Hi Alex, On Thu, Mar 2, 2023 at 11:09 AM Alexandre Ghiti <alex@xxxxxxxx> wrote: > On 3/2/23 10:47, Geert Uytterhoeven wrote: > > On Thu, Mar 2, 2023 at 10:35 AM Alexandre Ghiti <alexghiti@xxxxxxxxxxxx> wrote: > >> This all came up in the context of increasing COMMAND_LINE_SIZE in the > >> RISC-V port. In theory that's a UABI break, as COMMAND_LINE_SIZE is the > >> maximum length of /proc/cmdline and userspace could staticly rely on > >> that to be correct. > >> > >> Usually I wouldn't mess around with changing this sort of thing, but > >> PowerPC increased it with a5980d064fe2 ("powerpc: Bump COMMAND_LINE_SIZE > >> to 2048"). There are also a handful of examples of COMMAND_LINE_SIZE > >> increasing, but they're from before the UAPI split so I'm not quite sure > >> what that means: e5a6a1c90948 ("powerpc: derive COMMAND_LINE_SIZE from > >> asm-generic"), 684d2fd48e71 ("[S390] kernel: Append scpdata to kernel > >> boot command line"), 22242681cff5 ("MIPS: Extend COMMAND_LINE_SIZE"), > >> and 2b74b85693c7 ("sh: Derive COMMAND_LINE_SIZE from > >> asm-generic/setup.h."). > >> > >> It seems to me like COMMAND_LINE_SIZE really just shouldn't have been > >> part of the uapi to begin with, and userspace should be able to handle > >> /proc/cmdline of whatever length it turns out to be. I don't see any > >> references to COMMAND_LINE_SIZE anywhere but Linux via a quick Google > >> search, but that's not really enough to consider it unused on my end. > >> > >> This issue was already considered in s390 and they reached the same > >> conclusion in commit 622021cd6c56 ("s390: make command line > >> configurable"). > >> > >> The feedback on the v1 seemed to indicate that COMMAND_LINE_SIZE really > >> shouldn't be part of uapi, so this now touches all the ports. I've > >> tried to split this all out and leave it bisectable, but I haven't > >> tested it all that aggressively. > >> > >> Changes since v3 <https://lore.kernel.org/all/20230214074925.228106-1-alexghiti@xxxxxxxxxxxx/>: > >> * Added RB/AB > >> * Added a mention to commit 622021cd6c56 ("s390: make command line > >> configurable") in the cover letter > > Thanks for the update! > > > > Apparently you forgot to add your own SoB? > > I do not know, should I? Palmer did all the work, I only fixed 3 minor > things If you are picking up patches, and submitting them to someone else for upstream inclusion, you should add your own SoB. https://elixir.bootlin.com/linux/latest/source/Documentation/process/submitting-patches.rst#L419 Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds