Re: [PATCH] arch/microblaze: support get_user() of size 8 bytes

[Michal Simek]

On 17. 09. 19 3:39, Randy Dunlap wrote:
> From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> 
> arch/microblaze/ is missing support for get_user() of size 8 bytes,
> so add it by using __copy_from_user().
> 
> While there, also drop a lot of the code duplication.
> 
> Fixes these build errors:
>    drivers/infiniband/core/uverbs_main.o: In function `ib_uverbs_write':
>    drivers/infiniband/core/.tmp_gl_uverbs_main.o:(.text+0x13a4): undefined reference to `__user_bad'
>    drivers/android/binder.o: In function `binder_thread_write':
>    drivers/android/.tmp_gl_binder.o:(.text+0xda6c): undefined reference to `__user_bad'
>    drivers/android/.tmp_gl_binder.o:(.text+0xda98): undefined reference to `__user_bad'
>    drivers/android/.tmp_gl_binder.o:(.text+0xdf10): undefined reference to `__user_bad'
>    drivers/android/.tmp_gl_binder.o:(.text+0xe498): undefined reference to `__user_bad'
>    drivers/android/binder.o:drivers/android/.tmp_gl_binder.o:(.text+0xea78): more undefined references to `__user_bad' follow
> 
> 'make allmodconfig' now builds successfully for arch/microblaze/.
> 
> Fixes: 538722ca3b76 ("microblaze: fix get_user/put_user side-effects")
> Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Acked-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Cc: Steven J. Magnani <steve@xxxxxxxxxxxxxxx>
> Cc: Michal Simek <monstr@xxxxxxxxx>
> Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
> Cc: Leon Romanovsky <leonro@xxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Doug Ledford <dledford@xxxxxxxxxx>
> ---
> v4: drop code duplication (Linus).
> 
> 
>  arch/microblaze/include/asm/uaccess.h |   42 +++++-------------------
>  1 file changed, 9 insertions(+), 33 deletions(-)
> 
> --- lnx-53.orig/arch/microblaze/include/asm/uaccess.h
> +++ lnx-53/arch/microblaze/include/asm/uaccess.h
> @@ -163,44 +163,15 @@ extern long __user_bad(void);
>   * Returns zero on success, or -EFAULT on error.
>   * On error, the variable @x is set to zero.
>   */
> -#define get_user(x, ptr)						\
> -	__get_user_check((x), (ptr), sizeof(*(ptr)))
> -
> -#define __get_user_check(x, ptr, size)					\
> -({									\
> -	unsigned long __gu_val = 0;					\
> -	const typeof(*(ptr)) __user *__gu_addr = (ptr);			\
> -	int __gu_err = 0;						\
> -									\
> -	if (access_ok(__gu_addr, size)) {			\
> -		switch (size) {						\
> -		case 1:							\
> -			__get_user_asm("lbu", __gu_addr, __gu_val,	\
> -				       __gu_err);			\
> -			break;						\
> -		case 2:							\
> -			__get_user_asm("lhu", __gu_addr, __gu_val,	\
> -				       __gu_err);			\
> -			break;						\
> -		case 4:							\
> -			__get_user_asm("lw", __gu_addr, __gu_val,	\
> -				       __gu_err);			\
> -			break;						\
> -		default:						\
> -			__gu_err = __user_bad();			\
> -			break;						\
> -		}							\
> -	} else {							\
> -		__gu_err = -EFAULT;					\
> -	}								\
> -	x = (__force typeof(*(ptr)))__gu_val;				\
> -	__gu_err;							\
> +#define get_user(x, ptr) ({				\
> +	const typeof(*(ptr)) __user *__gu_ptr = (ptr);	\
> +	access_ok(__gu_ptr, sizeof(*__gu_ptr)) ?	\
> +		__get_user(x, __gu_ptr) : -EFAULT;	\
>  })
>  
>  #define __get_user(x, ptr)						\
>  ({									\
>  	unsigned long __gu_val = 0;					\
> -	/*unsigned long __gu_ptr = (unsigned long)(ptr);*/		\
>  	long __gu_err;							\
>  	switch (sizeof(*(ptr))) {					\
>  	case 1:								\
> @@ -212,6 +183,11 @@ extern long __user_bad(void);
>  	case 4:								\
>  		__get_user_asm("lw", (ptr), __gu_val, __gu_err);	\
>  		break;							\
> +	case 8:								\
> +		__gu_err = __copy_from_user(&__gu_val, ptr, 8);		\
> +		if (__gu_err)						\
> +			__gu_err = -EFAULT;				\
> +		break;							\
>  	default:							\
>  		/* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
>  	}								\
> 
> 

Applied.

Thanks,
Michal

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