From: Lukasz Majewski <lukma@denx.de>
To: Joseph Myers <joseph@codesourcery.com>
Cc: Florian Weimer <fweimer@redhat.com>,
Palmer Dabbelt <palmerdabbelt@google.com>,
GNU C Library <libc-alpha@sourceware.org>,
Arnd Bergmann <arnd@arndb.de>, Andreas Schwab <schwab@suse.de>,
Vineet Gupta <Vineet.Gupta1@synopsys.com>,
Helmut Grohne <helmutg@debian.org>, Zong Li <zongbox@gmail.com>,
debian-arm@lists.debian.org,
Alistair Francis <alistair.francis@wdc.com>,
Adhemerval Zanella <adhemerval.zanella@linaro.org>,
"Maciej W. Rozycki" <macro@wdc.com>,
Alistair Francis <alistair23@gmail.com>,
arcml <linux-snps-arc@lists.infradead.org>
Subject: Re: switching ARC to 64-bit time_t (Re: [RFC v6 07/23] RISC-V: Use 64-bit time_t and off_t for RV32 and RV64)
Date: Wed, 26 Feb 2020 14:18:42 +0100 [thread overview]
Message-ID: <20200226141842.652ebbcc@jawa> (raw)
In-Reply-To: <alpine.DEB.2.21.2002251427240.25788@digraph.polyomino.org.uk>
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Hi Joseph,
> On Tue, 25 Feb 2020, Lukasz Majewski wrote:
>
> > Lets consider for example __mq_timedsend_time64.
> >
> > With lib<name>_hidden_def/proto kept (NOT removed as in [1]):
> > GDB:
> > __GI___mq_timedsend_time64 [*]
> >
> > (No build errors, linking with test setup works as expected).
>
> What is the actual testcase, and the exact command line used to
> compile it?
The test case is a separate program [1] compiled with [2] (the
test_y2038 make target)
The glibc under test is installed on rootfs run by QEMU for ARM.
The lack of redirection, when I keep lib<name>_hidden_proto/
lib<name>_hidden_def for __mq_timedsend_time64, is seen when I debug
with GDB the 'test_y2038' program.
The glibc compiles correctly.
>
> _TIME_BITS=64 redirection is only relevant for programs built with
> glibc, using the installed headers - not for building glibc itself.
>
> lib<name>_hidden_proto is only relevant for building glibc, with its
> internal headers - not for programs built with glibc.
It seems like not removing lib<name>_hidden_proto/ lib<name>_hidden_def
for __mq_timedsend_time64 in glibc sources prevents the redirection on
installed glibc / headers when 'test_y2038' program is run.
>
> If you're talking about a glibc testcase, such tests should be in
> tests not tests-internal, so _ISOMAC is defined when they are built,
> so the glibc internal headers just wrap the public ones without
> defining anything else. In particular, the asm redirections from
> public headers should be in effect when tests are compiled, but not
> the lib<name>_hidden_proto redirections (but even for internal tests,
> lib<name>_hidden_proto shouldn't do anything because the build
> process knows they are tests not part of libc).
Unfortunately, mine Y2038 tests are a set of compiled programs (it is a
'legacy' code) and have nothing in common with glibc test suite.
The workflow is as follows (standard Yocto/OE):
1. Built the glibc and prepare "package" for other recipes.
2. For tests get the glibc "package" as a prerequisite. Use its
exported headers and libraries to build tests. Prepare test "package"
3. Install both above packages to rootfs
4. Run the rootfs with QEMU.
>
> You should look at the preprocessed source from building the test
> with -save-temps and find out why the asm redirection from the public
> header isn't being effective (or if it is effective in the .o file
> for the test, look at what happens afterwards in glibc). Since
> lib<name>_hidden_proto should not be called in the parts of headers
> included when building a test, its presence or absence should have no
> effect on the preprocessed source of the test.
Ok. I will dig the object files and generated temp files.
>
> > hidden_def (__mq_timedsend)
> > weak_alias (__mq_timedsend, mq_timedsend) [**]
> > hidden_weak (mq_timedsend)
>
> If you have lib<name>_hidden_weak note you also need a corresponding
> lib<name>_hidden_proto, for the name of the weak alias. But you
> probably don't need to have lib<name>_hidden* for the weak alias at
> all, just make sure internal calls use the internal name.
As fair as I can tell the weak_alias () is necessary for correct
operation of mq_timedsend when external programs call it.
