[PATCH 12/31] gpu: nova-core: add auto-detection of 32-bit, 64-bit firmware images

[John Hubbard <jhubbard@nvidia.com>]

Add elf_section() which checks the ELF magic and class byte to
automatically dispatch to elf32_section() or elf64_section().

Update existing callers to use elf_section() instead of calling
elf64_section() directly.

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 drivers/gpu/nova-core/firmware.rs     | 20 +++++++++++++++++---
 drivers/gpu/nova-core/firmware/gsp.rs |  4 ++--
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/nova-core/firmware.rs b/drivers/gpu/nova-core/firmware.rs
index c355e0d7e407..e45b91bb45a3 100644
--- a/drivers/gpu/nova-core/firmware.rs
+++ b/drivers/gpu/nova-core/firmware.rs
@@ -408,13 +408,27 @@ fn elf_section_generic<'a, H, S>(elf: &'a [u8], name: &str) -> Option<&'a [u8]>
     }
 
     /// Extract the section with name `name` from the ELF64 image `elf`.
-    pub(super) fn elf64_section<'a>(elf: &'a [u8], name: &str) -> Option<&'a [u8]> {
+    fn elf64_section<'a>(elf: &'a [u8], name: &str) -> Option<&'a [u8]> {
         elf_section_generic::<Elf64Hdr, Elf64SHdr>(elf, name)
     }
 
     /// Extract section with name `name` from the ELF32 image `elf`.
-    #[expect(dead_code)]
-    pub(super) fn elf32_section<'a>(elf: &'a [u8], name: &str) -> Option<&'a [u8]> {
+    fn elf32_section<'a>(elf: &'a [u8], name: &str) -> Option<&'a [u8]> {
         elf_section_generic::<Elf32Hdr, Elf32SHdr>(elf, name)
     }
+
+    /// Automatically detects ELF32 vs ELF64 based on the ELF header.
+    pub(super) fn elf_section<'a>(elf: &'a [u8], name: &str) -> Option<&'a [u8]> {
+        // Check ELF magic.
+        if elf.len() < 5 || elf.get(0..4)? != b"\x7fELF" {
+            return None;
+        }
+
+        // Check ELF class: 1 = 32-bit, 2 = 64-bit.
+        match elf.get(4)? {
+            1 => elf32_section(elf, name),
+            2 => elf64_section(elf, name),
+            _ => None,
+        }
+    }
 }
diff --git a/drivers/gpu/nova-core/firmware/gsp.rs b/drivers/gpu/nova-core/firmware/gsp.rs
index 4d84bd049d9c..1f473e73a428 100644
--- a/drivers/gpu/nova-core/firmware/gsp.rs
+++ b/drivers/gpu/nova-core/firmware/gsp.rs
@@ -98,10 +98,10 @@ pub(crate) fn new<'a, 'b>(
     ) -> Result<impl PinInit<Self, Error> + 'a> {
         let fw = super::request_firmware(dev, chipset, "gsp", ver)?;
 
-        let fw_section = elf::elf64_section(fw.data(), ".fwimage").ok_or(EINVAL)?;
+        let fw_section = elf::elf_section(fw.data(), ".fwimage").ok_or(EINVAL)?;
 
         let sigs_section = Self::get_gsp_sigs_section(chipset)?;
-        let signatures = elf::elf64_section(fw.data(), sigs_section)
+        let signatures = elf::elf_section(fw.data(), sigs_section)
             .ok_or(EINVAL)
             .and_then(|data| DmaObject::from_data(dev, data))?;
 
-- 
2.52.0