[PATCH] Remove obsolete PIC mode

PIC mode is an outdated way to drive the APICs that was used on
some early MP boards. It is not supported in the ACPI model.

It is unlikely to be ever configured by any x86-64 system

Remove it thus.

Signed-off-by: Andi Kleen <ak@suse.de>

3 files changed, 29 insertions, 72 deletions

diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index 78c43b1..20a76f2 100644
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -136,72 +136,40 @@ void clear_local_APIC(void)
 	apic_read(APIC_ESR);
 }
 
-void __init connect_bsp_APIC(void)
-{
-	if (pic_mode) {
-		/*
-		 * Do not trust the local APIC being empty at bootup.
-		 */
-		clear_local_APIC();
-		/*
-		 * PIC mode, enable APIC mode in the IMCR, i.e.
-		 * connect BSP's local APIC to INT and NMI lines.
-		 */
-		apic_printk(APIC_VERBOSE, "leaving PIC mode, enabling APIC mode.\n");
-		outb(0x70, 0x22);
-		outb(0x01, 0x23);
-	}
-}
-
 void disconnect_bsp_APIC(int virt_wire_setup)
 {
-	if (pic_mode) {
-		/*
-		 * Put the board back into PIC mode (has an effect
-		 * only on certain older boards).  Note that APIC
-		 * interrupts, including IPIs, won't work beyond
-		 * this point!  The only exception are INIT IPIs.
-		 */
-		apic_printk(APIC_QUIET, "disabling APIC mode, entering PIC mode.\n");
-		outb(0x70, 0x22);
-		outb(0x00, 0x23);
-	}
-	else {
-		/* Go back to Virtual Wire compatibility mode */
-		unsigned long value;
-
-		/* For the spurious interrupt use vector F, and enable it */
-		value = apic_read(APIC_SPIV);
-		value &= ~APIC_VECTOR_MASK;
-		value |= APIC_SPIV_APIC_ENABLED;
-		value |= 0xf;
-		apic_write(APIC_SPIV, value);
-
-		if (!virt_wire_setup) {
-			/* For LVT0 make it edge triggered, active high, external and enabled */
-			value = apic_read(APIC_LVT0);
-			value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
-				APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
-				APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED );
-			value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
-			value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXTINT);
-			apic_write(APIC_LVT0, value);
-		}
-		else {
-			/* Disable LVT0 */
-			apic_write(APIC_LVT0, APIC_LVT_MASKED);
-		}
+	/* Go back to Virtual Wire compatibility mode */
+	unsigned long value;
 
-		/* For LVT1 make it edge triggered, active high, nmi and enabled */
-		value = apic_read(APIC_LVT1);
-		value &= ~(
-			APIC_MODE_MASK | APIC_SEND_PENDING |
+	/* For the spurious interrupt use vector F, and enable it */
+	value = apic_read(APIC_SPIV);
+	value &= ~APIC_VECTOR_MASK;
+	value |= APIC_SPIV_APIC_ENABLED;
+	value |= 0xf;
+	apic_write(APIC_SPIV, value);
+
+	if (!virt_wire_setup) {
+		/* For LVT0 make it edge triggered, active high, external and enabled */
+		value = apic_read(APIC_LVT0);
+		value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
 			APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
-			APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
+			APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED );
 		value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
-		value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
-		apic_write(APIC_LVT1, value);
+		value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXTINT);
+		apic_write(APIC_LVT0, value);
+	} else {
+		/* Disable LVT0 */
+		apic_write(APIC_LVT0, APIC_LVT_MASKED);
 	}
+
+	/* For LVT1 make it edge triggered, active high, nmi and enabled */
+	value = apic_read(APIC_LVT1);
+	value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
+			APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
+			APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
+	value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
+	value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
+	apic_write(APIC_LVT1, value);
 }
 
 void disable_local_APIC(void)
@@ -418,7 +386,7 @@ void __cpuinit setup_local_APIC (void)
 	 * TODO: set up through-local-APIC from through-I/O-APIC? --macro
 	 */
 	value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
-	if (!smp_processor_id() && (pic_mode || !value)) {
+	if (!smp_processor_id() && !value) {
 		value = APIC_DM_EXTINT;
 		apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n", smp_processor_id());
 	} else {
@@ -1096,8 +1064,6 @@ int __init APIC_init_uniprocessor (void)
 
 	verify_local_APIC();
 
-	connect_bsp_APIC();
-
 	phys_cpu_present_map = physid_mask_of_physid(boot_cpu_id);
 	apic_write(APIC_ID, SET_APIC_ID(boot_cpu_id));
 
diff --git a/arch/x86_64/kernel/mpparse.c b/arch/x86_64/kernel/mpparse.c
index 90e99cf..0226245 100644
--- a/arch/x86_64/kernel/mpparse.c
+++ b/arch/x86_64/kernel/mpparse.c
@@ -56,7 +56,6 @@ struct mpc_config_intsrc mp_irqs[MAX_IRQ_SOURCES];
 int mp_irq_entries;
 
 int nr_ioapics;
-int pic_mode;
 unsigned long mp_lapic_addr = 0;
 
 
@@ -514,13 +513,6 @@ void __init get_smp_config (void)
  		printk(KERN_INFO "Using ACPI for processor (LAPIC) configuration information\n");
 
 	printk("Intel MultiProcessor Specification v1.%d\n", mpf->mpf_specification);
-	if (mpf->mpf_feature2 & (1<<7)) {
-		printk(KERN_INFO "    IMCR and PIC compatibility mode.\n");
-		pic_mode = 1;
-	} else {
-		printk(KERN_INFO "    Virtual Wire compatibility mode.\n");
-		pic_mode = 0;
-	}
 
 	/*
 	 * Now see if we need to read further.
diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c
index d29571e..ae7d6d8 100644
--- a/arch/x86_64/kernel/smpboot.c
+++ b/arch/x86_64/kernel/smpboot.c
@@ -1090,7 +1090,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	/*
 	 * Switch from PIC to APIC mode.
 	 */
-	connect_bsp_APIC();
 	setup_local_APIC();
 
 	if (GET_APIC_ID(apic_read(APIC_ID)) != boot_cpu_id) {