kernel/arch/arm64/include/arch/arch_ops.h

// Copyright 2016 The Fuchsia Authors
// Copyright (c) 2008-2014 Travis Geiselbrecht
//
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT

#pragma once

#ifndef ASSEMBLY

#include <stdbool.h>
#include <zircon/compiler.h>
#include <reg.h>
#include <arch/arm64.h>
#include <arch/arm64/mp.h>
#include <arch/arm64/interrupt.h>

__BEGIN_CDECLS

#define ENABLE_CYCLE_COUNTER 1

static inline void arch_spinloop_pause(void)
{
    __asm__ volatile("wfe" ::: "memory");
}

static inline void arch_spinloop_signal(void)
{
    __asm__ volatile("sev" ::: "memory");
}

#define mb()        __asm__ volatile("dsb sy" : : : "memory")
#define smp_mb()    __asm__ volatile("dmb ish" : : : "memory")

static inline uint64_t arch_cycle_count(void)
{
    return ARM64_READ_SYSREG(pmccntr_el0);
}

static inline uint32_t arch_dcache_line_size(void) {
    // According to ARMv8 manual D7.2.21, the Cache Type Register (CTR)
    // is a 32 bit control register that contains the smallest icache
    // line size and smallest dcache line size.
    uint32_t ctr = (uint32_t)ARM64_READ_SYSREG(ctr_el0);

    // Bits 16:19 of the CTR tell us the log_2 of the number of _words_
    // in the smallest _data_ cache line on this system.
    uint32_t dcache_log2 = (ctr >> 16) & 0xf;
    return 4u << dcache_log2;
}

static inline uint32_t arch_icache_line_size(void) {
    // According to ARMv8 manual D7.2.21, the Cache Type Register (CTR)
    // is a 32 bit control register that contains the smallest icache
    // line size and smallest dcache line size.
    uint32_t ctr = (uint32_t)ARM64_READ_SYSREG(ctr_el0);

    // Bits 0:3 of the CTR tell us the log_2 of the number of _words_
    // in the smallest _instruction_ cache line on this system.
    uint32_t icache_log2 = (ctr >> 0) & 0xf;
    return 4u << icache_log2;
}

// Log architecture-specific data for process creation.
// This can only be called after the process has been created and before
// it is running. Alas we can't use zx_koid_t here as the arch layer is at a
// lower level than zircon.
static inline void arch_trace_process_create(uint64_t pid, paddr_t tt_phys) {
    // nothing to do
}

__END_CDECLS

#endif // ASSEMBLY