[PATCH v9 08/31] gpu: nova-core: factor out an elf_str() function

John Hubbard
2026-03-26T01:39:37Z

Factor out a chunk of complexity into a new subroutine. This is an
incremental step in adding ELF32 support to the existing ELF64 section
support, for handling GPU firmware.

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
drivers/gpu/nova-core/firmware.rs | 40 ++++++++++++-------------------
1 file changed, 15 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/nova-core/firmware.rs b/drivers/gpu/nova-core/firmware.rs
index 177b8ede151c..6c2ab69cb605 100644
--- a/drivers/gpu/nova-core/firmware.rs
+++ b/drivers/gpu/nova-core/firmware.rs
@@ -484,6 +484,13 @@ unsafe impl FromBytes for Elf64Hdr {}
// SAFETY: all bit patterns are valid for this type, and it doesn't use interior mutability.
unsafe impl FromBytes for 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()?;
+ let bytes = elf.get(idx..)?;
+ 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
@@ -510,32 +517,15 @@ pub(super) fn elf64_section<'a, 'b>(elf: &'a [u8], name: &'b str) -> Option<&'a
.and_then(Elf64SHdr::from_bytes)?;

// Find the section which name matches `name` and return it.
- shdr.find(|&sh| {
- let Some(hdr) = Elf64SHdr::from_bytes(sh) else {
- return false;
- };
-
- let Some(name_idx) = strhdr
- .0
- .sh_offset
- .checked_add(u64::from(hdr.0.sh_name))
- .and_then(|idx| usize::try_from(idx).ok())
- else {
- return false;
- };
-
- // Get the start of the name.
- elf.get(name_idx..)
- .and_then(|nstr| CStr::from_bytes_until_nul(nstr).ok())
- // Convert into str.
- .and_then(|c_str| c_str.to_str().ok())
- // Check that the name matches.
- .map(|str| str == name)
- .unwrap_or(false)
- })
- // Return the slice containing the section.
- .and_then(|sh| {
+ 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))?;
+ 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)
.ok()
--
2.53.0