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refactor lock to kernel-sync

This commit is contained in:
DeathWish5 2022-03-22 17:25:43 +08:00
parent 8770e25478
commit 9916e19a83
15 changed files with 17 additions and 1224 deletions
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3
Cargo.toml
View File

@ -17,3 +17,6 @@ exclude = [
[profile.release] [profile.release]
lto = true lto = true
[patch.'https://github.com/DeathWish5/kernel-sync']
lock = { path = "../../ASYNC/kernel-sync" }

4
drivers/Cargo.toml
View File

@ -15,7 +15,7 @@ virtio = ["virtio-drivers"]
[dependencies] [dependencies]
log = "0.4" log = "0.4"
spin = "0.9" spin = "0.9"
lock = { path = "../lock" } lock = { git = "https://github.com/DeathWish5/kernel-sync" }
cfg-if = "1.0" cfg-if = "1.0"
bitflags = "1.3" bitflags = "1.3"
lazy_static = "1.4" lazy_static = "1.4"
@ -36,4 +36,4 @@ acpi = "4.0"
x2apic = "0.4" x2apic = "0.4"
[target.'cfg(any(target_arch = "riscv32", target_arch = "riscv64"))'.dependencies] [target.'cfg(any(target_arch = "riscv32", target_arch = "riscv64"))'.dependencies]
riscv = { git = "https://github.com/rust-embedded/riscv", rev = "418c1053", features = ["inline-asm"] } riscv = "0.7.0"

4
kernel-hal/Cargo.toml
View File

@ -16,7 +16,7 @@ graphic = ["zcore-drivers/graphic"]
[dependencies] [dependencies]
log = "0.4" log = "0.4"
spin = "0.9" spin = "0.9"
lock = { path = "../lock" } lock = { git = "https://github.com/DeathWish5/kernel-sync" }
cfg-if = "1.0" cfg-if = "1.0"
bitflags = "1.3" bitflags = "1.3"
trapframe = "0.8.0" trapframe = "0.8.0"
@ -52,4 +52,4 @@ x86-smpboot = { git = "https://github.com/rcore-os/x86-smpboot", rev = "43ffedf"
# Bare-metal mode on riscv64 # Bare-metal mode on riscv64
[target.'cfg(all(target_os = "none", target_arch = "riscv64"))'.dependencies] [target.'cfg(all(target_os = "none", target_arch = "riscv64"))'.dependencies]
riscv = { git = "https://github.com/rust-embedded/riscv", rev = "418c1053", features = ["inline-asm"] } riscv = "0.7.0"

2
linux-object/Cargo.toml
View File

@ -11,7 +11,7 @@ description = "Linux kernel objects"
async-trait = "0.1" async-trait = "0.1"
log = "0.4" log = "0.4"
spin = "0.9" spin = "0.9"
lock = { path = "../lock" } lock = { git = "https://github.com/DeathWish5/kernel-sync" }
xmas-elf = "0.7" xmas-elf = "0.7"
bitflags = "1.3" bitflags = "1.3"
hashbrown = "0.9" hashbrown = "0.9"

2
linux-syscall/Cargo.toml
View File

@ -10,7 +10,7 @@ description = "Linux syscalls implementation"
[dependencies] [dependencies]
log = "0.4" log = "0.4"
spin = "0.9" spin = "0.9"
lock = { path = "../lock" } lock = { git = "https://github.com/DeathWish5/kernel-sync" }
bitflags = "1.3" bitflags = "1.3"
numeric-enum-macro = "0.2" numeric-enum-macro = "0.2"
zircon-object = { path = "../zircon-object" } zircon-object = { path = "../zircon-object" }

9
lock/Cargo.toml
View File

@ -1,9 +0,0 @@
[package]
name = "lock"
version = "0.1.0"
edition = "2021"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
lazy_static = { version = "1.4", features = ["spin_no_std"] }

92
lock/src/interrupt.rs
View File

@ -1,92 +0,0 @@
use core::cell::{RefCell, RefMut};
use lazy_static::*;
mod lock_ffi {
extern "C" {
pub fn intr_on();
pub fn intr_off();
pub fn intr_get() -> bool;
pub fn cpu_id() -> u8;
}
}
pub fn intr_on() {
unsafe {
lock_ffi::intr_on();
}
}
pub fn intr_off() {
unsafe {
lock_ffi::intr_off();
}
}
pub fn intr_get() -> bool {
unsafe { lock_ffi::intr_get() }
}
pub fn cpu_id() -> u8 {
unsafe { lock_ffi::cpu_id() }
}
#[derive(Debug, Default, Clone, Copy)]
#[repr(C)]
pub struct Cpu {
pub noff: i32, // Depth of push_off() nesting.
pub interrupt_enable: bool, // Were interrupts enabled before push_off()?
}
impl Cpu {
const fn new() -> Self {
Self {
noff: 0,
interrupt_enable: false,
}
}
}
pub struct SafeRefCell<T>(RefCell<T>);
// #Safety: Only the corresponding cpu will access it.
unsafe impl<Cpu> Sync for SafeRefCell<Cpu> {}
impl<T> SafeRefCell<T> {
const fn new(t: T) -> Self {
Self(RefCell::new(t))
}
}
const DEFAULT_CPU: SafeRefCell<Cpu> = SafeRefCell::new(Cpu::new());
lazy_static! {
pub static ref CPUS: [SafeRefCell<Cpu>; 16] = [DEFAULT_CPU; 16];
}
pub fn mycpu() -> RefMut<'static, Cpu> {
return CPUS[cpu_id() as usize].0.borrow_mut();
}
// push_off/pop_off are like intr_off()/intr_on() except that they are matched:
// it takes two pop_off()s to undo two push_off()s. Also, if interrupts
// are initially off, then push_off, pop_off leaves them off.
pub(crate) fn push_off() {
let old = intr_get();
intr_off();
let mut cpu = mycpu();
if cpu.noff == 0 {
cpu.interrupt_enable = old;
}
cpu.noff += 1;
}
pub(crate) fn pop_off() {
let mut cpu = mycpu();
if intr_get() || cpu.noff < 1 {
panic!("pop_off");
}
cpu.noff -= 1;
if cpu.noff == 0 && cpu.interrupt_enable {
intr_on();
}
}

