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Merged
tarcieri merged 1 commit into from
Feb 1, 2026
Merged

cmov: gate asm! mask generation on miri #1436

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10 changes: 6 additions & 4 deletions .github/workflows/cmov.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -55,23 +55,23 @@ jobs:
strategy:
matrix:
include:
# 32-bit Linux
# `x86` Linux
- target: i686-unknown-linux-gnu
platform: ubuntu-latest
rust: 1.85.0 # MSRV
deps: sudo apt update && sudo apt install gcc-multilib

# 64-bit Linux
# `x86_64` Linux
- target: x86_64-unknown-linux-gnu
platform: ubuntu-latest
rust: 1.85.0 # MSRV

# 64-bit Windows
# `x86_64` Windows
- target: x86_64-pc-windows-msvc
platform: windows-latest
rust: 1.85.0 # MSRV

# 64-bit macOS
# `x86_64` macOS
- target: x86_64-apple-darwin
platform: macos-latest
rust: 1.85.0 # MSRV
Expand Down Expand Up @@ -138,7 +138,9 @@ jobs:
strategy:
matrix:
target:
- armv7-unknown-linux-gnueabi
- powerpc-unknown-linux-gnu
- riscv64gc-unknown-linux-gnu
- s390x-unknown-linux-gnu
- x86_64-unknown-linux-gnu
steps:
Expand Down
22 changes: 14 additions & 8 deletions cmov/src/backends/soft.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -122,13 +122,19 @@ fn maskne64(x: u64, y: u64) -> u64 {
}

/// Return a `u32::MAX` mask if `condition` is non-zero, otherwise return zero for a zero input.
#[cfg(not(any(target_arch = "arm", target_arch = "riscv32", target_arch = "riscv64")))]
#[cfg(any(
miri,
not(any(target_arch = "arm", target_arch = "riscv32", target_arch = "riscv64"))
))]
fn masknz32(condition: u32) -> u32 {
masknz!(condition: u32)
}

/// Return a `u64::MAX` mask if `condition` is non-zero, otherwise return zero for a zero input.
#[cfg(not(any(target_arch = "arm", target_arch = "riscv32", target_arch = "riscv64")))]
#[cfg(any(
miri,
not(any(target_arch = "arm", target_arch = "riscv32", target_arch = "riscv64"))
))]
fn masknz64(condition: u64) -> u64 {
masknz!(condition: u64)
}
Expand All @@ -138,7 +144,7 @@ fn masknz64(condition: u64) -> u64 {
/// This is written in assembly both for performance and because we've had problematic code
/// generation in this routine in the past which lead to the insertion of a branch, which using
/// assembly should guarantee won't happen again in the future (CVE-2026-23519).
#[cfg(target_arch = "arm")]
#[cfg(all(target_arch = "arm", not(miri)))]
fn masknz32(condition: u32) -> u32 {
let mut mask: u32;
unsafe {
Expand All @@ -154,7 +160,7 @@ fn masknz32(condition: u32) -> u32 {
}

/// Optimized mask generation for riscv32 targets.
#[cfg(target_arch = "riscv32")]
#[cfg(all(target_arch = "riscv32", not(miri)))]
fn masknz32(condition: u32) -> u32 {
let mut mask: u32;
unsafe {
Expand All @@ -170,13 +176,13 @@ fn masknz32(condition: u32) -> u32 {
}

/// Optimized mask generation for riscv32 targets.
#[cfg(target_arch = "riscv64")]
#[cfg(all(target_arch = "riscv64", not(miri)))]
fn masknz32(condition: u32) -> u32 {
(masknz64(condition.into()) & 0xFFFF_FFFF) as u32
}

/// Optimized mask generation for riscv32 targets.
#[cfg(target_arch = "riscv64")]
/// Optimized mask generation for riscv64 targets.
#[cfg(all(target_arch = "riscv64", not(miri)))]
fn masknz64(condition: u64) -> u64 {
let mut mask: u64;
unsafe {
Expand All @@ -192,7 +198,7 @@ fn masknz64(condition: u64) -> u64 {
}

/// 64-bit wrapper for targets that implement 32-bit mask generation in assembly.
#[cfg(any(target_arch = "arm", target_arch = "riscv32"))]
#[cfg(all(any(target_arch = "arm", target_arch = "riscv32"), not(miri)))]
fn masknz64(condition: u64) -> u64 {
let lo = masknz32((condition & 0xFFFF_FFFF) as u32);
let hi = masknz32((condition >> 32) as u32);
Expand Down