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-rw-r--r--library/stdarch/crates/std_detect/src/detect/os/linux/auxvec.rs61
1 files changed, 42 insertions, 19 deletions
diff --git a/library/stdarch/crates/std_detect/src/detect/os/linux/auxvec.rs b/library/stdarch/crates/std_detect/src/detect/os/linux/auxvec.rs
index e6447d0cd..c903903bd 100644
--- a/library/stdarch/crates/std_detect/src/detect/os/linux/auxvec.rs
+++ b/library/stdarch/crates/std_detect/src/detect/os/linux/auxvec.rs
@@ -7,6 +7,7 @@ pub(crate) const AT_NULL: usize = 0;
pub(crate) const AT_HWCAP: usize = 16;
/// Key to access the CPU Hardware capabilities 2 bitfield.
#[cfg(any(
+ target_arch = "aarch64",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "powerpc64"
@@ -21,6 +22,7 @@ pub(crate) const AT_HWCAP2: usize = 26;
pub(crate) struct AuxVec {
pub hwcap: usize,
#[cfg(any(
+ target_arch = "aarch64",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "powerpc64"
@@ -64,13 +66,14 @@ pub(crate) fn auxv() -> Result<AuxVec, ()> {
if let Ok(hwcap) = getauxval(AT_HWCAP) {
// Targets with only AT_HWCAP:
#[cfg(any(
- target_arch = "aarch64",
target_arch = "riscv32",
target_arch = "riscv64",
target_arch = "mips",
target_arch = "mips64"
))]
{
+ // Zero could indicate that no features were detected, but it's also used to
+ // indicate an error. In either case, try the fallback.
if hwcap != 0 {
return Ok(AuxVec { hwcap });
}
@@ -78,13 +81,18 @@ pub(crate) fn auxv() -> Result<AuxVec, ()> {
// Targets with AT_HWCAP and AT_HWCAP2:
#[cfg(any(
+ target_arch = "aarch64",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "powerpc64"
))]
{
if let Ok(hwcap2) = getauxval(AT_HWCAP2) {
- if hwcap != 0 && hwcap2 != 0 {
+ // Zero could indicate that no features were detected, but it's also used to
+ // indicate an error. In particular, on many platforms AT_HWCAP2 will be
+ // legitimately zero, since it contains the most recent feature flags. Use the
+ // fallback only if no features were detected at all.
+ if hwcap != 0 || hwcap2 != 0 {
return Ok(AuxVec { hwcap, hwcap2 });
}
}
@@ -97,7 +105,6 @@ pub(crate) fn auxv() -> Result<AuxVec, ()> {
{
// Targets with only AT_HWCAP:
#[cfg(any(
- target_arch = "aarch64",
target_arch = "riscv32",
target_arch = "riscv64",
target_arch = "mips",
@@ -105,6 +112,8 @@ pub(crate) fn auxv() -> Result<AuxVec, ()> {
))]
{
let hwcap = unsafe { libc::getauxval(AT_HWCAP as libc::c_ulong) as usize };
+ // Zero could indicate that no features were detected, but it's also used to indicate
+ // an error. In either case, try the fallback.
if hwcap != 0 {
return Ok(AuxVec { hwcap });
}
@@ -112,6 +121,7 @@ pub(crate) fn auxv() -> Result<AuxVec, ()> {
// Targets with AT_HWCAP and AT_HWCAP2:
#[cfg(any(
+ target_arch = "aarch64",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "powerpc64"
@@ -119,7 +129,11 @@ pub(crate) fn auxv() -> Result<AuxVec, ()> {
{
let hwcap = unsafe { libc::getauxval(AT_HWCAP as libc::c_ulong) as usize };
let hwcap2 = unsafe { libc::getauxval(AT_HWCAP2 as libc::c_ulong) as usize };
- if hwcap != 0 && hwcap2 != 0 {
+ // Zero could indicate that no features were detected, but it's also used to indicate
+ // an error. In particular, on many platforms AT_HWCAP2 will be legitimately zero,
+ // since it contains the most recent feature flags. Use the fallback only if no
+ // features were detected at all.
+ if hwcap != 0 || hwcap2 != 0 {
return Ok(AuxVec { hwcap, hwcap2 });
}
}
@@ -158,7 +172,7 @@ fn getauxval(key: usize) -> Result<usize, ()> {
/// Tries to read the auxiliary vector from the `file`. If this fails, this
/// function returns `Err`.
