linux-kernel - [PATCH 2/2] m68k,nommu: fix implicit cast from __user in __{get,put}_user

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Date:   Thu, 28 May 2020 22:25:14 +0200
From:   Luc Van Oostenryck <luc.vanoostenryck@...il.com>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Greg Ungerer <gerg@...ux-m68k.org>
Cc:     linux-m68k@...ts.linux-m68k.org, linux-kernel@...r.kernel.org,
        Luc Van Oostenryck <luc.vanoostenryck@...il.com>,
        kbuild test robot <lkp@...el.com>
Subject: [PATCH 2/2] m68k,nommu: fix implicit cast from __user in __{get,put}_user_asm()

The assembly for __get_user_asm() & __put_user_asm() uses memcpy()
when the size is 8.

However, the pointer is always a __user one while memcpy() expect
a plan one and so this cast creates a lot of warnings when using
Sparse.

So, fix this by adding a cast to 'void __force *' at memcpy()'s
argument.

Reported-by: kbuild test robot <lkp@...el.com>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@...il.com>
---
 arch/m68k/include/asm/uaccess_no.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/m68k/include/asm/uaccess_no.h b/arch/m68k/include/asm/uaccess_no.h
index 9651766a62af..f32f08a64eaa 100644
--- a/arch/m68k/include/asm/uaccess_no.h
+++ b/arch/m68k/include/asm/uaccess_no.h
@@ -42,7 +42,7 @@ static inline int _access_ok(unsigned long addr, unsigned long size)
 	__put_user_asm(__pu_err, __pu_val, ptr, l);	\
 	break;						\
     case 8:						\
-	memcpy(ptr, &__pu_val, sizeof (*(ptr))); \
+	memcpy((void __force*)ptr, &__pu_val, sizeof (*(ptr))); \
 	break;						\
     default:						\
 	__pu_err = __put_user_bad();			\
@@ -85,7 +85,7 @@ extern int __put_user_bad(void);
 	    u64 l;						\
 	    __typeof__(*(ptr)) t;				\
 	} __gu_val;						\
-	memcpy(&__gu_val.l, ptr, sizeof(__gu_val.l));		\
+	memcpy(&__gu_val.l, (const void __force*)ptr, sizeof(__gu_val.l));		\
 	(x) = __gu_val.t;					\
 	break;							\
     }								\
-- 
2.26.2