On Mon, Jan 05, 2026 at 12:58:23PM +0100, Ahmad Fatoum wrote: > Hi, > > On 1/5/26 12:26 PM, Sascha Hauer wrote: > > Implement architecture-specific ELF relocation handlers for ARM32 and ARM64. > > > > ARM32 implementation (arch/arm/lib32/elf_reloc.c): > > - Handles REL-format relocations (no explicit addend) > > - Supports R_ARM_RELATIVE and R_ARM_ABS32 relocation types > > - Addend is read from the target location > > > > ARM64 implementation (arch/arm/lib64/elf_reloc.c): > > - Handles RELA-format relocations (with explicit addend) > > - Supports R_AARCH64_RELATIVE and R_AARCH64_ABS64 relocation types > > - Addend is provided in relocation entry > > > > Both implementations: > > - Parse PT_DYNAMIC segment to locate relocation tables > > - Validate relocation table format and entry sizes > > - Apply relocations based on the computed load offset > > - Return appropriate errors for unsupported relocation types > > > > Signed-off-by: Sascha Hauer <[email protected]> > > Co-Authored-By: Claude Sonnet 4.5 <[email protected]> > > --- > > arch/arm/include/asm/elf.h | 11 +++++ > > arch/arm/lib32/Makefile | 1 + > > arch/arm/lib32/elf_reloc.c | 105 > > +++++++++++++++++++++++++++++++++++++++++++++ > > arch/arm/lib64/Makefile | 1 + > > arch/arm/lib64/elf_reloc.c | 105 > > +++++++++++++++++++++++++++++++++++++++++++++ > > 5 files changed, 223 insertions(+) > > > > diff --git a/arch/arm/include/asm/elf.h b/arch/arm/include/asm/elf.h > > index > > 4043e6fd5b991eb5cccb3fa0ea28d208006ee1fc..cceb92ee1a5f63c37b0e981c263676bd35a261c0 > > 100644 > > --- a/arch/arm/include/asm/elf.h > > +++ b/arch/arm/include/asm/elf.h > > @@ -36,6 +36,17 @@ typedef struct user_fp elf_fpregset_t; > > #define R_ARM_THM_CALL 10 > > #define R_ARM_THM_JUMP24 30 > > > > +/* Additional relocation types for dynamic linking */ > > +#define R_ARM_RELATIVE 23 > > This is already defined in arch/arm/cpu/common.c, you can guess where > this is going ;) > > > +#define R_ARM_GLOB_DAT 21 > > +#define R_ARM_JUMP_SLOT 22 > > These two are not used. > > > + > > +#define R_AARCH64_NONE 0 > > +#define R_AARCH64_ABS64 257 > > +#define R_AARCH64_RELATIVE 1027 > > +#define R_AARCH64_GLOB_DAT 1025 > > +#define R_AARCH64_JUMP_SLOT 1026 > > Likewise, only R_AARCH64_JUMP_SLOT and R_AARCH64_GLOB_DAT are not used. > > > +/* > > + * Parse dynamic section and extract relocation info for ARM32 > > + */ > > +static int parse_dynamic_section(struct elf_image *elf, Elf32_Dyn *dyn, > > + Elf32_Rel **rel_out, u64 *relsz_out) > > +{ > > + Elf32_Rel *rel = NULL; > > If we define ELF_CLASS depending on CONFIG_ARM32/CONFIG_ARM64, we can > write a generic parse_dynamic_section() that applies to all architectures. > > In this case, we would just collect both REL and RELA in the switch and > just use what's available. > > +int elf_apply_relocations(struct elf_image *elf, void *dyn_seg) > > +{ > > We already have relocate_to_current_adr(). If we change it to call > a new relocate_image(): > > relocate_image(get_runtime_offset(), > runtime_addr(__rel_dyn_start), > runtime_addr(__rel_dyn_end), > runtime_addr(__dynsym_start), > runtime_addr(__dynsym_end)); > > Then we could use relocate_image() in generic code instead of > duplicating it per architecture. > > > +/* > > + * Parse dynamic section and extract relocation info for ARM64 > > + */ > > +static int parse_dynamic_section(struct elf_image *elf, Elf64_Dyn *dyn, > > + Elf64_Rela **rela_out, u64 *relasz_out) > > Same comment as for ARM32. I believe this can go into generic code. > > > + case R_AARCH64_ABS64: > > + /* B(P) = S + A */ > > + *fixup_addr = base + rela->r_addend; > > + break; > > What did you do to get R_AARCH64_ABS64 relocations? We don't handle them > in relocate_to_current_adr() and they shouldn't have been generated.
Likely Claude just generated this for completeness. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
