powerpc/64s: Remove MSR[ISF] bit

No supported processor implements this mode. Setting the bit in
MSR values can be a bit confusing (and would prevent the bit from
ever being reused). Remove it.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201106045340.1935841-1-npiggin@gmail.com

arch/powerpc/include/asm/reg.h

@@ -29,7 +29,6 @@
 #include <asm/reg_8xx.h>
 
 #define MSR_SF_LG	63              /* Enable 64 bit mode */
-#define MSR_ISF_LG	61              /* Interrupt 64b mode valid on 630 */
 #define MSR_HV_LG 	60              /* Hypervisor state */
 #define MSR_TS_T_LG	34		/* Trans Mem state: Transactional */
 #define MSR_TS_S_LG	33		/* Trans Mem state: Suspended */
@@ -69,13 +68,11 @@
 
 #ifdef CONFIG_PPC64
 #define MSR_SF		__MASK(MSR_SF_LG)	/* Enable 64 bit mode */
-#define MSR_ISF		__MASK(MSR_ISF_LG)	/* Interrupt 64b mode valid on 630 */
 #define MSR_HV 		__MASK(MSR_HV_LG)	/* Hypervisor state */
 #define MSR_S		__MASK(MSR_S_LG)	/* Secure state */
 #else
 /* so tests for these bits fail on 32-bit */
 #define MSR_SF		0
-#define MSR_ISF		0
 #define MSR_HV		0
 #define MSR_S		0
 #endif
@@ -134,7 +131,7 @@
 #define MSR_64BIT	MSR_SF
 
 /* Server variant */
-#define __MSR		(MSR_ME | MSR_RI | MSR_IR | MSR_DR | MSR_ISF |MSR_HV)
+#define __MSR		(MSR_ME | MSR_RI | MSR_IR | MSR_DR | MSR_HV)
 #ifdef __BIG_ENDIAN__
 #define MSR_		__MSR
 #define MSR_IDLE	(MSR_ME | MSR_SF | MSR_HV)

arch/powerpc/kernel/entry_64.S

@@ -969,7 +969,7 @@ _GLOBAL(enter_prom)
 	mtsrr1	r11
 	rfi
 #else /* CONFIG_PPC_BOOK3E */
-	LOAD_REG_IMMEDIATE(r12, MSR_SF | MSR_ISF | MSR_LE)
+	LOAD_REG_IMMEDIATE(r12, MSR_SF | MSR_LE)
 	andc	r11,r11,r12
 	mtsrr1	r11
 	RFI_TO_KERNEL

arch/powerpc/kernel/head_64.S

@@ -870,8 +870,7 @@ enable_64b_mode:
 	oris	r11,r11,0x8000		/* CM bit set, we'll set ICM later */
 	mtmsr	r11
 #else /* CONFIG_PPC_BOOK3E */
-	li	r12,(MSR_64BIT | MSR_ISF)@highest
-	sldi	r12,r12,48
+	LOAD_REG_IMMEDIATE(r12, MSR_64BIT)
 	or	r11,r11,r12
 	mtmsrd	r11
 	isync

arch/powerpc/kvm/book3s_pr.c

@@ -239,7 +239,7 @@ static void kvmppc_recalc_shadow_msr(struct kvm_vcpu *vcpu)
 	smsr |= (guest_msr & vcpu->arch.guest_owned_ext);
 	/* 64-bit Process MSR values */
 #ifdef CONFIG_PPC_BOOK3S_64
-	smsr |= MSR_ISF | MSR_HV;
+	smsr |= MSR_HV;
 #endif
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 	/*