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authorMichael S. Tsirkin <mst@redhat.com>2014-12-14 18:52:51 +0200
committerMichael Ellerman <mpe@ellerman.id.au>2014-12-18 19:11:09 +1100
commit505e428374bc17a2c0bd388c2e8d892e9cd8eef2 (patch)
treed2ba58ba96fc9bc9c4e7e421d9e0058ccfb22f25 /arch/powerpc
parentc8742f85125dcfb27a2daa389283fffebffebb00 (diff)
downloadlinux-505e428374bc17a2c0bd388c2e8d892e9cd8eef2.tar.bz2
powerpc/uaccess: Allow get_user() with bitwise types
At the moment, if p and x are both of the same bitwise type (eg. __le32), get_user(x, p) produces a sparse warning. This is because *p is loaded into a long then cast back to typeof(*p). When typeof(*p) is a bitwise type (which is uncommon), such a cast needs __force, otherwise sparse produces a warning. For non-bitwise types __force should have no effect, and should not hide any legitimate errors. Note that we are casting to typeof(*p) not typeof(x). Even with the cast, if x and *p are of different types we should get the warning, so I think we are not loosing the ability to detect any actual errors. virtio would like to use bitwise types with get_user() so fix these spurious warnings by adding __force. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> [mpe: Fill in changelog with more details] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/include/asm/uaccess.h6
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 9485b43a7c00..a0c071d24e0e 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -284,7 +284,7 @@ do { \
if (!is_kernel_addr((unsigned long)__gu_addr)) \
might_fault(); \
__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
- (x) = (__typeof__(*(ptr)))__gu_val; \
+ (x) = (__force __typeof__(*(ptr)))__gu_val; \
__gu_err; \
})
#endif /* __powerpc64__ */
@@ -297,7 +297,7 @@ do { \
might_fault(); \
if (access_ok(VERIFY_READ, __gu_addr, (size))) \
__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
- (x) = (__typeof__(*(ptr)))__gu_val; \
+ (x) = (__force __typeof__(*(ptr)))__gu_val; \
__gu_err; \
})
@@ -308,7 +308,7 @@ do { \
const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
__chk_user_ptr(ptr); \
__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
- (x) = (__typeof__(*(ptr)))__gu_val; \
+ (x) = (__force __typeof__(*(ptr)))__gu_val; \
__gu_err; \
})