[PATCH] x86: fully honor "nolapic"

[PATCH] x86: fully honor "nolapic"

[Jan Beulich]

"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@novell.com>

---
 arch/x86/kernel/apic.c    |    7 ++++++-
 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	2009-01-13 14:57:59.000000000 +0100
@@ -1125,6 +1125,11 @@ void __cpuinit setup_local_APIC(void)
 	unsigned int value;
 	int i, j;
 
+	if (disable_apic) {
+		disable_ioapic_setup();
+		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;
 	}
 

Re: [PATCH] x86: fully honor "nolapic"

[Ingo Molnar]

* Jan Beulich <jbeulich@novell.com> wrote:

> "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@novell.com>
> 
> ---
>  arch/x86/kernel/apic.c    |    7 ++++++-
>  arch/x86/kernel/io_apic.c |    6 ++++++
>  arch/x86/kernel/smpboot.c |    1 +
>  3 files changed, 13 insertions(+), 1 deletion(-)

applied to tip/x86/urgent, thanks Jan!

	Ingo