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Date:   Thu, 18 Jan 2018 19:54:49 +0000
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References: <20180117065121.30437-1-antonynpavlov@gmail.com> <mhng-796aa108-a59e-433a-a037-925fbfaf905e@palmer-si-x1c4> <20180118230505.31af9784f543a2e067af5a39@gmail.com>
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Subject: Re: [PATCH] MIPS: use generic GCC library routines from lib/
To:     Antony Pavlov <antonynpavlov@gmail.com>,
        Palmer Dabbelt <palmer@sifive.com>
CC:     linux-mips@linux-mips.org, linux-kernel@vger.kernel.org,
        ralf@linux-mips.org, Matt Redfearn <matt.redfearn@mips.com>
From:   James Hogan <james@albanarts.com>
Message-ID: <57124790-F7C9-4180-AE89-A7FAA3DBDC9A@albanarts.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 18 January 2018 20:05:05 GMT+00:00, Antony Pavlov <antonynpavlov@gmail=
=2Ecom> wrote:
>On Wed, 17 Jan 2018 17:34:59 -0800 (PST)
>Palmer Dabbelt <palmer@sifive=2Ecom> wrote:
>
>> Ah, thanks for reminding me -- I'd originally posted a patch set that
>converted=20
>> every other port to use these routines, but I ended up dropping all
>those=2E =20
>> Here's my original MIPS attempt
>>=20
>>     https://marc=2Einfo/?l=3Dlinux-mips&m=3D149677651707103&w=3D2
>
>Now I see that I have dubbed your June 2017 patch=2E Sorry!
>
>Alas in June 2017 there was no chance to push your patch to linux-mips
>repo=2E
>Linus merged your patches in November 2017=2E Ralf merged your RISC-V
>changes
>into linux-mips repo AFAIR just several days ago=2E
>
>> Given that, I think you can also drop arch/mips/lib/libgcc=2Eh -- if
>it's used=20
>> from anywhere else, it should be possible to use
>include/linux/libgcc=2Eh=20
>> instead=2E
>
>I agree with you=2E

actually theres a patch in mips-next which implements __multi3 for mips64r=
6, which uses that file, and in fact extends it for 128bit types=2E

cheers
James

>
>>=20
>> Assuming it still seems sane do to that I can go give the rest of the
>patch set=20
>> another shot=2E  I'm a bit new to this, but I think I should do
>something like
>>=20
>> Reviewed-by: Palmer Dabbelt <palmer@sifive=2Ecom>
>
>I suppose that it's better to resurrect you patch and abandon my patch=2E
>
>Your original patch series
>(https://www=2Elinux-mips=2Eorg/archives/linux-mips/2017-06/msg00148=2Eht=
ml)
>has a disadvantage: it tries to change several architectures at once=2E
>
>I propose to create new short separate patch series for MIPS
>architecture=2E
>
>This patch series should contain two patches:
>
>   [PATCH 1/2] Add notrace to lib/ucmpdi2=2Ec
>   [PATCH 2/2] MIPS: Use generic libgcc intrinsics
>
>
>> Thanks!
>>=20
>> On Tue, 16 Jan 2018 22:51:21 PST (-0800), antonynpavlov@gmail=2Ecom
>wrote:
>> > The commit b35cd9884fa5 ("lib: Add shared copies of
>> > some GCC library routines") makes it possible
>> > to share generic GCC library routines by several
>> > architectures=2E
>> >
>> > This commit removes several generic GCC library
>> > routines from arch/mips/lib/ in favour of similar
>> > routines from lib/=2E
>> >
>> > Signed-off-by: Antony Pavlov <antonynpavlov@gmail=2Ecom>
>> > Cc: Palmer Dabbelt <palmer@sifive=2Ecom>
>> > Cc: Ralf Baechle <ralf@linux-mips=2Eorg>
>> > Cc: linux-mips@linux-mips=2Eorg
>> > Cc: linux-kernel@vger=2Ekernel=2Eorg
