mirror of https://github.com/F-Stack/f-stack.git
57 lines
1.2 KiB
C
57 lines
1.2 KiB
C
/* SPDX-License-Identifier: BSD-3-Clause
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* Copyright(c) 2017 Cavium, Inc
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*/
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#ifndef STACK_H
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#define STACK_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include "lthread_int.h"
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/*
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* Sets up the initial stack for the lthread.
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*/
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static inline void
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arch_set_stack(struct lthread *lt, void *func)
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{
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void **stack_top = (void *)((char *)(lt->stack) + lt->stack_size);
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/*
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* Align stack_top to 16 bytes. Arm64 has the constraint that the
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* stack pointer must always be quad-word aligned.
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*/
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stack_top = (void **)(((unsigned long)(stack_top)) & ~0xfUL);
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/*
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* First Stack Frame
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*/
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stack_top[0] = NULL;
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stack_top[-1] = NULL;
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/*
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* Initialize the context
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*/
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lt->ctx.fp = &stack_top[-1];
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lt->ctx.sp = &stack_top[-2];
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/*
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* Here only the address of _lthread_exec is saved as the link
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* register value. The argument to _lthread_exec i.e the address of
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* the lthread struct is not saved. This is because the first
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* argument to ctx_switch is the address of the new context,
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* which also happens to be the address of required lthread struct.
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* So while returning from ctx_switch into _thread_exec, parameter
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* register x0 will always contain the required value.
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*/
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lt->ctx.lr = func;
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* STACK_H_ */
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