powerpc/64s/exception: Add ISIDE option

Rather than using DAR=2 to select the i-side registers, add an
explicit option.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200225173541.1549955-10-npiggin@gmail.com

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

@@ -199,6 +199,7 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
 #define IVEC		.L_IVEC_\name\()
 #define IHSRR		.L_IHSRR_\name\()
 #define IAREA		.L_IAREA_\name\()
+#define IISIDE		.L_IISIDE_\name\()
 #define IDAR		.L_IDAR_\name\()
 #define IDSISR		.L_IDSISR_\name\()
 #define ISET_RI		.L_ISET_RI_\name\()
@@ -231,6 +232,9 @@ do_define_int n
 	.ifndef IAREA
 		IAREA=PACA_EXGEN
 	.endif
+	.ifndef IISIDE
+		IISIDE=0
+	.endif
 	.ifndef IDAR
 		IDAR=0
 	.endif
@@ -542,7 +546,7 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,948)
 	 */
 	GET_SCRATCH0(r10)
 	std	r10,IAREA+EX_R13(r13)
-	.if IDAR == 1
+	.if IDAR && !IISIDE
 	.if IHSRR
 	mfspr	r10,SPRN_HDAR
 	.else
@@ -550,7 +554,7 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,948)
 	.endif
 	std	r10,IAREA+EX_DAR(r13)
 	.endif
-	.if IDSISR == 1
+	.if IDSISR && !IISIDE
 	.if IHSRR
 	mfspr	r10,SPRN_HDSISR
 	.else
@@ -625,16 +629,18 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,948)
 	std	r9,GPR11(r1)
 	std	r10,GPR12(r1)
 	std	r11,GPR13(r1)
+
 	.if IDAR
-	.if IDAR == 2
+	.if IISIDE
 	ld	r10,_NIP(r1)
 	.else
 	ld	r10,IAREA+EX_DAR(r13)
 	.endif
 	std	r10,_DAR(r1)
 	.endif
+
 	.if IDSISR
-	.if IDSISR == 2
+	.if IISIDE
 	ld	r10,_MSR(r1)
 	lis	r11,DSISR_SRR1_MATCH_64S@h
 	and	r10,r10,r11
@@ -643,6 +649,7 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,948)
 	.endif
 	std	r10,_DSISR(r1)
 	.endif
+
 BEGIN_FTR_SECTION_NESTED(66)
 	ld	r10,IAREA+EX_CFAR(r13)
 	std	r10,ORIG_GPR3(r1)
@@ -1311,8 +1318,9 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
 
 INT_DEFINE_BEGIN(instruction_access)
 	IVEC=0x400
-	IDAR=2
-	IDSISR=2
+	IISIDE=1
+	IDAR=1
+	IDSISR=1
 	IKVM_REAL=1
 INT_DEFINE_END(instruction_access)
 
@@ -1341,7 +1349,8 @@ INT_DEFINE_BEGIN(instruction_access_slb)
 	IVEC=0x480
 	IAREA=PACA_EXSLB
 	IRECONCILE=0
-	IDAR=2
+	IISIDE=1
+	IDAR=1
 	IKVM_REAL=1
 INT_DEFINE_END(instruction_access_slb)