X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fi386%2Fkernel%2Fapic.c;fp=arch%2Fi386%2Fkernel%2Fapic.c;h=5bec4fbdb40b9ee9e99a4e3b66785662d9e495c9;hb=16c70f8c1b54b61c3b951b6fb220df250fe09b32;hp=3d4b2f3d116a796ffad8ef911353b6a71a2f43b7;hpb=4e76c8a9fa413ccc09d3f7f664183dcce3555d57;p=linux-2.6.git

diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 3d4b2f3d1..5bec4fbdb 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -14,7 +14,6 @@
  *	Mikael Pettersson	:	PM converted to driver model.
  */
 
-#include <linux/config.h>
 #include <linux/init.h>
 
 #include <linux/mm.h>
@@ -27,6 +26,7 @@
 #include <linux/sysdev.h>
 #include <linux/cpu.h>
 #include <linux/module.h>
+#include <linux/dmi.h>
 
 #include <asm/atomic.h>
 #include <asm/smp.h>
@@ -36,6 +36,7 @@
 #include <asm/arch_hooks.h>
 #include <asm/hpet.h>
 #include <asm/i8253.h>
+#include <asm/nmi.h>
 
 #include <mach_apic.h>
 #include <mach_apicdef.h>
@@ -53,6 +54,9 @@ static cpumask_t timer_bcast_ipi;
  * Knob to control our willingness to enable the local APIC.
  */
 int enable_local_apic __initdata = 0; /* -1=force-disable, +1=force-enable */
+int prefer_apic __initdata = 0;	/* when enable_local_apic == 0 prefer APIC but don't force against
+				   BIOS wishes */
+int apic_disabled_by_dmi __initdata;
 
 /*
  * Debug level
@@ -62,7 +66,7 @@ int apic_verbosity;
 
 static void apic_pm_activate(void);
 
-int modern_apic(void)
+static int modern_apic(void)
 {
 	unsigned int lvr, version;
 	/* AMD systems use old APIC versions, so check the CPU */
@@ -113,7 +117,7 @@ void __init apic_intr_init(void)
 }
 
 /* Using APIC to generate smp_local_timer_interrupt? */
-int using_apic_timer = 0;
+int using_apic_timer __read_mostly = 0;
 
 static int enabled_via_apicbase;
 
@@ -156,7 +160,7 @@ void clear_local_APIC(void)
 	maxlvt = get_maxlvt();
 
 	/*
-	 * Masking an LVT entry on a P6 can trigger a local APIC error
+	 * Masking an LVT entry can trigger a local APIC error
 	 * if the vector is zero. Mask LVTERR first to prevent this.
 	 */
 	if (maxlvt >= 3) {
@@ -753,6 +757,10 @@ static void apic_pm_activate(void) { }
 
 static int __init apic_set_verbosity(char *str)
 {
+	if (*str == '=')
+		++str;
+	if (*str == 0)
+		prefer_apic = 1;
 	if (strcmp("debug", str) == 0)
 		apic_verbosity = APIC_DEBUG;
 	else if (strcmp("verbose", str) == 0)
@@ -760,7 +768,7 @@ static int __init apic_set_verbosity(char *str)
 	return 1;
 }
 
-__setup("apic=", apic_set_verbosity);
+__setup("apic", apic_set_verbosity);
 
 static int __init detect_init_APIC (void)
 {
@@ -791,8 +799,9 @@ static int __init detect_init_APIC (void)
 		 * APIC only if "lapic" specified.
 		 */
 		if (enable_local_apic <= 0) {
-			printk("Local APIC disabled by BIOS -- "
-			       "you can enable it with \"lapic\"\n");
+			if (!apic_disabled_by_dmi)
+				printk("Local APIC disabled by BIOS -- "
+				       "you can enable it with \"lapic\"\n");
 			return -1;
 		}
 		/*
@@ -1117,7 +1126,18 @@ void disable_APIC_timer(void)
 		unsigned long v;
 
 		v = apic_read(APIC_LVTT);
-		apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
+		/*
+		 * When an illegal vector value (0-15) is written to an LVT
+		 * entry and delivery mode is Fixed, the APIC may signal an
+		 * illegal vector error, with out regard to whether the mask
+		 * bit is set or whether an interrupt is actually seen on input.
+		 *
+		 * Boot sequence might call this function when the LVTT has
+		 * '0' vector value. So make sure vector field is set to
+		 * valid value.
+		 */
+		v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR);
+		apic_write_around(APIC_LVTT, v);
 	}
 }
 
@@ -1315,6 +1335,64 @@ fastcall void smp_error_interrupt(struct pt_regs *regs)
 	irq_exit();
 }
 
+#ifdef CONFIG_X86_APIC_AUTO
+
+/* Some heuristics to decide when to enable the APICs */
+
+static __init int dmi_enable_apic(void)
+{
+	int year;
+	int apic;
+	char *vendor;
+
+	/* If the machine has more than one CPU try to use APIC because it'll
+	   be running the SMP kernel with APIC soon anyways.
+	   This won't cover dual core, but they are handled by the date check
+	   below. */
+	if (dmi_cpus > 1)
+		return 1;
+
+	year = dmi_get_year(DMI_BIOS_DATE);
+	vendor = dmi_get_system_info(DMI_BIOS_VENDOR);
+	apic = 0;
+
+	/* All Intel BIOS since 1998 assumed APIC on. Don't include 1998 itself
+	   because we're not sure for that. */
+	if (vendor && !strncmp(vendor, "Intel", 5))
+		apic = 1;
+	/* Use APIC for anything since 2001 */
+	else if (year >= 2001)
+		apic = 1;
+
+#ifdef CONFIG_ACPI
+	/* When ACPI is disabled also default to APIC off on very new systems (>= 2004)
+	   which typically don't have working mptables anymore */
+	if (acpi_noirq && year >= 2004)
+		apic = 0;
+#endif
+
+	if (!apic)
+		apic_disabled_by_dmi = 1;
+
+	return apic;
+}
+
+void __init dmi_check_apic(void)
+{
+	if (enable_local_apic != 0 || prefer_apic)
+		return;
+	if (!dmi_enable_apic()) {
+		clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
+		nr_ioapics = 0;
+		enable_local_apic = -1;
+		printk(KERN_INFO "IO/L-APIC disabled because your old system seems to be old\n");
+		printk(KERN_INFO "overwrite with \"apic\"\n");
+		return;
+	}
+	printk(KERN_INFO "IO/L-APIC allowed because system is MP or new enough\n");
+}
+#endif
+
 /*
  * This initializes the IO-APIC and APIC hardware if this is
  * a UP kernel.