Re: [PATCH 2/3] linux/bits.h: Add fixed-width GENMASK and BIT macros

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Jani Nikula <jani.nikula@linux.intel.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
	intel-gfx@lists.freedesktop.org,
	"Kevin Brodsky" <kevin.brodsky@arm.com>,
	"Lucas De Marchi" <lucas.demarchi@intel.com>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	"Christian König" <christian.koenig@amd.com>,
	"Alex Deucher" <alexander.deucher@amd.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Masahiro Yamada" <masahiroy@kernel.org>,
	intel-xe@lists.freedesktop.org
Subject: Re: [PATCH 2/3] linux/bits.h: Add fixed-width GENMASK and BIT macros
Date: Thu, 15 Jun 2023 18:53:44 +0300	[thread overview]
Message-ID: <ZIs0CC2J7nu0LHEK@smile.fi.intel.com> (raw)
In-Reply-To: <87mt29kc34.fsf@intel.com>

On Fri, May 12, 2023 at 02:45:19PM +0300, Jani Nikula wrote:
> On Fri, 12 May 2023, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> > On Fri, May 12, 2023 at 02:25:18PM +0300, Jani Nikula wrote:
> >> On Fri, 12 May 2023, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> >> > On Mon, May 08, 2023 at 10:14:02PM -0700, Lucas De Marchi wrote:
> >> >> Add GENMASK_U32(), GENMASK_U16() and GENMASK_U8()  macros to create
> >> >> masks for fixed-width types and also the corresponding BIT_U32(),
> >> >> BIT_U16() and BIT_U8().
> >> >
> >> > Why?
> >> 
> >> The main reason is that GENMASK() and BIT() size varies for 32/64 bit
> >> builds.
> >
> > When needed GENMASK_ULL() can be used (with respective castings perhaps)
> > and BIT_ULL(), no?
> 
> How does that help with making them the same 32-bit size on both 32 and
> 64 bit builds?

	u32 x = GENMASK();
	u64 y = GENMASK_ULL();

No? Then use in your code either x or y. Note that I assume that the parameters
to GENMASK*() are built-time constants. Is it the case for you?

-- 
With Best Regards,
Andy Shevchenko