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/* SPDX-License-Identifier: GPL-3.0-or-later */
/* Copyright 2021 - 2022, Kim Kuparinen < kimi.h.kuparinen@gmail.com > */
/**
* @file cpu.c
* riscv64 implementation of cpu handling.
*/
#include <apos/tcb.h>
#include <apos/atomic.h>
#include <arch/cpu.h>
#include "sbi.h"
/** Keeps track of initialized cpus. */
static atomic_long cpus = 0;
void cpu_assign(struct tcb *t)
{
/* bounce cpu id forward, or if first time here, get a cpu id */
struct tcb *c = cur_tcb();
if (likely(c))
t->cpu_id = c->cpu_id;
else
t->cpu_id = cpus++;
__asm__ volatile ("mv tp, %0\n" : : "r" (t) :);
}
id_t cpu_id()
{
struct tcb *t = cur_tcb();
return t->cpu_id;
}
/* override cur_tcb() in common/tcb.c since on risc-v this is apparently the
* optimal strategy. */
/* @todo should this be the default for all arches? */
struct tcb *cur_tcb()
{
struct tcb *t;
__asm__ volatile ("mv %0, tp" : "=r" (t) ::);
return t;
}
/**
* Helper for cpu_send_ipi() to convert linear \p cpu_id to SBI \c
* hart_mask_base.
*
* @param cpu_id CPU id to convert.
* @return Corresponding \c hart_mask_base.
*/
static long __cpu_offset(id_t cpu_id)
{
return cpu_id / (sizeof(long) * 8);
}
/**
* Helper for cpu_send_ipi() to convert linear \p cpu_id to SBI \c
* hart_mask.
*
* @param cpu_id CPU id to convert.
* @param offset Offset from __cpu_offset().
* @return Corresponding \c hart_mask.
*/
static long __cpu_mask(id_t cpu_id, long offset)
{
return cpu_id - offset * sizeof(long) * 8;
}
void cpu_send_ipi(id_t cpu_id)
{
long offset = __cpu_offset(cpu_id);
long mask = __cpu_mask(cpu_id, offset);
sbi_send_ipi(mask, offset);
}
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