Messages in this thread | | | Date | Thu, 2 Mar 2023 11:09:27 +0100 | Subject | Re: [PATCH v4 00/24] Remove COMMAND_LINE_SIZE from uapi | From | Alexandre Ghiti <> |
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Hi Geert,
On 3/2/23 10:47, Geert Uytterhoeven wrote: > Hi Alex, > > On Thu, Mar 2, 2023 at 10:35 AM Alexandre Ghiti <alexghiti@rivosinc.com> 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@rivosinc.com/>: >> * 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
> > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > 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
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