On 4/15/22 11:11, Niklas Cassel wrote: > On Fri, Apr 15, 2022 at 10:13:31AM +0900, Damien Le Moal wrote: >> On 4/15/22 10:08, Niklas Cassel wrote: >>> On Fri, Apr 15, 2022 at 09:56:38AM +0900, Damien Le Moal wrote: >>>> On 4/15/22 09:30, Niklas Cassel wrote: >>>>> On Fri, Apr 15, 2022 at 08:51:27AM +0900, Damien Le Moal wrote: >>>>>> On 4/14/22 18:10, Niklas Cassel wrote: >>> >>> (snip) >>> >>>> So if we are sure that we can just skip the first 16B/8B for riscv, I >>>> would not bother checking the header content. But as mentioned, the >>>> current code is fine too. >>> >>> That was my point, I'm not sure that we can be sure that we can always >>> skip it in the future. E.g. if the elf2flt linker script decides to swap >>> the order of .got and .got.plt for some random reason in the future, >>> we would skip data that really should have been relocated. >> >> Good point. Your current patch is indeed better then. BUT that would also >> mean that the skip header function needs to be called inside the loop >> then, no ? If the section orders are reversed, we would still need to skip >> that header in the middle of the relocation loop... > > So this is theoretical, but if the sections were swapped in the linker > script, and we have the patch in $subject applied, we will not skip data > that needs to be relocated. But after relocating all the entries in the > .got section we will still break too early, if we actually had any > .got.plt entries after the .got.plt header. The .got.plt entries would > not get relocated. > > However, the elf2flt maintainer explicitly asked ut to fix the kernel or > binutils, so that they can continue using the exact same linker script > that it has been using forever. (And we shouldn't need to change binutils > just for the bFLT format.) > > So the chance that the linker script changes in practice is really small. > (This .got.plt vs .got hasn't changed in 19 years.) > > But if it does, we will just have one problem instead of two :) > However, I think that applying this patch is sufficient for now, > since it makes the code work with the existing elf2flt linker script. > > Adapting the code to also handle this theoretical layout of the linker > script would just complicate things even more. I'm not even sure if we > would be able to handle this case, since the information about the .got > and .got.plt section sizes is lost once the ELF has been converted to > bFLT. OK. All good then. I maintain my reviewed-by tag :) -- Damien Le Moal Western Digital Research
