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* [PATCH 0/2] fix missing handling of __user in nommu's uaccess()
@ 2020-05-28 20:25 Luc Van Oostenryck
  2020-05-28 20:25 ` [PATCH 1/2] m68k,nommu: add missing __user in uaccess' __ptr() macro Luc Van Oostenryck
  2020-05-28 20:25 ` [PATCH 2/2] m68k,nommu: fix implicit cast from __user in __{get,put}_user_asm() Luc Van Oostenryck
  0 siblings, 2 replies; 4+ messages in thread
From: Luc Van Oostenryck @ 2020-05-28 20:25 UTC (permalink / raw)
  To: Geert Uytterhoeven, Greg Ungerer
  Cc: linux-m68k, linux-kernel, Luc Van Oostenryck

I received a bug report for an unrelated patch when used with m68k-nommu.
It appears that the origin of the problem is that __get_user() and
__put_user() doesn't handle correctly __user. These 2 patches fix this.

Note: this is only minimaly tested but is quite straightforward and
      since this only change __user annotation it will not change the
      generated code.

Luc Van Oostenryck (2):
  m68k,nommu: add missing __user in uaccess' __ptr() macro
  m68k,nommu: fix implicit cast from __user in __{get,put}_user_asm()

 arch/m68k/include/asm/uaccess_no.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH 1/2] m68k,nommu: add missing __user in uaccess' __ptr() macro
  2020-05-28 20:25 [PATCH 0/2] fix missing handling of __user in nommu's uaccess() Luc Van Oostenryck
@ 2020-05-28 20:25 ` Luc Van Oostenryck
  2020-05-28 20:25 ` [PATCH 2/2] m68k,nommu: fix implicit cast from __user in __{get,put}_user_asm() Luc Van Oostenryck
  1 sibling, 0 replies; 4+ messages in thread
From: Luc Van Oostenryck @ 2020-05-28 20:25 UTC (permalink / raw)
  To: Geert Uytterhoeven, Greg Ungerer
  Cc: linux-m68k, linux-kernel, Luc Van Oostenryck, kbuild test robot

The assembly for __get_user() & __put_user() uses a macro, __ptr(),
to cast the pointer to 'unsigned long *' but the pointer is always
a __user one and so this cast creates a lot of warnings when using
Sparse.

So, change to the cast to 'unsigned long __user *'.

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

diff --git a/arch/m68k/include/asm/uaccess_no.h b/arch/m68k/include/asm/uaccess_no.h
index a24cfe4a0d32..9651766a62af 100644
--- a/arch/m68k/include/asm/uaccess_no.h
+++ b/arch/m68k/include/asm/uaccess_no.h
@@ -60,7 +60,7 @@ extern int __put_user_bad(void);
  * aliasing issues.
  */
 
-#define __ptr(x) ((unsigned long *)(x))
+#define __ptr(x) ((unsigned long __user *)(x))
 
 #define __put_user_asm(err,x,ptr,bwl)				\
 	__asm__ ("move" #bwl " %0,%1"				\
-- 
2.26.2


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH 2/2] m68k,nommu: fix implicit cast from __user in __{get,put}_user_asm()
  2020-05-28 20:25 [PATCH 0/2] fix missing handling of __user in nommu's uaccess() Luc Van Oostenryck
  2020-05-28 20:25 ` [PATCH 1/2] m68k,nommu: add missing __user in uaccess' __ptr() macro Luc Van Oostenryck
@ 2020-05-28 20:25 ` Luc Van Oostenryck
  2020-05-29 13:21   ` Greg Ungerer
  1 sibling, 1 reply; 4+ messages in thread
From: Luc Van Oostenryck @ 2020-05-28 20:25 UTC (permalink / raw)
  To: Geert Uytterhoeven, Greg Ungerer
  Cc: linux-m68k, linux-kernel, Luc Van Oostenryck, kbuild test robot

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@intel.com>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.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


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH 2/2] m68k,nommu: fix implicit cast from __user in __{get,put}_user_asm()
  2020-05-28 20:25 ` [PATCH 2/2] m68k,nommu: fix implicit cast from __user in __{get,put}_user_asm() Luc Van Oostenryck
@ 2020-05-29 13:21   ` Greg Ungerer
  0 siblings, 0 replies; 4+ messages in thread
From: Greg Ungerer @ 2020-05-29 13:21 UTC (permalink / raw)
  To: Luc Van Oostenryck, Geert Uytterhoeven
  Cc: linux-m68k, linux-kernel, kbuild test robot

Hi Luc,

On 29/5/20 6:25 am, Luc Van Oostenryck wrote:
> 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     ^^^^
Did you mean "plain"?


> Sparse.
> 
> So, fix this by adding a cast to 'void __force *' at memcpy()'s
> argument.
> 
> Reported-by: kbuild test robot <lkp@intel.com>
> Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.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))); \
                            ^^^
checkpatch wants a ' ' space in there.

Otherwise I think it looks good.

Regards
Greg

  
>   	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;							\
>       }								\
> 

^ permalink raw reply	[flat|nested] 4+ messages in thread

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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-28 20:25 [PATCH 0/2] fix missing handling of __user in nommu's uaccess() Luc Van Oostenryck
2020-05-28 20:25 ` [PATCH 1/2] m68k,nommu: add missing __user in uaccess' __ptr() macro Luc Van Oostenryck
2020-05-28 20:25 ` [PATCH 2/2] m68k,nommu: fix implicit cast from __user in __{get,put}_user_asm() Luc Van Oostenryck
2020-05-29 13:21   ` Greg Ungerer

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