From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
To: Alistair Francis <alistair23@gmail.com>,
Joseph Myers <joseph@codesourcery.com>
Cc: Florian Weimer <fweimer@redhat.com>,
GNU C Library <libc-alpha@sourceware.org>,
Arnd Bergmann <arnd@arndb.de>,
Palmer Dabbelt <palmerdabbelt@google.com>,
Zong Li <zongbox@gmail.com>,
Alistair Francis <alistair.francis@wdc.com>,
Adhemerval Zanella <adhemerval.zanella@linaro.org>,
"Maciej W. Rozycki" <macro@wdc.com>,
arcml <linux-snps-arc@lists.infradead.org>
Subject: 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: Tue, 18 Feb 2020 23:05:28 +0000 [thread overview]
Message-ID: <8a9784b3-fc52-adc3-4595-33142b059388@synopsys.com> (raw)
In-Reply-To: <CAKmqyKOgFRfMOws_-48GqMnuS3ygmN9A4DzLg6UtEjRXVoM82A@mail.gmail.com>
Hi Alistair, Arnd
On 2/14/20 2:39 PM, Alistair Francis wrote:
> On Tue, Feb 11, 2020 at 5:30 PM Joseph Myers <joseph@codesourcery.com> wrote:
>> On Tue, 11 Feb 2020, Alistair Francis wrote:
>>
>>>>> diff --git a/sysdeps/unix/sysv/linux/riscv/bits/typesizes.h b/sysdeps/unix/sysv/linux/riscv/bits/typesizes.h
>>>>> new file mode 100644
>>>>> index 0000000000..0da3bdeb5d
>>>>> --- /dev/null
>>>>> +++ b/sysdeps/unix/sysv/linux/riscv/bits/typesizes.h
>>>> I was hoping newer arches could simply use the asm-generic one ?
>>> We need to specify that RV32 uses a 64-bit time_t. The generic ones
>>> don't do that for 32-bit arches.
>> Since it seems we'd like future 32-bit ports of glibc to use 64-bit time
>> and offsets, we should make that as easy as possible.
>>
>> That is, you need an RISC-V-specific bits/timesize.h. But you shouldn't
>> need an RISC-V-specific bits/typesizes.h - rather, make the linux/generic
>> one do the right thing for __TIME_T_TYPE based on bits/timesize.h. And
>> have some other header that 32-bit linux/generic ports can use to say
>> whether they use the 64-bit offset/stat/statfs interface, that
>> bits/typesizes.h can use together with its existing __LP64__ check, and
>> make the definitions of __OFF_T_TYPE etc. check that as well, and then you
>> shouldn't need an RISC-V-specific bits/typesizes.h - the RISC-V-specific
>> headers should be strictly minimal. (No architecture-specific
>> bits/time64.h headers should be needed in any case.)
> Ok, I have updated this. I'll send the patch once my "Always use
> 32-bit time_t for certain syscalls" series is in (the headers are
> changed in that series).
I guess you haven't pushed changes yet, which don't make full copy of typesizes.h ?
Anyhow I have a version based on your prior next branch where I switched ARC to
64-bit time_t - things work fine in general but I see some additional failures
with the testsuite.
Consider io/test-stat2.c which calls stat() and stat64() and compares the results:
it now fails for ctime mismatch
| ...
| st_atime: [72] 644245094405576070 vs [72] 644245094405576070 OK
| st_mtime: [88] 1975684956160000000 vs [88] 1975684956160000000 OK
| st_ctime: [104] 0 vs [104] 2306351876938924035 FAIL
In kernel asm-generic stat64 has 32-bit ctime (secs)
struct stat64 {
...
int st_atime; <-- offset 72
unsigned int st_atime_nsec;
int st_mtime; <-- offset *80*
unsigned int st_mtime_nsec;
int st_ctime; <-- offset 92
unsigned int st_ctime_nsec;
...
};
In glibc, we have 64-bit time_t based timestamps so the structure diverges with
kernel counterpart from time fields onwards.
__extension__ typedef __int64_t __time_t; <-- ARC switched to 64-bit time_t
struct timespec
{
__time_t tv_sec; <-- 8
long int tv_nsec; <-- 4
int: 32; <-- 4
};
struct stat64
{
...
struct timespec st_atim; <-- offset 72
struct timespec st_mtim; <-- offset *88*
struct timespec st_ctim; <-- offset 104
int __glibc_reserved[2];
};
However glibc stat64()wrapper calls
sysdeps/unix/sysv/linux/generic/wordsize-32/xstat64.c
which for ARC is just doing a pass thru syscall because we do have __NR_fstatat64
- hence the issues I see.
It needs itemized copy
__xstat64 (int vers, const char *name, struct stat64 *buf)
{
#ifdef __NR_fstatat64
return INLINE_SYSCALL (fstatat64, 4, AT_FDCWD, name, buf, 0);
#else
....
int rc = INLINE_SYSCALL (statx, 5, AT_FDCWD, name, AT_NO_AUTOMOUNT,
STATX_BASIC_STATS, &tmp);
__cp_stat64_statx (buf, &tmp);
#endif
An the reason this all works on RISCV is that your kernel doesn't define
__ARCH_WANT_STAT64 -> lacks __NR_statat64 and instead uses the statx call which
does itemized copy and would work fine when copying from 32-bits time (in kernel)
to 64-bits container in glibc. Is this is right understanding or am I missing
something here.
How do I build a latest RISCV 32-bit kernel + userland - do you have a buildroot
branch somewhere that I can build / test with qemu ?
Thx,
-Vineet
_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc
next prev parent reply other threads:[~2020-02-18 23:05 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 ` Vineet Gupta [this message]
2020-02-18 23:13 ` 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) 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
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=8a9784b3-fc52-adc3-4595-33142b059388@synopsys.com \
--to=vineet.gupta1@synopsys.com \
--cc=adhemerval.zanella@linaro.org \
--cc=alistair.francis@wdc.com \
--cc=alistair23@gmail.com \
--cc=arnd@arndb.de \
--cc=fweimer@redhat.com \
--cc=joseph@codesourcery.com \
--cc=libc-alpha@sourceware.org \
--cc=linux-snps-arc@lists.infradead.org \
--cc=macro@wdc.com \
--cc=palmerdabbelt@google.com \
--cc=zongbox@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).