On 06/08/2023 08:56 PM, Arnd Bergmann wrote:
On Thu, Jun 8, 2023, at 09:04, Tiezhu Yang wrote:
On 05/09/2023 05:37 PM, Arnd Bergmann wrote:
On Tue, May 9, 2023, at 09:05, Tiezhu Yang wrote:
I think we are completely safe on the architectures that were added since the linux-3.x days (arm64, riscv, csky, openrisc, loongarch, nios2, and hexagon), but for the older ones there is a regression risk. Especially on targets that are not that actively maintained (sparc, alpha, ia64, sh, ...) there is a good chance that users are stuck on ancient toolchains. It's probably also a safe assumption that anyone with an older libc version won't be using the latest kernel headers, so I think we can still do this across architectures if both glibc and musl already require a compiler that is new enough, or alternatively if we know that the kernel headers require a new compiler for other reasons and nobody has complained.
For glibc, it looks the minimum compiler version was raised from gcc-5 to gcc-8 four years ago, so we should be fine.
In musl, the documentation states that at least gcc-3.4 or clang-3.2 are required, which probably predate the __SIZEOF_LONG__ macro. On the other hand, musl was only released in 2011, and building musl itself explicitly does not require kernel uapi headers, so this may not be too critical.
There is also uClibc, but I could not find any minimum supported compiler version for that. Most commonly, this one is used for cross-build environments, so it's also less likely to have libc/gcc/headers being wildly out of sync. Not sure.
Arnd[1] https://sourceware.org/pipermail/libc-alpha/2019-January/101010.html
Thanks Arnd for the detailed reply. Any more comments? What should I do in the next step?
I think the summary is "it's probably fine", but I don't know for sure, and it may not be worth the benefit.
Thank you, it is very clear now.
Maybe you can prepare a v2 that only does this for the newer architectures I mentioned above, with and an explanation and link to my above reply in the file comments?
Only arm64, riscv and loongarch belong to the newer architectures which are related with this change, I am not sure it is necessary to "unify" uapi bitsperlong.h for them.
Anyway, let me try, I will send a new version, maybe this is going to progress in the right direction.
Thanks, Tiezhu