Messages in this thread | | | Subject | [PATCH] asm-generic: Remove asm/setup.h from the UABI. | Date | Thu, 22 Apr 2021 19:55:45 -0700 | From | Palmer Dabbelt <> |
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From: Palmer Dabbelt <palmerdabbelt@google.com>
I honestly have no idea if this is sane.
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 UABI 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.
I couldn't think of a better way to ask about this then just sending the patch.
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> --- include/{uapi => }/asm-generic/setup.h | 0 1 file changed, 0 insertions(+), 0 deletions(-) rename include/{uapi => }/asm-generic/setup.h (100%)
diff --git a/include/uapi/asm-generic/setup.h b/include/asm-generic/setup.h similarity index 100% rename from include/uapi/asm-generic/setup.h rename to include/asm-generic/setup.h -- 2.31.1.498.g6c1eba8ee3d-goog
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