Subject: Re: powerpc: Fix _ALIGN_* errors due to type difference.

From: Michael Ellerman <[email-masked]>
Date: Tue, 6 Oct 2015 20:48:43 +1100 (AEDT)

On Fri, 2015-02-10 at 14:33:48 UTC, "Aneesh Kumar K.V" wrote:
> This avoid errors like
> 
>         unsigned int usize = 1 << 30;
>         int size = 1 << 30;
>         unsigned long addr = 64UL << 30 ;
> 
>         value = _ALIGN_DOWN(addr, usize); -> 0
>         value = _ALIGN_DOWN(addr, size);  -> 0x1000000000

Are you actually seeing that anywhere? I assume not.

> diff --git a/arch/powerpc/boot/page.h b/arch/powerpc/boot/page.h
> index 14eca30fef64..87c42d7d283d 100644
> --- a/arch/powerpc/boot/page.h
> +++ b/arch/powerpc/boot/page.h
> @@ -22,8 +22,8 @@
>  #define PAGE_MASK	(~(PAGE_SIZE-1))
>  
>  /* align addr on a size boundary - adjust address up/down if needed */
> -#define _ALIGN_UP(addr,size)	(((addr)+((size)-1))&(~((size)-1)))
> -#define _ALIGN_DOWN(addr,size)	((addr)&(~((size)-1)))
> +#define _ALIGN_UP(addr, size)	(((addr)+((size)-1))&(~((typeof(addr))(size)-1)))
> +#define _ALIGN_DOWN(addr, size)	((addr)&(~((typeof(addr))(size)-1)))
>  
>  /* align addr on a size boundary - adjust address up if needed */
>  #define _ALIGN(addr,size)     _ALIGN_UP(addr,size)
> diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
> index 71294a6e976e..1dd69774a31c 100644
> --- a/arch/powerpc/include/asm/page.h
> +++ b/arch/powerpc/include/asm/page.h
> @@ -240,8 +240,8 @@ extern long long virt_phys_offset;
>  #endif
>  
>  /* align addr on a size boundary - adjust address up/down if needed */
> -#define _ALIGN_UP(addr,size)	(((addr)+((size)-1))&(~((size)-1)))
> -#define _ALIGN_DOWN(addr,size)	((addr)&(~((size)-1)))
> +#define _ALIGN_UP(addr, size)	(((addr)+((size)-1))&(~((typeof(addr))(size)-1)))
> +#define _ALIGN_DOWN(addr, size)	((addr)&(~((typeof(addr))(size)-1)))

It looks like ALIGN() in kernel.h already does this right, so can we just use
that instead for _ALIGN_UP() at least.

cheers