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Diffstat (limited to 'vendor/portable-atomic/src/gen/utils.rs')
-rw-r--r-- | vendor/portable-atomic/src/gen/utils.rs | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/vendor/portable-atomic/src/gen/utils.rs b/vendor/portable-atomic/src/gen/utils.rs new file mode 100644 index 0000000..61f6c99 --- /dev/null +++ b/vendor/portable-atomic/src/gen/utils.rs @@ -0,0 +1,147 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT +// This file is @generated by target_spec.sh. +// It is not intended for manual editing. + +#![allow(unused_macros)] + +// On AArch64, the base register of load/store/atomic instructions must be 64-bit. +// Passing a 32-bit value to `in(reg)` on AArch64 results in the upper bits +// having an undefined value, but to work correctly with ILP32 ABI, the upper +// bits must be zero, which is handled here by casting to u64. Another way to +// handle this is to pass it as a pointer and clear the upper bits inside asm, +// but it is easier to overlook than cast, which can catch overlooks by +// asm_sub_register lint. +// See also https://github.com/ARM-software/abi-aa/blob/2023Q1/aapcs64/aapcs64.rst#57pointers +// +// Except for x86_64, which can use 32-bit registers in the destination operand +// (on x86_64, we use the ptr_modifier macro to handle this), we need to do the +// same for ILP32 ABI on other 64-bit architectures. (At least, as far as I can +// see from the assembly generated by LLVM, this is also required for MIPS64 N32 +// ABI. I don't know about the RISC-V s64ilp32 ABI for which a patch was +// recently submitted to the kernel, but in any case, this should be a safe +// default for such ABIs). +// +// Known architectures that have such ABI are x86_64 (X32), aarch64 (ILP32), +// mips64 (N32), and riscv64 (s64ilp32, not merged yet though). (As of +// 2023-06-05, only the former two are supported by rustc.) However, we list all +// known 64-bit architectures because similar ABIs may exist or future added for +// other architectures. +#[cfg(all( + target_pointer_width = "32", + any( + target_arch = "aarch64", + target_arch = "bpf", + target_arch = "loongarch64", + target_arch = "mips64", + target_arch = "mips64r6", + target_arch = "nvptx64", + target_arch = "powerpc64", + target_arch = "riscv64", + target_arch = "s390x", + target_arch = "sparc64", + target_arch = "wasm64", + target_arch = "x86_64", + ), +))] +macro_rules! ptr_reg { + ($ptr:ident) => {{ + let _: *const _ = $ptr; // ensure $ptr is a pointer (*mut _ or *const _) + #[cfg(not(portable_atomic_no_asm_maybe_uninit))] + #[allow(clippy::ptr_as_ptr)] + { + // If we cast to u64 here, the provenance will be lost, + // so we convert to MaybeUninit<u64> via zero extend helper. + crate::utils::zero_extend64_ptr($ptr as *mut ()) + } + #[cfg(portable_atomic_no_asm_maybe_uninit)] + { + // Use cast on old rustc because it does not support MaybeUninit + // registers. This is still permissive-provenance compatible and + // is sound. + $ptr as u64 + } + }}; +} +#[cfg(not(all( + target_pointer_width = "32", + any( + target_arch = "aarch64", + target_arch = "bpf", + target_arch = "loongarch64", + target_arch = "mips64", + target_arch = "mips64r6", + target_arch = "nvptx64", + target_arch = "powerpc64", + target_arch = "riscv64", + target_arch = "s390x", + target_arch = "sparc64", + target_arch = "wasm64", + target_arch = "x86_64", + ), +)))] +macro_rules! ptr_reg { + ($ptr:ident) => {{ + let _: *const _ = $ptr; // ensure $ptr is a pointer (*mut _ or *const _) + $ptr // cast is unnecessary here. + }}; +} + +// Some 64-bit architectures have ABI with 32-bit pointer width (e.g., x86_64 X32 ABI, +// AArch64 ILP32 ABI, MIPS64 N32 ABI). On those targets, AtomicU64 is available +// and fast, so use it to implement normal sequence lock. +// +// See ptr_reg macro for the reason why all known 64-bit architectures are listed. +#[cfg(feature = "fallback")] +#[cfg(any( + not(any(target_pointer_width = "16", target_pointer_width = "32")), // i.e., 64-bit or greater + target_arch = "aarch64", + target_arch = "bpf", + target_arch = "loongarch64", + target_arch = "mips64", + target_arch = "mips64r6", + target_arch = "nvptx64", + target_arch = "powerpc64", + target_arch = "riscv64", + target_arch = "s390x", + target_arch = "sparc64", + target_arch = "wasm64", + target_arch = "x86_64", +))] +#[macro_use] +mod fast_atomic_64_macros { + macro_rules! cfg_has_fast_atomic_64 { + ($($tt:tt)*) => { + $($tt)* + }; + } + macro_rules! cfg_no_fast_atomic_64 { + ($($tt:tt)*) => {}; + } +} +#[cfg(feature = "fallback")] +#[cfg(not(any( + not(any(target_pointer_width = "16", target_pointer_width = "32")), // i.e., 64-bit or greater + target_arch = "aarch64", + target_arch = "bpf", + target_arch = "loongarch64", + target_arch = "mips64", + target_arch = "mips64r6", + target_arch = "nvptx64", + target_arch = "powerpc64", + target_arch = "riscv64", + target_arch = "s390x", + target_arch = "sparc64", + target_arch = "wasm64", + target_arch = "x86_64", +)))] +#[macro_use] +mod fast_atomic_64_macros { + macro_rules! cfg_has_fast_atomic_64 { + ($($tt:tt)*) => {}; + } + macro_rules! cfg_no_fast_atomic_64 { + ($($tt:tt)*) => { + $($tt)* + }; + } +} |