[PATCH] x86: sutomatically enable bigsmp when we have more than 8 CPUs
i386 generic subarchitecture requires explicit dmi strings or command line
to enable bigsmp mode. The patch below removes that restriction, and uses
bigsmp as soon as it finds more than 8 logical CPUs, Intel processors and
xAPIC support.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index b7808a8..34ee500 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -833,6 +833,9 @@
if (!error) {
acpi_lapic = 1;
+#ifdef CONFIG_X86_GENERICARCH
+ generic_bigsmp_probe();
+#endif
/*
* Parse MADT IO-APIC entries
*/
diff --git a/arch/i386/kernel/mpparse.c b/arch/i386/kernel/mpparse.c
index ce838ab..788efff 100644
--- a/arch/i386/kernel/mpparse.c
+++ b/arch/i386/kernel/mpparse.c
@@ -65,6 +65,8 @@
int pic_mode;
unsigned long mp_lapic_addr;
+unsigned int def_to_bigsmp = 0;
+
/* Processor that is doing the boot up */
unsigned int boot_cpu_physical_apicid = -1U;
/* Internal processor count */
@@ -213,6 +215,13 @@
ver = 0x10;
}
apic_version[m->mpc_apicid] = ver;
+ if ((num_processors > 8) &&
+ APIC_XAPIC(ver) &&
+ (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL))
+ def_to_bigsmp = 1;
+ else
+ def_to_bigsmp = 0;
+
bios_cpu_apicid[num_processors - 1] = m->mpc_apicid;
}
diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c
index 9adbf71..294bcca 100644
--- a/arch/i386/kernel/setup.c
+++ b/arch/i386/kernel/setup.c
@@ -1585,8 +1585,14 @@
*/
acpi_boot_table_init();
acpi_boot_init();
-#endif
+#if defined(CONFIG_SMP) && defined(CONFIG_X86_PC)
+ if (def_to_bigsmp)
+ printk(KERN_WARNING "More than 8 CPUs detected and "
+ "CONFIG_X86_PC cannot handle it.\nUse "
+ "CONFIG_X86_GENERICARCH or CONFIG_X86_BIGSMP.\n");
+#endif
+#endif
#ifdef CONFIG_X86_LOCAL_APIC
if (smp_found_config)
get_smp_config();