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| author | Michael S. Tsirkin <mst@redhat.com> | 2014-12-14 18:52:51 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2014-12-18 19:11:09 +1100 |
| commit | 505e428374bc17a2c0bd388c2e8d892e9cd8eef2 (patch) | |
| tree | d2ba58ba96fc9bc9c4e7e421d9e0058ccfb22f25 | |
| parent | c8742f85125dcfb27a2daa389283fffebffebb00 (diff) | |
| download | op-kernel-dev-505e428374bc17a2c0bd388c2e8d892e9cd8eef2.zip op-kernel-dev-505e428374bc17a2c0bd388c2e8d892e9cd8eef2.tar.gz | |
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>
| -rw-r--r-- | arch/powerpc/include/asm/uaccess.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index 9485b43..a0c071d 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; \ }) |
