[PATCH] i386: Convert PDA into the percpu section

Currently x86 (similar to x84-64) has a special per-cpu structure
called "i386_pda" which can be easily and efficiently referenced via
the %fs register.  An ELF section is more flexible than a structure,
allowing any piece of code to use this area.  Indeed, such a section
already exists: the per-cpu area.

So this patch:
(1) Removes the PDA and uses per-cpu variables for each current member.
(2) Replaces the __KERNEL_PDA segment with __KERNEL_PERCPU.
(3) Creates a per-cpu mirror of __per_cpu_offset called this_cpu_off, which
    can be used to calculate addresses for this CPU's variables.
(4) Simplifies startup, because %fs doesn't need to be loaded with a
    special segment at early boot; it can be deferred until the first
    percpu area is allocated (or never for UP).

The result is less code and one less x86-specific concept.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h
index 922260474646..ced2da8a0d65 100644
--- a/include/asm-i386/processor.h
+++ b/include/asm-i386/processor.h
@@ -377,7 +377,7 @@ struct thread_struct {
         .vm86_info = NULL,                                              \
         .sysenter_cs = __KERNEL_CS,                                     \
         .io_bitmap_ptr = NULL,                                          \
-        .fs = __KERNEL_PDA,                                             \
+        .fs = __KERNEL_PERCPU,                                          \
 }
 
 /*