[PATCH v6 05/33] x86/traps: add external_interrupt() to dispatch external interrupts

[Xin Li]

From: "H. Peter Anvin (Intel)" <hpa@xxxxxxxxx>

Add external_interrupt() to dispatch external interrupts to their handlers.

If an external interrupt is a system interrupt, dipatch it through
system_interrupt_handlers table, otherwise to dispatch_common_interrupt().

Signed-off-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx>
Co-developed-by: Xin Li <xin3.li@xxxxxxxxx>
Tested-by: Shan Kang <shan.kang@xxxxxxxxx>
Signed-off-by: Xin Li <xin3.li@xxxxxxxxx>
---

Changes since v5:
* Initialize system_interrupt_handlers with dispatch_table_spurious_interrupt()
  instead of NULL to get rid of a branch (Peter Zijlstra).
---
 arch/x86/kernel/traps.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 12072e2af4a6..f86cd233b00b 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -1511,6 +1511,32 @@ static system_interrupt_handler system_interrupt_handlers[NR_SYSTEM_VECTORS] = {
 
 #undef SYSV
 
+/*
+ * External interrupt dispatch function.
+ *
+ * Until/unless dispatch_common_interrupt() can be taught to deal with the
+ * special system vectors, split the dispatch.
+ *
+ * Note: dispatch_common_interrupt() already deals with IRQ_MOVE_CLEANUP_VECTOR.
+ */
+int external_interrupt(struct pt_regs *regs)
+{
+	unsigned int vector = regs->vector;
+	unsigned int sysvec = vector - FIRST_SYSTEM_VECTOR;
+
+	if (vector < FIRST_EXTERNAL_VECTOR) {
+		pr_err("invalid external interrupt vector %d\n", vector);
+		return -EINVAL;
+	}
+
+	if (sysvec < NR_SYSTEM_VECTORS)
+		system_interrupt_handlers[sysvec](regs);
+	else
+		dispatch_common_interrupt(regs, vector);
+
+	return 0;
+}
+
 #endif /* CONFIG_X86_64 */
 
 void __init install_system_interrupt_handler(unsigned int n, const void *asm_addr, const void *addr)
-- 
2.34.1