Replace the unsafe `kernel::transmute::FromBytes` trait implementation for the `FalconUCodeDescV3`, `PcirStruct`, `BitHeader`, `BitToken`, `NpdeStruct`, `PciRomHeader`, `PmuLookupTableEntry` and `PmuLookupTableHeader` structs with the derivable `zerocopy::FromBytes` trait.
This change eliminates the manual unsafe implementations in favor of a derivable trait. When this trait is derived, validity checks are performed at compile time to ensure that the type can safely implement `FromBytes`. Link: https://github.com/Rust-for-Linux/linux/issues/1241 Suggested-by: Miguel Ojeda <[email protected]> Signed-off-by: Nicolás Antinori <[email protected]> --- Changelog: v2: - Rebased on top of drm-rust-next - Added derive macro FromBytes for BitToken, PciRomHeader, and PmuLookupTableEntry v1: Link to lore [1] NOTE: Compile-tested only. I don't own a piece of hardware where I can test the nova driver. NOTE 2: In firmware.rs, the BinHdr struct is another user of transmute::FromBytes, but that conversion is intentionally omitted here as it is handled in Pedro's patch series [2]. [1]: https://lore.kernel.org/nova-gpu/[email protected]/ [2]: https://lore.kernel.org/nova-gpu/[email protected]/ drivers/gpu/nova-core/firmware.rs | 6 +-- drivers/gpu/nova-core/vbios.rs | 64 +++++++++---------------------- 2 files changed, 20 insertions(+), 50 deletions(-) diff --git a/drivers/gpu/nova-core/firmware.rs b/drivers/gpu/nova-core/firmware.rs index 80e948bf7511..a94820a3b335 100644 --- a/drivers/gpu/nova-core/firmware.rs +++ b/drivers/gpu/nova-core/firmware.rs @@ -88,7 +88,7 @@ pub(crate) struct FalconUCodeDescV2 { /// Structure used to describe some firmwares, notably FWSEC-FRTS. #[repr(C)] -#[derive(Debug, Clone)] +#[derive(Debug, Clone, FromBytes)] pub(crate) struct FalconUCodeDescV3 { /// Header defined by `NV_BIT_FALCON_UCODE_DESC_HEADER_VDESC*` in OpenRM. hdr: u32, @@ -119,10 +119,6 @@ pub(crate) struct FalconUCodeDescV3 { _reserved: u16, } -// SAFETY: all bit patterns are valid for this type, and it doesn't use -// interior mutability. -unsafe impl FromBytes for FalconUCodeDescV3 {} - /// Enum wrapping the different versions of Falcon microcode descriptors. /// /// This allows handling both V2 and V3 descriptor formats through a diff --git a/drivers/gpu/nova-core/vbios.rs b/drivers/gpu/nova-core/vbios.rs index c6e6bfcd6a1f..c03650ee5226 100644 --- a/drivers/gpu/nova-core/vbios.rs +++ b/drivers/gpu/nova-core/vbios.rs @@ -13,11 +13,8 @@ register, sizes::SZ_4K, sync::aref::ARef, - transmute::FromBytes, }; -use zerocopy::FromBytes as _; - use crate::{ driver::Bar0, firmware::{ @@ -359,7 +356,7 @@ pub(crate) fn fwsec_image(&self) -> &FwSecBiosImage { } /// PCI Data Structure as defined in PCI Firmware Specification -#[derive(Debug, Clone)] +#[derive(Debug, Clone, FromBytes)] #[repr(C)] struct PcirStruct { /// PCI Data Structure signature ("PCIR" or "NPDS") @@ -388,15 +385,12 @@ struct PcirStruct { max_runtime_image_len: u16, } -// SAFETY: all bit patterns are valid for `PcirStruct`. -unsafe impl FromBytes for PcirStruct {} - impl PcirStruct { /// The bit in `last_image` that indicates the last image. const LAST_IMAGE_BIT_MASK: u8 = 0x80; fn new(dev: &device::Device, data: &[u8]) -> Result<Self> { - let (pcir, _) = PcirStruct::from_bytes_copy_prefix(data).ok_or(EINVAL)?; + let (pcir, _) = PcirStruct::read_from_prefix(data).map_err(|_| EINVAL)?; // Signature should be "PCIR" (0x52494350) or "NPDS" (0x5344504e). if &pcir.signature != b"PCIR" && &pcir.signature != b"NPDS" { @@ -432,7 +426,7 @@ fn image_size_bytes(&self) -> usize { /// This is the head of the BIT table, that is used to locate the Falcon data. The BIT table (with /// its header) is in the [`PciAtBiosImage`] and the falcon data it is pointing to is in the /// [`FwSecBiosImage`]. -#[derive(Debug, Clone, Copy)] +#[derive(Debug, Clone, Copy, FromBytes)] #[repr(C)] struct BitHeader { /// 0h: BIT Header Identifier (BMP=0x7FFF/BIT=0xB8FF) @@ -451,12 +445,9 @@ struct BitHeader { checksum: u8, } -// SAFETY: all bit patterns are valid for `BitHeader`. -unsafe impl FromBytes for BitHeader {} - impl BitHeader { fn new(data: &[u8]) -> Result<Self> { - let (header, _) = BitHeader::from_bytes_copy_prefix(data).ok_or(EINVAL)?; + let (header, _) = BitHeader::read_from_prefix(data).map_err(|_| EINVAL)?; // Check header ID and signature if header.id != 0xB8FF || &header.signature != b"BIT\0" { @@ -468,7 +459,7 @@ fn new(data: &[u8]) -> Result<Self> { } /// BIT Token Entry: Records in the BIT table followed by the BIT header. -#[derive(Debug, Clone, Copy)] +#[derive(Debug, Clone, Copy, FromBytes)] #[repr(C)] struct BitToken { /// 00h: Token identifier @@ -481,9 +472,6 @@ struct BitToken { data_offset: u16, } -// SAFETY: all bit patterns are valid for `BitToken`. -unsafe impl FromBytes for BitToken {} - impl BitToken { /// BIT token ID for Falcon data. const ID_FALCON_DATA: u8 = 0x70; @@ -508,7 +496,7 @@ fn from_id(image: &PciAtBiosImage, token_id: u8) -> Result<Self> { .and_then(|data| data.get(..entry_size)) .ok_or(EINVAL)?; - let (token, _) = BitToken::from_bytes_copy_prefix(entry).ok_or(EINVAL)?; + let (token, _) = BitToken::read_from_prefix(entry).map_err(|_| EINVAL)?; // Check if this token has the requested ID if token.id == token_id { @@ -525,7 +513,7 @@ fn from_id(image: &PciAtBiosImage, token_id: u8) -> Result<Self> { /// /// This header is at the beginning of every image in the set of images in the ROM. It contains a /// pointer to the PCI Data Structure which describes the image. -#[derive(Debug, Clone, Copy)] +#[derive(Debug, Clone, Copy, FromBytes)] #[repr(C)] struct PciRomHeader { /// 00h: Signature (0xAA55) @@ -536,13 +524,10 @@ struct PciRomHeader { pci_data_struct_offset: u16, } -// SAFETY: all bit patterns are valid for `PciRomHeader`. -unsafe impl FromBytes for PciRomHeader {} - impl PciRomHeader { fn new(dev: &device::Device, data: &[u8]) -> Result<Self> { - let (rom_header, _) = PciRomHeader::from_bytes_copy_prefix(data) - .ok_or(EINVAL) + let (rom_header, _) = PciRomHeader::read_from_prefix(data) + .map_err(|_| EINVAL) .inspect_err(|_| dev_err!