powerpc/64s: Fix PACA_IRQ_HARD_DIS accounting in idle_power4()

When idle_power4() hard disables interrupts then finds a soft pending
interrupt, it returns with interrupts hard disabled but without
PACA_IRQ_HARD_DIS set. Commit 9b81c0211c ("powerpc/64s: make
PACA_IRQ_HARD_DIS track MSR[EE] closely") added a warning for that
condition (since disabled).

Fix this by adding the PACA_IRQ_HARD_DIS for that case.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/idle_power4.S b/arch/powerpc/kernel/idle_power4.S
index dd7471fe20bd4960e3a8db2cd34deb64fde061b2..a09b3c7ca176e1d52b3f0c8c538cee8be3abcf29 100644 (file)
--- a/arch/powerpc/kernel/idle_power4.S
+++ b/arch/powerpc/kernel/idle_power4.S
@@ -32,6 +32,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_CAN_NAP)
        cmpwi   0,r4,0
        beqlr
 
+       /* This sequence is similar to prep_irq_for_idle() */
+
        /* Hard disable interrupts */
        mfmsr   r7
        rldicl  r0,r7,48,1
@@ -41,10 +43,15 @@ END_FTR_SECTION_IFCLR(CPU_FTR_CAN_NAP)
        /* Check if something happened while soft-disabled */
        lbz     r0,PACAIRQHAPPENED(r13)
        cmpwi   cr0,r0,0
-       bnelr
+       bne-    2f
 
-       /* Soft-enable interrupts */
+       /*
+        * Soft-enable interrupts. This will make power4_fixup_nap return
+        * to our caller with interrupts enabled (soft and hard). The caller
+        * can cope with either interrupts disabled or enabled upon return.
+        */
 #ifdef CONFIG_TRACE_IRQFLAGS
+       /* Tell the tracer interrupts are on, because idle responds to them. */
        mflr    r0
        std     r0,16(r1)
        stdu    r1,-128(r1)
@@ -73,3 +80,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
        isync
        b       1b
 
+2:     /* Return if an interrupt had happened while soft disabled */
+       /* Set the HARD_DIS flag because interrupts are now hard disabled */
+       ori     r0,r0,PACA_IRQ_HARD_DIS
+       stb     r0,PACAIRQHAPPENED(r13)
+       blr