locations.

If doorbell support is not compiled in we handle it as an
unknown_exception.
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/exception-64s.h

@@ -305,6 +305,7 @@ label##_relon_hv:					\
 #define SOFTEN_VALUE_0x502	PACA_IRQ_EE
 #define SOFTEN_VALUE_0x900	PACA_IRQ_DEC
 #define SOFTEN_VALUE_0x982	PACA_IRQ_DEC
+#define SOFTEN_VALUE_0xa00	PACA_IRQ_DBELL
 #define SOFTEN_VALUE_0xe80	PACA_IRQ_DBELL
 #define SOFTEN_VALUE_0xe82	PACA_IRQ_DBELL
 

arch/powerpc/kernel/exceptions-64s.S

@@ -252,7 +252,7 @@ hardware_interrupt_hv:
 	MASKABLE_EXCEPTION_PSERIES(0x900, 0x900, decrementer)
 	STD_EXCEPTION_HV(0x980, 0x982, hdecrementer)
 
-	STD_EXCEPTION_PSERIES(0xa00, 0xa00, trap_0a)
+	MASKABLE_EXCEPTION_PSERIES(0xa00, 0xa00, doorbell_super)
 	KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0xa00)
 
 	STD_EXCEPTION_PSERIES(0xb00, 0xb00, trap_0b)
@@ -655,7 +655,11 @@ machine_check_common:
 	STD_EXCEPTION_COMMON_ASYNC(0x500, hardware_interrupt, do_IRQ)
 	STD_EXCEPTION_COMMON_ASYNC(0x900, decrementer, .timer_interrupt)
 	STD_EXCEPTION_COMMON(0x980, hdecrementer, .hdec_interrupt)
-	STD_EXCEPTION_COMMON(0xa00, trap_0a, .unknown_exception)
+#ifdef CONFIG_PPC_DOORBELL
+	STD_EXCEPTION_COMMON_ASYNC(0xa00, doorbell_super, .doorbell_exception)
+#else
+	STD_EXCEPTION_COMMON_ASYNC(0xa00, doorbell_super, .unknown_exception)
+#endif
 	STD_EXCEPTION_COMMON(0xb00, trap_0b, .unknown_exception)
 	STD_EXCEPTION_COMMON(0xd00, single_step, .single_step_exception)
 	STD_EXCEPTION_COMMON(0xe00, trap_0e, .unknown_exception)
@@ -755,6 +759,7 @@ hardware_interrupt_relon_hv:
 	STD_RELON_EXCEPTION_PSERIES(0x4800, 0x800, fp_unavailable)
 	MASKABLE_RELON_EXCEPTION_PSERIES(0x4900, 0x900, decrementer)
 	STD_RELON_EXCEPTION_HV(0x4980, 0x982, hdecrementer)
+	MASKABLE_RELON_EXCEPTION_PSERIES(0x4a00, 0xa00, doorbell_super)
 	STD_RELON_EXCEPTION_PSERIES(0x4b00, 0xb00, trap_0b)
 
 	. = 0x4c00