linux-kernel - Re: [PATCH 1/3] linux/const.h: move UL() macro to include/linux/const.h

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Date:   Thu, 5 Jan 2017 09:42:38 +0800 (CST)
From:   "Xuetao Guan" <gxt@...c.pku.edu.cn>
To:     "Masahiro Yamada" <yamada.masahiro@...ionext.com>
Cc:     "Andrew Morton" <akpm@...ux-foundation.org>,
        "H . Peter Anvin" <hpa@...or.com>, "Arnd Bergmann" <arnd@...db.de>,
        "David Howells" <dhowells@...hat.com>, x86@...nel.org,
        "Thomas Gleixner" <tglx@...utronix.de>,
        "Russell King" <linux@...linux.org.uk>,
        "Srinivas Pandruvada" <srinivas.pandruvada@...ux.intel.com>,
        "Ingo Molnar" <mingo@...hat.com>,
        "Will Deacon" <will.deacon@....com>,
        "Mark Rutland" <mark.rutland@....com>,
        "Olof Johansson" <olof@...om.net>,
        "Catalin Marinas" <catalin.marinas@....com>,
        linux-arm-kernel@...ts.infradead.org,
        "Masahiro Yamada" <yamada.masahiro@...ionext.com>,
        "Chris Brandt" <chris.brandt@...esas.com>,
        "James Morse" <james.morse@....com>, linux-kernel@...r.kernel.org,
        "Santosh Shilimkar" <ssantosh@...nel.org>,
        "Geert Uytterhoeven" <geert@...ux-m68k.org>,
        linux-m68k@...r.kernel.org, "Laura Abbott" <labbott@...hat.com>,
        "Guan Xuetao" <gxt@...c.pku.edu.cn>,
        "Nicolas Pitre" <nicolas.pitre@...aro.org>,
        "Neeraj Upadhyay" <neeraju@...eaurora.org>,
        "Ard Biesheuvel" <ard.biesheuvel@...aro.org>
Subject: Re: [PATCH 1/3] linux/const.h: move UL() macro to 
     include/linux/const.h

