Re: [ptxdist] [ANNOUNCE] OSELAS.Toolchain() 2021.07.0 released

[Michael Olbrich <m.olbrich@pengutronix.de>]

Hi,

I've put the list back in Cc. I think this is interesting for others as
well.

On Sun, Jul 11, 2021 at 02:00:33PM +0200, Felix Mellmann wrote:
> thanks for releasing an updated toolchain!
> 
> Do the ARM 32bit toolchains already make use of the 64 bit unix timestamps
> to overcome the 2k38 problem?

I assume you mean the compat stuff where time_t is 64 bit (with _TIME_BITS
defined).
No. The support for this is still missing in glibc 2.33. I looked into this
when I was working on the toolchains and at the time, there where quite a
few patches that had not been merged for this. From what I can tell, they
have been merged in the meantime. I've not checked if there are still some
bits missing. But I hope that glibc 2.34 will have the full support.

> As far as I can see, glibc is compiled against the kernel 3.16 headers which
> do not include support for 64 bit timestamps on 32 bit machines (https://git.pengutronix.de/cgit/OSELAS.Toolchain/tree/ptxconfigs/arm-v7a-linux-gnueabihf_gcc-11.1.1_clang-12.0.0_glibc-2.33_binutils-2.36.1_kernel-5.12.4-sanitized.ptxconfig?h=v2021.07.0
> , line 51)

That's something else. The toolchain is built with 5.12.4 kernel headers
(line 62). The PTXCONF_GLIBC_ENABLE_KERNEL specifies the oldest kernel this
glibc will run on. Basically how much compat code should be added for
syscalls etc. that did not exist in old kernel versions.

> If the toolchain still uses 32 bit timestamps - are there any plans to
> implement support in an upcoming release?

Yes definitively. Right now I'm still waiting for a glibc release that has
the necessary support. I don't think we actually need to do anything here.
At least in the toolchain. It should just work once we have a glibc that
supports it.

I think the hard part will be all the other userspace software. We need to
compile it with _TIME_BITS (and _FILE_OFFSET_BITS=64). That's the easy
part. But someone need to check all the code to check that time_t is never
cast to/from int...

Regards,
Michael

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