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92 lines
2.1 KiB
C
92 lines
2.1 KiB
C
/* See the end of this file for copyright and license terms. */
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#pragma once
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#include <gay/cdefs.h>
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#include <gay/types.h>
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static __always_inline void enable_intr(void)
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{
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__asm__ volatile("sti");
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}
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static __always_inline void disable_intr(void)
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{
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__asm__ volatile("cli" ::: "memory");
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}
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static inline register_t read_flags(void)
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{
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register_t flags;
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#ifdef __x86_64__
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__asm__(
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" pushfq \n"
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" popq %0 \n"
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: "=r"(flags)
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);
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#else
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__asm__(
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" pushfl \n"
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" popl %0 \n"
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: "=r"(flags)
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);
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#endif
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return flags;
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}
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/**
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* @brief Temporarily disable interrupts.
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*
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* It should be noted that yes, there is also `disable_intr()`, which does the
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* exact same thing except it has no return value. This is yet another instance
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* of me finding it funny to cause unnecessary confusion, but this time it's
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* also because FreeBSD uses the same unfortunate naming scheme.
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*
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* @return The contents of the status register before disabling interrupts.
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* This should be passed to `intr_restore()` after the atomic operation
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* is complete so that the interrupt enable flag can be restored to what
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* it was before.
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*/
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static inline register_t intr_disable(void)
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{
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register_t eflags = read_flags();
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disable_intr();
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return eflags;
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}
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static inline void intr_restore(register_t flags)
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{
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/* bit 9 is IF (Interrupt Enable Flag) */
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if (flags & (1 << 9))
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enable_intr();
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}
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static __always_inline void halt(void)
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{
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__asm__ volatile("hlt");
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}
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static __always_inline void x86_pause(void)
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{
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__asm__ volatile("pause");
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}
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/** @brief Use this macro to build spin-wait loops. */
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#define spin_loop for (;; x86_pause())
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/*
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* This file is part of GayBSD.
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* Copyright (c) 2021 fef <owo@fef.moe>.
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*
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* GayBSD is nonviolent software: you may only use, redistribute, and/or
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* modify it under the terms of the Cooperative Nonviolent Public License
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* (CNPL) as found in the LICENSE file in the source code root directory
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* or at <https://git.pixie.town/thufie/npl-builder>; either version 7
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* of the license, or (at your option) any later version.
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*
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* GayBSD comes with ABSOLUTELY NO WARRANTY, to the extent
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* permitted by applicable law. See the CNPL for details.
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*/
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