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authorValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
committerValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
commit1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch)
tree7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/portable-atomic/src/imp/fallback/outline_atomics.rs
parent5ecd8cf2cba827454317368b68571df0d13d7842 (diff)
downloadfparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.tar.xz
fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.zip
Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
Diffstat (limited to 'vendor/portable-atomic/src/imp/fallback/outline_atomics.rs')
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+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+// Helper for outline-atomics.
+//
+// On architectures where DW atomics are not supported on older CPUs, we use
+// fallback implementation when DW atomic instructions are not supported and
+// outline-atomics is enabled.
+//
+// This module provides helpers to implement them.
+
+use core::sync::atomic::Ordering;
+
+#[cfg(any(target_arch = "x86_64", target_arch = "powerpc64"))]
+pub(crate) type Udw = u128;
+#[cfg(any(target_arch = "x86_64", target_arch = "powerpc64"))]
+pub(crate) type AtomicUdw = super::super::fallback::AtomicU128;
+#[cfg(any(target_arch = "x86_64", target_arch = "powerpc64"))]
+pub(crate) type AtomicIdw = super::super::fallback::AtomicI128;
+
+#[cfg(target_arch = "arm")]
+pub(crate) type Udw = u64;
+#[cfg(target_arch = "arm")]
+pub(crate) type AtomicUdw = super::super::fallback::AtomicU64;
+#[cfg(target_arch = "arm")]
+pub(crate) type AtomicIdw = super::super::fallback::AtomicI64;
+
+// Asserts that the function is called in the correct context.
+macro_rules! debug_assert_outline_atomics {
+ () => {
+ #[cfg(target_arch = "x86_64")]
+ {
+ debug_assert!(!super::detect::detect().has_cmpxchg16b());
+ }
+ #[cfg(target_arch = "powerpc64")]
+ {
+ debug_assert!(!super::detect::detect().has_quadword_atomics());
+ }
+ #[cfg(target_arch = "arm")]
+ {
+ debug_assert!(!super::has_kuser_cmpxchg64());
+ }
+ };
+}
+
+#[cold]
+pub(crate) unsafe fn atomic_load(src: *mut Udw, order: Ordering) -> Udw {
+ debug_assert_outline_atomics!();
+ #[allow(clippy::cast_ptr_alignment)]
+ // SAFETY: the caller must uphold the safety contract.
+ unsafe {
+ (*(src as *const AtomicUdw)).load(order)
+ }
+}
+fn_alias! {
+ #[cold]
+ pub(crate) unsafe fn(src: *mut Udw) -> Udw;
+ // fallback's atomic load has at least acquire semantics.
+ #[cfg(not(any(target_arch = "arm", target_arch = "x86_64")))]
+ atomic_load_non_seqcst = atomic_load(Ordering::Acquire);
+ atomic_load_seqcst = atomic_load(Ordering::SeqCst);
+}
+
+#[cold]
+pub(crate) unsafe fn atomic_store(dst: *mut Udw, val: Udw, order: Ordering) {
+ debug_assert_outline_atomics!();
+ #[allow(clippy::cast_ptr_alignment)]
+ // SAFETY: the caller must uphold the safety contract.
+ unsafe {
+ (*(dst as *const AtomicUdw)).store(val, order);
+ }
+}
+fn_alias! {
+ #[cold]
+ pub(crate) unsafe fn(dst: *mut Udw, val: Udw);
+ // fallback's atomic store has at least release semantics.
+ #[cfg(not(target_arch = "arm"))]
+ atomic_store_non_seqcst = atomic_store(Ordering::Release);
+ atomic_store_seqcst = atomic_store(Ordering::SeqCst);
+}
+
+#[cold]
+pub(crate) unsafe fn atomic_compare_exchange(
+ dst: *mut Udw,
+ old: Udw,
+ new: Udw,
+ success: Ordering,
+ failure: Ordering,
+) -> (Udw, bool) {
+ debug_assert_outline_atomics!();
+ #[allow(clippy::cast_ptr_alignment)]
+ // SAFETY: the caller must uphold the safety contract.
+ unsafe {
+ match (*(dst as *const AtomicUdw)).compare_exchange(old, new, success, failure) {
+ Ok(v) => (v, true),
+ Err(v) => (v, false),
+ }
+ }
+}
+fn_alias! {
+ #[cold]
+ pub(crate) unsafe fn(dst: *mut Udw, old: Udw, new: Udw) -> (Udw, bool);
+ // fallback's atomic CAS has at least AcqRel semantics.
