From: Ingo Molnar <mingo@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: x86@kernel.org, Jan Kara <jack@suse.com>,
linux-arm-kernel@lists.infradead.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: improve compat handling for the i386 u64 alignment quirk v2
Date: Thu, 6 Aug 2020 15:50:36 +0200 [thread overview]
Message-ID: <20200806135036.GA2077896@gmail.com> (raw)
In-Reply-To: <20200731122202.213333-1-hch@lst.de>
* Christoph Hellwig <hch@lst.de> wrote:
> Hi all,
>
> the i386 ABI is a little special in that it uses less than natural
> alignment for 64-bit integer types (u64 and s64), and a significant
> amount of our compat handlers deals with just that. Unfortunately
> there is no good way to check for this specific quirk at runtime,
> similar how in_compat_syscall() checks for a compat syscall. This
> series adds such a check, and then uses the quota code as an example
> of how this improves the compat handling. I have a few other places
> in mind where this will also be useful going forward.
>
> Changes since v1:
> - use asm-generic/compat.h instead of linux/compat.h for
> compat_u64 and compat_s64
> - fix a typo
>
> Diffstat:
> b/arch/arm64/include/asm/compat.h | 2
> b/arch/mips/include/asm/compat.h | 2
> b/arch/parisc/include/asm/compat.h | 2
> b/arch/powerpc/include/asm/compat.h | 2
> b/arch/s390/include/asm/compat.h | 2
> b/arch/sparc/include/asm/compat.h | 3
> b/arch/x86/entry/syscalls/syscall_32.tbl | 2
> b/arch/x86/include/asm/compat.h | 3
> b/fs/quota/Kconfig | 5 -
> b/fs/quota/Makefile | 1
> b/fs/quota/compat.h | 34 ++++++++
> b/fs/quota/quota.c | 73 +++++++++++++++---
> b/include/asm-generic/compat.h | 8 ++
> b/include/linux/compat.h | 9 ++
> b/include/linux/quotaops.h | 3
> b/kernel/sys_ni.c | 1
> fs/quota/compat.c | 120 -------------------------------
> 17 files changed, 113 insertions(+), 159 deletions(-)
If nobody objects to this being done at runtime, and if it's 100% ABI
compatible, then the x86 impact looks good to me:
Acked-by: Ingo Molnar <mingo@kernel.org>
Thanks,
Ingo
prev parent reply other threads:[~2020-08-06 17:27 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 12:21 improve compat handling for the i386 u64 alignment quirk v2 Christoph Hellwig
2020-07-31 12:22 ` [PATCH 1/3] compat: lift compat_s64 and compat_u64 to <asm-generic/compat.h> Christoph Hellwig
2020-07-31 12:22 ` [PATCH 2/3] compat: add a compat_need_64bit_alignment_fixup() helper Christoph Hellwig
2020-07-31 12:22 ` [PATCH 3/3] quota: simplify the quotactl compat handling Christoph Hellwig
2020-08-07 9:07 ` David Laight
2020-08-07 9:38 ` David Laight
2020-08-06 13:50 ` Ingo Molnar [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200806135036.GA2077896@gmail.com \
--to=mingo@kernel.org \
--cc=hch@lst.de \
--cc=jack@suse.com \
--cc=linux-api@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).