On Wed, Feb 19, 2025 at 11:55:44AM +0100, Ard Biesheuvel wrote:
From: Ard Biesheuvel ardb@kernel.org
BTW, I was copied on the cover letter but not the individual patches.
When using -fPIE codegen, the compiler will emit const global objects (which are useless unless statically initialized) into .data.rel.ro rather than .rodata if the object contains fields that carry absolute addresses of other code or data objects. This permits the linker to annotate such regions as requiring read-write access only at load time, but not at execution time (in user space).
Hm, this sounds more like __ro_after_init, are we sure the kernel doesn't need to write it early?
This distinction does not matter for the kernel, but it does imply that const data will end up in writable memory if the .data.rel.ro sections are not treated in a special way.
So emit .data.rel.ro into the .rodata segment.
This is a bug fix, right? Since the RO data wasn't actually RO? That's not clear in the title.