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Date:   Thu, 28 Nov 2019 16:07:21 +0100
From:   Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To:     "H. Nikolaus Schaller" <hns@goldelico.com>
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
Message-ID: <20191128150721.GA20142@alpha.franken.de>
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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.

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.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]