x86: Initialize GDT entry 1 to be the 32-bit CS as well

Some OS (like VxWorks) requires GDT entry 1 to be the 32-bit CS.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Jian Luo <jian.luo4@boschrexroth.de>

diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c
index 1b76ca117ee3df339d981bfe3cde74cbd4a9ee9d..812c5e4e6bee312c7d4a273ec12964aa08311c99 100644 (file)
--- a/arch/x86/cpu/cpu.c
+++ b/arch/x86/cpu/cpu.c
@@ -142,7 +142,12 @@ void arch_setup_gd(gd_t *new_gd)
 
        gdt_addr = new_gd->arch.gdt;
 
-       /* CS: code, read/execute, 4 GB, base 0 */
+       /*
+        * CS: code, read/execute, 4 GB, base 0
+        *
+        * Some OS (like VxWorks) requires GDT entry 1 to be the 32-bit CS
+        */
+       gdt_addr[X86_GDT_ENTRY_UNUSED] = GDT_ENTRY(0xc09b, 0, 0xfffff);
        gdt_addr[X86_GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff);
 
        /* DS: data, read/write, 4 GB, base 0 */