[PATCH 05/10] powerpc/64s/exception: remove confusing IEARLY option

[Nicholas Piggin]

Replace IEARLY=1 and IEARLY=2 with IBRANCH_COMMON, which controls if
the entry code branches to a common handler; and IREALMODE_COMMON,
which controls whether the common handler should remain in real mode.

These special cases no longer avoid loading the SRR registers, there
is no point as most of them load the registers immediately anyway.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 arch/powerpc/kernel/exceptions-64s.S | 48 ++++++++++++++--------------
 1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index e5d5d81d6107..705cca95e03c 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -174,7 +174,8 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
 #define IDAR		.L_IDAR_\name\()
 #define IDSISR		.L_IDSISR_\name\()
 #define ISET_RI		.L_ISET_RI_\name\()
-#define IEARLY		.L_IEARLY_\name\()
+#define IBRANCH_COMMON	.L_IBRANCH_COMMON_\name\()
+#define IREALMODE_COMMON	.L_IREALMODE_COMMON_\name\()
 #define IMASK		.L_IMASK_\name\()
 #define IKVM_SKIP	.L_IKVM_SKIP_\name\()
 #define IKVM_REAL	.L_IKVM_REAL_\name\()
@@ -218,8 +219,15 @@ do_define_int n
 	.ifndef ISET_RI
 		ISET_RI=1
 	.endif
-	.ifndef IEARLY
-		IEARLY=0
+	.ifndef IBRANCH_COMMON
+		IBRANCH_COMMON=1
+	.endif
+	.ifndef IREALMODE_COMMON
+		IREALMODE_COMMON=0
+	.else
+		.if ! IBRANCH_COMMON
+			.error "IREALMODE_COMMON=1 but IBRANCH_COMMON=0"
+		.endif
 	.endif
 	.ifndef IMASK
 		IMASK=0
@@ -356,6 +364,11 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,948)
 #define GEN_OOL		1
 
 .macro GEN_BRANCH_TO_COMMON name virt
+	.if IREALMODE_COMMON
+	LOAD_HANDLER(r10, \name\()_common)
+	mtctr	r10
+	bctr
+	.else
 	.if \virt
 #ifndef CONFIG_RELOCATABLE
 	b	\name\()_common_virt
@@ -369,6 +382,7 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,948)
 	mtctr	r10
 	bctr
 	.endif
+	.endif
 .endm
 
 .macro GEN_INT_ENTRY name virt ool=0
@@ -424,11 +438,6 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,948)
 	stw	r10,IAREA+EX_DSISR(r13)
 	.endif
 
-	.if IEARLY == 2
-	/* nothing more */
-	.elseif IEARLY
-	BRANCH_TO_C000(r11, \name\()_common)
-	.else
 	.if IHSRR == EXC_HV_OR_STD
 	BEGIN_FTR_SECTION
 	mfspr	r11,SPRN_HSRR0		/* save HSRR0 */
@@ -444,6 +453,8 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,948)
 	mfspr	r11,SPRN_SRR0		/* save SRR0 */
 	mfspr	r12,SPRN_SRR1		/* and SRR1 */
 	.endif
+
+	.if IBRANCH_COMMON
 	GEN_BRANCH_TO_COMMON \name \virt
 	.endif
 
@@ -923,6 +934,7 @@ INT_DEFINE_BEGIN(machine_check_early)
 	IHSRR=EXC_STD
 	IAREA=PACA_EXMC
 	IVIRT=0 /* no virt entry point */
+	IREALMODE_COMMON=1
 	/*
 	 * MSR_RI is not enabled, because PACA_EXMC is being used, so a
 	 * nested machine check corrupts it. machine_check_common enables
@@ -930,7 +942,6 @@ INT_DEFINE_BEGIN(machine_check_early)
 	 */
 	ISET_RI=0
 	ISTACK=0
-	IEARLY=1
 	IDAR=1
 	IDSISR=1
 	IRECONCILE=0
@@ -971,9 +982,6 @@ TRAMP_REAL_BEGIN(machine_check_fwnmi)
 	EXCEPTION_RESTORE_REGS EXC_STD
 
 EXC_COMMON_BEGIN(machine_check_early_common)
-	mfspr	r11,SPRN_SRR0
-	mfspr	r12,SPRN_SRR1
-
 	/*
 	 * Switch to mc_emergency stack and handle re-entrancy (we limit
 	 * the nested MCE upto level 4 to avoid stack overflow).
@@ -1849,7 +1857,7 @@ INT_DEFINE_BEGIN(hmi_exception_early)
 	IHSRR=EXC_HV
 	IAREA=PACA_EXGEN
 	IVIRT=0 /* no virt entry point */
-	IEARLY=1
+	IREALMODE_COMMON=1
 	ISTACK=0
 	IRECONCILE=0
 	IKUAP=0 /* We don't touch AMR here, we never go to virtual mode */
@@ -1871,8 +1879,6 @@ EXC_REAL_END(hmi_exception, 0xe60, 0x20)
 EXC_VIRT_NONE(0x4e60, 0x20)
 
 EXC_COMMON_BEGIN(hmi_exception_early_common)
-	mfspr	r11,SPRN_HSRR0		/* Save HSRR0 */
-	mfspr	r12,SPRN_HSRR1		/* Save HSRR1 */
 	mr	r10,r1			/* Save r1 */
 	ld	r1,PACAEMERGSP(r13)	/* Use emergency stack for realmode */
 	subi	r1,r1,INT_FRAME_SIZE	/* alloc stack frame		*/
@@ -2213,29 +2219,23 @@ INT_DEFINE_BEGIN(denorm_exception)
 	IVEC=0x1500
 	IHSRR=EXC_HV
 	IAREA=PACA_EXGEN
-	IEARLY=2
+	IBRANCH_COMMON=0
 	IKVM_REAL=1
 INT_DEFINE_END(denorm_exception)
 
 EXC_REAL_BEGIN(denorm_exception, 0x1500, 0x100)
 	GEN_INT_ENTRY denorm_exception, GEN_REAL
 #ifdef CONFIG_PPC_DENORMALISATION
-	mfspr	r10,SPRN_HSRR1
-	andis.	r10,r10,(HSRR1_DENORM)@h /* denorm? */
+	andis.	r10,r12,(HSRR1_DENORM)@h /* denorm? */
 	bne+	denorm_assist
 #endif
-	mfspr	r11,SPRN_HSRR0
-	mfspr	r12,SPRN_HSRR1
 	GEN_BRANCH_TO_COMMON denorm_exception, GEN_REAL
 EXC_REAL_END(denorm_exception, 0x1500, 0x100)
 #ifdef CONFIG_PPC_DENORMALISATION
 EXC_VIRT_BEGIN(denorm_exception, 0x5500, 0x100)
 	GEN_INT_ENTRY denorm_exception, GEN_VIRT
-	mfspr	r10,SPRN_HSRR1
-	andis.	r10,r10,(HSRR1_DENORM)@h /* denorm? */
+	andis.	r10,r12,(HSRR1_DENORM)@h /* denorm? */
 	bne+	denorm_assist
-	mfspr	r11,SPRN_HSRR0
-	mfspr	r12,SPRN_HSRR1
 	GEN_BRANCH_TO_COMMON denorm_exception, GEN_VIRT
 EXC_VIRT_END(denorm_exception, 0x5500, 0x100)
 #else
-- 
2.22.0