>> > ---
>> >  arch/mips/Kconfig       |  5 +++++
>> >  arch/mips/lib/Makefile  |  2 +-
>> >  arch/mips/lib/ashldi3=2Ec | 30 ------------------------------
>> >  arch/mips/lib/ashrdi3=2Ec | 32 --------------------------------
>> >  arch/mips/lib/cmpdi2=2Ec  | 28 ----------------------------
>> >  arch/mips/lib/lshrdi3=2Ec | 30 ------------------------------
>> >  arch/mips/lib/ucmpdi2=2Ec | 22 ----------------------
>> >  7 files changed, 6 insertions(+), 143 deletions(-)
>> >  delete mode 100644 arch/mips/lib/ashldi3=2Ec
>> >  delete mode 100644 arch/mips/lib/ashrdi3=2Ec
>> >  delete mode 100644 arch/mips/lib/cmpdi2=2Ec
>> >  delete mode 100644 arch/mips/lib/lshrdi3=2Ec
>> >  delete mode 100644 arch/mips/lib/ucmpdi2=2Ec
>> >
>> > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
>> > index 350a990fc719=2E=2E9cd49ee848c6 100644
>> > --- a/arch/mips/Kconfig
>> > +++ b/arch/mips/Kconfig
>> > @@ -73,6 +73,11 @@ config MIPS
>> >  	select RTC_LIB if !MACH_LOONGSON64
>> >  	select SYSCTL_EXCEPTION_TRACE
>> >  	select VIRT_TO_BUS
>> > +	select GENERIC_ASHLDI3
>> > +	select GENERIC_ASHRDI3
>> > +	select GENERIC_LSHRDI3
>> > +	select GENERIC_CMPDI2
>> > +	select GENERIC_UCMPDI2
>> >
>> >  menu "Machine selection"
>> >
>> > diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
>> > index 78c2affeabf8=2E=2E195ab4cb0840 100644
>> > --- a/arch/mips/lib/Makefile
>> > +++ b/arch/mips/lib/Makefile
>> > @@ -16,4 +16,4 @@ obj-$(CONFIG_CPU_R3000)		+=3D r3k_dump_tlb=2Eo
>> >  obj-$(CONFIG_CPU_TX39XX)	+=3D r3k_dump_tlb=2Eo
>> >
>> >  # libgcc-style stuff needed in the kernel
>> > -obj-y +=3D ashldi3=2Eo ashrdi3=2Eo bswapsi=2Eo bswapdi=2Eo cmpdi2=2E=
o
>lshrdi3=2Eo ucmpdi2=2Eo
>> > +obj-y +=3D bswapsi=2Eo bswapdi=2Eo
>> > diff --git a/arch/mips/lib/ashldi3=2Ec b/arch/mips/lib/ashldi3=2Ec
>> > deleted file mode 100644
>> > index 24cd6903e797=2E=2E000000000000
>> > --- a/arch/mips/lib/ashldi3=2Ec
>> > +++ /dev/null
>> > @@ -1,30 +0,0 @@
>> > -// SPDX-License-Identifier: GPL-2=2E0
>> > -#include <linux/export=2Eh>
>> > -
>> > -#include "libgcc=2Eh"
>> > -
>> > -long long notrace __ashldi3(long long u, word_type b)
>> > -{
>> > -	DWunion uu, w;
>> > -	word_type bm;
>> > -
>> > -	if (b =3D=3D 0)
>> > -		return u;
>> > -
>> > -	uu=2Ell =3D u;
>> > -	bm =3D 32 - b;
>> > -
>> > -	if (bm <=3D 0) {
>> > -		w=2Es=2Elow =3D 0;
>> > -		w=2Es=2Ehigh =3D (unsigned int) uu=2Es=2Elow << -bm;
>> > -	} else {
>> > -		const unsigned int carries =3D (unsigned int) uu=2Es=2Elow >> bm;
>> > -
>> > -		w=2Es=2Elow =3D (unsigned int) uu=2Es=2Elow << b;
>> > -		w=2Es=2Ehigh =3D ((unsigned int) uu=2Es=2Ehigh << b) | carries;
>> > -	}
>> > -
>> > -	return w=2Ell;
>> > -}
>> > -
>> > -EXPORT_SYMBOL(__ashldi3);
>> > diff --git a/arch/mips/lib/ashrdi3=2Ec b/arch/mips/lib/ashrdi3=2Ec
>> > deleted file mode 100644
>> > index 23f5295af51e=2E=2E000000000000
>> > --- a/arch/mips/lib/ashrdi3=2Ec
>> > +++ /dev/null
>> > @@ -1,32 +0,0 @@
>> > -// SPDX-License-Identifier: GPL-2=2E0
>> > -#include <linux/export=2Eh>
>> > -
>> > -#include "libgcc=2Eh"
>> > -
>> > -long long notrace __ashrdi3(long long u, word_type b)
>> > -{
>> > -	DWunion uu, w;
>> > -	word_type bm;
>> > -
>> > -	if (b =3D=3D 0)
>> > -		return u;
>> > -
>> > -	uu=2Ell =3D u;
>> > -	bm =3D 32 - b;
>> > -
>> > -	if (bm <=3D 0) {