Glibc internally defines __mq_timedsend (also for archs with
__WORDSIZE==64), but it exports mq_timedsend (and user space programs
call it). One needs an alias (at least a weak one) between mq_timedsend
and __mq_timedsend{_time}. Am I correct?
>
Links:
[1] -
https://github.com/lmajewski/y2038-tests/blob/master/test_mq_timedsend.c#L25
[2] - https://github.com/lmajewski/y2038-tests/blob/master/Makefile
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
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next prev parent reply other threads:[~2020-02-26 13:19 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1578824547.git.alistair.francis@wdc.com>
[not found] ` <4e95f95966d8d7c6a8339160dc62d81c1f6a1bfb.1578824547.git.alistair.francis@wdc.com>
2020-02-12 0:14 ` [RFC v6 07/23] RISC-V: Use 64-bit time_t and off_t for RV32 and RV64 Vineet Gupta
2020-02-12 0:14 ` Alistair Francis
2020-02-12 1:30 ` Joseph Myers
2020-02-14 22:39 ` Alistair Francis
2020-02-18 23:05 ` switching ARC to 64-bit time_t (Re: [RFC v6 07/23] RISC-V: Use 64-bit time_t and off_t for RV32 and RV64) Vineet Gupta
2020-02-18 23:13 ` Joseph Myers
2020-02-19 23:09 ` Lukasz Majewski
2020-02-19 23:11 ` Lukasz Majewski
2020-02-20 8:31 ` Arnd Bergmann
2020-02-20 9:37 ` Lukasz Majewski
2020-02-20 12:37 ` Arnd Bergmann
2020-02-20 13:14 ` Lukasz Majewski
2020-02-20 14:44 ` Arnd Bergmann
2020-02-20 15:42 ` Lukasz Majewski
2020-02-20 16:08 ` Arnd Bergmann
2020-02-20 16:31 ` Lukasz Majewski
2020-02-24 2:48 ` Viresh Kumar
2020-02-21 19:56 ` Alistair Francis
2020-02-22 8:42 ` Arnd Bergmann
2020-02-24 9:00 ` Lukasz Majewski
2020-02-24 9:46 ` Andreas Schwab
2020-02-24 10:14 ` Lukasz Majewski
2020-02-24 10:23 ` Andreas Schwab
2020-02-24 10:36 ` Lukasz Majewski
2020-02-24 10:42 ` Andreas Schwab
2020-02-24 11:13 ` Lukasz Majewski
2020-02-24 12:41 ` Lukasz Majewski
2020-02-25 0:03 ` Joseph Myers
2020-02-25 11:39 ` Lukasz Majewski
2020-02-25 14:36 ` Joseph Myers
2020-02-26 13:18 ` Lukasz Majewski [this message]
2020-02-26 14:48 ` Joseph Myers
2020-02-26 16:28 ` Lukasz Majewski
2020-02-25 9:03 ` Arnd Bergmann
2020-02-20 16:27 ` Helmut Grohne
2020-03-26 0:25 ` ARC rebootstrap prereq (was Re: switching ARC to 64-bit time_t ) Vineet Gupta
2020-03-26 5:54 ` Helmut Grohne
2020-03-26 11:51 ` Alexey Brodkin
2020-03-26 12:24 ` Helmut Grohne
2020-03-26 12:53 ` Alexey Brodkin
2020-03-26 14:28 ` Helmut Grohne
2020-03-26 19:04 ` Lennart Sorensen
2020-08-26 14:39 ` Vineet Gupta
2020-08-26 15:43 ` Helmut Grohne
2020-08-26 21:16 ` Aurelien Jarno
2021-02-24 20:17 ` Vineet Gupta
2021-02-26 9:47 ` Helmut Grohne
2021-02-26 15:58 ` Vineet Gupta
2021-08-21 17:36 ` Aurelien Jarno
2020-02-12 1:42 ` [RFC v6 07/23] RISC-V: Use 64-bit time_t and off_t for RV32 and RV64 Vineet Gupta
2020-02-12 12:58 ` Arnd Bergmann
2020-02-19 0:56 ` Vineet Gupta
2020-02-19 1:03 ` Alistair Francis
2020-02-19 1:31 ` Vineet Gupta
2020-02-19 8:30 ` Andreas Schwab
2020-02-19 18:42 ` Vineet Gupta
2020-02-19 23:18 ` Lukasz Majewski
2020-02-20 0:26 ` Vineet Gupta
2020-02-20 0:46 ` Joseph Myers
2020-02-20 8:24 ` Arnd Bergmann
2020-02-20 10:28 ` Lukasz Majewski
2020-02-20 14:14 ` Joseph Myers
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