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Fix broken rdrand implementation #154

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merged 1 commit into from
Jan 15, 2021
Merged

Fix broken rdrand implementation #154

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28 changes: 14 additions & 14 deletions src/arch/x86_64/kernel/processor.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,8 +15,7 @@ use crate::environment;
use crate::x86::controlregs::*;
use crate::x86::cpuid::*;
use crate::x86::msr::*;
use core::arch::x86_64::__rdtscp as rdtscp;
use core::arch::x86_64::_rdtsc as rdtsc;
use core::arch::x86_64::{__rdtscp as rdtscp, _rdrand32_step, _rdrand64_step, _rdtsc as rdtsc};
use core::convert::TryInto;
use core::sync::atomic::spin_loop_hint;
use core::{fmt, u32};
Expand All @@ -35,6 +34,9 @@ const EFER_LMSLE: u64 = 1 << 13;
const EFER_FFXSR: u64 = 1 << 14;
const EFER_TCE: u64 = 1 << 15;

// See Intel SDM - Volume 1 - Section 7.3.17.1
const RDRAND_RETRY_LIMIT: usize = 10;

static mut CPU_FREQUENCY: CpuFrequency = CpuFrequency::new();
static mut CPU_SPEEDSTEP: CpuSpeedStep = CpuSpeedStep::new();
static mut PHYSICAL_ADDRESS_BITS: u8 = 0;
Expand Down Expand Up @@ -894,14 +896,13 @@ pub fn generate_random_number32() -> Option<u32> {
if SUPPORTS_RDRAND {
let mut value: u32 = 0;

while core::arch::x86_64::_rdrand32_step(&mut value) == 1 {
spin_loop_hint();
for _ in 0..RDRAND_RETRY_LIMIT {
if _rdrand32_step(&mut value) == 1 {
return Some(value);
}
}

Some(value)
} else {
None
}
None
}
}

Expand All @@ -910,14 +911,13 @@ pub fn generate_random_number64() -> Option<u64> {
if SUPPORTS_RDRAND {
let mut value: u64 = 0;

while core::arch::x86_64::_rdrand64_step(&mut value) == 1 {
spin_loop_hint();
for _ in 0..RDRAND_RETRY_LIMIT {
if _rdrand64_step(&mut value) == 1 {
return Some(value);
}
}

Some(value)
} else {
None
}
None
}
}

Expand Down
2 changes: 1 addition & 1 deletion src/drivers/virtio/transport/channel_io.rs
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Expand Up @@ -3,4 +3,4 @@
// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
// http://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.
// copied, modified, or distributed except according to those terms.
2 changes: 1 addition & 1 deletion src/drivers/virtio/transport/mmio.rs
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Expand Up @@ -3,4 +3,4 @@
// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
// http://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.
// copied, modified, or distributed except according to those terms.