x86, apic: Print verbose error interrupt reason on apic=debug (2b398bd9) · Commits · 戴 / test

End users worry about the error interrupt printout we generate currently: pr_debug("APIC error on CPU%d: %02x(%02x)\n", smp_processor_id(), v , v1); ... and would like to know the reason why error interrupts are generated. This patch prints out more detailed debug information. Another practical problem is that dynamic debug is not initialized yet when the APIC initializes, so the pr_debug() will not output the error interrupt debug information on bootup. In this patch, we use apic_printk(APIC_DEBUG, ...), so the apic=debug boot option will print verbose error interupts during bootup. Signed-off-by:

Youquan Song <youquan.song@intel.com> Cc: Joe Perches <joe@perches.com> Cc: hpa@linux.intel.com Cc: suresh.b.siddha@intel.com Cc: yong.y.wang@linux.intel.com Cc: jbaron@redhat.com Cc: trenn@suse.de Cc: kent.liu@intel.com Cc: chaohong.guo@intel.com Link: http://lkml.kernel.org/r/1302762968-24380-2-git-send-email-youquan.song@intel.com Signed-off-by:

Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/apic/apic.c

+26 −15

Original line number	Diff line number	Diff line
		@@ -1812,30 +1812,41 @@ void smp_spurious_interrupt(struct pt_regs *regs)
		*/
		void smp_error_interrupt(struct pt_regs *regs)
		{
		u32 v, v1;
		u32 v0, v1;
		u32 i = 0;
		static const char * const error_interrupt_reason[] = {
		"Send CS error", /* APIC Error Bit 0 */
		"Receive CS error", /* APIC Error Bit 1 */
		"Send accept error", /* APIC Error Bit 2 */
		"Receive accept error", /* APIC Error Bit 3 */
		"Redirectable IPI", /* APIC Error Bit 4 */
		"Send illegal vector", /* APIC Error Bit 5 */
		"Received illegal vector", /* APIC Error Bit 6 */
		"Illegal register address", /* APIC Error Bit 7 */
		};

		exit_idle();
		irq_enter();
		/* First tickle the hardware, only then report what went on. -- REW */
		v = apic_read(APIC_ESR);
		v0 = apic_read(APIC_ESR);
		apic_write(APIC_ESR, 0);
		v1 = apic_read(APIC_ESR);
		ack_APIC_irq();
		atomic_inc(&irq_err_count);

		/*
		* Here is what the APIC error bits mean:
		* 0: Send CS error
		* 1: Receive CS error
		* 2: Send accept error
		* 3: Receive accept error
		* 4: Reserved
		* 5: Send illegal vector
		* 6: Received illegal vector
		* 7: Illegal register address
		*/
		pr_debug("APIC error on CPU%d: %02x(%02x)\n",
		smp_processor_id(), v , v1);
		apic_printk(APIC_DEBUG, KERN_DEBUG "APIC error on CPU%d: %02x(%02x)",
		smp_processor_id(), v0 , v1);

		v1 = v1 & 0xff;
		while (v1) {
		if (v1 & 0x1)
		apic_printk(APIC_DEBUG, KERN_CONT " : %s", error_interrupt_reason[i]);
		i++;
		v1 >>= 1;
		};

		apic_printk(APIC_DEBUG, KERN_CONT "\n");

		irq_exit();
		}

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