diff --git a/.clippy.toml b/.clippy.toml
index 5cccb362..550d4759 100644
--- a/.clippy.toml
+++ b/.clippy.toml
@@ -1 +1 @@
-msrv = "1.57"
+msrv = "1.63"
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index f3831d5c..e36d4d90 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -44,7 +44,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-22.04, windows-2022]
-        toolchain: [nightly, beta, stable, 1.57]
+        toolchain: [nightly, beta, stable, 1.63]
         # Only Test macOS on stable to reduce macOS CI jobs
         include:
           # x86_64-apple-darwin.
@@ -348,6 +348,8 @@ jobs:
         ]
         include:
           # Supported tier 3 targets with libstd support
+          - target: aarch64-unknown-nto-qnx710
+            features: ["std"]
           - target: x86_64-unknown-openbsd
             features: ["std"]
           - target: x86_64-unknown-dragonfly
diff --git a/Cargo.toml b/Cargo.toml
index b9357bce..6899c03b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,7 +2,7 @@
 name = "getrandom"
 version = "0.2.15" # Also update html_root_url in lib.rs when bumping this
 edition = "2021"
-rust-version = "1.57" # Sync .clippy.toml, tests.yml, and README.md.
+rust-version = "1.63" # Sync .clippy.toml, tests.yml, and README.md.
 authors = ["The Rand Project Developers"]
 license = "MIT OR Apache-2.0"
 description = "A small cross-platform library for retrieving random data from system source"
diff --git a/README.md b/README.md
index 56af89dd..bbab4f28 100644
--- a/README.md
+++ b/README.md
@@ -52,7 +52,7 @@ crate features, WASM support and Custom RNGs see the
 
 ## Minimum Supported Rust Version
 
-This crate requires Rust 1.57.0 or later.
+This crate requires Rust 1.63.0 or later.
 
 ## Platform Support
 
diff --git a/src/error.rs b/src/error.rs
index 5eff99eb..4317efd0 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -58,6 +58,8 @@ impl Error {
     pub const NODE_ES_MODULE: Error = internal_error(14);
     /// Calling Windows ProcessPrng failed.
     pub const WINDOWS_PROCESS_PRNG: Error = internal_error(15);
+    /// The mutex used when opening the random file was poisoned.
+    pub const UNEXPECTED_FILE_MUTEX_POISONED: Error = internal_error(15);
 
     /// Codes below this point represent OS Errors (i.e. positive i32 values).
     /// Codes at or above this point, but below [`Error::CUSTOM_START`] are
diff --git a/src/use_file.rs b/src/use_file.rs
index b47b54d7..470b1378 100644
--- a/src/use_file.rs
+++ b/src/use_file.rs
@@ -4,7 +4,6 @@ extern crate std;
 
 use crate::{util_libc::sys_fill_exact, Error};
 use core::{
-    cell::UnsafeCell,
     ffi::c_void,
     mem::MaybeUninit,
     sync::atomic::{AtomicI32, Ordering::Relaxed},
@@ -12,6 +11,7 @@ use core::{
 use std::{
     fs, io,
     os::fd::{IntoRawFd as _, RawFd},
+    sync::{Mutex, PoisonError},
 };
 
 /// For all platforms, we use `/dev/urandom` rather than `/dev/random`.
@@ -47,11 +47,10 @@ fn get_rng_fd() -> Result<RawFd, Error> {
 
     #[cold]
     fn get_fd_locked() -> Result<RawFd, Error> {
-        // SAFETY: We use the mutex only in this method, and we always unlock it
-        // before returning, making sure we don't violate the pthread_mutex_t API.
-        static MUTEX: Mutex = Mutex::new();
-        unsafe { MUTEX.lock() };
-        let _guard = DropGuard(|| unsafe { MUTEX.unlock() });
+        static MUTEX: Mutex<()> = Mutex::new(());
+        let _guard = MUTEX
+            .lock()
+            .map_err(|_: PoisonError<_>| Error::UNEXPECTED_FILE_MUTEX_POISONED)?;
 
         if let Some(fd) = get_fd() {
             return Ok(fd);
@@ -151,29 +150,3 @@ fn map_io_error(err: io::Error) -> Error {
             }
         })
 }
-
-struct Mutex(UnsafeCell<libc::pthread_mutex_t>);
-
-impl Mutex {
-    const fn new() -> Self {
-        Self(UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER))
-    }
-    unsafe fn lock(&self) {
-        let r = libc::pthread_mutex_lock(self.0.get());
-        debug_assert_eq!(r, 0);
-    }
-    unsafe fn unlock(&self) {
-        let r = libc::pthread_mutex_unlock(self.0.get());
-        debug_assert_eq!(r, 0);
-    }
-}
-
-unsafe impl Sync for Mutex {}
-
-struct DropGuard<F: FnMut()>(F);
-
-impl<F: FnMut()> Drop for DropGuard<F> {
-    fn drop(&mut self) {
-        self.0()
-    }
-}