9
lock/src/lib.rs
View File

@ -1,9 +0,0 @@
#![no_std]
#![feature(asm)]
extern crate alloc;
mod interrupt;
pub mod mutex;
pub mod rwlock;

150
lock/src/mutex.rs
View File

@ -1,150 +0,0 @@
use core::{
cell::UnsafeCell,
default::Default,
fmt,
ops::{Deref, DerefMut},
sync::atomic::{AtomicBool, Ordering},
};
use crate::interrupt::{pop_off, push_off};
pub struct Mutex<T: ?Sized> {
pub(crate) locked: AtomicBool,
data: UnsafeCell<T>,
}
/// An RAII implementation of a “scoped lock” of a mutex.
/// When this structure is dropped (falls out of scope),
/// the lock will be unlocked.
///
pub struct MutexGuard<'a, T: ?Sized + 'a> {
spinlock: &'a Mutex<T>,
data: &'a mut T,
}
unsafe impl<T: ?Sized + Send> Sync for Mutex<T> {}
unsafe impl<T: ?Sized + Send> Send for Mutex<T> {}
impl<T> Mutex<T> {
#[inline(always)]
pub const fn new(data: T) -> Self {
Mutex {
locked: AtomicBool::new(false),
data: UnsafeCell::new(data),
}
}
#[inline(always)]
pub fn into_inner(self) -> T {
// We know statically that there are no outstanding references to
// `self` so there's no need to lock.
let Mutex { data, .. } = self;
data.into_inner()
}
#[inline(always)]
pub fn as_mut_ptr(&self) -> *mut T {
self.data.get()
}
}
impl<T: ?Sized> Mutex<T> {
#[inline(always)]
pub fn lock(&self) -> MutexGuard<T> {
push_off();
while self
.locked
.compare_exchange_weak(false, true, Ordering::Acquire, Ordering::Relaxed)
.is_err()
{
// Wait until the lock looks unlocked before retrying
while self.is_locked() {
core::hint::spin_loop();
}
}
MutexGuard {
spinlock: self,
data: unsafe { &mut *self.data.get() },
}
}
#[inline(always)]
pub fn try_lock(&self) -> Option<MutexGuard<T>> {
push_off();
if self
.locked
.compare_exchange(false, true, Ordering::Acquire, Ordering::Relaxed)
.is_ok()
{
Some(MutexGuard {
spinlock: self,
data: unsafe { &mut *self.data.get() },
})
} else {
pop_off();
None
}
}
#[inline(always)]
pub fn get_mut(&mut self) -> &mut T {
// We know statically that there are no other references to `self`, so
// there's no need to lock the inner mutex.
unsafe { &mut *self.data.get() }
}
#[inline(always)]
pub fn is_locked(&self) -> bool {
self.locked.load(Ordering::Relaxed)
}
}
impl<'a, T: ?Sized + fmt::Display> fmt::Display for MutexGuard<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Display::fmt(&**self, f)
}
}
impl<'a, T: ?Sized> Deref for MutexGuard<'a, T> {
type Target = T;
fn deref(&self) -> &T {
self.data
}
}
impl<'a, T: ?Sized> DerefMut for MutexGuard<'a, T> {
fn deref_mut(&mut self) -> &mut T {
self.data
}
}
impl<'a, T: ?Sized> Drop for MutexGuard<'a, T> {
/// The dropping of the MutexGuard will release the lock it was created from.
fn drop(&mut self) {
if !self.spinlock.is_locked() {
panic!("current cpu doesn't hold the lock{}", self.spinlock);
}
self.spinlock.locked.store(false, Ordering::Release);
pop_off();
}
}
// Not make sence, just to use #[drive(Debug)]
impl<T: ?Sized> fmt::Display for Mutex<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "Mutex{{locked={}}}", self.locked.load(Ordering::Relaxed),)
}
}
// Not make sence, just to use #[drive(Debug)]
impl<T: ?Sized> fmt::Debug for Mutex<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "Mutex{{locked={}}}", self.locked.load(Ordering::Relaxed))
}
}
impl<T: ?Sized + Default> Default for Mutex<T> {
fn default() -> Self {
Mutex::new(T::default())
}
}

