From: Christoph Hellwig <hch@lst.de>
To: x86@kernel.org, Jan Kara <jack@suse.com>
Cc: 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: improve compat handling for the i386 u64 alignment quirk v2
Date: Fri, 31 Jul 2020 14:21:59 +0200 [thread overview]
Message-ID: <20200731122202.213333-1-hch@lst.de> (raw)
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(-)
next reply other threads:[~2020-07-31 12:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 12:21 Christoph Hellwig [this message]
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 ` improve compat handling for the i386 u64 alignment quirk v2 Ingo Molnar
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