From dee2d0f33351491c322e5ce15c7e90a61f425b67 Mon Sep 17 00:00:00 2001
From: Ayush Singh <ayushdevel1325@gmail.com>
Date: Sun, 11 Feb 2024 00:01:43 +0530
Subject: [PATCH] Implement Instant for UEFI
- Uses Timestamp Protocol if present. Else use rdtsc for x86 and x86-64
Signed-off-by: Ayush Singh <ayushdevel1325@gmail.com>
---
library/std/src/lib.rs | 4 +
library/std/src/sys/pal/uefi/time.rs | 116 +++++++++++++++++++++++++++
2 files changed, 120 insertions(+)
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 571e475c336..ad694f6d04b 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -263,6 +263,10 @@
#![cfg_attr(any(windows, target_os = "uefi"), feature(round_char_boundary))]
#![cfg_attr(target_os = "xous", feature(slice_ptr_len))]
#![cfg_attr(target_family = "wasm", feature(stdarch_wasm_atomic_wait))]
+#![cfg_attr(
+ all(any(target_arch = "x86_64", target_arch = "x86"), target_os = "uefi"),
+ feature(stdarch_x86_has_cpuid)
+)]
//
// Language features:
// tidy-alphabetical-start
diff --git a/library/std/src/sys/pal/uefi/time.rs b/library/std/src/sys/pal/uefi/time.rs
index 68f428c38fb..76562cf9f51 100644
--- a/library/std/src/sys/pal/uefi/time.rs
+++ b/library/std/src/sys/pal/uefi/time.rs
@@ -14,6 +14,15 @@ pub const UNIX_EPOCH: SystemTime = SystemTime(Duration::from_secs(0));
impl Instant {
pub fn now() -> Instant {
+ // If we have a timestamp protocol, use it.
+ if let Some(x) = instant_internal::timestamp_protocol() {
+ return x;
+ }
+
+ if let Some(x) = instant_internal::platform_specific() {
+ return x;
+ }
+
panic!("time not implemented on this platform")
}
@@ -103,3 +112,110 @@ pub(crate) mod system_time_internal {
Duration::new(utc_epoch, t.nanosecond)
}
}
+
+pub(crate) mod instant_internal {
+ use super::super::helpers;
+ use super::*;
+ use crate::mem::MaybeUninit;
+ use crate::ptr::NonNull;
+ use crate::sync::atomic::{AtomicPtr, Ordering};
+ use crate::sys_common::mul_div_u64;
+ use r_efi::protocols::timestamp;
+
+ const NS_PER_SEC: u64 = 1_000_000_000;
+
+ pub fn timestamp_protocol() -> Option<Instant> {
+ fn try_handle(handle: NonNull<crate::ffi::c_void>) -> Option<u64> {
+ let protocol: NonNull<timestamp::Protocol> =
+ helpers::open_protocol(handle, timestamp::PROTOCOL_GUID).ok()?;
+ let mut properties: MaybeUninit<timestamp::Properties> = MaybeUninit::uninit();
+
+ let r = unsafe { ((*protocol.as_ptr()).get_properties)(properties.as_mut_ptr()) };
+ if r.is_error() {
+ return None;
+ }
+
+ let freq = unsafe { properties.assume_init().frequency };
+ let ts = unsafe { ((*protocol.as_ptr()).get_timestamp)() };
+ Some(mul_div_u64(ts, NS_PER_SEC, freq))
+ }
+
+ static LAST_VALID_HANDLE: AtomicPtr<crate::ffi::c_void> =
+ AtomicPtr::new(crate::ptr::null_mut());
+
+ if let Some(handle) = NonNull::new(LAST_VALID_HANDLE.load(Ordering::Acquire)) {
+ if let Some(ns) = try_handle(handle) {
+ return Some(Instant(Duration::from_nanos(ns)));
+ }
+ }
+
+ if let Ok(handles) = helpers::locate_handles(timestamp::PROTOCOL_GUID) {
+ for handle in handles {
+ if let Some(ns) = try_handle(handle) {
+ LAST_VALID_HANDLE.store(handle.as_ptr(), Ordering::Release);
+ return Some(Instant(Duration::from_nanos(ns)));
+ }
+ }
+ }
+
+ None
+ }
+
+ pub fn platform_specific() -> Option<Instant> {
+ cfg_if::cfg_if! {
+ if #[cfg(any(target_arch = "x86_64", target_arch = "x86"))] {
+ timestamp_rdtsc().map(Instant)
+ } else {
+ None
+ }
+ }
+ }
+
+ #[cfg(target_arch = "x86_64")]
+ fn timestamp_rdtsc() -> Option<Duration> {
+ if !crate::arch::x86_64::has_cpuid() {
+ return None;
+ }
+
+ static FREQUENCY: crate::sync::OnceLock<u64> = crate::sync::OnceLock::new();
+
+ // Get Frequency in Mhz
+ // Inspired by [`edk2/UefiCpuPkg/Library/CpuTimerLib/CpuTimerLib.c`](https://github.com/tianocore/edk2/blob/master/UefiCpuPkg/Library/CpuTimerLib/CpuTimerLib.c)
+ let freq = FREQUENCY
+ .get_or_try_init(|| {
+ let cpuid = unsafe { crate::arch::x86_64::__cpuid(0x15) };
+ if cpuid.eax == 0 || cpuid.ebx == 0 || cpuid.ecx == 0 {
+ return Err(());
+ }
+ Ok(mul_div_u64(cpuid.ecx as u64, cpuid.ebx as u64, cpuid.eax as u64))
+ })
+ .ok()?;
+
+ let ts = unsafe { crate::arch::x86_64::_rdtsc() };
+ let ns = mul_div_u64(ts, 1000, *freq);
+ Some(Duration::from_nanos(ns))
+ }
+
+ #[cfg(target_arch = "x86")]
+ fn timestamp_rdtsc() -> Option<Duration> {
+ if !crate::arch::x86::has_cpuid() {
+ return None;
+ }
+
+ static FREQUENCY: crate::sync::OnceLock<u64> = crate::sync::OnceLock::new();
+
+ let freq = FREQUENCY
+ .get_or_try_init(|| {
+ let cpuid = unsafe { crate::arch::x86::__cpuid(0x15) };
+ if cpuid.eax == 0 || cpuid.ebx == 0 || cpuid.ecx == 0 {
+ return Err(());
+ }
+ Ok(mul_div_u64(cpuid.ecx as u64, cpuid.ebx as u64, cpuid.eax as u64))
+ })
+ .ok()?;
+
+ let ts = unsafe { crate::arch::x86::_rdtsc() };
+ let ns = mul_div_u64(ts, 1000, *freq);
+ Some(Duration::from_nanos(ns))
+ }
+}