linux-kernel - [patch V2 04/13] x86/apic: Split out spurious handling code

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Message-Id: <20210210002512.469379641@linutronix.de>
Date:   Wed, 10 Feb 2021 00:40:45 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Josh Poimboeuf <jpoimboe@...hat.com>,
        Helge Deller <deller@....de>,
        "David S. Miller" <davem@...emloft.net>,
        Michael Ellerman <mpe@...erman.id.au>,
        Rich Felker <dalias@...c.org>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Kees Cook <keescook@...omium.org>,
        Lai Jiangshan <jiangshanlai+lkml@...il.com>
Subject: [patch V2 04/13] x86/apic: Split out spurious handling code

From: Thomas Gleixner <tglx@...utronix.de>

sysvec_spurious_apic_interrupt() calls into the handling body of
__spurious_interrupt() which is not obvious as that function is declared
inside the DEFINE_IDTENTRY_IRQ(spurious_interrupt) macro.

As __spurious_interrupt() is currently always inlined this ends up with two
copies of the same code for no reason.

Split the handling function out and invoke it from both entry points.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Kees Cook <keescook@...omium.org>

---
 arch/x86/kernel/apic/apic.c |   31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -2137,18 +2137,11 @@ void __init register_lapic_address(unsig
  * Local APIC interrupts
  */
 
-/**
- * spurious_interrupt - Catch all for interrupts raised on unused vectors
- * @regs:	Pointer to pt_regs on stack
- * @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
- * point.
- *
- * Also called from sysvec_spurious_apic_interrupt().
+/*
+ * Common handling code for spurious_interrupt and spurious_vector entry
+ * points below. No point in allowing the compiler to inline it twice.
  */
-DEFINE_IDTENTRY_IRQ(spurious_interrupt)
+static noinline void handle_spurious_interrupt(u8 vector)
 {
 	u32 v;
 
@@ -2183,9 +2176,23 @@ DEFINE_IDTENTRY_IRQ(spurious_interrupt)
 	trace_spurious_apic_exit(vector);
 }
 
+/**
+ * spurious_interrupt - Catch all for interrupts raised on unused vectors
+ * @regs:	Pointer to pt_regs on stack
+ * @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
+ * point.
+ */
+DEFINE_IDTENTRY_IRQ(spurious_interrupt)
+{
+	handle_spurious_interrupt(vector);
+}
+
 DEFINE_IDTENTRY_SYSVEC(sysvec_spurious_apic_interrupt)
 {
-	__spurious_interrupt(regs, SPURIOUS_APIC_VECTOR);
+	handle_spurious_interrupt(SPURIOUS_APIC_VECTOR);
 }
 
 /*