950
lock/src/rwlock.rs
View File

@ -1,950 +0,0 @@
//! A lock that provides data access to either one writer or many readers.
use core::{
cell::UnsafeCell,
fmt,
hint::spin_loop,
// marker::PhantomData,
mem,
ops::{Deref, DerefMut},
sync::atomic::{AtomicUsize, Ordering},
};
use crate::interrupt::{pop_off, push_off};
pub struct RwLock<T: ?Sized> {
lock: AtomicUsize,
data: UnsafeCell<T>,
}
const READER: usize = 1 << 2;
const UPGRADED: usize = 1 << 1;
const WRITER: usize = 1;
/// A guard that provides immutable data access.
///
/// When the guard falls out of scope it will decrement the read count,
/// potentially releasing the lock.
pub struct RwLockReadGuard<'a, T: 'a + ?Sized> {
lock: &'a AtomicUsize,
data: &'a T,
}
/// A guard that provides mutable data access.
///
/// When the guard falls out of scope it will release the lock.
pub struct RwLockWriteGuard<'a, T: 'a + ?Sized> {
// phantom: PhantomData<R>,
inner: &'a RwLock<T>,
data: &'a mut T,
}
/// A guard that provides immutable data access but can be upgraded to [`RwLockWriteGuard`].
///
/// No writers or other upgradeable guards can exist while this is in scope. New reader
/// creation is prevented (to alleviate writer starvation) but there may be existing readers
/// when the lock is acquired.
///
/// When the guard falls out of scope it will release the lock.
pub struct RwLockUpgradableGuard<'a, T: 'a + ?Sized> {
// phantom: PhantomData<R>,
inner: &'a RwLock<T>,
data: &'a T,
}
// Same unsafe impls as `std::sync::RwLock`
unsafe impl<T: ?Sized + Send> Send for RwLock<T> {}
unsafe impl<T: ?Sized + Send + Sync> Sync for RwLock<T> {}
impl<T> RwLock<T> {
/// Creates a new spinlock wrapping the supplied data.
///
/// May be used statically:
///
/// ```
/// use spin;
///
/// static RW_LOCK: spin::RwLock<()> = spin::RwLock::new(());
///
/// fn demo() {
/// let lock = RW_LOCK.read();
/// // do something with lock
/// drop(lock);
/// }
/// ```
#[inline]
pub const fn new(data: T) -> Self {
RwLock {
// phantom: PhantomData,
lock: AtomicUsize::new(0),
data: UnsafeCell::new(data),
}
}
/// Consumes this `RwLock`eturning the underlying data.
#[inline]
pub fn into_inner(self) -> T {
// We know statically that there are no outstanding references to
// `self` so there's no need to lock.
let RwLock { data, .. } = self;
data.into_inner()
}
/// Returns a mutable pointer to the underying data.
///
/// This is mostly meant to be used for applications which require manual unlocking, but where
/// storing both the lock and the pointer to the inner data gets inefficient.
///
/// While this is safe, writing to the data is undefined behavior unless the current thread has
/// acquired a write lock, and reading requires either a read or write lock.
///
/// # Example
/// ```
/// let lock = spin::RwLock::new(42);
///
/// unsafe {
/// core::mem::forget(lock.write());
///
/// assert_eq!(lock.as_mut_ptr().read(), 42);
/// lock.as_mut_ptr().write(58);
///
/// lock.force_write_unlock();
/// }
///
/// assert_eq!(*lock.read(), 58);
///
/// ```
#[inline(always)]
pub fn as_mut_ptr(&self) -> *mut T {
self.data.get()
}
}
impl<T: ?Sized> RwLock<T> {
/// Locks this rwlock with shared read access, blocking the current thread
/// until it can be acquired.
///
/// The calling thread will be blocked until there are no more writers which
/// hold the lock. There may be other readers currently inside the lock when
/// this method returns. This method does not provide any guarantees with
/// respect to the ordering of whether contentious readers or writers will
/// acquire the lock first.
///
/// Returns an RAII guard which will release this thread's shared access
/// once it is dropped.
///
/// ```
/// let mylock = spin::RwLock::new(0);
/// {
/// let mut data = mylock.read();
/// // The lock is now locked and the data can be read
/// println!("{}", *data);
/// // The lock is dropped
/// }
/// ```
#[inline]
pub fn read(&self) -> RwLockReadGuard<T> {
loop {
match self.try_read() {
Some(guard) => return guard,
None => spin_loop(),
}
}
}
/// Lock this rwlock with exclusive write access, blocking the current
/// thread until it can be acquired.
///
/// This function will not return while other writers or other readers
/// currently have access to the lock.
///
/// Returns an RAII guard which will drop the write access of this rwlock
/// when dropped.
///
/// ```
/// let mylock = spin::RwLock::new(0);
/// {
/// let mut data = mylock.write();
/// // The lock is now locked and the data can be written
/// *data += 1;
/// // The lock is dropped
/// }
/// ```
#[inline]
pub fn write(&self) -> RwLockWriteGuard<T> {
loop {
match self.try_write_internal(false) {
Some(guard) => return guard,
None => spin_loop(),
}
}
}