> Some architectures are duplicating the definition of UL():
>
>   #define UL(x) _AC(x, UL)
>
> This is not actually arch-specific, so it will be useful to move it
> to a common header.  Currently, we only have the uapi variant for
> linux/const.h, so I am creating include/linux/const.h.
>
> I am also adding _UL(x), _ULL(x), ULL(x) because _AC() is used for
> UL in most places (and ULL in some places).  I expect _AC(..., UL)
> will be replaced with _UL(...) or UL(...).  The underscore-prefixed
> one should be used for exported headers.
>
> Note:
> I renamed UL(x) in arch/m68k/mm/init.c, where it is used for a
> different meaning.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
> ---
>
>  arch/arm/include/asm/memory.h       | 6 ------
>  arch/arm64/include/asm/memory.h     | 6 ------
>  arch/m68k/mm/init.c                 | 6 +++---
>  arch/unicore32/include/asm/memory.h | 6 ------
>  include/linux/const.h               | 9 +++++++++
>  include/uapi/linux/const.h          | 9 ++++++---
>  6 files changed, 18 insertions(+), 24 deletions(-)
>  create mode 100644 include/linux/const.h
>
> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
> index 76cbd9c..7558247 100644
> --- a/arch/arm/include/asm/memory.h
> +++ b/arch/arm/include/asm/memory.h
> @@ -22,12 +22,6 @@
>  #include <mach/memory.h>
>  #endif
>
> -/*
> - * Allow for constants defined here to be used from assembly code
> - * by prepending the UL suffix only with actual C code compilation.
> - */
> -#define UL(x) _AC(x, UL)
> -
>  /* PAGE_OFFSET - the virtual address of the start of the kernel image */
>  #define PAGE_OFFSET		UL(CONFIG_PAGE_OFFSET)
>
> diff --git a/arch/arm64/include/asm/memory.h
> b/arch/arm64/include/asm/memory.h
> index bfe6328..4310bcc 100644
> --- a/arch/arm64/include/asm/memory.h
> +++ b/arch/arm64/include/asm/memory.h
> @@ -28,12 +28,6 @@
>  #include <asm/sizes.h>
>
>  /*
> - * Allow for constants defined here to be used from assembly code
> - * by prepending the UL suffix only with actual C code compilation.
> - */
> -#define UL(x) _AC(x, UL)
> -
> -/*
>   * Size of the PCI I/O space. This must remain a power of two so that
>   * IO_SPACE_LIMIT acts as a mask for the low bits of I/O addresses.
>   */
> diff --git a/arch/m68k/mm/init.c b/arch/m68k/mm/init.c
> index 9c1e656..a625144 100644
> --- a/arch/m68k/mm/init.c
> +++ b/arch/m68k/mm/init.c
> @@ -121,9 +121,9 @@ void free_initmem(void)
>
>  void __init print_memmap(void)
>  {
> -#define UL(x) ((unsigned long) (x))
> -#define MLK(b, t) UL(b), UL(t), (UL(t) - UL(b)) >> 10
> -#define MLM(b, t) UL(b), UL(t), (UL(t) - UL(b)) >> 20
> +#define TO_UL(x) ((unsigned long) (x))
> +#define MLK(b, t) TO_UL(b), TO_UL(t), (TO_UL(t) - TO_UL(b)) >> 10
> +#define MLM(b, t) TO_UL(b), TO_UL(t), (TO_UL(t) - TO_UL(b)) >> 20
>  #define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), 1024)
>
>  	pr_notice("Virtual kernel memory layout:\n"
> diff --git a/arch/unicore32/include/asm/memory.h
> b/arch/unicore32/include/asm/memory.h
> index 3bb0a29..66bb9f6 100644
> --- a/arch/unicore32/include/asm/memory.h
> +++ b/arch/unicore32/include/asm/memory.h
> @@ -20,12 +20,6 @@
>  #include <mach/memory.h>
>
>  /*
> - * Allow for constants defined here to be used from assembly code
> - * by prepending the UL suffix only with actual C code compilation.
> - */
> -#define UL(x) _AC(x, UL)
> -
> -/*
>   * PAGE_OFFSET - the virtual address of the start of the kernel image
>   * TASK_SIZE - the maximum size of a user space task.
>   * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area

For UniCore32 codes:
Acked-by: Guan Xuetao <gxt@...c.pku.edu.cn>

Thanks.

Xuetao

> diff --git a/include/linux/const.h b/include/linux/const.h
> new file mode 100644
> index 0000000..7b55a55
> --- /dev/null
> +++ b/include/linux/const.h
> @@ -0,0 +1,9 @@
> +#ifndef _LINUX_CONST_H
> +#define _LINUX_CONST_H
> +
> +#include <uapi/linux/const.h>
> +
> +#define UL(x)		(_UL(x))
> +#define ULL(x)		(_ULL(x))
> +
> +#endif /* _LINUX_CONST_H */
> diff --git a/include/uapi/linux/const.h b/include/uapi/linux/const.h
> index c872bfd..76fb0f9 100644
> --- a/include/uapi/linux/const.h
> +++ b/include/uapi/linux/const.h
> @@ -1,7 +1,7 @@
>  /* const.h: Macros for dealing with constants.  */
>
> -#ifndef _LINUX_CONST_H
> -#define _LINUX_CONST_H
> +#ifndef _UAPI_LINUX_CONST_H
> +#define _UAPI_LINUX_CONST_H
>
>  /* Some constant macros are used in both assembler and
>   * C code.  Therefore we cannot annotate them always with
> @@ -21,7 +21,10 @@
>  #define _AT(T,X)	((T)(X))
>  #endif
>
> +#define _UL(x)		(_AC(x, UL))
> +#define _ULL(x)		(_AC(x, ULL))
> +
>  #define _BITUL(x)	(_AC(1,UL) << (x))
>  #define _BITULL(x)	(_AC(1,ULL) << (x))
>
> -#endif /* !(_LINUX_CONST_H) */
> +#endif /* _UAPI_LINUX_CONST_H */
> --
> 2.7.4
>