47 lines
1.2 KiB
C
47 lines
1.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#ifndef CPULOCAL_H
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#define CPULOCAL_H
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/**
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* \file
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*
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* Provides functions to allocate and access thread-local flags.
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*
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*//*
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* Copyright (C) 2022 Martin Whitaker.
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*/
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#include <stdbool.h>
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#include <stdint.h>
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#include "boot.h"
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/**
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* A single thread-local flag. These are spaced out in memory to ensure each
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* flag occupies a different cache line.
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*/
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typedef struct __attribute__((packed)) {
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bool flag;
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uint8_t spacing[AP_STACK_SIZE - sizeof(bool)];
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} local_flag_t;
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/**
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* Allocates an array of thread-local flags, one per CPU core, and returns
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* a ID number that identifies the allocated array. Returns -1 if there is
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* insufficient thread local storage remaining to allocate a new array of
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* flags.
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*/
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int allocate_local_flag(void);
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/**
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* Returns a pointer to the previously allocated array of thread-local flags
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* identified by flag_num.
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*/
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static inline local_flag_t *local_flags(int flag_num)
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{
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// The number returned by allocate_local_flag is the byte offset of the
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// flag from the start of the thread-local storage.
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return (local_flag_t *)(_stacks + BSP_STACK_SIZE - LOCALS_SIZE + flag_num);
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}
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#endif // CPULOCAL_H
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