Customized relocation type about riscv-elf-psabi-doc HOT 6 CLOSED

They were already implemented before I started doing ARM work, so I don't have any direct experiences with development issues. I've only dealt with them as a user, and have found them useful. There are other targets with attribute support besides ARM, and I think we can just use the generic binutils support for this, customized with RISC-V specific hooks. Though the generic attribute support is based on the ARM support, as I think the ARM target was the first to do this.

from riscv-elf-psabi-doc.

I agree we should reserve a block of relocations for nonstandard extensions to the ABI. @palmer-dabbelt @asb any objections with reserving 192-255 for this purpose?

from riscv-elf-psabi-doc.

No objections, we should reserve some space for non-standard relocations.

The other missing piece is metadata in the ELF which describes the non-standard extensions which are targeted. Kito was hoping to propose something for that, based on the discussion in #47.

from riscv-elf-psabi-doc.

Indeed. Whatever the solution to #47 might be, it should also provide enough information to decode what the nonstandard relocs mean.

from riscv-elf-psabi-doc.

BTW #47 is getting higher priority to me, I am working on implement that on biinutils now, and I've changed to implement an attribute section (ref [1] ELF for the ARM® Architecture, 4.3.6 Build Attributes).

[1] http://infocenter.arm.com/help/topic/com.arm.doc.ihi0044f/IHI0044F_aaelf.pdf

from riscv-elf-psabi-doc.

Cool. @jim-wilson are there any lessons to be learned from using the ARM attribute section?

from riscv-elf-psabi-doc.