x86: Add 64-bit entries to the GDT

At present it is not possible to execution 64-bit code without
installing an entire new Global Descriptor Table. This is inconvenient
since kvm does not seem to like switching into long mode with a new
table.

It isn't actually necessary, since we can just extend the existing
table. Add some new entries to this effect.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/arch/x86/cpu/i386/cpu.c b/arch/x86/cpu/i386/cpu.c
index a51a244..3bbad3b 100644 (file)
--- a/arch/x86/cpu/i386/cpu.c
+++ b/arch/x86/cpu/i386/cpu.c
@@ -160,6 +160,9 @@ void arch_setup_gd(gd_t *new_gd)
 
        gdt_addr[X86_GDT_ENTRY_16BIT_FLAT_CS] = GDT_ENTRY(0x809b, 0, 0xfffff);
        gdt_addr[X86_GDT_ENTRY_16BIT_FLAT_DS] = GDT_ENTRY(0x8093, 0, 0xfffff);
+       gdt_addr[X86_GDT_ENTRY_64BIT_CS] = GDT_ENTRY(0xaf9b, 0, 0xfffff);
+       gdt_addr[X86_GDT_ENTRY_64BIT_TS1] = GDT_ENTRY(0x8980, 0, 0xfffff);
+       gdt_addr[X86_GDT_ENTRY_64BIT_TS2] = 0;
 
        load_gdt(gdt_addr, X86_GDT_NUM_ENTRIES);
        load_ds(X86_GDT_ENTRY_32BIT_DS);

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index d7b6836..ad8240b 100644 (file)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -18,7 +18,10 @@
 #define X86_GDT_ENTRY_16BIT_DS         6
 #define X86_GDT_ENTRY_16BIT_FLAT_CS    7
 #define X86_GDT_ENTRY_16BIT_FLAT_DS    8
-#define X86_GDT_NUM_ENTRIES            9
+#define X86_GDT_ENTRY_64BIT_CS         9
+#define X86_GDT_ENTRY_64BIT_TS1                10
+#define X86_GDT_ENTRY_64BIT_TS2                11
+#define X86_GDT_NUM_ENTRIES            12
 
 #define X86_GDT_SIZE           (X86_GDT_NUM_ENTRIES * X86_GDT_ENTRY_SIZE)