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Message-ID: <1420558883-10131-18-git-send-email-mst@redhat.com>
Date: Tue, 6 Jan 2015 17:44:27 +0200
From: "Michael S. Tsirkin" <mst@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: Arnd Bergmann <arnd@...db.de>, linux-arch@...r.kernel.org,
Russell King <linux@....linux.org.uk>,
Daniel Thompson <daniel.thompson@...aro.org>,
Nicolas Pitre <nicolas.pitre@...aro.org>,
Victor Kamensky <victor.kamensky@...aro.org>,
=?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?=
<u.kleine-koenig@...gutronix.de>,
Andrey Ryabinin <a.ryabinin@...sung.com>,
linux-arm-kernel@...ts.infradead.org
Subject: [PATCH v2 17/40] arm: fix put_user sparse errors
virtio wants to write bitwise types to userspace using put_user.
At the moment this triggers sparse errors, since the value is passed
through an integer.
For example:
__le32 __user *p;
__le32 x;
put_user(x, p);
is safe, but currently triggers a sparse warning.
Fix that up using __force.
Note: this does not suppress any useful sparse checks since caller
assigns x to typeof(*p), which in turn forces all the necessary type
checks.
Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
---
arch/arm/include/asm/uaccess.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 4767eb9..74fcde7 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -413,14 +413,14 @@ do { \
#ifndef __ARMEB__
#define __put_user_asm_half(x,__pu_addr,err) \
({ \
- unsigned long __temp = (unsigned long)(x); \
+ unsigned long __temp = (__force unsigned long)(x); \
__put_user_asm_byte(__temp, __pu_addr, err); \
__put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \
})
#else
#define __put_user_asm_half(x,__pu_addr,err) \
({ \
- unsigned long __temp = (unsigned long)(x); \
+ unsigned long __temp = (__force unsigned long)(x); \
__put_user_asm_byte(__temp >> 8, __pu_addr, err); \
__put_user_asm_byte(__temp, __pu_addr + 1, err); \
})
--
MST
--
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