/// Obtain a readable lock guard that can later be upgraded to a writable lock guard.
/// Upgrades can be done through the [`RwLockUpgradableGuard::upgrade`](RwLockUpgradableGuard::upgrade) method.
#[inline]
pub fn upgradeable_read(&self) -> RwLockUpgradableGuard<T> {
loop {
match self.try_upgradeable_read() {
Some(guard) => return guard,
None => spin_loop(),
}
}
}
/// Attempt to acquire this lock with shared read access.
///
/// This function will never block and will return immediately if `read`
/// would otherwise succeed. Returns `Some` of an RAII guard which will
/// release the shared access of this thread when dropped, or `None` if the
/// access could not be granted. This method does not provide any
/// guarantees with respect to the ordering of whether contentious readers
/// or writers will acquire the lock first.
///
/// ```
/// let mylock = spin::RwLock::new(0);
/// {
/// match mylock.try_read() {
/// Some(data) => {
/// // The lock is now locked and the data can be read
/// println!("{}", *data);
/// // The lock is dropped
/// },
/// None => (), // no cigar
/// };
/// }
/// ```
#[inline]
pub fn try_read(&self) -> Option<RwLockReadGuard<T>> {
push_off();
let value = self.lock.fetch_add(READER, Ordering::Acquire);
// We check the UPGRADED bit here so that new readers are prevented when an UPGRADED lock is held.
// This helps reduce writer starvation.
if value & (WRITER | UPGRADED) != 0 {
// Lock is taken, undo.
self.lock.fetch_sub(READER, Ordering::Release);
pop_off();
None
} else {
Some(RwLockReadGuard {
lock: &self.lock,
data: unsafe { &*self.data.get() },
})
}
}
/// Return the number of readers that currently hold the lock (including upgradable readers).
///
/// # Safety
///
/// This function provides no synchronization guarantees and so its result should be considered 'out of date'
/// the instant it is called. Do not use it for synchronization purposes. However, it may be useful as a heuristic.
pub fn reader_count(&self) -> usize {
let state = self.lock.load(Ordering::Relaxed);
state / READER + (state & UPGRADED) / UPGRADED
}
/// Return the number of writers that currently hold the lock.
///
/// Because [`RwLock`] guarantees exclusive mutable access, this function may only return either `0` or `1`.
///
/// # Safety
///
/// This function provides no synchronization guarantees and so its result should be considered 'out of date'
/// the instant it is called. Do not use it for synchronization purposes. However, it may be useful as a heuristic.
pub fn writer_count(&self) -> usize {
(self.lock.load(Ordering::Relaxed) & WRITER) / WRITER
}
/// Force decrement the reader count.
///
/// # Safety
///
/// This is *extremely* unsafe if there are outstanding `RwLockReadGuard`s
/// live, or if called more times than `read` has been called, but can be
/// useful in FFI contexts where the caller doesn't know how to deal with
/// RAII. The underlying atomic operation uses `Ordering::Release`.
#[inline]
pub unsafe fn force_read_decrement(&self) {
debug_assert!(self.lock.load(Ordering::Relaxed) & !WRITER > 0);
self.lock.fetch_sub(READER, Ordering::Release);
}
/// Force unlock exclusive write access.
///
/// # Safety
///
/// This is *extremely* unsafe if there are outstanding `RwLockWriteGuard`s
/// live, or if called when there are current readers, but can be useful in
/// FFI contexts where the caller doesn't know how to deal with RAII. The
/// underlying atomic operation uses `Ordering::Release`.
#[inline]
pub unsafe fn force_write_unlock(&self) {
debug_assert_eq!(self.lock.load(Ordering::Relaxed) & !(WRITER | UPGRADED), 0);
self.lock.fetch_and(!(WRITER | UPGRADED), Ordering::Release);
}
#[inline(always)]
fn try_write_internal(&self, strong: bool) -> Option<RwLockWriteGuard<T>> {
push_off();
if compare_exchange(
&self.lock,
0,
WRITER,
Ordering::Acquire,
Ordering::Relaxed,
strong,
)
.is_ok()
{
Some(RwLockWriteGuard {
// phantom: PhantomData,
inner: self,
data: unsafe { &mut *self.data.get() },
})
} else {
pop_off();
None
}
}
/// Attempt to lock this rwlock with exclusive write access.
///
/// This function does not ever block, and it will return `None` if a call
/// to `write` would otherwise block. If successful, an RAII guard is
/// returned.
///
/// ```
/// let mylock = spin::RwLock::new(0);
/// {
/// match mylock.try_write() {
/// Some(mut data) => {
/// // The lock is now locked and the data can be written
/// *data += 1;
/// // The lock is implicitly dropped
/// },
/// None => (), // no cigar
/// };
/// }
/// ```
#[inline]
pub fn try_write(&self) -> Option<RwLockWriteGuard<T>> {
self.try_write_internal(true)
}
/// Tries to obtain an upgradeable lock guard.
#[inline]
pub fn try_upgradeable_read(&self) -> Option<RwLockUpgradableGuard<T>> {
push_off();
