* Ard Biesheuvel <ard.biesheu...@linaro.org> wrote: > This implements text-relative kallsyms address tables. This was developed as > part of my series to implement KASLR/CONFIG_RELOCATABLE for arm64, but I > think > it may be beneficial to other architectures as well, so I am presenting it as > a > separate series. > > The idea is that on 64-bit builds, it is rather wasteful to use absolute > addressing for kernel symbols since they are all within a couple of MBs of > each > other. On top of that, the absolute addressing implies that, when the kernel > is > relocated at runtime, each address in the table needs to be fixed up > individually. > > Since all section-relative addresses are already emitted relative to _text, > it > is quite straight-forward to record only the offset, and add the absolute > address of _text at runtime when referring to the address table. > > The reduction ranges from around 250 KB uncompressed vmlinux size and 10 KB > compressed size (s390) to 3 MB/500 KB for ppc64 (although, in the latter > case, > the reduction in uncompressed size is primarily __init data)
So since kallsyms is in unswappable kernel RAM, the uncompressed size reduction is what we care about mostly. How much bootloader load times are impacted is a third order concern. IOW a nice change! Thanks, Ingo _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev