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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, linux-sh@vger.kernel.org
Subject: [PATCH v2 21/40] sh: fix put_user sparse errors
Date: Tue, 06 Jan 2015 15:44:41 +0000	[thread overview]
Message-ID: <1420558883-10131-22-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/sh/include/asm/uaccess_64.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/sh/include/asm/uaccess_64.h b/arch/sh/include/asm/uaccess_64.h
index 2e07e0f..c01376c 100644
--- a/arch/sh/include/asm/uaccess_64.h
+++ b/arch/sh/include/asm/uaccess_64.h
@@ -59,19 +59,19 @@ do {								\
 	switch (size) {						\
 	case 1:							\
 		retval = __put_user_asm_b((void *)&x,		\
-					  (long)ptr);		\
+					  (__force long)ptr);	\
 		break;						\
 	case 2:							\
 		retval = __put_user_asm_w((void *)&x,		\
-					  (long)ptr);		\
+					  (__force long)ptr);	\
 		break;						\
 	case 4:							\
 		retval = __put_user_asm_l((void *)&x,		\
-					  (long)ptr);		\
+					  (__force long)ptr);	\
 		break;						\
 	case 8:							\
 		retval = __put_user_asm_q((void *)&x,		\
-					  (long)ptr);		\
+					  (__force long)ptr);	\
 		break;						\
 	default:						\
 		__put_user_unknown();				\
-- 
MST


  parent reply	other threads:[~2015-01-06 15:44 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1420558883-10131-1-git-send-email-mst@redhat.com>
2015-01-06 15:44 ` [PATCH v2 13/40] sh/uaccess: fix sparse errors Michael S. Tsirkin
2015-01-06 15:44 ` Michael S. Tsirkin [this message]
2015-01-06 15:45 ` [PATCH v2 39/40] sh: macro whitespace fixes Michael S. Tsirkin

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