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From: "Michael S. Tsirkin" <mst@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: "Arnd Bergmann" <arnd@arndb.de>,
	linux-arch@vger.kernel.org,
	"Russell King" <linux@arm.linux.org.uk>,
	"Daniel Thompson" <daniel.thompson@linaro.org>,
	"Nicolas Pitre" <nicolas.pitre@linaro.org>,
	"Victor Kamensky" <victor.kamensky@linaro.org>,
	=?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?=
	<u.kleine-koenig@pengutronix.de>,
	"Andrey Ryabinin" <a.ryabinin@samsung.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 17/40] arm: fix put_user sparse errors
Date: Tue, 6 Jan 2015 17:44:27 +0200	[thread overview]
Message-ID: <1420558883-10131-18-git-send-email-mst@redhat.com> (raw)
In-Reply-To: <1420558883-10131-1-git-send-email-mst@redhat.com>

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@redhat.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


  parent reply	other threads:[~2015-01-06 15:45 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-06 15:43 [PATCH v2 00/40] uaccess: fix sparse warning on get/put_user for bitwise types Michael S. Tsirkin
2015-01-06 15:43 ` [PATCH v2 01/40] x86/uaccess: fix sparse errors Michael S. Tsirkin
2015-01-13 12:33   ` Thomas Gleixner
2015-01-06 15:43 ` [PATCH v2 02/40] alpha/uaccess: " Michael S. Tsirkin
2015-01-06 15:43 ` [PATCH v2 03/40] arm64/uaccess: " Michael S. Tsirkin
2015-01-06 19:14   ` Will Deacon
2015-01-06 21:48     ` Michael S. Tsirkin
2015-01-06 21:51       ` Michael S. Tsirkin
2015-01-07 10:09         ` Will Deacon
2015-01-06 15:43 ` [PATCH v2 04/40] avr32/uaccess: " Michael S. Tsirkin
2015-01-06 15:43 ` [PATCH v2 05/40] blackfin/uaccess: " Michael S. Tsirkin
2015-01-06 15:43 ` [PATCH v2 06/40] cris/uaccess: " Michael S. Tsirkin
2015-01-27 16:27   ` Jesper Nilsson
2015-01-06 15:43 ` [PATCH v2 07/40] ia64/uaccess: " Michael S. Tsirkin
2015-01-06 15:43 ` [PATCH v2 08/40] m32r/uaccess: " Michael S. Tsirkin
2015-01-06 15:43 ` [PATCH v2 09/40] metag/uaccess: " Michael S. Tsirkin
2015-01-07  9:47   ` James Hogan
2015-01-07  9:55     ` Michael S. Tsirkin
2015-01-06 15:44 ` [PATCH v2 10/40] microblaze/uaccess: " Michael S. Tsirkin
2015-01-07 10:14   ` Michal Simek
2015-01-06 15:44 ` [PATCH v2 11/40] openrisc/uaccess: " Michael S. Tsirkin
2015-01-06 15:44 ` [PATCH v2 12/40] parisc/uaccess: " Michael S. Tsirkin
2015-01-06 15:44 ` [PATCH v2 13/40] sh/uaccess: " Michael S. Tsirkin
2015-01-06 15:44 ` [PATCH v2 14/40] sparc32/uaccess: " Michael S. Tsirkin
2015-01-06 18:21   ` David Miller
2015-01-06 15:44 ` [PATCH v2 15/40] sparc64/uaccess: " Michael S. Tsirkin
2015-01-06 18:21   ` David Miller
2015-01-06 15:44 ` [PATCH v2 16/40] m68k/uaccess: " Michael S. Tsirkin
2015-01-07 10:38   ` Geert Uytterhoeven
2015-01-06 15:44 ` Michael S. Tsirkin [this message]
2015-01-06 15:44 ` [PATCH v2 18/40] blackfin: fix put_user " Michael S. Tsirkin