if self.lock.fetch_or(UPGRADED, Ordering::Acquire) & (WRITER | UPGRADED) == 0 {
Some(RwLockUpgradableGuard {
// phantom: PhantomData,
inner: self,
data: unsafe { &*self.data.get() },
})
} else {
// We can't unflip the UPGRADED bit back just yet as there is another upgradeable or write lock.
// When they unlock, they will clear the bit.
pop_off();
None
}
}
/// Returns a mutable reference to the underlying data.
///
/// Since this call borrows the `RwLock` mutably, no actual locking needs to
/// take place -- the mutable borrow statically guarantees no locks exist.
///
/// # Examples
///
/// ```
/// let mut lock = spin::RwLock::new(0);
/// *lock.get_mut() = 10;
/// assert_eq!(*lock.read(), 10);
/// ```
pub fn get_mut(&mut self) -> &mut T {
// We know statically that there are no other references to `self`, so
// there's no need to lock the inner lock.
unsafe { &mut *self.data.get() }
}
}
impl<T: ?Sized + fmt::Debug> fmt::Debug for RwLock<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self.try_read() {
Some(guard) => write!(f, "RwLock {{ data: ")
.and_then(|()| (&*guard).fmt(f))
.and_then(|()| write!(f, "}}")),
None => write!(f, "RwLock {{ <locked> }}"),
}
}
}
impl<T: ?Sized + Default> Default for RwLock<T> {
fn default() -> Self {
Self::new(Default::default())
}
}
impl<T> From<T> for RwLock<T> {
fn from(data: T) -> Self {
Self::new(data)
}
}
impl<'rwlock, T: ?Sized> RwLockReadGuard<'rwlock, T> {
/// Leak the lock guard, yielding a reference to the underlying data.
///
/// Note that this function will permanently lock the original lock for all but reading locks.
///
/// ```
/// let mylock = spin::RwLock::new(0);
///
/// let data: &i32 = spin::RwLockReadGuard::leak(mylock.read());
///
/// assert_eq!(*data, 0);
/// ```
#[inline]
pub fn leak(this: Self) -> &'rwlock T {
let Self { data, .. } = this;
data
}
}
impl<'rwlock, T: ?Sized + fmt::Debug> fmt::Debug for RwLockReadGuard<'rwlock, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Debug::fmt(&**self, f)
}
}
impl<'rwlock, T: ?Sized + fmt::Display> fmt::Display for RwLockReadGuard<'rwlock, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Display::fmt(&**self, f)
}
}
impl<'rwlock, T: ?Sized> RwLockUpgradableGuard<'rwlock, T> {
/// Upgrades an upgradeable lock guard to a writable lock guard.
///
/// ```
/// let mylock = spin::RwLock::new(0);
///
/// let upgradeable = mylock.upgradeable_read(); // Readable, but not yet writable
/// let writable = upgradeable.upgrade();
/// ```
#[inline]
pub fn upgrade(mut self) -> RwLockWriteGuard<'rwlock, T> {
loop {
self = match self.try_upgrade_internal(false) {
Ok(guard) => return guard,
Err(e) => e,
};
spin_loop();
}
}
}
impl<'rwlock, T: ?Sized> RwLockUpgradableGuard<'rwlock, T> {
#[inline(always)]
fn try_upgrade_internal(self, strong: bool) -> Result<RwLockWriteGuard<'rwlock, T>, Self> {
if compare_exchange(
&self.inner.lock,
UPGRADED,
WRITER,
Ordering::Acquire,
Ordering::Relaxed,
strong,
)
.is_ok()
{
let inner = self.inner;
// Forget the old guard so its destructor doesn't run (before mutably aliasing data below)
mem::forget(self);
// Upgrade successful
Ok(RwLockWriteGuard {
// phantom: PhantomData,
inner,
data: unsafe { &mut *inner.data.get() },
})
} else {
Err(self)
}
}
/// Tries to upgrade an upgradeable lock guard to a writable lock guard.
///
/// ```
/// let mylock = spin::RwLock::new(0);
/// let upgradeable = mylock.upgradeable_read(); // Readable, but not yet writable
///
/// match upgradeable.try_upgrade() {
/// Ok(writable) => /* upgrade successful - use writable lock guard */ (),
/// Err(upgradeable) => /* upgrade unsuccessful */ (),
/// };
/// ```
#[inline]
pub fn try_upgrade(self) -> Result<RwLockWriteGuard<'rwlock, T>, Self> {
self.try_upgrade_internal(true)
}
#[inline]
/// Downgrades the upgradeable lock guard to a readable, shared lock guard. Cannot fail and is guaranteed not to spin.
///
/// ```
/// let mylock = spin::RwLock::new(1);
///
/// let upgradeable = mylock.upgradeable_read();
/// assert!(mylock.try_read().is_none());
/// assert_eq!(*upgradeable, 1);
///
/// let readable = upgradeable.downgrade(); // This is guaranteed not to spin
/// assert!(mylock.try_read().is_some());
/// assert_eq!(*readable, 1);
/// ```
pub fn downgrade(self) -> RwLockReadGuard<'rwlock, T> {
// Reserve the read guard for ourselves
self.inner.lock.fetch_add(READER, Ordering::Acquire);
let inner = self.inner;
// Dropping self removes the UPGRADED bit
mem::drop(self);
RwLockReadGuard {
lock: &inner.lock,
data: unsafe { &*inner.data.get() },
}
}
/// Leak the lock guard, yielding a reference to the underlying data.
///
/// Note that this function will permanently lock the original lock.
///
/// ```
/// let mylock = spin::RwLock::new(0);
///
