From 505e428374bc17a2c0bd388c2e8d892e9cd8eef2 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Sun, 14 Dec 2014 18:52:51 +0200 Subject: [PATCH] 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 [mpe: Fill in changelog with more details] Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/uaccess.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index 9485b43a7c0..a0c071d24e0 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; \ }) -- 2.46.0