>> > -		/* w=2Es=2Ehigh =3D 1=2E=2E1 or 0=2E=2E0 */
>> > -		w=2Es=2Ehigh =3D
>> > -		    uu=2Es=2Ehigh >> 31;
>> > -		w=2Es=2Elow =3D uu=2Es=2Ehigh >> -bm;
>> > -	} else {
>> > -		const unsigned int carries =3D (unsigned int) uu=2Es=2Ehigh << bm;
>> > -
>> > -		w=2Es=2Ehigh =3D uu=2Es=2Ehigh >> b;
>> > -		w=2Es=2Elow =3D ((unsigned int) uu=2Es=2Elow >> b) | carries;
>> > -	}
>> > -
>> > -	return w=2Ell;
>> > -}
>> > -
>> > -EXPORT_SYMBOL(__ashrdi3);
>> > diff --git a/arch/mips/lib/cmpdi2=2Ec b/arch/mips/lib/cmpdi2=2Ec
>> > deleted file mode 100644
>> > index 93cfc785927d=2E=2E000000000000
>> > --- a/arch/mips/lib/cmpdi2=2Ec
>> > +++ /dev/null
>> > @@ -1,28 +0,0 @@
>> > -// SPDX-License-Identifier: GPL-2=2E0
>> > -#include <linux/export=2Eh>
>> > -
>> > -#include "libgcc=2Eh"
>> > -
>> > -word_type notrace __cmpdi2(long long a, long long b)
>> > -{
>> > -	const DWunion au =3D {
>> > -		=2Ell =3D a
>> > -	};
>> > -	const DWunion bu =3D {
>> > -		=2Ell =3D b
>> > -	};
>> > -
>> > -	if (au=2Es=2Ehigh < bu=2Es=2Ehigh)
>> > -		return 0;
>> > -	else if (au=2Es=2Ehigh > bu=2Es=2Ehigh)
>> > -		return 2;
>> > -
>> > -	if ((unsigned int) au=2Es=2Elow < (unsigned int) bu=2Es=2Elow)
>> > -		return 0;
>> > -	else if ((unsigned int) au=2Es=2Elow > (unsigned int) bu=2Es=2Elow)
>> > -		return 2;
>> > -
>> > -	return 1;
>> > -}
>> > -
>> > -EXPORT_SYMBOL(__cmpdi2);
>> > diff --git a/arch/mips/lib/lshrdi3=2Ec b/arch/mips/lib/lshrdi3=2Ec
>> > deleted file mode 100644
>> > index 914b971aca3b=2E=2E000000000000
>> > --- a/arch/mips/lib/lshrdi3=2Ec
>> > +++ /dev/null
>> > @@ -1,30 +0,0 @@
>> > -// SPDX-License-Identifier: GPL-2=2E0
>> > -#include <linux/export=2Eh>
>> > -
>> > -#include "libgcc=2Eh"
>> > -
>> > -long long notrace __lshrdi3(long long u, word_type b)
>> > -{
>> > -	DWunion uu, w;
>> > -	word_type bm;
>> > -
>> > -	if (b =3D=3D 0)
>> > -		return u;
>> > -
>> > -	uu=2Ell =3D u;
>> > -	bm =3D 32 - b;
>> > -
>> > -	if (bm <=3D 0) {
>> > -		w=2Es=2Ehigh =3D 0;
>> > -		w=2Es=2Elow =3D (unsigned int) uu=2Es=2Ehigh >> -bm;
>> > -	} else {
>> > -		const unsigned int carries =3D (unsigned int) uu=2Es=2Ehigh << bm;
>> > -
>> > -		w=2Es=2Ehigh =3D (unsigned int) uu=2Es=2Ehigh >> b;
>> > -		w=2Es=2Elow =3D ((unsigned int) uu=2Es=2Elow >> b) | carries;
>> > -	}
>> > -
>> > -	return w=2Ell;
>> > -}
>> > -
>> > -EXPORT_SYMBOL(__lshrdi3);
>> > diff --git a/arch/mips/lib/ucmpdi2=2Ec b/arch/mips/lib/ucmpdi2=2Ec
>> > deleted file mode 100644
>> > index c31c78ca4175=2E=2E000000000000
>> > --- a/arch/mips/lib/ucmpdi2=2Ec
>> > +++ /dev/null
>> > @@ -1,22 +0,0 @@
>> > -// SPDX-License-Identifier: GPL-2=2E0
>> > -#include <linux/export=2Eh>
>> > -
>> > -#include "libgcc=2Eh"
>> > -
>> > -word_type notrace __ucmpdi2(unsigned long long a, unsigned long
>long b)
>> > -{
>> > -	const DWunion au =3D {=2Ell =3D a};
>> > -	const DWunion bu =3D {=2Ell =3D b};
>> > -
>> > -	if ((unsigned int) au=2Es=2Ehigh < (unsigned int) bu=2Es=2Ehigh)
>> > -		return 0;
>> > -	else if ((unsigned int) au=2Es=2Ehigh > (unsigned int) bu=2Es=2Ehig=
h)
>> > -		return 2;
>> > -	if ((unsigned int) au=2Es=2Elow < (unsigned int) bu=2Es=2Elow)
>> > -		return 0;
>> > -	else if ((unsigned int) au=2Es=2Elow > (unsigned int) bu=2Es=2Elow)
>> > -		return 2;
>> > -	return 1;
>> > -}
>> > -
>> > -EXPORT_SYMBOL(__ucmpdi2);


--=20
Cheers
James Hogan