x86: L-APIC: Always fully configure IRQ0

Unlike the 32-bit one, the 64-bit variation of the LVT0 setup code for
the "8259A Virtual Wire" through the local APIC timer configuration does
not fully configure the relevant irq_chip structure.  Instead it relies on
the preceding I/O APIC code to have set it up, which does not happen if
the I/O APIC variants have not been tried.

The patch includes corresponding changes to the 32-bit variation too
which make them both the same, barring a small syntactic difference
involving sequence of functions in the source.  That should work as an aid
with the upcoming merge.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 26 insertions, 18 deletions

diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
index 50e1131a6ec6..74d49e04de58 100644
--- a/arch/x86/kernel/io_apic_32.c
+++ b/arch/x86/kernel/io_apic_32.c
@@ -2027,7 +2027,7 @@ static inline void init_IO_APIC_traps(void)
  * The local APIC irq-chip implementation:
  */
 
-static void ack_apic(unsigned int irq)
+static void ack_lapic_irq(unsigned int irq)
 {
         ack_APIC_irq();
 }
@@ -2052,9 +2052,17 @@ static struct irq_chip lapic_chip __read_mostly = {
         .name           = "local-APIC",
         .mask           = mask_lapic_irq,
         .unmask         = unmask_lapic_irq,
-        .ack            = ack_apic,
+        .ack            = ack_lapic_irq,
 };
 
+static void lapic_register_intr(int irq, int vector)
+{
+        irq_desc[irq].status &= ~IRQ_LEVEL;
+        set_irq_chip_and_handler_name(irq, &lapic_chip, handle_edge_irq,
+                                      "edge");
+        set_intr_gate(vector, interrupt[irq]);
+}
+
 static void __init setup_nmi(void)
 {
         /*
@@ -2257,8 +2265,7 @@ static inline void __init check_timer(void)
 
         printk(KERN_INFO "...trying to set up timer as Virtual Wire IRQ...");
 
-        set_irq_chip_and_handler_name(0, &lapic_chip, handle_edge_irq,
-                                      "edge");
+        lapic_register_intr(0, vector);
         apic_write_around(APIC_LVT0, APIC_DM_FIXED | vector);   /* Fixed mode */
         enable_8259A_irq(0);
 
diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index 848411753c7c..07ebcd305fb7 100644
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -1561,7 +1561,7 @@ static inline void init_IO_APIC_traps(void)
         }
 }
 
-static void enable_lapic_irq (unsigned int irq)
+static void unmask_lapic_irq(unsigned int irq)
 {
         unsigned long v;
 
@@ -1569,7 +1569,7 @@ static void enable_lapic_irq (unsigned int irq)
         apic_write(APIC_LVT0, v & ~APIC_LVT_MASKED);
 }
 
-static void disable_lapic_irq (unsigned int irq)
+static void mask_lapic_irq(unsigned int irq)
 {
         unsigned long v;
 
@@ -1582,19 +1582,20 @@ static void ack_lapic_irq (unsigned int irq)
         ack_APIC_irq();
 }
 
-static void end_lapic_irq (unsigned int i) { /* nothing */ }
-
-static struct hw_interrupt_type lapic_irq_type __read_mostly = {
-        .name = "local-APIC",
-        .typename = "local-APIC-edge",
-        .startup = NULL, /* startup_irq() not used for IRQ0 */
-        .shutdown = NULL, /* shutdown_irq() not used for IRQ0 */
-        .enable = enable_lapic_irq,
-        .disable = disable_lapic_irq,
-        .ack = ack_lapic_irq,
-        .end = end_lapic_irq,
+static struct irq_chip lapic_chip __read_mostly = {
+        .name           = "local-APIC",
+        .mask           = mask_lapic_irq,
+        .unmask         = unmask_lapic_irq,
+        .ack            = ack_lapic_irq,
 };
 
+static void lapic_register_intr(int irq)
+{
+        irq_desc[irq].status &= ~IRQ_LEVEL;
+        set_irq_chip_and_handler_name(irq, &lapic_chip, handle_edge_irq,
+                                      "edge");
+}
+
 static void __init setup_nmi(void)
 {
         /*
@@ -1784,7 +1785,7 @@ static inline void __init check_timer(void)
 
         apic_printk(APIC_VERBOSE, KERN_INFO "...trying to set up timer as Virtual Wire IRQ...");
 
-        irq_desc[0].chip = &lapic_irq_type;
+        lapic_register_intr(0);
         apic_write(APIC_LVT0, APIC_DM_FIXED | cfg->vector);     /* Fixed mode */
         enable_8259A_irq(0);