From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- library/std/src/sys/sgx/abi/tls/mod.rs | 132 +++++++++++++++++++++ library/std/src/sys/sgx/abi/tls/sync_bitset.rs | 85 +++++++++++++ .../std/src/sys/sgx/abi/tls/sync_bitset/tests.rs | 25 ++++ 3 files changed, 242 insertions(+) create mode 100644 library/std/src/sys/sgx/abi/tls/mod.rs create mode 100644 library/std/src/sys/sgx/abi/tls/sync_bitset.rs create mode 100644 library/std/src/sys/sgx/abi/tls/sync_bitset/tests.rs (limited to 'library/std/src/sys/sgx/abi/tls') diff --git a/library/std/src/sys/sgx/abi/tls/mod.rs b/library/std/src/sys/sgx/abi/tls/mod.rs new file mode 100644 index 000000000..13d96e9a6 --- /dev/null +++ b/library/std/src/sys/sgx/abi/tls/mod.rs @@ -0,0 +1,132 @@ +mod sync_bitset; + +use self::sync_bitset::*; +use crate::cell::Cell; +use crate::mem; +use crate::num::NonZeroUsize; +use crate::ptr; +use crate::sync::atomic::{AtomicUsize, Ordering}; + +#[cfg(target_pointer_width = "64")] +const USIZE_BITS: usize = 64; +const TLS_KEYS: usize = 128; // Same as POSIX minimum +const TLS_KEYS_BITSET_SIZE: usize = (TLS_KEYS + (USIZE_BITS - 1)) / USIZE_BITS; + +#[cfg_attr(test, linkage = "available_externally")] +#[export_name = "_ZN16__rust_internals3std3sys3sgx3abi3tls14TLS_KEY_IN_USEE"] +static TLS_KEY_IN_USE: SyncBitset = SYNC_BITSET_INIT; +macro_rules! dup { + ((* $($exp:tt)*) $($val:tt)*) => (dup!( ($($exp)*) $($val)* $($val)* )); + (() $($val:tt)*) => ([$($val),*]) +} +#[cfg_attr(test, linkage = "available_externally")] +#[export_name = "_ZN16__rust_internals3std3sys3sgx3abi3tls14TLS_DESTRUCTORE"] +static TLS_DESTRUCTOR: [AtomicUsize; TLS_KEYS] = dup!((* * * * * * *) (AtomicUsize::new(0))); + +extern "C" { + fn get_tls_ptr() -> *const u8; + fn set_tls_ptr(tls: *const u8); +} + +#[derive(Copy, Clone)] +#[repr(C)] +pub struct Key(NonZeroUsize); + +impl Key { + fn to_index(self) -> usize { + self.0.get() - 1 + } + + fn from_index(index: usize) -> Self { + Key(NonZeroUsize::new(index + 1).unwrap()) + } + + pub fn as_usize(self) -> usize { + self.0.get() + } + + pub fn from_usize(index: usize) -> Self { + Key(NonZeroUsize::new(index).unwrap()) + } +} + +#[repr(C)] +pub struct Tls { + data: [Cell<*mut u8>; TLS_KEYS], +} + +pub struct ActiveTls<'a> { + tls: &'a Tls, +} + +impl<'a> Drop for ActiveTls<'a> { + fn drop(&mut self) { + let value_with_destructor = |key: usize| { + let ptr = TLS_DESTRUCTOR[key].load(Ordering::Relaxed); + unsafe { mem::transmute::<_, Option>(ptr) } + .map(|dtor| (&self.tls.data[key], dtor)) + }; + + let mut any_non_null_dtor = true; + while any_non_null_dtor { + any_non_null_dtor = false; + for (value, dtor) in TLS_KEY_IN_USE.iter().filter_map(&value_with_destructor) { + let value = value.replace(ptr::null_mut()); + if !value.is_null() { + any_non_null_dtor = true; + unsafe { dtor(value) } + } + } + } + } +} + +impl Tls { + pub fn new() -> Tls { + Tls { data: dup!((* * * * * * *) (Cell::new(ptr::null_mut()))) } + } + + pub unsafe fn activate(&self) -> ActiveTls<'_> { + // FIXME: Needs safety information. See entry.S for `set_tls_ptr` definition. + unsafe { set_tls_ptr(self as *const Tls as _) }; + ActiveTls { tls: self } + } + + #[allow(unused)] + pub unsafe fn activate_persistent(self: Box) { + // FIXME: Needs safety information. See entry.S for `set_tls_ptr` definition. + unsafe { set_tls_ptr((&*self) as *const Tls as _) }; + mem::forget(self); + } + + unsafe fn current<'a>() -> &'a Tls { + // FIXME: Needs safety information. See entry.S for `set_tls_ptr` definition. + unsafe { &*(get_tls_ptr() as *const Tls) } + } + + pub fn create(dtor: Option) -> Key { + let index = if let Some(index) = TLS_KEY_IN_USE.set() { + index + } else { + rtabort!