alpha: reorganize copy_process(), prepare to saner fork_idle()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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b960f30344
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25906730ec
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@ -266,18 +266,22 @@ alpha_vfork(void)
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int
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copy_thread(unsigned long clone_flags, unsigned long usp,
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unsigned long arg,
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struct task_struct * p, struct pt_regs * regs)
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struct task_struct *p, struct pt_regs *wontuse)
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{
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extern void ret_from_fork(void);
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extern void ret_from_kernel_thread(void);
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struct thread_info *childti = task_thread_info(p);
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struct pt_regs *childregs = task_pt_regs(p);
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struct pt_regs *regs = current_pt_regs();
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struct switch_stack *childstack, *stack;
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unsigned long settls;
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childstack = ((struct switch_stack *) childregs) - 1;
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if (unlikely(!regs)) {
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childti->pcb.ksp = (unsigned long) childstack;
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childti->pcb.flags = 1; /* set FEN, clear everything else */
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if (unlikely(p->flags & PF_KTHREAD)) {
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/* kernel thread */
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memset(childstack, 0,
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sizeof(struct switch_stack) + sizeof(struct pt_regs));
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@ -286,12 +290,17 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
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childstack->r10 = arg;
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childregs->hae = alpha_mv.hae_cache,
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childti->pcb.usp = 0;
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childti->pcb.ksp = (unsigned long) childstack;
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childti->pcb.flags = 1; /* set FEN, clear everything else */
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return 0;
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}
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/* Note: if CLONE_SETTLS is not set, then we must inherit the
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value from the parent, which will have been set by the block
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copy in dup_task_struct. This is non-intuitive, but is
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required for proper operation in the case of a threaded
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application calling fork. */
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if (clone_flags & CLONE_SETTLS)
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childti->pcb.unique = regs->r20;
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childti->pcb.usp = usp ?: rdusp();
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*childregs = *regs;
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settls = regs->r20;
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childregs->r0 = 0;
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childregs->r19 = 0;
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childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */
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@ -299,22 +308,6 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
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stack = ((struct switch_stack *) regs) - 1;
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*childstack = *stack;
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childstack->r26 = (unsigned long) ret_from_fork;
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childti->pcb.usp = usp ?: rdusp();
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childti->pcb.ksp = (unsigned long) childstack;
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childti->pcb.flags = 1; /* set FEN, clear everything else */
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/* Set a new TLS for the child thread? Peek back into the
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syscall arguments that we saved on syscall entry. Oops,
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except we'd have clobbered it with the parent/child set
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of r20. Read the saved copy. */
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/* Note: if CLONE_SETTLS is not set, then we must inherit the
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value from the parent, which will have been set by the block
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copy in dup_task_struct. This is non-intuitive, but is
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required for proper operation in the case of a threaded
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application calling fork. */
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if (clone_flags & CLONE_SETTLS)
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childti->pcb.unique = settls;
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return 0;
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}
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