* Kees Cook: > On Tue, Dec 05, 2023 at 07:01:34PM +0300, Alexey Dobriyan wrote: >> Report available page shifts in arch independent manner, so that >> userspace developers won't have to parse /proc/cpuinfo hunting >> for arch specific strings: >> >> Note! >> >> This is strictly for userspace, if some page size is shutdown due >> to kernel command line option or CPU bug workaround, than is must not >> be reported in aux vector! > > Given Florian in CC, I assume this is something glibc would like to be > using? Please mention this in the commit log. Nope, I just wrote a random drive-by comment on the first version. >> x86_64 machine with 1 GiB pages: >> >> 00000030 06 00 00 00 00 00 00 00 00 10 00 00 00 00 00 00 >> 00000040 1d 00 00 00 00 00 00 00 00 10 20 40 00 00 00 00 >> >> x86_64 machine with 2 MiB pages only: >> >> 00000030 06 00 00 00 00 00 00 00 00 10 00 00 00 00 00 00 >> 00000040 1d 00 00 00 00 00 00 00 00 10 20 00 00 00 00 00 >> >> AT_PAGESZ is always 4096 which is not that interesting. > > That's not always true. For example, see arm64: > arch/arm64/include/asm/elf.h:#define ELF_EXEC_PAGESIZE PAGE_SIZE I'm pretty sure the comment refers to the x86-64 situation. 8-) > I'm not actually sure why x86 forces it to 4096. I'd need to go look > through the history there. On x86-64, page size 4096 is architectural. Likewise on s390x and a few other architectures. Thanks, Florian
