From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Arnd Bergmann <arnd@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org, Alexander Viro <viro@zeniv.linux.org.uk>,
Linus Walleij <linus.walleij@linaro.org>
Subject: Re: [PATCH v5 08/10] ARM: uaccess: add __{get,put}_kernel_nofault
Date: Wed, 12 Jan 2022 18:08:17 +0000 [thread overview]
Message-ID: <Yd8ZEbywqjXkAx9k@shell.armlinux.org.uk> (raw)
In-Reply-To: <Yd8P37V/N9EkwmYq@wychelm>
On Wed, Jan 12, 2022 at 05:29:03PM +0000, Daniel Thompson wrote:
> On Mon, Jul 26, 2021 at 04:11:39PM +0200, Arnd Bergmann wrote:
> > From: Arnd Bergmann <arnd@arndb.de>
> >
> > These mimic the behavior of get_user and put_user, except
> > for domain switching, address limit checking and handling
> > of mismatched sizes, none of which are relevant here.
> >
> > To work with pre-Armv6 kernels, this has to avoid TUSER()
> > inside of the new macros, the new approach passes the "t"
> > string along with the opcode, which is a bit uglier but
> > avoids duplicating more code.
> >
> > As there is no __get_user_asm_dword(), I work around it
> > by copying 32 bit at a time, which is possible because
> > the output size is known.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>
> I've just been bisecting some regressions running the kgdbts tests on
> arm and this patch came up.
So the software PAN code is working :)
The kernel attempted to access an address that is in the userspace
domain (NULL pointer) and took an exception.
I suppose we should handle a domain fault more gracefully - what are
the required semantics if the kernel attempts a userspace access
using one of the _nofault() accessors?
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
next prev parent reply other threads:[~2022-01-12 18:10 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-26 14:11 [PATCH v5 00/10] ARM: remove set_fs callers and implementation Arnd Bergmann
2021-07-26 14:11 ` [PATCH v5 01/10] mm/maccess: fix unaligned copy_{from,to}_kernel_nofault Arnd Bergmann
2021-07-26 14:11 ` [PATCH v5 02/10] ARM: traps: use get_kernel_nofault instead of set_fs() Arnd Bergmann
2021-07-26 14:11 ` [PATCH v5 03/10] ARM: oabi-compat: add epoll_pwait handler Arnd Bergmann
2021-07-26 14:11 ` [PATCH v5 04/10] ARM: syscall: always store thread_info->abi_syscall Arnd Bergmann
2023-08-03 23:17 ` Kees Cook
2023-08-04 8:13 ` Kees Cook
2023-08-09 19:42 ` Arnd Bergmann
2021-07-26 14:11 ` [PATCH v5 05/10] ARM: oabi-compat: rework epoll_wait/epoll_pwait emulation Arnd Bergmann
2021-07-26 14:11 ` [PATCH v5 06/10] ARM: oabi-compat: rework sys_semtimedop emulation Arnd Bergmann
2021-07-26 14:11 ` [PATCH v5 07/10] ARM: oabi-compat: rework fcntl64() emulation Arnd Bergmann
2021-07-26 14:11 ` [PATCH v5 08/10] ARM: uaccess: add __{get,put}_kernel_nofault Arnd Bergmann
2022-01-12 17:29 ` Daniel Thompson
2022-01-12 18:08 ` Russell King (Oracle) [this message]
2022-01-13 9:47 ` Daniel Thompson
2022-01-13 11:14 ` Arnd Bergmann
2022-02-01 17:29 ` Daniel Thompson
2021-07-26 14:11 ` [PATCH v5 09/10] ARM: uaccess: remove set_fs() implementation Arnd Bergmann
2021-07-26 14:11 ` [PATCH v5 10/10] ARM: oabi-compat: fix oabi epoll sparse warning Arnd Bergmann
2021-08-11 6:39 ` [PATCH v5 00/10] ARM: remove set_fs callers and implementation Christoph Hellwig
2021-08-11 7:31 ` Arnd Bergmann
2022-07-05 13:07 [PATCH v5 08/10] ARM: uaccess: add __{get,put}_kernel_nofault Chen Zhongjin
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