alpha: reorganize copy_process(), prepare to saner fork_idle() (25906730) · Commits · e / devices / android_kernel_teracube_2e

arch/alpha/kernel/process.c

+14 −21

Original line number	Diff line number	Diff line
		@@ -266,18 +266,22 @@ alpha_vfork(void)
		int
		copy_thread(unsigned long clone_flags, unsigned long usp,
		unsigned long arg,
		struct task_struct * p, struct pt_regs * regs)
		struct task_struct p, struct pt_regs wontuse)
		{
		extern void ret_from_fork(void);
		extern void ret_from_kernel_thread(void);

		struct thread_info *childti = task_thread_info(p);
		struct pt_regs *childregs = task_pt_regs(p);
		struct pt_regs *regs = current_pt_regs();
		struct switch_stack childstack, stack;
		unsigned long settls;

		childstack = ((struct switch_stack *) childregs) - 1;
		if (unlikely(!regs)) {
		childti->pcb.ksp = (unsigned long) childstack;
		childti->pcb.flags = 1; /* set FEN, clear everything else */

		if (unlikely(p->flags & PF_KTHREAD)) {
		/* kernel thread */
		memset(childstack, 0,
		sizeof(struct switch_stack) + sizeof(struct pt_regs));
		@@ -286,12 +290,17 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
		childstack->r10 = arg;
		childregs->hae = alpha_mv.hae_cache,
		childti->pcb.usp = 0;
		childti->pcb.ksp = (unsigned long) childstack;
		childti->pcb.flags = 1; /* set FEN, clear everything else */
		return 0;
		}
		/* Note: if CLONE_SETTLS is not set, then we must inherit the
		value from the parent, which will have been set by the block
		copy in dup_task_struct. This is non-intuitive, but is
		required for proper operation in the case of a threaded
		application calling fork. */
		if (clone_flags & CLONE_SETTLS)
		childti->pcb.unique = regs->r20;
		childti->pcb.usp = usp ?: rdusp();
		childregs = regs;
		settls = regs->r20;
		childregs->r0 = 0;
		childregs->r19 = 0;
		childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */
		@@ -299,22 +308,6 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
		stack = ((struct switch_stack *) regs) - 1;
		childstack = stack;
		childstack->r26 = (unsigned long) ret_from_fork;
		childti->pcb.usp = usp ?: rdusp();
		childti->pcb.ksp = (unsigned long) childstack;
		childti->pcb.flags = 1; /* set FEN, clear everything else */

		/* Set a new TLS for the child thread? Peek back into the
		syscall arguments that we saved on syscall entry. Oops,
		except we'd have clobbered it with the parent/child set
		of r20. Read the saved copy. */
		/* Note: if CLONE_SETTLS is not set, then we must inherit the
		value from the parent, which will have been set by the block
		copy in dup_task_struct. This is non-intuitive, but is
		required for proper operation in the case of a threaded
		application calling fork. */
		if (clone_flags & CLONE_SETTLS)
		childti->pcb.unique = settls;

		return 0;
		}