4 * Copyright (C) Cavium networks Ltd. 2017.
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40 #include "lthread_int.h"
43 * Sets up the initial stack for the lthread.
46 arch_set_stack(struct lthread *lt, void *func)
48 void **stack_top = (void *)((char *)(lt->stack) + lt->stack_size);
51 * Align stack_top to 16 bytes. Arm64 has the constraint that the
52 * stack pointer must always be quad-word aligned.
54 stack_top = (void **)(((unsigned long)(stack_top)) & ~0xfUL);
63 * Initialize the context
65 lt->ctx.fp = &stack_top[-1];
66 lt->ctx.sp = &stack_top[-2];
69 * Here only the address of _lthread_exec is saved as the link
70 * register value. The argument to _lthread_exec i.e the address of
71 * the lthread struct is not saved. This is because the first
72 * argument to ctx_switch is the address of the new context,
73 * which also happens to be the address of required lthread struct.
74 * So while returning from ctx_switch into _thread_exec, parameter
75 * register x0 will always contain the required value.