[PATCH v11 1/5] uaccess: add generic fallback version of copy_mc_to_user()

[Jonathan Cameron]

On Wed, 7 Feb 2024 21:22:00 +0800
Tong Tiangen <tongtiangen at huawei.com> wrote:

> x86/powerpc has it's implementation of copy_mc_to_user(), we add generic
> fallback in include/linux/uaccess.h prepare for other architechures to
architectures

(only bother fixing if you end up doing a v12 - hence off list reply!)

> enable CONFIG_ARCH_HAS_COPY_MC.
> 
> Signed-off-by: Tong Tiangen <tongtiangen at huawei.com>
> Acked-by: Michael Ellerman <mpe at ellerman.id.au>
> ---
>  arch/powerpc/include/asm/uaccess.h | 1 +
>  arch/x86/include/asm/uaccess.h     | 1 +
>  include/linux/uaccess.h            | 9 +++++++++
>  3 files changed, 11 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
> index f1f9890f50d3..4bfd1e6f0702 100644
> --- a/arch/powerpc/include/asm/uaccess.h
> +++ b/arch/powerpc/include/asm/uaccess.h
> @@ -381,6 +381,7 @@ copy_mc_to_user(void __user *to, const void *from, unsigned long n)
>  
>  	return n;
>  }
> +#define copy_mc_to_user copy_mc_to_user
>  #endif
>  
>  extern long __copy_from_user_flushcache(void *dst, const void __user *src,
> diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
> index 5c367c1290c3..fd56282ee9a8 100644
> --- a/arch/x86/include/asm/uaccess.h
> +++ b/arch/x86/include/asm/uaccess.h
> @@ -497,6 +497,7 @@ copy_mc_to_kernel(void *to, const void *from, unsigned len);
>  
>  unsigned long __must_check
>  copy_mc_to_user(void __user *to, const void *from, unsigned len);
> +#define copy_mc_to_user copy_mc_to_user
>  #endif
>  
>  /*
> diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
> index 3064314f4832..550287c92990 100644
> --- a/include/linux/uaccess.h
> +++ b/include/linux/uaccess.h
> @@ -205,6 +205,15 @@ copy_mc_to_kernel(void *dst, const void *src, size_t cnt)
>  }
>  #endif
>  
> +#ifndef copy_mc_to_user
> +static inline unsigned long __must_check
> +copy_mc_to_user(void *dst, const void *src, size_t cnt)
> +{
> +	check_object_size(src, cnt, true);
> +	return raw_copy_to_user(dst, src, cnt);
> +}
> +#endif
> +
>  static __always_inline void pagefault_disabled_inc(void)
>  {
>  	current->pagefault_disabled++;