Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

[firefly-linux-kernel-4.4.55.git] / arch / x86 / kernel / process_32.c

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index b9ff83c7135bad337d4e5d7e7554be6e833204a0..44e0bff38e724de5b9e02e5bd9581133999ad40e 100644 (file)
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -57,6 +57,7 @@
 #include <asm/switch_to.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
+asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");
 
 /*
  * Return saved PC of a blocked thread.
@@ -127,23 +128,39 @@ void release_thread(struct task_struct *dead_task)
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long sp,
-       unsigned long unused,
+       unsigned long arg,
        struct task_struct *p, struct pt_regs *regs)
 {
-       struct pt_regs *childregs;
+       struct pt_regs *childregs = task_pt_regs(p);
        struct task_struct *tsk;
        int err;
 
-       childregs = task_pt_regs(p);
+       p->thread.sp = (unsigned long) childregs;
+       p->thread.sp0 = (unsigned long) (childregs+1);
+
+       if (unlikely(!regs)) {
+               /* kernel thread */
+               memset(childregs, 0, sizeof(struct pt_regs));
+               p->thread.ip = (unsigned long) ret_from_kernel_thread;
+               task_user_gs(p) = __KERNEL_STACK_CANARY;
+               childregs->ds = __USER_DS;
+               childregs->es = __USER_DS;
+               childregs->fs = __KERNEL_PERCPU;
+               childregs->bx = sp;     /* function */
+               childregs->bp = arg;
+               childregs->orig_ax = -1;
+               childregs->cs = __KERNEL_CS | get_kernel_rpl();
+               childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_BIT1;
+               p->fpu_counter = 0;
+               p->thread.io_bitmap_ptr = NULL;
+               memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
+               return 0;
+       }
        *childregs = *regs;
        childregs->ax = 0;
        childregs->sp = sp;
 
-       p->thread.sp = (unsigned long) childregs;
-       p->thread.sp0 = (unsigned long) (childregs+1);
-
        p->thread.ip = (unsigned long) ret_from_fork;
-
        task_user_gs(p) = get_user_gs(regs);
 
        p->fpu_counter = 0;
@@ -190,6 +207,12 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
        regs->cs                = __USER_CS;
        regs->ip                = new_ip;
        regs->sp                = new_sp;
+       regs->flags             = X86_EFLAGS_IF;
+       /*
+        * force it to the iret return path by making it look as if there was
+        * some work pending.
+        */
+       set_thread_flag(TIF_NOTIFY_RESUME);
 }
 EXPORT_SYMBOL_GPL(start_thread);