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uefi-raw: Add explicit padding field for MemoryDescriptor #1334

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uefi-raw: Add explicit padding field for MemoryDescriptor #1334

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74c981b
treewide: allow std in tests
phip1611 Aug 17, 2024
ee2e9a1
uefi-raw: Add explicit padding field for MemoryDescriptor + add test
phip1611 Aug 17, 2024
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3 changes: 3 additions & 0 deletions uefi-raw/CHANGELOG.md
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Original file line number Diff line number Diff line change
@@ -1,5 +1,8 @@
# uefi-raw - [Unreleased]

## Changed
- `MemoryDescriptor` now has an explicit padding field, allowing trivial
memory-safe serialization and deserialization

# uefi-raw - 0.8.0 (2024-09-09)

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5 changes: 5 additions & 0 deletions uefi-raw/src/lib.rs
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Expand Up @@ -20,6 +20,11 @@
unused
)]

// Useful for convenience in tests, such as `dbg!`
#[cfg_attr(test, macro_use)]
#[cfg(test)]
extern crate std;

#[macro_use]
mod enums;

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38 changes: 36 additions & 2 deletions uefi-raw/src/table/boot.rs
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Expand Up @@ -350,7 +350,8 @@ bitflags! {
pub struct MemoryDescriptor {
/// Type of memory occupying this range.
pub ty: MemoryType,
// Implicit 32-bit padding.
/// Padding field. Ignore.
pub padding0: u32,
/// Starting physical address.
pub phys_start: PhysicalAddress,
/// Starting virtual address.
Expand All @@ -370,6 +371,7 @@ impl Default for MemoryDescriptor {
fn default() -> Self {
Self {
ty: MemoryType::RESERVED,
padding0: 0,
phys_start: 0,
virt_start: 0,
page_count: 0,
Expand All @@ -379,7 +381,7 @@ impl Default for MemoryDescriptor {
}

newtype_enum! {
/// The type of a memory range.
/// The type of memory range.
///
/// UEFI allows firmwares and operating systems to introduce new memory types
/// in the `0x7000_0000..=0xFFFF_FFFF` range. Therefore, we don't know the full set
Expand Down Expand Up @@ -484,3 +486,35 @@ pub enum Tpl: usize => {
/// Note that this is not necessarily the processor's page size. The UEFI page
/// size is always 4 KiB.
pub const PAGE_SIZE: usize = 4096;

#[cfg(test)]
mod tests {
use core::{mem, slice};
use super::*;

// This tests succeeds if Miri doesn't complain about uninitialized memory.
#[test]
fn memory_descriptor_trivial_serialization() {
let descs = [
MemoryDescriptor {
ty: MemoryType::CONVENTIONAL,
padding0: 0,
phys_start: 0x1000,
virt_start: 0x1000,
page_count: 1,
att: Default::default(),
},
];


let raw_bytes: &[u8] = {
let ptr = descs.as_ptr().cast::<u8>();
let len = mem::size_of_val(&descs);
unsafe { slice::from_raw_parts(ptr.cast(), len) }
};

// Test succeeds if Miri doesn't complain about initialized memory
// (implicit padding fields).
dbg!(&raw_bytes);
}
}
7 changes: 6 additions & 1 deletion uefi/src/lib.rs
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Expand Up @@ -24,7 +24,7 @@
//!
//! Status::SUCCESS
//! }
//! # extern crate std;
//! # extern crate std; // For panic handler
//! ```
//!
//! Please find more info in our [Rust UEFI Book].
Expand Down Expand Up @@ -235,6 +235,11 @@ extern crate self as uefi;
#[macro_use]
extern crate uefi_raw;

// Useful for convenience in tests, such as `dbg!`
#[cfg_attr(test, macro_use)]
#[cfg(test)]
extern crate std;

#[macro_use]
pub mod data_types;
pub mod allocator;
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3 changes: 3 additions & 0 deletions uefi/src/mem/memory_map/impl_.rs
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Expand Up @@ -432,20 +432,23 @@ mod tests {
const BASE_MMAP_UNSORTED: [MemoryDescriptor; 3] = [
MemoryDescriptor {
ty: MemoryType::CONVENTIONAL,
padding0: 0,
phys_start: 0x3000,
virt_start: 0x3000,
page_count: 1,
att: MemoryAttribute::WRITE_BACK,
},
MemoryDescriptor {
ty: MemoryType::CONVENTIONAL,
padding0: 0,
phys_start: 0x2000,
virt_start: 0x2000,
page_count: 1,
att: MemoryAttribute::WRITE_BACK,
},
MemoryDescriptor {
ty: MemoryType::CONVENTIONAL,
padding0: 0,
phys_start: 0x1000,
virt_start: 0x1000,
page_count: 1,
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12 changes: 12 additions & 0 deletions uefi/src/mem/memory_map/mod.rs
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Expand Up @@ -131,6 +131,7 @@ mod tests_mmap_artificial {

const BASE: MemoryDescriptor = MemoryDescriptor {
ty: TY,
padding0: 0,
phys_start: 0,
virt_start: 0,
page_count: 0,
Expand Down Expand Up @@ -169,6 +170,7 @@ mod tests_mmap_artificial {

