alpha: simplify fork and friends
* no need to restore everything from switch_stack when we only need $26 * no need to pass current_pt_regs() manually, we can just as easily calculate it in alpha_clone/alpha_vfork ($8 + constant) * interpretation of zero usp as "use the parent's" is simpler in copy_thread(); let fork and vfork just pass 0. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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2b067fc9dd
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@ -617,7 +617,6 @@ ret_from_kernel_thread:
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.ent sys_fork
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sys_fork:
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.prologue 0
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mov $sp, $21
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bsr $1, do_switch_stack
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bis $31, SIGCHLD, $16
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mov $31, $17
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@ -625,7 +624,9 @@ sys_fork:
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mov $31, $19
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mov $31, $20
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jsr $26, alpha_clone
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bsr $1, undo_switch_stack
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fork_out:
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ldq $26, 56($sp)
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lda $sp, SWITCH_STACK_SIZE($sp)
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ret
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.end sys_fork
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@ -634,12 +635,10 @@ sys_fork:
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.ent sys_clone
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sys_clone:
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.prologue 0
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mov $sp, $21
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bsr $1, do_switch_stack
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/* $16, $17, $18, $19, $20 come from the user. */
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jsr $26, alpha_clone
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bsr $1, undo_switch_stack
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ret
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lda $26, fork_out
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jsr $31, alpha_clone
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.end sys_clone
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.align 4
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@ -647,11 +646,9 @@ sys_clone:
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.ent sys_vfork
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sys_vfork:
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.prologue 0
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mov $sp, $16
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bsr $1, do_switch_stack
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jsr $26, alpha_vfork
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bsr $1, undo_switch_stack
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ret
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lda $26, fork_out
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jsr $31, alpha_vfork
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.end sys_vfork
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.align 4
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@ -246,19 +246,17 @@ release_thread(struct task_struct *dead_task)
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int
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alpha_clone(unsigned long clone_flags, unsigned long usp,
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int __user *parent_tid, int __user *child_tid,
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unsigned long tls_value, struct pt_regs *regs)
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unsigned long tls_value)
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{
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if (!usp)
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usp = rdusp();
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return do_fork(clone_flags, usp, regs, 0, parent_tid, child_tid);
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return do_fork(clone_flags, usp, current_pt_regs(), 0,
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parent_tid, child_tid);
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}
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int
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alpha_vfork(struct pt_regs *regs)
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alpha_vfork(void)
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{
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return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(),
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regs, 0, NULL, NULL);
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return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 0,
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current_pt_regs(), 0, NULL, NULL);
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}
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/*
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@ -301,7 +299,7 @@ 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;
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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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