From: Lukasz Majewski <lukma@denx.de> To: Vineet Gupta <Vineet.Gupta1@synopsys.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>, Alistair Francis <alistair23@gmail.com>, arcml <linux-snps-arc@lists.infradead.org>, Joseph Myers <joseph@codesourcery.com> 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: Thu, 20 Feb 2020 00:11:36 +0100 Message-ID: <20200220001136.2f14236e@jawa> (raw) In-Reply-To: <8a9784b3-fc52-adc3-4595-33142b059388@synopsys.com> [-- Attachment #1.1: Type: text/plain, Size: 5379 bytes --] Hi Vineet, > 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 ? Maybe a bit off topic - there is such QEMU and Yocto/OE based test sandbox for ARM32: https://github.com/lmajewski/meta-y2038 (the README provides steps for setup). > > Thx, > -Vineet > > > 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 [-- Attachment #1.2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 488 bytes --] [-- Attachment #2: Type: text/plain, Size: 170 bytes --] _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
next prev parent reply index Thread overview: 58+ 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 [this message] 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 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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