powerpc: Add book3s hypervisor doorbell exception vectors

Directed Hypervisor Doorbell Interrupts come in at 0xe80 (or
0xc000000000004e80 if relocation on exceptions 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 +305,8 @@ 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_0xe80	PACA_IRQ_DBELL
+#define SOFTEN_VALUE_0xe82	PACA_IRQ_DBELL
 
 #define __SOFTEN_TEST(h, vec)						\
 	lbz	r10,PACASOFTIRQEN(r13);					\

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

@@ -293,6 +293,8 @@ hv_exception_trampoline:
 	b	hmi_exception_hv
 	. = 0xe60
 	b	hmi_exception_hv
+	. = 0xe80
+	b	h_doorbell_hv
 
 	/* We need to deal with the Altivec unavailable exception
 	 * here which is at 0xf20, thus in the middle of the
@@ -514,6 +516,8 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_206)
 	KVM_HANDLER(PACA_EXGEN, EXC_HV, 0xe42)
 	STD_EXCEPTION_HV(., 0xe62, hmi_exception) /* need to flush cache ? */
 	KVM_HANDLER(PACA_EXGEN, EXC_HV, 0xe62)
+	MASKABLE_EXCEPTION_HV(., 0xe82, h_doorbell)
+	KVM_HANDLER(PACA_EXGEN, EXC_HV, 0xe82)
 
 	/* moved from 0xf00 */
 	STD_EXCEPTION_PSERIES(., 0xf00, performance_monitor)
@@ -657,6 +661,11 @@ machine_check_common:
 	STD_EXCEPTION_COMMON(0xe00, trap_0e, .unknown_exception)
 	STD_EXCEPTION_COMMON(0xe40, emulation_assist, .program_check_exception)
 	STD_EXCEPTION_COMMON(0xe60, hmi_exception, .unknown_exception)
+#ifdef CONFIG_PPC_DOORBELL
+	STD_EXCEPTION_COMMON_ASYNC(0xe80, h_doorbell, .doorbell_exception)
+#else
+	STD_EXCEPTION_COMMON_ASYNC(0xe80, h_doorbell, .unknown_exception)
+#endif
 	STD_EXCEPTION_COMMON_ASYNC(0xf00, performance_monitor, .performance_monitor_exception)
 	STD_EXCEPTION_COMMON(0x1300, instruction_breakpoint, .instruction_breakpoint_exception)
 	STD_EXCEPTION_COMMON(0x1502, denorm, .unknown_exception)
@@ -773,9 +782,8 @@ system_call_relon_pSeries:
 	. = 0x4e60
 	b	hmi_exception_relon_hv
 
-	/* For when we support the doorbell interrupt:
-	STD_RELON_EXCEPTION_HYPERVISOR(0x4e80, 0xe80, doorbell_hyper)
-	*/
+	. = 0x4e80
+	b	h_doorbell_relon_hv
 
 performance_monitor_relon_pSeries_1:
 	. = 0x4f00
@@ -1355,6 +1363,8 @@ _GLOBAL(do_stab_bolted)
 	KVM_HANDLER(PACA_EXGEN, EXC_HV, 0xe40)
 	STD_RELON_EXCEPTION_HV(., 0xe60, hmi_exception)
 	KVM_HANDLER(PACA_EXGEN, EXC_HV, 0xe60)
+	MASKABLE_RELON_EXCEPTION_HV(., 0xe80, h_doorbell)
+	KVM_HANDLER(PACA_EXGEN, EXC_HV, 0xe80)
 
 	STD_RELON_EXCEPTION_PSERIES(., 0xf00, performance_monitor)
 	STD_RELON_EXCEPTION_PSERIES(., 0xf20, altivec_unavailable)