Hi Dave, you are pointing to an (IMHO) interesting question. How to document different CPUs ? Given that an operating system should hide the different CPU's using CPU specific features should be used sparsely at best. the easy part are adds-on like flags for prctrl etc. simply add it to the page. Other things should go to a cpu specific pages (can of worms). The problem will be to keep that small but informative. I have no idea about the level of detail (and i have worked with a range of CPUs) that could be interesting for a programmer. An of cause every other CPU now needs also a page. jm2c wh ________________________________________ Von: linux-man-owner@xxxxxxxxxxxxxxx <linux-man-owner@xxxxxxxxxxxxxxx> im Auftrag von Dave Martin <Dave.Martin@xxxxxxx> Gesendet: Montag, 4. Mai 2020 17:32:35 An: Michael Kerrisk Cc: Catalin Marinas; Will Deacon; Vincenzo Frascino; linux-man@xxxxxxxxxxxxxxx; linux-arch@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Betreff: RFC: Adding arch-specific user ABI documentation in linux-man Hi all, I considering trying to plug some gaps in the arch-specific ABI documentation in the linux man-pages, specifically for arm64 (and possibly arm, where compat means we have some overlap). For arm64, there are now significant new extensions (Pointer authentication, SVE, MTE etc.) Currently there is some user-facing documentation mixed in with the kernel-facing documentation in the kernel tree, but this situation isn't ideal. Do you have an opinion on where in the man-pages documentation should be added, and how to structure it? Affected areas include: * exec interface * aux vector, hwcaps * arch-specific signals * signal frame * mmap/mprotect extensions * prctl calls * ptrace quirks and extensions * coredump contents Not everything has an obvious home in an existing page, and adding specifics for every architecture could make some existing manpages very unwieldy. I think for some arch features, we really need some "overview" pages too: just documenting the low-level details is of limited value without some guide as to how to use them together. Does the following sketch look reasonable? * man7/arm64.7: new page: overview of arm64-specific ABI extensions * man7/sve.7 (or man7/arm64-sve.7 or man7/sve.7arm64): new page: overview of arm64 SVE ABI * man2/arm64-ptrace.2 (or man2/ptrace.2arm64): new page: arm64 ptrace extensions * man2/mmap.2: extend with arm64-specific flags (only two flags, so we add them to the existing man page rather than creating a new one). etc. Ideally, I'd like to adopt a pattern that other arches can follow. Thoughts? Cheers ---Dave