/// let data: &i32 = spin::RwLockUpgradableGuard::leak(mylock.upgradeable_read());
///
/// assert_eq!(*data, 0);
/// ```
#[inline]
pub fn leak(this: Self) -> &'rwlock T {
let Self { data, .. } = this;
data
}
}
impl<'rwlock, T: ?Sized + fmt::Debug> fmt::Debug for RwLockUpgradableGuard<'rwlock, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Debug::fmt(&**self, f)
}
}
impl<'rwlock, T: ?Sized + fmt::Display> fmt::Display for RwLockUpgradableGuard<'rwlock, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Display::fmt(&**self, f)
}
}
impl<'rwlock, T: ?Sized> RwLockWriteGuard<'rwlock, T> {
/// Downgrades the writable lock guard to a readable, shared lock guard. Cannot fail and is guaranteed not to spin.
///
/// ```
/// let mylock = spin::RwLock::new(0);
///
/// let mut writable = mylock.write();
/// *writable = 1;
///
/// let readable = writable.downgrade(); // This is guaranteed not to spin
/// # let readable_2 = mylock.try_read().unwrap();
/// assert_eq!(*readable, 1);
/// ```
#[inline]
pub fn downgrade(self) -> RwLockReadGuard<'rwlock, T> {
// Reserve the read guard for ourselves
self.inner.lock.fetch_add(READER, Ordering::Acquire);
let inner = self.inner;
// Dropping self removes the UPGRADED bit
mem::drop(self);
RwLockReadGuard {
lock: &inner.lock,
data: unsafe { &*inner.data.get() },
}
}
/// Downgrades the writable lock guard to an upgradable, shared lock guard. Cannot fail and is guaranteed not to spin.
///
/// ```
/// let mylock = spin::RwLock::new(0);
///
/// let mut writable = mylock.write();
/// *writable = 1;
///
/// let readable = writable.downgrade_to_upgradeable(); // This is guaranteed not to spin
/// assert_eq!(*readable, 1);
/// ```
#[inline]
pub fn downgrade_to_upgradeable(self) -> RwLockUpgradableGuard<'rwlock, T> {
debug_assert_eq!(
self.inner.lock.load(Ordering::Acquire) & (WRITER | UPGRADED),
WRITER
);
// Reserve the read guard for ourselves
self.inner.lock.store(UPGRADED, Ordering::Release);
let inner = self.inner;
// Dropping self removes the UPGRADED bit
mem::forget(self);
RwLockUpgradableGuard {
// phantom: PhantomData,
inner,
data: unsafe { &*inner.data.get() },
}
}
/// Leak the lock guard, yielding a mutable reference to the underlying data.
///
/// Note that this function will permanently lock the original lock.
///
/// ```
/// let mylock = spin::RwLock::new(0);
///
/// let data: &mut i32 = spin::RwLockWriteGuard::leak(mylock.write());
///
/// *data = 1;
/// assert_eq!(*data, 1);
/// ```
#[inline]
pub fn leak(this: Self) -> &'rwlock mut T {
let data = this.data as *mut _; // Keep it in pointer form temporarily to avoid double-aliasing
core::mem::forget(this);
unsafe { &mut *data }
}
}
impl<'rwlock, T: ?Sized + fmt::Debug> fmt::Debug for RwLockWriteGuard<'rwlock, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Debug::fmt(&**self, f)
}
}
impl<'rwlock, T: ?Sized + fmt::Display> fmt::Display for RwLockWriteGuard<'rwlock, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Display::fmt(&**self, f)
}
}
impl<'rwlock, T: ?Sized> Deref for RwLockReadGuard<'rwlock, T> {
type Target = T;
fn deref(&self) -> &T {
self.data
}
}
impl<'rwlock, T: ?Sized> Deref for RwLockUpgradableGuard<'rwlock, T> {
type Target = T;
fn deref(&self) -> &T {
self.data
}
}
impl<'rwlock, T: ?Sized> Deref for RwLockWriteGuard<'rwlock, T> {
type Target = T;
fn deref(&self) -> &T {
self.data
}
}
impl<'rwlock, T: ?Sized> DerefMut for RwLockWriteGuard<'rwlock, T> {
fn deref_mut(&mut self) -> &mut T {
self.data
}
}
impl<'rwlock, T: ?Sized> Drop for RwLockReadGuard<'rwlock, T> {
fn drop(&mut self) {
debug_assert!(self.lock.load(Ordering::Relaxed) & !(WRITER | UPGRADED) > 0);
self.lock.fetch_sub(READER, Ordering::Release);
pop_off();
}
}
impl<'rwlock, T: ?Sized> Drop for RwLockUpgradableGuard<'rwlock, T> {
fn drop(&mut self) {
debug_assert_eq!(
self.inner.lock.load(Ordering::Relaxed) & (WRITER | UPGRADED),
UPGRADED
);
self.inner.lock.fetch_sub(UPGRADED, Ordering::AcqRel);
pop_off();
}
}
impl<'rwlock, T: ?Sized> Drop for RwLockWriteGuard<'rwlock, T> {
fn drop(&mut self) {
debug_assert_eq!(self.inner.lock.load(Ordering::Relaxed) & WRITER, WRITER);
// Writer is responsible for clearing both WRITER and UPGRADED bits.
// The UPGRADED bit may be set if an upgradeable lock attempts an upgrade while this lock is held.
self.inner
.lock
.fetch_and(!(WRITER | UPGRADED), Ordering::Release);
pop_off();
}
}
#[inline(always)]
fn compare_exchange(
atomic: &AtomicUsize,
current: usize,
new: usize,
success: Ordering,
failure: Ordering,
strong: bool,
) -> Result<usize, usize> {
if strong {
atomic.compare_exchange(current, new, success, failure)
} else {
atomic.compare_exchange_weak(current, new, success, failure)
}
}
// #[cfg(test)]
// mod tests {
// use std::prelude::v1::*;
// use std::sync::atomic::{AtomicUsize, Ordering};
