x86-64, modify_ldt: Make support for 16-bit segments a runtime option

[pandora-kernel.git] / arch / x86 / kernel / ldt.c

diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 4ac4531..3e0ccbf 100644 (file)
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -21,6 +21,8 @@
 #include <asm/mmu_context.h>
 #include <asm/syscalls.h>
 
+int sysctl_ldt16 = 0;
+
 #ifdef CONFIG_SMP
 static void flush_ldt(void *current_mm)
 {
@@ -235,7 +237,7 @@ static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode)
         * IRET leaking the high bits of the kernel stack address.
         */
 #ifdef CONFIG_X86_64
-       if (!ldt_info.seg_32bit) {
+       if (!ldt_info.seg_32bit && !sysctl_ldt16) {
                error = -EINVAL;
                goto out_unlock;
        }