[PATCH v10 12/28] gpu: nova-core: don't assume 64-bit firmware images

John Hubbard
2026-04-11T02:50:20Z

Introduce a single ELF format abstraction that ties each ELF header
type to its matching section-header type. This keeps the shared
section parser ready for upcoming ELF32 support and avoids mixing
32-bit and 64-bit ELF layouts by mistake.

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
drivers/gpu/nova-core/firmware.rs | 111 ++++++++++++++++++++++--------
1 file changed, 84 insertions(+), 27 deletions(-)

diff --git a/drivers/gpu/nova-core/firmware.rs b/drivers/gpu/nova-core/firmware.rs
index 6c2ab69cb605..46c26d749a65 100644
--- a/drivers/gpu/nova-core/firmware.rs
+++ b/drivers/gpu/nova-core/firmware.rs
@@ -473,17 +473,72 @@ mod elf {
transmute::FromBytes, //
};

+ /// Trait to abstract over ELF header differences.
+ trait ElfHeader: FromBytes {
+ fn shnum(&self) -> u16;
+ fn shoff(&self) -> u64;
+ fn shstrndx(&self) -> u16;
+ }
+
+ /// Trait to abstract over ELF section-header differences.
+ trait ElfSectionHeader: FromBytes {
+ fn name(&self) -> u32;
+ fn offset(&self) -> u64;
+ fn size(&self) -> u64;
+ }
+
+ /// Trait describing a matching ELF header and section-header format.
+ trait ElfFormat {
+ type Header: ElfHeader;
+ type SectionHeader: ElfSectionHeader;
+ }
+
/// Newtype to provide a [`FromBytes`] implementation.
#[repr(transparent)]
struct Elf64Hdr(bindings::elf64_hdr);
// SAFETY: all bit patterns are valid for this type, and it doesn't use interior mutability.
unsafe impl FromBytes for Elf64Hdr {}

+ impl ElfHeader for Elf64Hdr {
+ fn shnum(&self) -> u16 {
+ self.0.e_shnum
+ }
+
+ fn shoff(&self) -> u64 {
+ self.0.e_shoff
+ }
+
+ fn shstrndx(&self) -> u16 {
+ self.0.e_shstrndx
+ }
+ }
+
#[repr(transparent)]
struct Elf64SHdr(bindings::elf64_shdr);
// SAFETY: all bit patterns are valid for this type, and it doesn't use interior mutability.
unsafe impl FromBytes for Elf64SHdr {}

+ impl ElfSectionHeader for Elf64SHdr {
+ fn name(&self) -> u32 {
+ self.0.sh_name
+ }
+
+ fn offset(&self) -> u64 {
+ self.0.sh_offset
+ }
+
+ fn size(&self) -> u64 {
+ self.0.sh_size
+ }
+ }
+
+ struct Elf64Format;
+
+ impl ElfFormat for Elf64Format {
+ type Header = Elf64Hdr;
+ type SectionHeader = Elf64SHdr;
+ }
+
/// Returns a NULL-terminated string from the ELF image at `offset`.
fn elf_str(elf: &[u8], offset: u64) -> Option<&str> {
let idx = usize::try_from(offset).ok()?;
@@ -491,47 +546,49 @@ fn elf_str(elf: &[u8], offset: u64) -> Option<&str> {
CStr::from_bytes_until_nul(bytes).ok()?.to_str().ok()
}

- /// Tries to extract section with name `name` from the ELF64 image `elf`, and returns it.
- pub(super) fn elf64_section<'a, 'b>(elf: &'a [u8], name: &'b str) -> Option<&'a [u8]> {
- let hdr = &elf
- .get(0..size_of::<bindings::elf64_hdr>())
- .and_then(Elf64Hdr::from_bytes)?
- .0;
-
- // Get all the section headers.
- let mut shdr = {
- let shdr_num = usize::from(hdr.e_shnum);
- let shdr_start = usize::try_from(hdr.e_shoff).ok()?;
- let shdr_end = shdr_num
- .checked_mul(size_of::<Elf64SHdr>())
- .and_then(|v| v.checked_add(shdr_start))?;
-
- elf.get(shdr_start..shdr_end)
- .map(|slice| slice.chunks_exact(size_of::<Elf64SHdr>()))?
- };
+ fn elf_section_generic<'a, F>(elf: &'a [u8], name: &str) -> Option<&'a [u8]>
+ where
+ F: ElfFormat,
+ {
+ let hdr = F::Header::from_bytes(elf.get(0..size_of::<F::Header>())?)?;
+
+ let shdr_num = usize::from(hdr.shnum());
+ let shdr_start = usize::try_from(hdr.shoff()).ok()?;
+ let shdr_end = shdr_num
+ .checked_mul(size_of::<F::SectionHeader>())
+ .and_then(|v| v.checked_add(shdr_start))?;
+
+ // Get all the section headers as an iterator over byte chunks.
+ let shdr_bytes = elf.get(shdr_start..shdr_end)?;
+ let mut shdr_iter = shdr_bytes.chunks_exact(size_of::<F::SectionHeader>());

// Get the strings table.
- let strhdr = shdr
+ let strhdr = shdr_iter
.clone()
- .nth(usize::from(hdr.e_shstrndx))
- .and_then(Elf64SHdr::from_bytes)?;
+ .nth(usize::from(hdr.shstrndx()))
+ .and_then(F::SectionHeader::from_bytes)?;

// Find the section which name matches `name` and return it.
- shdr.find_map(|sh| {
- let hdr = Elf64SHdr::from_bytes(sh)?;
- let name_offset = strhdr.0.sh_offset.checked_add(u64::from(hdr.0.sh_name))?;
+ shdr_iter.find_map(|sh_bytes| {
+ let sh = F::SectionHeader::from_bytes(sh_bytes)?;
+ let name_offset = strhdr.offset().checked_add(u64::from(sh.name()))?;
let section_name = elf_str(elf, name_offset)?;

if section_name != name {
return None;
}

- let start = usize::try_from(hdr.0.sh_offset).ok()?;
- let end = usize::try_from(hdr.0.sh_size)
+ let start = usize::try_from(sh.offset()).ok()?;
+ let end = usize::try_from(sh.size())
.ok()
- .and_then(|sh_size| start.checked_add(sh_size))?;
+ .and_then(|sz| start.checked_add(sz))?;

elf.get(start..end)
})
}
+
+ /// Tries to extract section with name `name` from the ELF64 image `elf`, and returns it.
+ pub(super) fn elf64_section<'a>(elf: &'a [u8], name: &str) -> Option<&'a [u8]> {
+ elf_section_generic::<Elf64Format>(elf, name)
+ }
}
--
2.53.0