powerpc/64s: Add support to mask perf interrupts and replay them

Two new bit mask field "IRQ_DISABLE_MASK_PMU" is introduced to support
the masking of PMI and "IRQ_DISABLE_MASK_ALL" to aid interrupt masking
checking.

Couple of new irq #defs "PACA_IRQ_PMI" and "SOFTEN_VALUE_0xf0*" added
to use in the exception code to check for PMI interrupts.

In the masked_interrupt handler, for PMIs we reset the MSR[EE] and
return. In the __check_irq_replay(), replay the PMI interrupt by
calling performance_monitor_common handler.

Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/exception-64s.h

@@ -518,6 +518,7 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
 #define SOFTEN_VALUE_0xe80	PACA_IRQ_DBELL
 #define SOFTEN_VALUE_0xe60	PACA_IRQ_HMI
 #define SOFTEN_VALUE_0xea0	PACA_IRQ_EE
+#define SOFTEN_VALUE_0xf00	PACA_IRQ_PMI
 
 #define __SOFTEN_TEST(h, vec, bitmask)					\
 	lbz	r10,PACAIRQSOFTMASK(r13);				\
@@ -582,6 +583,10 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
 	_MASKABLE_RELON_EXCEPTION_PSERIES(vec, label,			\
 					  EXC_STD, SOFTEN_NOTEST_PR, bitmask)
 
+#define MASKABLE_RELON_EXCEPTION_PSERIES_OOL(vec, label, bitmask)	\
+	MASKABLE_EXCEPTION_PROLOG_1(PACA_EXGEN, SOFTEN_NOTEST_PR, vec, bitmask);\
+	EXCEPTION_PROLOG_PSERIES_1(label, EXC_STD);
+
 #define MASKABLE_RELON_EXCEPTION_HV(loc, vec, label, bitmask)		\
 	_MASKABLE_RELON_EXCEPTION_PSERIES(vec, label,			\
 					  EXC_HV, SOFTEN_TEST_HV, bitmask)

arch/powerpc/include/asm/hw_irq.h

@@ -27,12 +27,15 @@
 #define PACA_IRQ_DEC		0x08 /* Or FIT */
 #define PACA_IRQ_EE_EDGE	0x10 /* BookE only */
 #define PACA_IRQ_HMI		0x20
+#define PACA_IRQ_PMI		0x40
 
 /*
  * flags for paca->irq_soft_mask
  */
 #define IRQS_ENABLED		0
-#define IRQS_DISABLED		1
+#define IRQS_DISABLED		1 /* local_irq_disable() interrupts */
+#define IRQS_PMI_DISABLED	2
+#define IRQS_ALL_DISABLED	(IRQS_DISABLED | IRQS_PMI_DISABLED)
 
 #endif /* CONFIG_PPC64 */
 
@@ -152,13 +155,13 @@ static inline bool arch_irqs_disabled(void)
 #define __hard_irq_disable()	__mtmsrd(local_paca->kernel_msr, 1)
 #endif
 
-#define hard_irq_disable()	do {				\
-	unsigned long flags;					\
-	__hard_irq_disable();					\
-	flags = irq_soft_mask_set_return(IRQS_DISABLED);	\
-	local_paca->irq_happened |= PACA_IRQ_HARD_DIS;		\
-	if (!arch_irqs_disabled_flags(flags))			\
-		trace_hardirqs_off();				\
+#define hard_irq_disable()	do {					\
+	unsigned long flags;						\
+	__hard_irq_disable();						\
+	flags = irq_soft_mask_set_return(IRQS_ALL_DISABLED);		\
+	local_paca->irq_happened |= PACA_IRQ_HARD_DIS;			\
+	if (!arch_irqs_disabled_flags(flags))				\
+		trace_hardirqs_off();					\
 } while(0)
 
 static inline bool lazy_irq_pending(void)

arch/powerpc/kernel/entry_64.S

@@ -954,6 +954,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 	addi	r3,r1,STACK_FRAME_OVERHEAD;
  	bl	do_IRQ
 	b	ret_from_except
+1:	cmpwi	cr0,r3,0xf00
+	bne	1f
+	addi	r3,r1,STACK_FRAME_OVERHEAD;
+	bl	performance_monitor_exception
+	b	ret_from_except
 1:	cmpwi	cr0,r3,0xe60
 	bne	1f
 	addi	r3,r1,STACK_FRAME_OVERHEAD;

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

@@ -1111,8 +1111,8 @@ EXC_REAL_NONE(0xee0, 0x20)
 EXC_VIRT_NONE(0x4ee0, 0x20)
 
 
-EXC_REAL_OOL(performance_monitor, 0xf00, 0x20)
-EXC_VIRT_OOL(performance_monitor, 0x4f00, 0x20, 0xf00)
+EXC_REAL_OOL_MASKABLE(performance_monitor, 0xf00, 0x20, IRQS_PMI_DISABLED)
+EXC_VIRT_OOL_MASKABLE(performance_monitor, 0x4f00, 0x20, 0xf00, IRQS_PMI_DISABLED)
 TRAMP_KVM(PACA_EXGEN, 0xf00)
 EXC_COMMON_ASYNC(performance_monitor_common, 0xf00, performance_monitor_exception)
 
@@ -1723,6 +1723,8 @@ BEGIN_FTR_SECTION
 FTR_SECTION_ELSE
 	beq	hardware_interrupt_common
 ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_300)
+	cmpwi	r3,0xf00
+	beq	performance_monitor_common
 BEGIN_FTR_SECTION
 	cmpwi	r3,0xa00
 	beq	h_doorbell_common_msgclr

arch/powerpc/kernel/irq.c

@@ -186,6 +186,11 @@ notrace unsigned int __check_irq_replay(void)
 		return 0x900;
 	}
 
+	if (happened & PACA_IRQ_PMI) {
+		local_paca->irq_happened &= ~PACA_IRQ_PMI;
+		return 0xf00;
+	}
+
 	if (happened & PACA_IRQ_EE) {
 		local_paca->irq_happened &= ~PACA_IRQ_EE;
 		return 0x500;
@@ -272,7 +277,7 @@ notrace void arch_local_irq_restore(unsigned long mask)
 	}
 #endif /* CONFIG_TRACE_IRQFLAGS */
 
-	irq_soft_mask_set(IRQS_DISABLED);
+	irq_soft_mask_set(IRQS_ALL_DISABLED);
 	trace_hardirqs_off();
 
 	/*