// use std::sync::mpsc::channel;
// use std::sync::Arc;
// use std::thread;
// type RwLock<T> = super::RwLock<T>;
// #[derive(Eq, PartialEq, Debug)]
// struct NonCopy(i32);
// #[test]
// fn smoke() {
// let l = RwLock::new(());
// drop(l.read());
// drop(l.write());
// drop((l.read(), l.read()));
// drop(l.write());
// }
// // TODO: needs RNG
// //#[test]
// //fn frob() {
// // static R: RwLock = RwLock::new();
// // const N: usize = 10;
// // const M: usize = 1000;
// //
// // let (txx) = channel::<()>();
// // for _ in 0..N {
// // let tx = tx.clone();
// // thread::spawn(move|| {
// // let mut rng = rand::thread_rng();
// // for _ in 0..M {
// // if rng.gen_weighted_bool(N) {
// // drop(R.write());
// // } else {
// // drop(R.read());
// // }
// // }
// // drop(tx);
// // });
// // }
// // drop(tx);
// // let _ = rx.recv();
// // unsafe { R.destroy(); }
// //}
// #[test]
// fn test_rw_arc() {
// let arc = Arc::new(RwLock::new(0));
// let arc2 = arc.clone();
// let (txx) = channel();
// thread::spawn(move || {
// let mut lock = arc2.write();
// for _ in 0..10 {
// let tmp = *lock;
// *lock = -1;
// thread::yield_now();
// *lock = tmp + 1;
// }
// tx.send(()).unwrap();
// });
// // Readers try to catch the writer in the act
// let mut children = Vec::new();
// for _ in 0..5 {
// let arc3 = arc.clone();
// children.push(thread::spawn(move || {
// let lock = arc3.read();
// assert!(*lock >= 0);
// }));
// }
// // Wait for children to pass their asserts
// for r in children {
// assert!(r.join().is_ok());
// }
// // Wait for writer to finish
// rx.recv().unwrap();
// let lock = arc.read();
// assert_eq!(*lock, 10);
// }
// #[test]
// fn test_rw_access_in_unwind() {
// let arc = Arc::new(RwLock::new(1));
// let arc2 = arc.clone();
// let _ = thread::spawn(move || -> () {
// struct Unwinder {
// i: Arc<RwLock<isize>>,
// }
// impl Drop for Unwinder {
// fn drop(&mut self) {
// let mut lock = self.i.write();
// *lock += 1;
// }
// }
// let _u = Unwinder { i: arc2 };
// panic!();
// })
// .join();
// let lock = arc.read();
// assert_eq!(*lock, 2);
// }
// #[test]
// fn test_rwlock_unsized() {
// let rw: &RwLock<[i32]> = &RwLock::new([1, 2, 3]);
// {
// let b = &mut *rw.write();
// b[0] = 4;
// b[2] = 5;
// }
// let comp: &[i32] = &[4, 2, 5];
// assert_eq!(&*rw.read(), comp);
// }
// #[test]
// fn test_rwlock_try_write() {
// use std::mem::drop;
// let lock = RwLock::new(0isize);
// let read_guard = lock.read();
// let write_result = lock.try_write();
// match write_result {
// None => (),
// Some(_) => assert!(
// false,
// "try_write should not succeed while read_guard is in scope"
// ),
// }
// drop(read_guard);
// }
// #[test]
// fn test_rw_try_read() {
// let m = RwLock::new(0);
// ::std::mem::forget(m.write());
// assert!(m.try_read().is_none());
// }
// #[test]
// fn test_into_inner() {
// let m = RwLock::new(NonCopy(10));
// assert_eq!(m.into_inner(), NonCopy(10));
// }
// #[test]
// fn test_into_inner_drop() {
// struct Foo(Arc<AtomicUsize>);
// impl Drop for Foo {
// fn drop(&mut self) {
// self.0.fetch_add(1, Ordering::SeqCst);
// }
// }
// let num_drops = Arc::new(AtomicUsize::new(0));
// let m = RwLock::new(Foo(num_drops.clone()));
// assert_eq!(num_drops.load(Ordering::SeqCst), 0);
// {
// let _inner = m.into_inner();
// assert_eq!(num_drops.load(Ordering::SeqCst), 0);
// }
// assert_eq!(num_drops.load(Ordering::SeqCst), 1);
// }
// #[test]
// fn test_force_read_decrement() {
// let m = RwLock::new(());
// ::std::mem::forget(m.read());
// ::std::mem::forget(m.read());
// ::std::mem::forget(m.read());
// assert!(m.try_write().is_none());
// unsafe {
// m.force_read_decrement();
// m.force_read_decrement();
// }
// assert!(m.try_write().is_none());
// unsafe {
// m.force_read_decrement();
// }
// assert!(m.try_write().is_some());
// }
// #[test]
// fn test_force_write_unlock() {
// let m = RwLock::new(());
// ::std::mem::forget(m.write());
// assert!(m.try_read().is_none());
// unsafe {
// m.force_write_unlock();
// }
// assert!(m.try_read().is_some());
// }
// #[test]
// fn test_upgrade_downgrade() {
// let m = RwLock::new(());
// {
// let _r = m.read();
// let upg = m.try_upgradeable_read().unwrap();
// assert!(m.try_read().is_none());
// assert!(m.try_write().is_none());
// assert!(upg.try_upgrade().is_err());
// }
// {
// let w = m.write();
// assert!(m.try_upgradeable_read().is_none());
// let _r = w.downgrade();
// assert!(m.try_upgradeable_read().is_some());
// assert!(m.try_read().is_some());
// assert!(m.try_write().is_none());
// }
// {
// let _u = m.upgradeable_read();
// assert!(m.try_upgradeable_read().is_none());
// }
// assert!(m.try_upgradeable_read().unwrap().try_upgrade().is_ok());
// }
// }

