2 files changed, 30 insertions, 0 deletions

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 2cd89b8a7050..9230ce060d09 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -512,6 +512,21 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
         return err;
 }
 
+void
+start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
+{
+        __asm__("movl %0, %%gs" :: "r"(0));
+        regs->fs                = 0;
+        set_fs(USER_DS);
+        regs->ds                = __USER_DS;
+        regs->es                = __USER_DS;
+        regs->ss                = __USER_DS;
+        regs->cs                = __USER_CS;
+        regs->ip                = new_ip;
+        regs->sp                = new_sp;
+}
+EXPORT_SYMBOL_GPL(start_thread);
+
 #ifdef CONFIG_SECCOMP
 static void hard_disable_TSC(void)
 {
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 46c4c546b499..1ffce14cff6e 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -528,6 +528,21 @@ out:
         return err;
 }
 
+void
+start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
+{
+        asm volatile("movl %0, %%fs; movl %0, %%es; movl %0, %%ds" :: "r"(0));
+        load_gs_index(0);
+        regs->ip                = new_ip;
+        regs->sp                = new_sp;
+        write_pda(oldrsp, new_sp);
+        regs->cs                = __USER_CS;
+        regs->ss                = __USER_DS;
+        regs->flags             = 0x200;
+        set_fs(USER_DS);
+}
+EXPORT_SYMBOL_GPL(start_thread);
+
 /*
  * This special macro can be used to load a debugging register
  */