[PATCH] i386: Fix UP gdt bugs
Fixes two problems with the GDT when compiling for uniprocessor:
- There's no percpu segment, so trying to load its selector into %fs fails.
Use a null selector instead.
- The real gdt needs to be loaded at some point. Do it in cpu_init().
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c
index 27e0056..794d593 100644
--- a/arch/i386/kernel/cpu/common.c
+++ b/arch/i386/kernel/cpu/common.c
@@ -638,6 +638,18 @@
return regs;
}
+/* Current gdt points %fs at the "master" per-cpu area: after this,
+ * it's on the real one. */
+void switch_to_new_gdt(void)
+{
+ struct Xgt_desc_struct gdt_descr;
+
+ gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id());
+ gdt_descr.size = GDT_SIZE - 1;
+ load_gdt(&gdt_descr);
+ asm("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory");
+}
+
/*
* cpu_init() initializes state that is per-CPU. Some data is already
* initialized (naturally) in the bootstrap process, such as the GDT
@@ -668,6 +680,7 @@
}
load_idt(&idt_descr);
+ switch_to_new_gdt();
/*
* Set up and load the per-CPU TSS and LDT
diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c
index f79b623..7c1dbef 100644
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -1177,18 +1177,6 @@
smp_boot_cpus(max_cpus);
}
-/* Current gdt points %fs at the "master" per-cpu area: after this,
- * it's on the real one. */
-static inline void switch_to_new_gdt(void)
-{
- struct Xgt_desc_struct gdt_descr;
-
- gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id());
- gdt_descr.size = GDT_SIZE - 1;
- load_gdt(&gdt_descr);
- asm("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory");
-}
-
void __init native_smp_prepare_boot_cpu(void)
{
unsigned int cpu = smp_processor_id();