x86: Add early platform detection

Platforms like Moorestown require early setup and want to avoid the
call to reserve_ebda_region. The x86_init override is too late when
the MRST detection happens in setup_arch. Move the default i386
x86_init overrides and the call to reserve_ebda_region into a separate
function which is called as the default of a switch case depending on
the hardware_subarch id in boot params. This allows us to add a case
for MRST and let MRST have its own early setup function.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 17 insertions, 5 deletions

diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index a21398fac4fa..441c075e2b80 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -15,6 +15,17 @@
 #include <asm/trampoline.h>
 #include <asm/apic.h>
 #include <asm/io_apic.h>
+#include <asm/bios_ebda.h>
+
+static void __init i386_default_early_setup(void)
+{
+        /* Initilize 32bit specific setup functions */
+        x86_init.resources.probe_roms = probe_roms;
+        x86_init.resources.reserve_resources = i386_reserve_resources;
+        x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc;
+
+        reserve_ebda_region();
+}
 
 void __init i386_start_kernel(void)
 {
@@ -31,12 +42,13 @@ void __init i386_start_kernel(void)
                 reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");
         }
 #endif
-        /* Initilize 32bit specific setup functions */
-        x86_init.resources.probe_roms = probe_roms;
-        x86_init.resources.reserve_resources = i386_reserve_resources;
-        x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc;
 
-        x86_init.resources.reserve_ebda_region();
+        /* Call the subarch specific early setup function */
+        switch (boot_params.hdr.hardware_subarch) {
+        default:
+                i386_default_early_setup();
+                break;
+        }
 
         /*
          * At this point everything still needed from the boot loader