1 // 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
17 pub mod trng;
18 use self::trng::Error;
19 use smccc::{
20 error::{positive_or_error_64, success_or_error_64},
21 hvc64,
22 };
23
24 const ARM_SMCCC_TRNG_VERSION: u32 = 0x8400_0050;
25 const ARM_SMCCC_TRNG_FEATURES: u32 = 0x8400_0051;
26 #[allow(dead_code)]
27 const ARM_SMCCC_TRNG_GET_UUID: u32 = 0x8400_0052;
28 #[allow(dead_code)]
29 const ARM_SMCCC_TRNG_RND32: u32 = 0x8400_0053;
30 pub const ARM_SMCCC_TRNG_RND64: u32 = 0xc400_0053;
31
32 /// Returns the (major, minor) version tuple, as defined by the SMCCC TRNG.
trng_version() -> trng::Result<trng::Version>33 pub fn trng_version() -> trng::Result<trng::Version> {
34 let args = [0u64; 17];
35
36 let version = positive_or_error_64::<Error>(hvc64(ARM_SMCCC_TRNG_VERSION, args)[0])?;
37 (version as u32 as i32).try_into()
38 }
39
40 pub type TrngRng64Entropy = [u64; 3];
41
trng_rnd64(nbits: u64) -> trng::Result<TrngRng64Entropy>42 pub fn trng_rnd64(nbits: u64) -> trng::Result<TrngRng64Entropy> {
43 let mut args = [0u64; 17];
44 args[0] = nbits;
45
46 let regs = hvc64(ARM_SMCCC_TRNG_RND64, args);
47 success_or_error_64::<Error>(regs[0])?;
48
49 Ok([regs[1], regs[2], regs[3]])
50 }
51
trng_features(fid: u32) -> trng::Result<u64>52 pub fn trng_features(fid: u32) -> trng::Result<u64> {
53 let mut args = [0u64; 17];
54 args[0] = fid as u64;
55
56 positive_or_error_64::<Error>(hvc64(ARM_SMCCC_TRNG_FEATURES, args)[0])
57 }
58