[RFC 2/7] x86/gdt: Put per-cpu GDT remaps in ascending order

[Andy Lutomirski]

We currently have CPU 0's GDT at the top of the GDT range and
higher-numbered CPUs at lower addreses.  This happens because the
fixmap is upside down (index 0 is the top of the fixmap).

Flip it so that GDTs are in ascending order by virtual address.
This will simplify a future patch that will generalize the GDT
remap to contain multiple pages.

Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
 arch/x86/include/asm/desc.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 9d0e13738ed3..02a414cda30f 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -62,7 +62,7 @@ static inline struct desc_struct *get_current_gdt_rw(void)
 /* Get the fixmap index for a specific processor */
 static inline unsigned int get_cpu_gdt_ro_index(int cpu)
 {
-	return FIX_GDT_REMAP_BEGIN + cpu;
+	return FIX_GDT_REMAP_END - cpu;
 }
 
 /* Provide the fixmap address of the remapped GDT */
-- 
2.13.6