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-rw-r--r--arch/powerpc/kernel/time.c44
1 files changed, 13 insertions, 31 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 2d9d3a3c61d6..6fcae436ae51 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -522,35 +522,6 @@ static inline void clear_irq_work_pending(void)
"i" (offsetof(struct paca_struct, irq_work_pending)));
}
-void arch_irq_work_raise(void)
-{
- preempt_disable();
- set_irq_work_pending_flag();
- /*
- * Non-nmi code running with interrupts disabled will replay
- * irq_happened before it re-enables interrupts, so setthe
- * decrementer there instead of causing a hardware exception
- * which would immediately hit the masked interrupt handler
- * and have the net effect of setting the decrementer in
- * irq_happened.
- *
- * NMI interrupts can not check this when they return, so the
- * decrementer hardware exception is raised, which will fire
- * when interrupts are next enabled.
- *
- * BookE does not support this yet, it must audit all NMI
- * interrupt handlers to ensure they call nmi_enter() so this
- * check would be correct.
- */
- if (IS_ENABLED(CONFIG_BOOKE) || !irqs_disabled() || in_nmi()) {
- set_dec(1);
- } else {
- hard_irq_disable();
- local_paca->irq_happened |= PACA_IRQ_DEC;
- }
- preempt_enable();
-}
-
#else /* 32-bit */
DEFINE_PER_CPU(u8, irq_work_pending);
@@ -559,16 +530,27 @@ DEFINE_PER_CPU(u8, irq_work_pending);
#define test_irq_work_pending() __this_cpu_read(irq_work_pending)
#define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0)
+#endif /* 32 vs 64 bit */
+
void arch_irq_work_raise(void)
{
+ /*
+ * 64-bit code that uses irq soft-mask can just cause an immediate
+ * interrupt here that gets soft masked, if this is called under
+ * local_irq_disable(). It might be possible to prevent that happening
+ * by noticing interrupts are disabled and setting decrementer pending
+ * to be replayed when irqs are enabled. The problem there is that
+ * tracing can call irq_work_raise, including in code that does low
+ * level manipulations of irq soft-mask state (e.g., trace_hardirqs_on)
+ * which could get tangled up if we're messing with the same state
+ * here.
+ */
preempt_disable();
set_irq_work_pending_flag();
set_dec(1);
preempt_enable();
}
-#endif /* 32 vs 64 bit */
-
#else /* CONFIG_IRQ_WORK */
#define test_irq_work_pending() 0