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/*
* BSD LICENSE
*
* Copyright (C) Cavium, Inc. 2017.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Cavium, Inc nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef STACK_H
#define STACK_H
#ifdef __cplusplus
extern "C" {
#endif
#include "lthread_int.h"
/*
* Sets up the initial stack for the lthread.
*/
static inline void
arch_set_stack(struct lthread *lt, void *func)
{
void **stack_top = (void *)((char *)(lt->stack) + lt->stack_size);
/*
* Align stack_top to 16 bytes. Arm64 has the constraint that the
* stack pointer must always be quad-word aligned.
*/
stack_top = (void **)(((unsigned long)(stack_top)) & ~0xfUL);
/*
* First Stack Frame
*/
stack_top[0] = NULL;
stack_top[-1] = NULL;
/*
* Initialize the context
*/
lt->ctx.fp = &stack_top[-1];
lt->ctx.sp = &stack_top[-2];
/*
* Here only the address of _lthread_exec is saved as the link
* register value. The argument to _lthread_exec i.e the address of
* the lthread struct is not saved. This is because the first
* argument to ctx_switch is the address of the new context,
* which also happens to be the address of required lthread struct.
* So while returning from ctx_switch into _thread_exec, parameter
* register x0 will always contain the required value.
*/
lt->ctx.lr = func;
}
#ifdef __cplusplus
}
#endif
#endif /* STACK_H_ */
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