Rusty Russell <[EMAIL PROTECTED]> writes: > Now we are no longer dynamically allocating the GDT, we don't need the > "cpu_gdt_table" at all: we can switch straight from "boot_gdt_table" > to the per-cpu GDT. This means initializing the cpu_gdt array in C. > > The boot CPU uses the per-cpu var directly, then in smp_prepare_cpus() > it switches to the per-cpu copy just allocated. For secondary CPUs, > the early_gdt_descr is set to point directly to their per-cpu copy. > > For UP the code is very simple: it keeps using the "per-cpu" GDT as > per SMP, but we never have to move.
> diff -r a8a4e2f9da08 arch/i386/kernel/head.S > --- a/arch/i386/kernel/head.S Wed Mar 21 15:20:48 2007 +1100 > +++ b/arch/i386/kernel/head.S Wed Mar 21 15:32:38 2007 +1100 > @@ -599,67 +599,10 @@ idt_descr: > .word 0 # 32 bit align gdt_desc.address > ENTRY(early_gdt_descr) > .word GDT_ENTRIES*8-1 > - .long cpu_gdt_table > - > -/* > - * The boot_gdt_table must mirror the equivalent in setup.S and is > - * used only for booting. > - */ It looks like you are killing a useful comment here for no good reason. > + .long per_cpu__cpu_gdt /* Overwritten for secondary CPUs */ > + > .align L1_CACHE_BYTES > ENTRY(boot_gdt_table) > .fill GDT_ENTRY_BOOT_CS,8,0 > .quad 0x00cf9a000000ffff /* kernel 4GB code at 0x00000000 */ > .quad 0x00cf92000000ffff /* kernel 4GB data at 0x00000000 */ Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