#[cfg(feature = "std_detect_file_io")]
-fn auxv_from_file(file: &str) -> Result<AuxVec, ()> {
+pub(super) fn auxv_from_file(file: &str) -> Result<AuxVec, ()> {
let file = super::read_file(file)?;
// See <https://github.com/torvalds/linux/blob/v3.19/include/uapi/linux/auxvec.h>.
@@ -181,7 +195,6 @@ fn auxv_from_file(file: &str) -> Result<AuxVec, ()> {
fn auxv_from_buf(buf: &[usize; 64]) -> Result<AuxVec, ()> {
// Targets with only AT_HWCAP:
#[cfg(any(
- target_arch = "aarch64",
target_arch = "riscv32",
target_arch = "riscv64",
target_arch = "mips",
@@ -198,23 +211,25 @@ fn auxv_from_buf(buf: &[usize; 64]) -> Result<AuxVec, ()> {
}
// Targets with AT_HWCAP and AT_HWCAP2:
#[cfg(any(
+ target_arch = "aarch64",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "powerpc64"
))]
{
let mut hwcap = None;
- let mut hwcap2 = None;
+ // For some platforms, AT_HWCAP2 was added recently, so let it default to zero.
+ let mut hwcap2 = 0;
for el in buf.chunks(2) {
match el[0] {
AT_NULL => break,
AT_HWCAP => hwcap = Some(el[1]),
- AT_HWCAP2 => hwcap2 = Some(el[1]),
+ AT_HWCAP2 => hwcap2 = el[1],
_ => (),
}
}
- if let (Some(hwcap), Some(hwcap2)) = (hwcap, hwcap2) {
+ if let Some(hwcap) = hwcap {
return Ok(AuxVec { hwcap, hwcap2 });
}
}
@@ -256,7 +271,6 @@ mod tests {
// FIXME: on mips/mips64 getauxval returns 0, and /proc/self/auxv
// does not always contain the AT_HWCAP key under qemu.
#[cfg(any(
- target_arch = "aarch64",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "powerpc64"
@@ -271,6 +285,7 @@ mod tests {
// Targets with AT_HWCAP and AT_HWCAP2:
#[cfg(any(
+ target_arch = "aarch64",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "powerpc64"
@@ -305,24 +320,31 @@ mod tests {
}
#[test]
- #[should_panic]
fn linux_macos_vb() {
let file = concat!(env!("CARGO_MANIFEST_DIR"), "/src/detect/test_data/macos-virtualbox-linux-x86-4850HQ.auxv");
println!("file: {}", file);
+ // The file contains HWCAP but not HWCAP2. In that case, we treat HWCAP2 as zero.
let v = auxv_from_file(file).unwrap();
- // this file is incomplete (contains hwcap but not hwcap2), we
- // want to fall back to /proc/cpuinfo in this case, so
- // reading should fail. assert_eq!(v.hwcap, 126614527);
- // assert_eq!(v.hwcap2, 0);
- let _ = v;
+ assert_eq!(v.hwcap, 126614527);
+ assert_eq!(v.hwcap2, 0);
}
} else if #[cfg(target_arch = "aarch64")] {
#[test]
- fn linux_x64() {
- let file = concat!(env!("CARGO_MANIFEST_DIR"), "/src/detect/test_data/linux-x64-i7-6850k.auxv");
+ fn linux_artificial_aarch64() {
+ let file = concat!(env!("CARGO_MANIFEST_DIR"), "/src/detect/test_data/linux-artificial-aarch64.auxv");
println!("file: {}", file);
let v = auxv_from_file(file).unwrap();
- assert_eq!(v.hwcap, 3219913727);
+ assert_eq!(v.hwcap, 0x0123456789abcdef);
+ assert_eq!(v.hwcap2, 0x02468ace13579bdf);
+ }
+ #[test]
+ fn linux_no_hwcap2_aarch64() {
+ let file = concat!(env!("CARGO_MANIFEST_DIR"), "/src/detect/test_data/linux-no-hwcap2-aarch64.auxv");
+ println!("file: {}", file);
+ let v = auxv_from_file(file).unwrap();
+ // An absent HWCAP2 is treated as zero, and does not prevent acceptance of HWCAP.
+ assert_ne!(v.hwcap, 0);
+ assert_eq!(v.hwcap2, 0);
}
}
}
@@ -353,6 +375,7 @@ mod tests {
// Targets with AT_HWCAP and AT_HWCAP2:
#[cfg(any(
+ target_arch = "aarch64",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "powerpc64"
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-10 02:47:09 +0000