2015-01-06 15:44 ` [PATCH v2 19/40] ia64: " Michael S. Tsirkin
2015-01-06 15:44 ` [PATCH v2 20/40] metag: " Michael S. Tsirkin
2015-01-07  9:55   ` James Hogan
2015-01-06 15:44 ` [PATCH v2 21/40] sh: " Michael S. Tsirkin
2015-01-06 15:44 ` [PATCH v2 22/40] tile: " Michael S. Tsirkin
2015-01-12 21:56   ` Chris Metcalf
2015-01-13  9:35     ` Michael S. Tsirkin
2015-01-13  9:40       ` Michael S. Tsirkin
2015-01-13 13:30       ` Chris Metcalf
2015-01-13  9:50     ` Michael S. Tsirkin
2015-01-06 15:44 ` [PATCH v2 23/40] tile: enable sparse checks for get/put_user Michael S. Tsirkin
2015-01-13  0:08   ` Chris Metcalf
2015-01-13  9:45     ` Michael S. Tsirkin
2015-01-13 15:55       ` Chris Metcalf
2015-01-13 16:05         ` Michael S. Tsirkin
2015-01-06 15:44 ` [PATCH v2 24/40] avr32: whitespace fix Michael S. Tsirkin
2015-01-07  6:50   ` Hans-Christian Egtvedt
2015-01-06 15:44 ` [PATCH v2 25/40] arch/sparc: uaccess_32 macro whitespace fixes Michael S. Tsirkin
2015-01-06 18:22   ` David Miller
2015-01-06 15:44 ` [PATCH v2 26/40] arch/sparc: uaccess_64 " Michael S. Tsirkin
2015-01-06 16:53   ` Sam Ravnborg
2015-01-06 17:19     ` Michael S. Tsirkin
2015-01-06 18:27       ` Sam Ravnborg
2015-01-06 20:23         ` Michael S. Tsirkin
2015-01-06 20:46           ` Sam Ravnborg
2015-01-06 21:44             ` Michael S. Tsirkin
2015-01-06 18:22   ` David Miller
2015-01-06 15:45 ` [PATCH v2 27/40] blackfin: " Michael S. Tsirkin
2015-01-06 15:45 ` [PATCH v2 28/40] microblaze: whitespace fix Michael S. Tsirkin
2015-01-07 10:14   ` Michal Simek
2015-01-06 15:45 ` [PATCH v2 29/40] alpha: macro whitespace fixes Michael S. Tsirkin
2015-01-06 15:45 ` [PATCH v2 30/40] arm: " Michael S. Tsirkin
2015-01-06 15:45 ` [PATCH v2 31/40] arm64: " Michael S. Tsirkin
2015-01-07 10:10   ` Will Deacon
2015-01-06 15:45 ` [PATCH v2 32/40] avr32: " Michael S. Tsirkin
2015-01-07  6:52   ` Hans-Christian Egtvedt
2015-01-06 15:45 ` [PATCH v2 33/40] cris: " Michael S. Tsirkin
2015-01-27 16:28   ` Jesper Nilsson
2015-01-06 15:45 ` [PATCH v2 34/40] frv: " Michael S. Tsirkin
2015-01-06 15:45 ` [PATCH v2 35/40] m32r: " Michael S. Tsirkin
2015-01-06 15:45 ` [PATCH v2 36/40] m68k: " Michael S. Tsirkin
2015-01-07  9:56   ` Geert Uytterhoeven
2015-01-06 15:45 ` [PATCH v2 37/40] parisc: " Michael S. Tsirkin
2015-01-06 15:45 ` [PATCH v2 38/40] s390: " Michael S. Tsirkin
2015-01-07  8:33   ` Heiko Carstens
2015-01-07  9:07     ` Michael S. Tsirkin
2015-01-06 15:45 ` [PATCH v2 39/40] sh: " Michael S. Tsirkin
2015-01-06 15:45 ` [PATCH v2 40/40] xtensa: " Michael S. Tsirkin
2015-01-06 23:12   ` Max Filippov
2015-01-06 19:08 ` [PATCH v2 00/40] uaccess: fix sparse warning on get/put_user for bitwise types Arnd Bergmann
2015-01-06 21:54   ` Michael S. Tsirkin
2015-01-11 11:55   ` Michael S. Tsirkin
2015-01-13 10:19     ` Michael S. Tsirkin

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