linux-kernel - [PATCH] x86: fully honor "nolapic" (take 2)

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Date:	Fri, 16 Jan 2009 11:46:02 +0000
From:	"Jan Beulich" <jbeulich@...ell.com>
To:	<mingo@...e.hu>, <tglx@...utronix.de>, <hpa@...or.com>
Cc:	<linux-kernel@...r.kernel.org>
Subject: [PATCH] x86: fully honor "nolapic" (take 2)

"nolapic" should not only suppress SMP and use of the LAPIC, but it
also ought to have the effect of disabling all IO-APIC related activity
as well as PCI MSI and HT-IRQs.

Signed-off-by: Jan Beulich <jbeulich@...ell.com>

---
 arch/x86/kernel/apic.c    |    9 ++++++++-
 arch/x86/kernel/io_apic.c |    6 ++++++
 arch/x86/kernel/smpboot.c |    1 +
 3 files changed, 13 insertions(+), 1 deletion(-)

--- linux-2.6.29-rc1/arch/x86/kernel/apic.c	2009-01-14 11:36:05.000000000 +0100
+++ 2.6.29-rc1-x86-no-lapic/arch/x86/kernel/apic.c	2009-01-16 11:57:45.000000000 +0100
@@ -1125,6 +1125,13 @@ void __cpuinit setup_local_APIC(void)
 	unsigned int value;
 	int i, j;
 
+	if (disable_apic) {
+#ifdef CONFIG_X86_IO_APIC
+		disable_ioapic_setup();
+#endif
+		return;
+	}
+
 #ifdef CONFIG_X86_32
 	/* Pound the ESR really hard over the head with a big hammer - mbligh */
 	if (lapic_is_integrated() && esr_disable) {
@@ -1565,11 +1570,11 @@ int apic_version[MAX_APICS];
 
 int __init APIC_init_uniprocessor(void)
 {
-#ifdef CONFIG_X86_64
 	if (disable_apic) {
 		pr_info("Apic disabled\n");
 		return -1;
 	}
+#ifdef CONFIG_X86_64
 	if (!cpu_has_apic) {
 		disable_apic = 1;
 		pr_info("Apic disabled by BIOS\n");
--- linux-2.6.29-rc1/arch/x86/kernel/io_apic.c	2009-01-14 11:36:05.000000000 +0100
+++ 2.6.29-rc1-x86-no-lapic/arch/x86/kernel/io_apic.c	2009-01-13 15:05:37.000000000 +0100
@@ -3258,6 +3258,9 @@ static int msi_compose_msg(struct pci_de
 	int err;
 	unsigned dest;
 
+	if (disable_apic)
+		return -ENXIO;
+
 	cfg = irq_cfg(irq);
 	err = assign_irq_vector(irq, cfg, TARGET_CPUS);
 	if (err)
@@ -3726,6 +3729,9 @@ int arch_setup_ht_irq(unsigned int irq, 
 	struct irq_cfg *cfg;
 	int err;
 
+	if (disable_apic)
+		return -ENXIO;
+
 	cfg = irq_cfg(irq);
 	err = assign_irq_vector(irq, cfg, TARGET_CPUS);
 	if (!err) {
--- linux-2.6.29-rc1/arch/x86/kernel/smpboot.c	2009-01-14 11:36:05.000000000 +0100
+++ 2.6.29-rc1-x86-no-lapic/arch/x86/kernel/smpboot.c	2009-01-14 09:14:16.000000000 +0100
@@ -1125,6 +1125,7 @@ static int __init smp_sanity_check(unsig
 		printk(KERN_ERR "... forcing use of dummy APIC emulation."
 				"(tell your hw vendor)\n");
 		smpboot_clear_io_apic();
+		disable_ioapic_setup();
 		return -1;
 	}
 



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