From 064025f7ea1ebcd9bbb99cfa9492a803e8b01d36 Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Tue, 1 Nov 2016 15:49:24 +0000 Subject: [PATCH] x86/boot: Simplify the GDTR calculation assembly code a bit This patch calculates the GDTR's base address via a single instruction. ( EBP contains the address where it is loaded and GDTR's base address is already set to "gdt" in compilation. It is fine to get the correct base address by adding the delta to GDTR's base address. ) Signed-off-by: Wei Yang Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1478015364-5547-1-git-send-email-richard.weiyang@gmail.com Signed-off-by: Ingo Molnar --- arch/x86/boot/compressed/head_64.S | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index efdfba21a5b2..4d85e600db78 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -119,8 +119,7 @@ ENTRY(startup_32) */ /* Load new GDT with the 64bit segments using 32bit descriptor */ - leal gdt(%ebp), %eax - movl %eax, gdt+2(%ebp) + addl %ebp, gdt+2(%ebp) lgdt gdt(%ebp) /* Enable PAE mode */ -- 2.20.1