From: luc.vanoostenryck@gmail.com (Luc Van Oostenryck)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: traps: Mark __le16, __le32, __user variables properly
Date: Sun, 19 Feb 2017 02:58:09 +0100 [thread overview]
Message-ID: <20170219015808.2vc2kvpde7nlrey4@macbook.local> (raw)
In-Reply-To: <20170217165112.17512-1-stephen.boyd@linaro.org>
On Fri, Feb 17, 2017 at 08:51:12AM -0800, Stephen Boyd wrote:
> Sparse complains a bit on this file about endian issues and
> __user casting:
>
> arch/arm64/kernel/traps.c:87:37: warning: incorrect type in argument 1 (different address spaces)
> arch/arm64/kernel/traps.c:87:37: expected void const volatile [noderef] <asn:1>*<noident>
> arch/arm64/kernel/traps.c:87:37: got unsigned long *<noident>
> arch/arm64/kernel/traps.c:116:23: warning: incorrect type in argument 1 (different address spaces)
> arch/arm64/kernel/traps.c:116:23: expected void const volatile [noderef] <asn:1>*<noident>
> arch/arm64/kernel/traps.c:116:23: got unsigned int [usertype] *
The fact that __get_user() can and is used for both __kernel & __user pointers
defeat any sensible annotation. The proper way would be to have a special
version of __get_user() which would ignore the __user part of the pointer,
something like "__get_user_but_accept_any_pointer()" ...
> arch/arm64/kernel/traps.c:346:25: warning: cast to restricted __le16
> arch/arm64/kernel/traps.c:352:34: warning: cast to restricted __le16
> arch/arm64/kernel/traps.c:359:25: warning: cast to restricted __le32
Your patch looked correct to me for those.
> Mark the types appropriately, and force the cast in get_user()
> when assigning to 0 so sparse doesn't complain.
I didn't looked deeply at this one but I don't think it is needed.
Care to give more details?
> Noticed while making other changes to this file. There are other issues still
> about marking symbols static, but I'm not sure we want to introduce another
> header file for the asmlinkage functions?
Probably not, indeed.
> arch/arm64/kernel/traps.c:567:10: warning: Initializer entry defined twice
> arch/arm64/kernel/traps.c:568:10: also defined here
This one I find strange. Can you tell which are those two entries?
> diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
> index 46da3ea638bb..2f5b4ae98ee0 100644
> --- a/arch/arm64/include/asm/uaccess.h
> +++ b/arch/arm64/include/asm/uaccess.h
> @@ -287,7 +287,7 @@ do { \
> might_fault(); \
> access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \
> __get_user((x), __p) : \
> - ((x) = 0, -EFAULT); \
> + ((x) = (__force __typeof__(*(ptr)))0, -EFAULT); \
> })
As said above, this one is dubious.
Luc Van Oostenryck
next prev parent reply other threads:[~2017-02-19 1:58 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-17 16:51 [PATCH] arm64: traps: Mark __le16, __le32, __user variables properly Stephen Boyd
2017-02-17 17:31 ` Russell King - ARM Linux
2017-02-17 17:46 ` Stephen Boyd
2017-02-19 1:58 ` Luc Van Oostenryck [this message]
2017-02-20 8:47 ` Stephen Boyd
2017-02-20 10:04 ` Luc Van Oostenryck
2017-02-20 10:49 ` Mark Rutland
2017-02-20 21:33 ` Luc Van Oostenryck
2017-02-21 11:03 ` Will Deacon
2017-02-22 13:00 ` Luc Van Oostenryck
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