+ #[cfg(not(any(target_arch = "arm", target_arch = "x86_64")))]
+ atomic_compare_exchange_non_seqcst
+ = atomic_compare_exchange(Ordering::AcqRel, Ordering::Acquire);
+ atomic_compare_exchange_seqcst
+ = atomic_compare_exchange(Ordering::SeqCst, Ordering::SeqCst);
+}
+
+macro_rules! atomic_rmw_3 {
+ (
+ $name:ident($atomic_type:ident::$method_name:ident),
+ $non_seqcst_alias:ident, $seqcst_alias:ident
+ ) => {
+ #[cold]
+ pub(crate) unsafe fn $name(dst: *mut Udw, val: Udw, order: Ordering) -> Udw {
+ debug_assert_outline_atomics!();
+ #[allow(clippy::cast_ptr_alignment)]
+ // SAFETY: the caller must uphold the safety contract.
+ unsafe {
+ (*(dst as *const $atomic_type)).$method_name(val as _, order) as Udw
+ }
+ }
+ fn_alias! {
+ #[cold]
+ pub(crate) unsafe fn(dst: *mut Udw, val: Udw) -> Udw;
+ // fallback's atomic RMW has at least AcqRel semantics.
+ #[cfg(not(any(target_arch = "arm", target_arch = "x86_64")))]
+ $non_seqcst_alias = $name(Ordering::AcqRel);
+ $seqcst_alias = $name(Ordering::SeqCst);
+ }
+ };
+}
+macro_rules! atomic_rmw_2 {
+ (
+ $name:ident($atomic_type:ident::$method_name:ident),
+ $non_seqcst_alias:ident, $seqcst_alias:ident
+ ) => {
+ #[cold]
+ pub(crate) unsafe fn $name(dst: *mut Udw, order: Ordering) -> Udw {
+ debug_assert_outline_atomics!();
+ #[allow(clippy::cast_ptr_alignment)]
+ // SAFETY: the caller must uphold the safety contract.
+ unsafe {
+ (*(dst as *const $atomic_type)).$method_name(order) as Udw
+ }
+ }
+ fn_alias! {
+ #[cold]
+ pub(crate) unsafe fn(dst: *mut Udw) -> Udw;
+ // fallback's atomic RMW has at least AcqRel semantics.
+ #[cfg(not(any(target_arch = "arm", target_arch = "x86_64")))]
+ $non_seqcst_alias = $name(Ordering::AcqRel);
+ $seqcst_alias = $name(Ordering::SeqCst);
+ }
+ };
+}
+
+atomic_rmw_3!(atomic_swap(AtomicUdw::swap), atomic_swap_non_seqcst, atomic_swap_seqcst);
+atomic_rmw_3!(atomic_add(AtomicUdw::fetch_add), atomic_add_non_seqcst, atomic_add_seqcst);
+atomic_rmw_3!(atomic_sub(AtomicUdw::fetch_sub), atomic_sub_non_seqcst, atomic_sub_seqcst);
+atomic_rmw_3!(atomic_and(AtomicUdw::fetch_and), atomic_and_non_seqcst, atomic_and_seqcst);
+atomic_rmw_3!(atomic_nand(AtomicUdw::fetch_nand), atomic_nand_non_seqcst, atomic_nand_seqcst);
+atomic_rmw_3!(atomic_or(AtomicUdw::fetch_or), atomic_or_non_seqcst, atomic_or_seqcst);
+atomic_rmw_3!(atomic_xor(AtomicUdw::fetch_xor), atomic_xor_non_seqcst, atomic_xor_seqcst);
+atomic_rmw_3!(atomic_max(AtomicIdw::fetch_max), atomic_max_non_seqcst, atomic_max_seqcst);
+atomic_rmw_3!(atomic_umax(AtomicUdw::fetch_max), atomic_umax_non_seqcst, atomic_umax_seqcst);
+atomic_rmw_3!(atomic_min(AtomicIdw::fetch_min), atomic_min_non_seqcst, atomic_min_seqcst);
+atomic_rmw_3!(atomic_umin(AtomicUdw::fetch_min), atomic_umin_non_seqcst, atomic_umin_seqcst);
+
+atomic_rmw_2!(atomic_not(AtomicUdw::fetch_not), atomic_not_non_seqcst, atomic_not_seqcst);
+atomic_rmw_2!(atomic_neg(AtomicUdw::fetch_neg), atomic_neg_non_seqcst, atomic_neg_seqcst);