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Message-ID: <20200907214554.GO3265@brightrain.aerifal.cx>
Date: Mon, 7 Sep 2020 17:45:54 -0400
From: Rich Felker <dalias@...c.org>
To: musl@...ts.openwall.com
Subject: Re: riscv32 v2
On Mon, Sep 07, 2020 at 11:35:45PM +0200, Arnd Bergmann wrote:
> On Mon, Sep 7, 2020 at 8:06 PM Rich Felker <dalias@...c.org> wrote:
> > On Mon, Sep 07, 2020 at 06:47:00AM -0400, Stefan O'Rear wrote:
>
> > > * Copy the IPC_TIME64 bits from arch/arm/bits to trigger the musl code
> > > for fixing time64 IPC_STAT results. I'm not super happy with this,
> > > maybe there should be a new mechanism in musl for fixing IPC_STAT for
> > > unconditionally-time64 architectures.
> >
> > If the riscv32 IPC syscalls don't actually provide in-place time64 but
> > require translation, I think it's fairly appropriate as-is.
> >
> > From the definitions in your patch, it looks like all the time fields
> > are fixed-word-order (little endian) and possibly not aligned, so it
> > seems like they can't be used in-place. Is this correct?
>
> Yes, rv32 uses the generic system call arguments, which are
> unfortunately defined this way. In retrospect I wish I had
> replaced the ipc syscalls with a sane version for time64, but at
> the time time it seemed as easy way out to use the fields that
> had been reserved for this purpose despite the broken
> byte order and alignment.
Thanks for clarifying. BTW does passing IPC_64 produce an error on
rv32? If so, this is another advantage of keeping the IPC_TIME64 bit
-- it would catch programs bypassing libc and making the syscalls
directly.
Rich
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