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Subject[PATCH 5/5] x86: unify ack_apic_edge
Date
use code in 64 to replace
move_native_irq(irq, desc);
in 32 bit

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

---
arch/x86/kernel/io_apic.c | 73 ++++++++++++++++++++++------------------------
1 file changed, 35 insertions(+), 38 deletions(-)

Index: linux-2.6/arch/x86/kernel/io_apic.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/io_apic.c
+++ linux-2.6/arch/x86/kernel/io_apic.c
@@ -389,7 +389,6 @@ static inline void io_apic_modify(unsign
writel(value, &io_apic->data);
}

-#ifdef CONFIG_X86_64
static bool io_apic_level_ack_pending(unsigned int irq)
{
struct irq_pin_list *entry;
@@ -419,7 +418,6 @@ static bool io_apic_level_ack_pending(un

return false;
}
-#endif

union entry_union {
struct { u32 w1, w2; };
@@ -2397,9 +2395,16 @@ static void ack_apic_edge(unsigned int i
ack_APIC_irq();
}

-#ifdef CONFIG_X86_64
+#ifdef CONFIG_X86_32
+atomic_t irq_mis_count;
+#endif
+
static void ack_apic_level(unsigned int irq, struct irq_desc *desc)
{
+#ifdef CONFIG_X86_32
+ unsigned long v;
+ int i;
+#endif
int do_unmask_irq = 0;

irq_complete_move(irq);
@@ -2411,6 +2416,31 @@ static void ack_apic_level(unsigned int
}
#endif

+#ifdef CONFIG_X86_32
+ /*
+ * It appears there is an erratum which affects at least version 0x11
+ * of I/O APIC (that's the 82093AA and cores integrated into various
+ * chipsets). Under certain conditions a level-triggered interrupt is
+ * erroneously delivered as edge-triggered one but the respective IRR
+ * bit gets set nevertheless. As a result the I/O unit expects an EOI
+ * message but it will never arrive and further interrupts are blocked
+ * from the source. The exact reason is so far unknown, but the
+ * phenomenon was observed when two consecutive interrupt requests
+ * from a given source get delivered to the same CPU and the source is
+ * temporarily disabled in between.
+ *
+ * A workaround is to simulate an EOI message manually. We achieve it
+ * by setting the trigger mode to edge and then to level when the edge
+ * trigger mode gets detected in the TMR of a local APIC for a
+ * level-triggered interrupt. We mask the source for the time of the
+ * operation to prevent an edge-triggered interrupt escaping meanwhile.
+ * The idea is from Manfred Spraul. --macro
+ */
+ i = irq_cfg(irq)->vector;
+
+ v = apic_read(APIC_TMR + ((i & ~0x1f) >> 1));
+#endif
+
/*
* We must acknowledge the irq before we move it or the acknowledge will
* not propagate properly.
@@ -2449,41 +2479,8 @@ static void ack_apic_level(unsigned int
move_masked_irq(irq, desc);
unmask_IO_APIC_irq(irq);
}
-}
-#else
-atomic_t irq_mis_count;
-static void ack_apic_level(unsigned int irq, struct irq_desc *desc)
-{
- unsigned long v;
- int i;
-
- irq_complete_move(irq);
- move_native_irq(irq, desc);
- /*
- * It appears there is an erratum which affects at least version 0x11
- * of I/O APIC (that's the 82093AA and cores integrated into various
- * chipsets). Under certain conditions a level-triggered interrupt is
- * erroneously delivered as edge-triggered one but the respective IRR
- * bit gets set nevertheless. As a result the I/O unit expects an EOI
- * message but it will never arrive and further interrupts are blocked
- * from the source. The exact reason is so far unknown, but the
- * phenomenon was observed when two consecutive interrupt requests
- * from a given source get delivered to the same CPU and the source is
- * temporarily disabled in between.
- *
- * A workaround is to simulate an EOI message manually. We achieve it
- * by setting the trigger mode to edge and then to level when the edge
- * trigger mode gets detected in the TMR of a local APIC for a
- * level-triggered interrupt. We mask the source for the time of the
- * operation to prevent an edge-triggered interrupt escaping meanwhile.
- * The idea is from Manfred Spraul. --macro
- */
- i = irq_cfg(irq)->vector;
-
- v = apic_read(APIC_TMR + ((i & ~0x1f) >> 1));
-
- ack_APIC_irq();

+#ifdef CONFIG_X86_32
if (!(v & (1 << (i & 0x1f)))) {
atomic_inc(&irq_mis_count);
spin_lock(&ioapic_lock);
@@ -2491,8 +2488,8 @@ static void ack_apic_level(unsigned int
__unmask_and_level_IO_APIC_irq(irq);
spin_unlock(&ioapic_lock);
}
-}
#endif
+}

static struct irq_chip ioapic_chip __read_mostly = {
.name = "IO-APIC",

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