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.

Reviewed-by: Nicholas Piggin <npig...@gmail.com>
Signed-off-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/exception-64s.h |  5 +++++
 arch/powerpc/include/asm/hw_irq.h        |  5 ++++-
 arch/powerpc/kernel/entry_64.S           |  5 +++++
 arch/powerpc/kernel/exceptions-64s.S     |  6 ++++--
 arch/powerpc/kernel/irq.c                | 25 ++++++++++++++++++++++++-
 5 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/exception-64s.h 
b/arch/powerpc/include/asm/exception-64s.h
index d04f519c7b75..b97a52718365 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -431,6 +431,7 @@ 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,PACASOFTIRQEN(r13);                                 \
@@ -495,6 +496,10 @@ 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_NOTEST_HV, bitmask)
diff --git a/arch/powerpc/include/asm/hw_irq.h 
b/arch/powerpc/include/asm/hw_irq.h
index f7c761902dc9..5bcadd139fca 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -26,12 +26,15 @@
 #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->soft_enabled
  */
 #define IRQ_DISABLE_MASK_NONE  0
 #define IRQ_DISABLE_MASK_LINUX 1
+#define IRQ_DISABLE_MASK_PMU   2
+#define IRQ_DISABLE_MASK_ALL   3
 
 #endif /* CONFIG_PPC64 */
 
@@ -132,7 +135,7 @@ static inline bool arch_irqs_disabled(void)
        u8 _was_enabled;                                \
        __hard_irq_disable();                           \
        _was_enabled = local_paca->soft_enabled;        \
-       local_paca->soft_enabled = IRQ_DISABLE_MASK_LINUX;\
+       local_paca->soft_enabled = IRQ_DISABLE_MASK_ALL;\
        local_paca->irq_happened |= PACA_IRQ_HARD_DIS;  \
        if (!(_was_enabled & IRQ_DISABLE_MASK_LINUX))   \
                trace_hardirqs_off();                   \
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index f3afa0b9332d..d021f7de79bd 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -931,6 +931,11 @@ restore_check_irq_replay:
        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;
diff --git a/arch/powerpc/kernel/exceptions-64s.S 
b/arch/powerpc/kernel/exceptions-64s.S
index 66f5334870bf..e914b9f6cd2f 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1041,8 +1041,8 @@ EXC_REAL_NONE(0xec0, 0xf00)
 EXC_VIRT_NONE(0x4ec0, 0x4f00)
 
 
-EXC_REAL_OOL(performance_monitor, 0xf00, 0xf20)
-EXC_VIRT_OOL(performance_monitor, 0x4f00, 0x4f20, 0xf00)
+EXC_REAL_OOL_MASKABLE(performance_monitor, 0xf00, 0xf20, IRQ_DISABLE_MASK_PMU)
+EXC_VIRT_OOL_MASKABLE(performance_monitor, 0x4f00, 0x4f20, 0xf00, 
IRQ_DISABLE_MASK_PMU)
 TRAMP_KVM(PACA_EXGEN, 0xf00)
 EXC_COMMON_ASYNC(performance_monitor_common, 0xf00, 
performance_monitor_exception)
 
@@ -1580,6 +1580,8 @@ _GLOBAL(__replay_interrupt)
        beq     decrementer_common
        cmpwi   r3,0x500
        beq     hardware_interrupt_common
+       cmpwi   r3,0xf00
+       beq     performance_monitor_common
 BEGIN_FTR_SECTION
        cmpwi   r3,0xe80
        beq     h_doorbell_common
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 6055b04d2592..da538ec0fd47 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -169,6 +169,27 @@ notrace unsigned int __check_irq_replay(void)
        if ((happened & PACA_IRQ_DEC) || decrementer_check_overflow())
                return 0x900;
 
+       /*
+        * In masked_handler() for PMI, we disable MSR[EE] and return.
+        * Replay it here.
+        *
+        * After this point, PMIs could still be disabled in certain
+        * scenarios like this one.
+        *
+        * local_irq_disable();
+        * powerpc_irq_pmu_save();
+        * powerpc_irq_pmu_restore();
+        * local_irq_restore();
+        *
+        * Even though powerpc_irq_pmu_restore() would have replayed the PMIs
+        * if any, we have still not enabled EE and this will happen only at
+        * complition of last *_restore in this nested cases. And PMIs will
+        * once again start firing only when we have MSR[EE] enabled.
+        */
+       local_paca->irq_happened &= ~PACA_IRQ_PMI;
+       if (happened & PACA_IRQ_PMI)
+               return 0xf00;
+
        /* Finally check if an external interrupt happened */
        local_paca->irq_happened &= ~PACA_IRQ_EE;
        if (happened & PACA_IRQ_EE)
@@ -208,7 +229,9 @@ notrace void arch_local_irq_restore(unsigned long en)
 
        /* Write the new soft-enabled value */
        soft_enabled_set(en);
-       if (en == IRQ_DISABLE_MASK_LINUX)
+
+       /* any bits still disabled */
+       if (en)
                return;
        /*
         * From this point onward, we can take interrupts, preempt,
-- 
2.7.4

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