powerpc/64s: runlatch interrupt handling in C

There is no need for this to be in asm, use the new intrrupt entry wrapper.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-42-npiggin@gmail.com

arch/powerpc/include/asm/interrupt.h

@@ -6,6 +6,7 @@
 #include <linux/hardirq.h>
 #include <asm/cputime.h>
 #include <asm/ftrace.h>
+#include <asm/runlatch.h>
 
 struct interrupt_state {
 #ifdef CONFIG_PPC_BOOK3E_64
@@ -83,6 +84,12 @@ static inline void interrupt_exit_prepare(struct pt_regs *regs, struct interrupt
 
 static inline void interrupt_async_enter_prepare(struct pt_regs *regs, struct interrupt_state *state)
 {
+#ifdef CONFIG_PPC_BOOK3S_64
+	if (cpu_has_feature(CPU_FTR_CTRL) &&
+	    !test_thread_local_flags(_TLF_RUNLATCH))
+		__ppc64_runlatch_on();
+#endif
+
 	interrupt_enter_prepare(regs, state);
 	irq_enter();
 }

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

@@ -692,14 +692,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
 	ld	r1,GPR1(r1)
 .endm
 
-#define RUNLATCH_ON				\
-BEGIN_FTR_SECTION				\
-	ld	r3, PACA_THREAD_INFO(r13);	\
-	ld	r4,TI_LOCAL_FLAGS(r3);		\
-	andi.	r0,r4,_TLF_RUNLATCH;		\
-	beql	ppc64_runlatch_on_trampoline;	\
-END_FTR_SECTION_IFSET(CPU_FTR_CTRL)
-
 /*
  * When the idle code in power4_idle puts the CPU into NAP mode,
  * it has to do so in a loop, and relies on the external interrupt
@@ -1585,7 +1577,6 @@ EXC_VIRT_END(hardware_interrupt, 0x4500, 0x100)
 EXC_COMMON_BEGIN(hardware_interrupt_common)
 	GEN_COMMON hardware_interrupt
 	FINISH_NAP
-	RUNLATCH_ON
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	do_IRQ
 	b	interrupt_return
@@ -1771,7 +1762,6 @@ EXC_VIRT_END(decrementer, 0x4900, 0x80)
 EXC_COMMON_BEGIN(decrementer_common)
 	GEN_COMMON decrementer
 	FINISH_NAP
-	RUNLATCH_ON
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	timer_interrupt
 	b	interrupt_return
@@ -1857,7 +1847,6 @@ EXC_VIRT_END(doorbell_super, 0x4a00, 0x100)
 EXC_COMMON_BEGIN(doorbell_super_common)
 	GEN_COMMON doorbell_super
 	FINISH_NAP
-	RUNLATCH_ON
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 #ifdef CONFIG_PPC_DOORBELL
 	bl	doorbell_exception
@@ -2212,7 +2201,6 @@ EXC_COMMON_BEGIN(hmi_exception_early_common)
 EXC_COMMON_BEGIN(hmi_exception_common)
 	GEN_COMMON hmi_exception
 	FINISH_NAP
-	RUNLATCH_ON
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	handle_hmi_exception
 	b	interrupt_return
@@ -2242,7 +2230,6 @@ EXC_VIRT_END(h_doorbell, 0x4e80, 0x20)
 EXC_COMMON_BEGIN(h_doorbell_common)
 	GEN_COMMON h_doorbell
 	FINISH_NAP
-	RUNLATCH_ON
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 #ifdef CONFIG_PPC_DOORBELL
 	bl	doorbell_exception
@@ -2276,7 +2263,6 @@ EXC_VIRT_END(h_virt_irq, 0x4ea0, 0x20)
 EXC_COMMON_BEGIN(h_virt_irq_common)
 	GEN_COMMON h_virt_irq
 	FINISH_NAP
-	RUNLATCH_ON
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	do_IRQ
 	b	interrupt_return
@@ -2323,7 +2309,6 @@ EXC_VIRT_END(performance_monitor, 0x4f00, 0x20)
 EXC_COMMON_BEGIN(performance_monitor_common)
 	GEN_COMMON performance_monitor
 	FINISH_NAP
-	RUNLATCH_ON
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	performance_monitor_exception
 	b	interrupt_return
@@ -3038,9 +3023,6 @@ kvmppc_skip_Hinterrupt:
 	 * come here.
 	 */
 
-EXC_COMMON_BEGIN(ppc64_runlatch_on_trampoline)
-	b	__ppc64_runlatch_on
-
 USE_FIXED_SECTION(virt_trampolines)
 	/*
 	 * All code below __end_interrupts is treated as soft-masked. If