This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: framebuffer corruption due to overlapping stp instructions on arm64
- From: Ramana Radhakrishnan <ramana dot gcc at googlemail dot com>
- To: Ard Biesheuvel <ard dot biesheuvel at linaro dot org>
- Cc: Florian Weimer <fweimer at redhat dot com>, Thomas Petazzoni <thomas dot petazzoni at free-electrons dot com>, GNU C Library <libc-alpha at sourceware dot org>, Andrew Pinski <pinskia at gmail dot com>, Catalin Marinas <catalin dot marinas at arm dot com>, Will Deacon <will dot deacon at arm dot com>, Russell King <linux at armlinux dot org dot uk>, LKML <linux-kernel at vger dot kernel dot org>, Mikulas Patocka <mpatocka at redhat dot com>, linux-arm-kernel <linux-arm-kernel at lists dot infradead dot org>
- Date: Fri, 3 Aug 2018 10:37:29 +0100
- Subject: Re: framebuffer corruption due to overlapping stp instructions on arm64
- References: <alpine.LRH.2.02.1808021242320.31834@file01.intranet.prod.int.rdu2.redhat.com> <CA+=Sn1mWkjuwVnjw6OWWUM=UcP76bdFa680FebCseewHfx3NpA@mail.gmail.com> <9acdacdb-3bd5-b71a-3003-e48132ee1371@redhat.com> <CAJA7tRZbmnZq7RfvQeYEy_a1ZObWqpFpVdvgsXgsioQ3RyPMuA@mail.gmail.com> <CAKv+Gu97QvwoLLK_zueiA_gjg_4Q5cqU4YVUyHUVFFfffdyJaw@mail.gmail.com>
< snip>
> I guess the semantics of a framebuffer are not strictly defined, but
> the current reality is that it is expected to have memory semantics
> (by Linux/glibc)
>
> Matt is saying fundamental properties of the underlying interconnects
> (AMBA) make that impossible on ARM, but I'd like to understand better
> if that is universally the case, and whether such a system is still
> PCIe compliant.
I don't know that side of the architecture enough to make any
definitive statements.
>
> The discussion about whether memcpy() should rely on unaligned
> accesses, and whether you should use it on device memory is orthogonal
> to that, and not the heart of the matter IMO
Then maybe take libc-alpha off if it isn't relevant.
regards
Ramana