(dev, "Not enough data for ROM header\n"))?; // Check for valid ROM signatures. @@ -564,7 +549,7 @@ fn new(dev: &device::Device, data: &[u8]) -> Result<Self> { /// PCI Data Structure. It contains some fields that are redundant with the PCI Data Structure, but /// are needed for traversing the BIOS images. It is expected to be present in all BIOS images /// except for NBSI images. -#[derive(Debug, Clone)] +#[derive(Debug, Clone, FromBytes)] #[repr(C)] struct NpdeStruct { /// 00h: Signature ("NPDE") @@ -579,15 +564,12 @@ struct NpdeStruct { last_image: u8, } -// SAFETY: all bit patterns are valid for `NpdeStruct`. -unsafe impl FromBytes for NpdeStruct {} - impl NpdeStruct { /// The bit in `last_image` that indicates the last image. const LAST_IMAGE_BIT_MASK: u8 = 0x80; fn new(dev: &device::Device, data: &[u8]) -> Option<Self> { - let (npde, _) = NpdeStruct::from_bytes_copy_prefix(data)?; + let (npde, _) = NpdeStruct::read_from_prefix(data).ok()?; // Signature should be "NPDE" (0x4544504E). if &npde.signature != b"NPDE" { @@ -784,7 +766,7 @@ fn falcon_data_offset(&self, dev: &device::Device) -> Result<usize> { let data = &self.base.data; let (ptr, _) = data .get(offset..) - .and_then(u32::from_bytes_copy_prefix) + .and_then(|p| u32::read_from_prefix(p).ok()) .ok_or(EINVAL)?; usize::from_safe_cast(ptr) @@ -814,6 +796,7 @@ fn try_from(base: BiosImage) -> Result<Self> { /// The [`PmuLookupTableEntry`] structure is a single entry in the [`PmuLookupTable`]. /// /// See the [`PmuLookupTable`] description for more information. +#[derive(FromBytes)] #[repr(C, packed)] struct PmuLookupTableEntry { application_id: u8, @@ -821,9 +804,6 @@ struct PmuLookupTableEntry { data: u32, } -// SAFETY: all bit patterns are valid for `PmuLookupTableEntry`. -unsafe impl FromBytes for PmuLookupTableEntry {} - impl PmuLookupTableEntry { /// PMU lookup table application ID for firmware security license ucode. #[expect(dead_code)] @@ -836,6 +816,7 @@ impl PmuLookupTableEntry { } #[repr(C)] +#[derive(FromBytes)] struct PmuLookupTableHeader { version: u8, header_len: u8, @@ -843,9 +824,6 @@ struct PmuLookupTableHeader { entry_count: u8, } -// SAFETY: all bit patterns are valid for `PmuLookupTableHeader`. -unsafe impl FromBytes for PmuLookupTableHeader {} - /// The [`PmuLookupTableEntry`] structure is used to find the [`PmuLookupTableEntry`] for a given /// application ID. /// @@ -857,7 +835,7 @@ struct PmuLookupTable { impl PmuLookupTable { fn new(dev: &device::Device, data: &[u8]) -> Result<Self> { - let (header, _) = PmuLookupTableHeader::from_bytes_copy_prefix(data).ok_or(EINVAL)?; + let (header, _) = PmuLookupTableHeader::read_from_prefix(data).map_err(|_| EINVAL)?; let header_len = usize::from(header.header_len); let entry_len = usize::from(header.entry_len); @@ -872,8 +850,8 @@ fn new(dev: &device::Device, data: &[u8]) -> Result<Self> { let mut entries = KVVec::with_capacity(entry_count, GFP_KERNEL)?; for i in 0..entry_count { - let (entry, _) = PmuLookupTableEntry::from_bytes_copy_prefix(&data[i * entry_len..]) - .ok_or(EINVAL)?; + let (entry, _) = PmuLookupTableEntry::read_from_prefix(&data[i * entry_len..]) + .map_err(|_| EINVAL)?; entries.push(entry, GFP_KERNEL)?; } @@ -929,15 +907,11 @@ pub(crate) fn header(&self) -> Result<FalconUCodeDesc> { let ver = data.get(1).copied().ok_or(EINVAL)?; match ver { 2 => { - let v2 = FalconUCodeDescV2::read_from_prefix(data) - .map_err(|_| EINVAL)? - .0; + let (v2, _) = FalconUCodeDescV2::read_from_prefix(data).map_err(|_| EINVAL)?; Ok(FalconUCodeDesc::V2(v2)) } 3 => { - let v3 = FalconUCodeDescV3::from_bytes_copy_prefix(data) - .ok_or(EINVAL)? - .0; + let (v3, _) = FalconUCodeDescV3::read_from_prefix(data).map_err(|_| EINVAL)?; Ok(FalconUCodeDesc::V3(v3)) } _ => { -- 2.47.3
