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Andrew Walbranba47d1d2022-12-14 15:21:44 +00001// Copyright 2022, The Android Open Source Project
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15//! Wrappers around calls to the hypervisor.
16
Pierre-Clément Tosia59103d2023-02-02 14:46:55 +000017pub mod trng;
Andrew Walbran9afab672023-04-17 14:26:23 +000018use self::trng::Error;
Andrew Walbranf44f1602023-05-30 14:59:19 +000019use smccc::{
Andrew Walbran9afab672023-04-17 14:26:23 +000020 error::{positive_or_error_64, success_or_error_64},
21 hvc64,
22};
Pierre-Clément Tosia59103d2023-02-02 14:46:55 +000023
Pierre-Clément Tosia59103d2023-02-02 14:46:55 +000024const ARM_SMCCC_TRNG_VERSION: u32 = 0x8400_0050;
25#[allow(dead_code)]
26const ARM_SMCCC_TRNG_FEATURES: u32 = 0x8400_0051;
27#[allow(dead_code)]
28const ARM_SMCCC_TRNG_GET_UUID: u32 = 0x8400_0052;
29#[allow(dead_code)]
30const ARM_SMCCC_TRNG_RND32: u32 = 0x8400_0053;
31const ARM_SMCCC_TRNG_RND64: u32 = 0xc400_0053;
Pierre-Clément Tosia59103d2023-02-02 14:46:55 +000032
33/// Returns the (major, minor) version tuple, as defined by the SMCCC TRNG.
34pub fn trng_version() -> trng::Result<(u16, u16)> {
35 let args = [0u64; 17];
36
Andrew Walbran9afab672023-04-17 14:26:23 +000037 let version = positive_or_error_64::<Error>(hvc64(ARM_SMCCC_TRNG_VERSION, args)[0])?;
Pierre-Clément Tosia59103d2023-02-02 14:46:55 +000038 Ok(((version >> 16) as u16, version as u16))
39}
40
41pub type TrngRng64Entropy = (u64, u64, u64);
42
43pub fn trng_rnd64(nbits: u64) -> trng::Result<TrngRng64Entropy> {
44 let mut args = [0u64; 17];
45 args[0] = nbits;
46
Andrew Walbran9afab672023-04-17 14:26:23 +000047 let regs = hvc64(ARM_SMCCC_TRNG_RND64, args);
48 success_or_error_64::<Error>(regs[0])?;
Pierre-Clément Tosia59103d2023-02-02 14:46:55 +000049
50 Ok((regs[1], regs[2], regs[3]))
51}