2
rboot

@ -1 +1 @@
Subproject commit 97e48ba1bd7a3be7d0b6bd63c4afe3fc25dd09be Subproject commit 39d6e2443edd4e4c4e912b10ac9890c5b83be77b

2
zCore/Cargo.toml
View File

@ -30,7 +30,7 @@ board-d1 = ["link-user-img"]
[dependencies] [dependencies]
log = "0.4" log = "0.4"
spin = "0.9" spin = "0.9"
lock = { path = "../lock" } lock = { git = "https://github.com/DeathWish5/kernel-sync" }
cfg-if = "1.0" cfg-if = "1.0"
lazy_static = { version = "1.4", features = ["spin_no_std" ] } lazy_static = { version = "1.4", features = ["spin_no_std" ] }
bitmap-allocator = { git = "https://github.com/rcore-os/bitmap-allocator", rev = "b3f9f51" } bitmap-allocator = { git = "https://github.com/rcore-os/bitmap-allocator", rev = "b3f9f51" }

8
zCore/Makefile
View File

@ -1,10 +1,10 @@
################ Arguments ################ ################ Arguments ################
ARCH ?= x86_64 ARCH ?= riscv64
PLATFORM ?= qemu PLATFORM ?= qemu
MODE ?= debug MODE ?= release
LOG ?= warn LOG ?= debug
LINUX ?= LINUX ?= 1
LIBOS ?= LIBOS ?=
GRAPHIC ?= GRAPHIC ?=
HYPERVISOR ?= HYPERVISOR ?=

2
zircon-object/Cargo.toml
View File

@ -15,7 +15,7 @@ elf = ["xmas-elf"]
[dependencies] [dependencies]
bitflags = "1.3" bitflags = "1.3"
spin = "0.9" spin = "0.9"
lock = { path = "../lock" } lock = { git = "https://github.com/DeathWish5/kernel-sync" }
log = "0.4" log = "0.4"
hashbrown = "0.9" hashbrown = "0.9"
downcast-rs = { version = "1.2", default-features = false } downcast-rs = { version = "1.2", default-features = false }

2
zircon-syscall/Cargo.toml
View File

@ -14,7 +14,7 @@ deny-page-fault = []
[dependencies] [dependencies]
log = "0.4" log = "0.4"
spin = "0.9" spin = "0.9"
lock = { path = "../lock" } lock = { git = "https://github.com/DeathWish5/kernel-sync" }
bitflags = "1.3" bitflags = "1.3"
numeric-enum-macro = "0.2" numeric-enum-macro = "0.2"
zircon-object = { path = "../zircon-object" } zircon-object = { path = "../zircon-object" }