("TLS limit exceeded") + }; + TLS_DESTRUCTOR[index].store(dtor.map_or(0, |f| f as usize), Ordering::Relaxed); + Key::from_index(index) + } + + pub fn set(key: Key, value: *mut u8) { + let index = key.to_index(); + rtassert!(TLS_KEY_IN_USE.get(index)); + unsafe { Self::current() }.data[index].set(value); + } + + pub fn get(key: Key) -> *mut u8 { + let index = key.to_index(); + rtassert!(TLS_KEY_IN_USE.get(index)); + unsafe { Self::current() }.data[index].get() + } + + pub fn destroy(key: Key) { + TLS_KEY_IN_USE.clear(key.to_index()); + } +} diff --git a/library/std/src/sys/sgx/abi/tls/sync_bitset.rs b/library/std/src/sys/sgx/abi/tls/sync_bitset.rs new file mode 100644 index 000000000..4eeff8f6e --- /dev/null +++ b/library/std/src/sys/sgx/abi/tls/sync_bitset.rs @@ -0,0 +1,85 @@ +#[cfg(test)] +mod tests; + +use super::{TLS_KEYS_BITSET_SIZE, USIZE_BITS}; +use crate::iter::{Enumerate, Peekable}; +use crate::slice::Iter; +use crate::sync::atomic::{AtomicUsize, Ordering}; + +/// A bitset that can be used synchronously. +pub(super) struct SyncBitset([AtomicUsize; TLS_KEYS_BITSET_SIZE]); + +pub(super) const SYNC_BITSET_INIT: SyncBitset = + SyncBitset([AtomicUsize::new(0), AtomicUsize::new(0)]); + +impl SyncBitset { + pub fn get(&self, index: usize) -> bool { + let (hi, lo) = Self::split(index); + (self.0[hi].load(Ordering::Relaxed) & lo) != 0 + } + + /// Not atomic. + pub fn iter(&self) -> SyncBitsetIter<'_> { + SyncBitsetIter { iter: self.0.iter().enumerate().peekable(), elem_idx: 0 } + } + + pub fn clear(&self, index: usize) { + let (hi, lo) = Self::split(index); + self.0[hi].fetch_and(!lo, Ordering::Relaxed); + } + + /// Sets any unset bit. Not atomic. Returns `None` if all bits were + /// observed to be set. + pub fn set(&self) -> Option { + 'elems: for (idx, elem) in self.0.iter().enumerate() { + let mut current = elem.load(Ordering::Relaxed); + loop { + if 0 == !current { + continue 'elems; + } + let trailing_ones = (!current).trailing_zeros() as usize; + match elem.compare_exchange( + current, + current | (1 << trailing_ones), + Ordering::AcqRel, + Ordering::Relaxed, + ) { + Ok(_) => return Some(idx * USIZE_BITS + trailing_ones), + Err(previous) => current = previous, + } + } + } + None + } + + fn split(index: usize) -> (usize, usize) { + (index / USIZE_BITS, 1 << (index % USIZE_BITS)) + } +} + +pub(super) struct SyncBitsetIter<'a> { + iter: Peekable>>, + elem_idx: usize, +} + +impl<'a> Iterator for SyncBitsetIter<'a> { + type Item = usize; + + fn next(&mut self) -> Option { + self.iter.peek().cloned().and_then(|(idx, elem)| { + let elem = elem.load(Ordering::Relaxed); + let low_mask = (1 << self.elem_idx) - 1; + let next = elem & !low_mask; + let next_idx = next.trailing_zeros() as usize; + self.elem_idx = next_idx + 1; + if self.elem_idx >= 64 { + self.elem_idx = 0; + self.iter.next(); + } + match next_idx { + 64 => self.next(), + _ => Some(idx * USIZE_BITS + next_idx), + } + }) + } +} diff --git a/library/std/src/sys/sgx/abi/tls/sync_bitset/tests.rs b/library/std/src/sys/sgx/abi/tls/sync_bitset/tests.rs new file mode 100644 index 000000000..d7eb2e139 --- /dev/null +++ b/library/std/src/sys/sgx/abi/tls/sync_bitset/tests.rs @@ -0,0 +1,25 @@ +use super::*; + +fn test_data(bitset: [usize; 2], bit_indices: &[usize]) { + let set = SyncBitset([AtomicUsize::new(bitset[0]), AtomicUsize::new(bitset[1])]); + assert_eq!(set.iter().collect::>(), bit_indices); + for &i in bit_indices { + assert!(set.get(i)); + } +} + +#[test] +fn iter() { + test_data([0b0110_1001, 0], &[0, 3, 5, 6]); + test_data([0x8000_0000_0000_0000, 0x8000_0000_0000_0001], &[63, 64, 127]); + test_data([0, 0], &[]); +} + +#[test] +fn set_get_clear() { + let set = SYNC_BITSET_INIT; + let key = set.set().unwrap(); + assert!(set.get(key)); + set.clear(key); + assert!(!set.get(key)); +} -- cgit v1.2.3