x86: Tidy up the 64-bit calling code

The GDT works but technically the length is incorrect. Fix this and add a
comment.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

diff --git a/arch/x86/cpu/call64.S b/arch/x86/cpu/call64.S
index 74dd5a89dceeb3e55dcb6e7400b154d7b7cf2444..08dc473d6af40e528f574c19f26fae07cb658778 100644 (file)
--- a/arch/x86/cpu/call64.S
+++ b/arch/x86/cpu/call64.S
@@ -82,8 +82,8 @@ lret_target:
 
        .data
 gdt:
-       .word   gdt_end - gdt
-       .long   gdt
+       .word   gdt_end - gdt - 1
+       .long   gdt                     /* Fixed up by code above */
        .word   0
        .quad   0x0000000000000000      /* NULL descriptor */
        .quad   0x00af9a000000ffff      /* __KERNEL_CS */