vmbase: Trivial changes to prepare for smccc::trng
Split the changes to move to smccc::trng into a first patch that can
already be merged (this one) and another that will be blocked on
importing the new version of the crate, to minimize the size of the
latter.
No functional change intended.
Test: atest DebugPolicyHostTests#testNoAdbInDebugPolicy_withDebugLevelNone_boots
Test: atest rialto_test vmbase_example.integration_test
Change-Id: Ic2603365bd1cb5a0c12143aab308454b6fb3568e
diff --git a/vmbase/src/hvc.rs b/vmbase/src/hvc.rs
index 4d489d5..ebd1625 100644
--- a/vmbase/src/hvc.rs
+++ b/vmbase/src/hvc.rs
@@ -30,11 +30,11 @@
pub const ARM_SMCCC_TRNG_RND64: u32 = 0xc400_0053;
/// Returns the (major, minor) version tuple, as defined by the SMCCC TRNG.
-pub fn trng_version() -> trng::Result<(u16, u16)> {
+pub fn trng_version() -> trng::Result<trng::Version> {
let args = [0u64; 17];
let version = positive_or_error_64::<Error>(hvc64(ARM_SMCCC_TRNG_VERSION, args)[0])?;
- Ok(((version >> 16) as u16, version as u16))
+ (version as u32 as i32).try_into()
}
pub type TrngRng64Entropy = (u64, u64, u64);
diff --git a/vmbase/src/hvc/trng.rs b/vmbase/src/hvc/trng.rs
index 1a27d64..efb86f6 100644
--- a/vmbase/src/hvc/trng.rs
+++ b/vmbase/src/hvc/trng.rs
@@ -55,3 +55,40 @@
}
pub type Result<T> = result::Result<T, Error>;
+
+/// A version of the SMCCC TRNG interface.
+#[derive(Copy, Clone, Eq, Ord, PartialEq, PartialOrd)]
+pub struct Version {
+ pub major: u16,
+ pub minor: u16,
+}
+
+impl fmt::Display for Version {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ write!(f, "{}.{}", self.major, self.minor)
+ }
+}
+
+impl fmt::Debug for Version {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::Display::fmt(self, f)
+ }
+}
+
+impl TryFrom<i32> for Version {
+ type Error = Error;
+
+ fn try_from(value: i32) -> core::result::Result<Self, Error> {
+ if value < 0 {
+ Err((value as i64).into())
+ } else {
+ Ok(Self { major: (value >> 16) as u16, minor: value as u16 })
+ }
+ }
+}
+
+impl From<Version> for u32 {
+ fn from(version: Version) -> Self {
+ (u32::from(version.major) << 16) | u32::from(version.minor)
+ }
+}
diff --git a/vmbase/src/rand.rs b/vmbase/src/rand.rs
index a5a5f5f..6b8d7e0 100644
--- a/vmbase/src/rand.rs
+++ b/vmbase/src/rand.rs
@@ -14,7 +14,7 @@
//! Functions and drivers for obtaining true entropy.
-use crate::hvc;
+use crate::hvc::{self, TrngRng64Entropy};
use core::fmt;
use core::mem::size_of;
use smccc::{self, Hvc};
@@ -30,7 +30,7 @@
/// Unsupported SMCCC version.
UnsupportedSmcccVersion(smccc::arch::Version),
/// Unsupported SMCCC TRNG version.
- UnsupportedVersion((u16, u16)),
+ UnsupportedTrngVersion(hvc::trng::Version),
}
impl From<smccc::arch::Error> for Error {
@@ -55,9 +55,7 @@
Self::Smccc(e) => write!(f, "Architectural SMCCC error: {e}"),
Self::Trng(e) => write!(f, "SMCCC TRNG error: {e}"),
Self::UnsupportedSmcccVersion(v) => write!(f, "Unsupported SMCCC version {v}"),
- Self::UnsupportedVersion((x, y)) => {
- write!(f, "Unsupported SMCCC TRNG version v{x}.{y}")
- }
+ Self::UnsupportedTrngVersion(v) => write!(f, "Unsupported SMCCC TRNG version {v}"),
}
}
}
@@ -78,8 +76,8 @@
// TRNG_RND requires SMCCC TRNG v1.0.
match hvc::trng_version()? {
- (1, _) => (),
- version => return Err(Error::UnsupportedVersion(version)),
+ hvc::trng::Version { major: 1, minor: _ } => (),
+ version => return Err(Error::UnsupportedTrngVersion(version)),
}
// TRNG_RND64 doesn't define any special capabilities so ignore the successful result.
@@ -97,7 +95,7 @@
/// Fills a slice of bytes with true entropy.
pub fn fill_with_entropy(s: &mut [u8]) -> Result<()> {
- const MAX_BYTES_PER_CALL: usize = size_of::<hvc::TrngRng64Entropy>();
+ const MAX_BYTES_PER_CALL: usize = size_of::<TrngRng64Entropy>();
let (aligned, remainder) = s.split_at_mut(s.len() - s.len() % MAX_BYTES_PER_CALL);
@@ -125,13 +123,14 @@
Ok(())
}
-fn repeat_trng_rnd(n_bytes: usize) -> hvc::trng::Result<hvc::TrngRng64Entropy> {
+fn repeat_trng_rnd(n_bytes: usize) -> Result<TrngRng64Entropy> {
let bits = usize::try_from(u8::BITS).unwrap();
let n_bits = (n_bytes * bits).try_into().unwrap();
loop {
match hvc::trng_rnd64(n_bits) {
- Err(hvc::trng::Error::NoEntropy) => continue,
- res => return res,
+ Ok(entropy) => return Ok(entropy),
+ Err(hvc::trng::Error::NoEntropy) => (),
+ Err(e) => return Err(e.into()),
}
}
}