Re: [Xen-devel] [PATCH v8 07/13] arm/mem_access: Introduce GENMASK_ULL bit operation

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

Hi all,

On 08/09/2017 10:20 AM, Sergej Proskurin wrote:
> The current implementation of GENMASK is capable of creating bitmasks of
> 32-bit values on AArch32 and 64-bit values on AArch64. As we need to
> create masks for 64-bit values on AArch32 as well, in this commit we
> introduce the GENMASK_ULL bit operation. Please note that the
> GENMASK_ULL implementation has been lifted from the linux kernel source
> code.
> 

As all other patches of this patch series have been Acked, I would like
to friendly remind "The REST" maintainers to provide me with your
opinion/review on this particular patch. Thank you very much in advance :)

> Signed-off-by: Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
> ---
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
> Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Julien Grall <julien.grall@xxxxxxx>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> Cc: Tim Deegan <tim@xxxxxxx>
> Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
> ---
> v6: As similar patches have been already submitted and NACKED in the
>     past, we resubmit this patch with 'THE REST' maintainers in Cc to
>     discuss whether this patch shall be applied into common or put into
>     ARM related code.
> 
> v7: Change the introduced macro BITS_PER_LONG_LONG to BITS_PER_LLONG.
> 
>     Define BITS_PER_LLONG also in asm-x86/config.h in order to allow
>     global usage of the introduced macro GENMASK_ULL.
> 
>     Remove previously unintended whitespace elimination in the function
>     get_bitmask_order as it is not the right patch to address cleanup.
> ---
>  xen/include/asm-arm/config.h | 2 ++
>  xen/include/asm-x86/config.h | 2 ++
>  xen/include/xen/bitops.h     | 3 +++
>  3 files changed, 7 insertions(+)
> 
> diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h
> index 5b6f3c985d..7da94698e1 100644
> --- a/xen/include/asm-arm/config.h
> +++ b/xen/include/asm-arm/config.h
> @@ -19,6 +19,8 @@
>  #define BITS_PER_LONG (BYTES_PER_LONG << 3)
>  #define POINTER_ALIGN BYTES_PER_LONG
>  
> +#define BITS_PER_LLONG 64
> +
>  /* xen_ulong_t is always 64 bits */
>  #define BITS_PER_XEN_ULONG 64
>  
> diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h
> index bc0730fd9d..8b1de07dbc 100644
> --- a/xen/include/asm-x86/config.h
> +++ b/xen/include/asm-x86/config.h
> @@ -15,6 +15,8 @@
>  #define BITS_PER_BYTE 8
>  #define POINTER_ALIGN BYTES_PER_LONG
>  
> +#define BITS_PER_LLONG 64
> +
>  #define BITS_PER_XEN_ULONG BITS_PER_LONG
>  
>  #define CONFIG_PAGING_ASSISTANCE 1
> diff --git a/xen/include/xen/bitops.h b/xen/include/xen/bitops.h
> index bd0883ab22..e2019b02a3 100644
> --- a/xen/include/xen/bitops.h
> +++ b/xen/include/xen/bitops.h
> @@ -10,6 +10,9 @@
>  #define GENMASK(h, l) \
>      (((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>  
> +#define GENMASK_ULL(h, l) \
> +    (((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LLONG - 1 - (h))))
> +
>  /*
>   * ffs: find first bit set. This is defined the same way as
>   * the libc and compiler builtin ffs routines, therefore


Cheers,
~Sergej

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