const BASE: MemoryDescriptor = MemoryDescriptor {
ty: TY,
padding0: 0,
phys_start: 0,
virt_start: 0,
page_count: 0,
Expand Down Expand Up @@ -278,6 +280,7 @@ mod tests_mmap_real {
| MemoryAttribute::WRITE_COMBINE
| MemoryAttribute::WRITE_THROUGH
| MemoryAttribute::WRITE_BACK,
..Default::default()
},
MemoryDescriptor {
ty: MemoryType::CONVENTIONAL,
Expand All @@ -288,6 +291,7 @@ mod tests_mmap_real {
| MemoryAttribute::WRITE_COMBINE
| MemoryAttribute::WRITE_THROUGH
| MemoryAttribute::WRITE_BACK,
..Default::default()
},
MemoryDescriptor {
ty: MemoryType::BOOT_SERVICES_DATA,
Expand All @@ -298,6 +302,7 @@ mod tests_mmap_real {
| MemoryAttribute::WRITE_COMBINE
| MemoryAttribute::WRITE_THROUGH
| MemoryAttribute::WRITE_BACK,
..Default::default()
},
MemoryDescriptor {
ty: MemoryType::CONVENTIONAL,
Expand All @@ -308,6 +313,7 @@ mod tests_mmap_real {
| MemoryAttribute::WRITE_COMBINE
| MemoryAttribute::WRITE_THROUGH
| MemoryAttribute::WRITE_BACK,
..Default::default()
},
MemoryDescriptor {
ty: MemoryType::CONVENTIONAL,
Expand All @@ -318,6 +324,7 @@ mod tests_mmap_real {
| MemoryAttribute::WRITE_COMBINE
| MemoryAttribute::WRITE_THROUGH
| MemoryAttribute::WRITE_BACK,
..Default::default()
},
MemoryDescriptor {
ty: MemoryType::ACPI_NON_VOLATILE,
Expand All @@ -328,6 +335,7 @@ mod tests_mmap_real {
| MemoryAttribute::WRITE_COMBINE
| MemoryAttribute::WRITE_THROUGH
| MemoryAttribute::WRITE_BACK,
..Default::default()
},
MemoryDescriptor {
ty: MemoryType::CONVENTIONAL,
Expand All @@ -338,6 +346,7 @@ mod tests_mmap_real {
| MemoryAttribute::WRITE_COMBINE
| MemoryAttribute::WRITE_THROUGH
| MemoryAttribute::WRITE_BACK,
..Default::default()
},
MemoryDescriptor {
ty: MemoryType::ACPI_NON_VOLATILE,
Expand All @@ -348,6 +357,7 @@ mod tests_mmap_real {
| MemoryAttribute::WRITE_COMBINE
| MemoryAttribute::WRITE_THROUGH
| MemoryAttribute::WRITE_BACK,
..Default::default()
},
MemoryDescriptor {
ty: MemoryType::CONVENTIONAL,
Expand All @@ -358,6 +368,7 @@ mod tests_mmap_real {
| MemoryAttribute::WRITE_COMBINE
| MemoryAttribute::WRITE_THROUGH
| MemoryAttribute::WRITE_BACK,
..Default::default()
},
MemoryDescriptor {
ty: MemoryType::ACPI_NON_VOLATILE,
Expand All @@ -368,6 +379,7 @@ mod tests_mmap_real {
| MemoryAttribute::WRITE_COMBINE
| MemoryAttribute::WRITE_THROUGH
| MemoryAttribute::WRITE_BACK,
..Default::default()
},
];
assert_eq!(entries.as_slice(), &expected);
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3 changes: 3 additions & 0 deletions uefi/tests/memory_map.rs
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Expand Up @@ -12,20 +12,23 @@ fn parse_boot_information_efi_mmap() {
virt_start: 0x3000,
page_count: 1,
att: MemoryAttribute::WRITE_BACK,
..Default::default()
},
MemoryDescriptor {
ty: MemoryType::CONVENTIONAL,
phys_start: 0x2000,
virt_start: 0x2000,
page_count: 1,
att: MemoryAttribute::WRITE_BACK,
..Default::default()
},
MemoryDescriptor {
ty: MemoryType::CONVENTIONAL,
phys_start: 0x1000,
virt_start: 0x1000,
page_count: 1,
att: MemoryAttribute::WRITE_BACK,
..Default::default()
},
];
let map_size = mmap_source.len() * desc_size;
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8 changes: 7 additions & 1 deletion xtask/src/check_raw.rs
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Expand Up @@ -354,7 +354,13 @@ fn check_item(item: &Item, src: &Path) -> Result<(), Error> {
// Allow.
}
item => {
return Err(Error::new(ErrorKind::ForbiddenItemKind, src, item));
let allowed_exception = match item {
Item::ExternCrate(x) => x.ident == "std",
_ => false,
};
if !allowed_exception {
return Err(Error::new(ErrorKind::ForbiddenItemKind, src, item));
}
}
}

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