x86/entry: Use idtentry for interrupts

Replace the extra interrupt handling code and reuse the existing idtentry
machinery. This moves the irq stack switching on 64-bit from ASM to C code;
32-bit already does the stack switching in C.

This requires to remove HAVE_IRQ_EXIT_ON_IRQ_STACK as the stack switch is
not longer in the low level entry code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202119.078690991@linutronix.de

3 files changed, 17 insertions, 36 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 6c2b807a7eae..b7bfd3a1abb7 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -2121,9 +2121,9 @@ void __init register_lapic_address(unsigned long address)
  */
 
 /**
- * smp_spurious_interrupt - Catch all for interrupts raised on unused vectors
+ * spurious_interrupt - Catch all for interrupts raised on unused vectors
  * @regs:	Pointer to pt_regs on stack
- * @error_code:	The vector number is in the lower 8 bits
+ * @vector:	The vector number
  *
  * This is invoked from ASM entry code to catch all interrupts which
  * trigger on an entry which is routed to the common_spurious idtentry
@@ -2131,18 +2131,10 @@ void __init register_lapic_address(unsigned long address)
  *
  * Also called from smp_spurious_apic_interrupt().
  */
-__visible void __irq_entry smp_spurious_interrupt(struct pt_regs *regs,
-						  unsigned long vector)
+DEFINE_IDTENTRY_IRQ(spurious_interrupt)
 {
 	u32 v;
 
-	entering_irq();
-	/*
-	 * The push in the entry ASM code which stores the vector number on
-	 * the stack in the error code slot is sign expanding. Just use the
-	 * lower 8 bits.
-	 */
-	vector &= 0xFF;
 	trace_spurious_apic_entry(vector);
 
 	inc_irq_stat(irq_spurious_count);
@@ -2163,21 +2155,22 @@ __visible void __irq_entry smp_spurious_interrupt(struct pt_regs *regs,
 	 */
 	v = apic_read(APIC_ISR + ((vector & ~0x1f) >> 1));
 	if (v & (1 << (vector & 0x1f))) {
-		pr_info("Spurious interrupt (vector 0x%02lx) on CPU#%d. Acked\n",
+		pr_info("Spurious interrupt (vector 0x%02x) on CPU#%d. Acked\n",
 			vector, smp_processor_id());
 		ack_APIC_irq();
 	} else {
-		pr_info("Spurious interrupt (vector 0x%02lx) on CPU#%d. Not pending!\n",
+		pr_info("Spurious interrupt (vector 0x%02x) on CPU#%d. Not pending!\n",
 			vector, smp_processor_id());
 	}
 out:
 	trace_spurious_apic_exit(vector);
-	exiting_irq();
 }
 
 __visible void smp_spurious_apic_interrupt(struct pt_regs *regs)
 {
-	smp_spurious_interrupt(regs, SPURIOUS_APIC_VECTOR);
+	entering_irq();
+	__spurious_interrupt(regs, SPURIOUS_APIC_VECTOR);
+	exiting_irq();
 }
 
 /*
diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
index 159bd0cb8548..5cbaca58af95 100644
--- a/arch/x86/kernel/apic/msi.c
+++ b/arch/x86/kernel/apic/msi.c
@@ -115,7 +115,8 @@ msi_set_affinity(struct irq_data *irqd, const struct cpumask *mask, bool force)
 	 * denote it as spurious which is no harm as this is a rare event
 	 * and interrupt handlers have to cope with spurious interrupts
 	 * anyway. If the vector is unused, then it is marked so it won't
-	 * trigger the 'No irq handler for vector' warning in do_IRQ().
+	 * trigger the 'No irq handler for vector' warning in
+	 * common_interrupt().
 	 *
 	 * This requires to hold vector lock to prevent concurrent updates to
 	 * the affected vector.
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 5495ea4debba..c449b8434036 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -20,6 +20,7 @@
 #include <asm/mce.h>
 #include <asm/hw_irq.h>
 #include <asm/desc.h>
+#include <asm/traps.h>
 
 #define CREATE_TRACE_POINTS
 #include <asm/trace/irq_vectors.h>
@@ -232,37 +233,25 @@ static __always_inline void handle_irq(struct irq_desc *desc,
 }
 
 /*
- * do_IRQ handles all normal device IRQ's (the special
- * SMP cross-CPU interrupts have their own specific
- * handlers).
+ * common_interrupt() handles all normal device IRQ's (the special SMP
+ * cross-CPU interrupts have their own entry points).
  */
-__visible void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long vector)
+DEFINE_IDTENTRY_IRQ(common_interrupt)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
 	struct irq_desc *desc;
 
-	entering_irq();
-	/*
-	 * The push in the entry ASM code which stores the vector number on
-	 * the stack in the error code slot is sign expanding. Just use the
-	 * lower 8 bits.
-	 */
-	vector &= 0xFF;
-
-	/* entering_irq() tells RCU that we're not quiescent.  Check it. */
+	/* entry code tells RCU that we're not quiescent.  Check it. */
 	RCU_LOCKDEP_WARN(!rcu_is_watching(), "IRQ failed to wake up RCU");
 
 	desc = __this_cpu_read(vector_irq[vector]);
 	if (likely(!IS_ERR_OR_NULL(desc))) {
-		if (IS_ENABLED(CONFIG_X86_32))
-			__handle_irq(desc, regs);
-		else
-			generic_handle_irq_desc(desc);
+		handle_irq(desc, regs);
 	} else {
 		ack_APIC_irq();
 
 		if (desc == VECTOR_UNUSED) {
-			pr_emerg_ratelimited("%s: %d.%lu No irq handler for vector\n",
+			pr_emerg_ratelimited("%s: %d.%u No irq handler for vector\n",
 					     __func__, smp_processor_id(),
 					     vector);
 		} else {
@@ -270,8 +259,6 @@ __visible void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long vector)
 		}
 	}
 
-	exiting_irq();
-
 	set_irq_regs(old_regs);
 }