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From: "H. Nikolaus Schaller" <hns@goldelico.com>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Maarten ter Huurne <maarten@treewalker.org>,
	mips-creator-ci20-dev@googlegroups.com,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Ralf Baechle <ralf@linux-mips.org>,
	Paul Burton <paul.burton@mips.com>,
	linux-mips@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Discussions about the Letux Kernel 
	<letux-kernel@openphoenux.org>
Subject: Re: MIPS: bug: gettimeofday syscall broken on CI20 board
Date: Thu, 28 Nov 2019 16:41:57 +0100	[thread overview]
Message-ID: <4F75970F-81DA-4727-8ADC-17CF6D77829B@goldelico.com> (raw)
In-Reply-To: <20191128150721.GA20142@alpha.franken.de>


> Am 28.11.2019 um 16:07 schrieb Thomas Bogendoerfer <tsbogend@alpha.franken.de>:
> 
> On Thu, Nov 28, 2019 at 02:48:46PM +0100, H. Nikolaus Schaller wrote:
>> 
>> What still does not fit into the picture is the errno = 1 i.e. EPERM.
>> Maybe I have to study the libc code that tries to read the ELF symbols
>> you have mentioned. It may fail for unknown reasons.
> 
> to understand vdso you might look at arch/mips/vdso and lib/vdso
> kernel sources.

Yes that is what I know, but I do not know how glibc can return an EPERM
through VDSO.

> 
> And if I understand it correctly you neither have a working high resolution
> timer usable bei do_hres() in lib/vdso/gettimeofday.c or a working
> gettimeofday_fallback(), which is enabled via CONFIG_MIPS_CLOCK_VSYSCALL
> and needs either CSRC_R4K or CLKSRC_MIPS_GIC.

Well, on kernel v4.19 or using v5.4 with Jessie, gettimeofday() works.

So this may only be part of the reason it starts to fail with commit
24640f233b466051ad3a5d2786d2951e43026c9d.

MIPS_CLOCK_VSYSCALL is neither defined nor undefined in the defconfig.
And removed if I manually add it to my defconfig.
And yes, it depends on either CSRC_R4K || CLKSRC_MIPS_GIC by arch/mips/Kconfig.

Maybe this was just forgotten to properly handle for the ci20_defconfig
or jz4780?

What does CSRC_R4K resp. CLKSRC_MIPS_GIC ecactly mean? Does the jz4780 have this
feature?

BR and thanks,
Nikolaus


  reply	other threads:[~2019-11-28 15:42 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-07 16:21 MIPS: bug: gettimeofday syscall broken on CI20 board? H. Nikolaus Schaller
2019-11-17 13:14 ` MIPS: bug: gettimeofday syscall broken on CI20 board H. Nikolaus Schaller
2019-11-23  7:29   ` H. Nikolaus Schaller
2019-11-26 10:52   ` MIPS: " Vincenzo Frascino
2019-11-27 13:53     ` H. Nikolaus Schaller
2019-11-27 14:29       ` H. Nikolaus Schaller
2019-11-28 12:05         ` Vincenzo Frascino
2019-11-28 12:16           ` H. Nikolaus Schaller
2019-11-28 14:04             ` Vincenzo Frascino
2019-11-28 15:10               ` H. Nikolaus Schaller
2019-11-28 11:51       ` Vincenzo Frascino
2019-11-28 12:11         ` H. Nikolaus Schaller
2019-11-28 12:21           ` Vincenzo Frascino
2019-11-28 12:33             ` H. Nikolaus Schaller
2019-11-28 13:29               ` Maarten ter Huurne
2019-11-28 13:48                 ` H. Nikolaus Schaller
2019-11-28 14:01                   ` Vincenzo Frascino
2019-11-28 15:42                     ` H. Nikolaus Schaller
2019-11-28 15:07                   ` Thomas Bogendoerfer
2019-11-28 15:41                     ` H. Nikolaus Schaller [this message]
2019-11-28 15:46                       ` Vincenzo Frascino
2019-11-28 16:47                         ` H. Nikolaus Schaller
2019-11-29  8:57                           ` Vincenzo Frascino
2019-11-29 10:53                             ` Vincenzo Frascino
2019-11-29 11:51                               ` H. Nikolaus Schaller
2019-12-01  3:08                         ` [PATCH] Mips32 gettimeofday fix kbuild test robot

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