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Message-ID: <3c52c57f8bf4bedc0e7757937464d97f3f825394.camel@physik.fu-berlin.de>
Subject: Re: [PATCH v3] sh: Use generic GCC library routines
From:   John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
To:     Geert Uytterhoeven <geert+renesas@glider.be>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>
Cc:     Palmer Dabbelt <palmer@rivosinc.com>, linux-sh@vger.kernel.org,
        linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Mon, 24 Apr 2023 09:45:29 +0200
In-Reply-To: <74dbe68dc8e2ffb6180092f73723fe21ab692c7a.1679566500.git.geert+renesas@glider.be>
References: <74dbe68dc8e2ffb6180092f73723fe21ab692c7a.1679566500.git.geert+renesas@glider.be>
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On Thu, 2023-03-23 at 11:18 +0100, Geert Uytterhoeven wrote:
> The C implementations of __ashldi3(), __ashrdi3__(), and __lshrdi3() in
> arch/sh/lib/ are identical to the generic C implementations in lib/.
> Reduce duplication by switching SH to the generic versions.
> 
> Update the include path in arch/sh/boot/compressed accordingly.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
> ---
> v3:
>   - Add Acked-by,
> 
> v2:
>   - Fix silly typo in subject.
> 
> Tested on landisk and qemu/rts7751r2d.
> 
> Note that it also works without the change to arch/sh/boot/compressed/,
> as lib/ashldi3.c can be reached via both include/uapi/../../lib/ashldi3.c
> and arch/sh/boot/compressed/../../../../lib/ashldi3.c.
> 
> Palmer tried a similar thing before:
> https://lore.kernel.org/linux-arch/20170523220546.16758-1-palmer@dabbelt.com/
> but initially it broke the SH build due to a missing change to
> arch/sh/boot/compressed/, and the later update never got picked up.
> In the mean time, arch/sh/boot/compressed/ was changed, so his patch no
> longer applies.
> 
> Similar for the other architectures, I guess?
> ---
>  arch/sh/Kconfig                   |  3 +++
>  arch/sh/boot/compressed/ashldi3.c |  4 ++--
>  arch/sh/lib/Makefile              |  4 +---
>  arch/sh/lib/ashldi3.c             | 30 -----------------------------
>  arch/sh/lib/ashrdi3.c             | 32 -------------------------------
>  arch/sh/lib/lshrdi3.c             | 30 -----------------------------
>  6 files changed, 6 insertions(+), 97 deletions(-)
>  delete mode 100644 arch/sh/lib/ashldi3.c
>  delete mode 100644 arch/sh/lib/ashrdi3.c
>  delete mode 100644 arch/sh/lib/lshrdi3.c
> 
> diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
> index ccb866750a884643..892903dc74990c36 100644
> --- a/arch/sh/Kconfig
> +++ b/arch/sh/Kconfig
> @@ -20,6 +20,9 @@ config SUPERH
>  	select GENERIC_CMOS_UPDATE if SH_SH03 || SH_DREAMCAST
>  	select GENERIC_IDLE_POLL_SETUP
>  	select GENERIC_IRQ_SHOW
> +	select GENERIC_LIB_ASHLDI3
> +	select GENERIC_LIB_ASHRDI3
> +	select GENERIC_LIB_LSHRDI3
>  	select GENERIC_PCI_IOMAP if PCI
>  	select GENERIC_SCHED_CLOCK
>  	select GENERIC_SMP_IDLE_THREAD
> diff --git a/arch/sh/boot/compressed/ashldi3.c b/arch/sh/boot/compressed/ashldi3.c
> index 7cebd646df839b48..7c12121702309e8c 100644
> --- a/arch/sh/boot/compressed/ashldi3.c
> +++ b/arch/sh/boot/compressed/ashldi3.c
> @@ -1,2 +1,2 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -#include "../../lib/ashldi3.c"
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +#include "../../../../lib/ashldi3.c"
> diff --git a/arch/sh/lib/Makefile b/arch/sh/lib/Makefile
> index eb473d373ca43a4b..d20a0768b31fa2b6 100644
> --- a/arch/sh/lib/Makefile
> +++ b/arch/sh/lib/Makefile
> @@ -7,9 +7,7 @@ lib-y  = delay.o memmove.o memchr.o \
>  	 checksum.o strlen.o div64.o div64-generic.o
>  
>  # Extracted from libgcc
> -obj-y += movmem.o ashldi3.o ashrdi3.o lshrdi3.o \
> -	 ashlsi3.o ashrsi3.o ashiftrt.o lshrsi3.o \
> -	 udiv_qrnnd.o
> +obj-y += movmem.o ashlsi3.o ashrsi3.o ashiftrt.o lshrsi3.o udiv_qrnnd.o
>  
>  udivsi3-y			:= udivsi3_i4i-Os.o
>  
> diff --git a/arch/sh/lib/ashldi3.c b/arch/sh/lib/ashldi3.c
> deleted file mode 100644
> index e5afe0935847427f..0000000000000000
> --- a/arch/sh/lib/ashldi3.c
> +++ /dev/null
> @@ -1,30 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -#include <linux/module.h>
> -
> -#include "libgcc.h"
> -
> -long long __ashldi3(long long u, word_type b)
> -{
> -	DWunion uu, w;
> -	word_type bm;
> -
> -	if (b == 0)
> -		return u;
> -
> -	uu.ll = u;
> -	bm = 32 - b;
> -
> -	if (bm <= 0) {
> -		w.s.low = 0;
> -		w.s.high = (unsigned int) uu.s.low << -bm;
> -	} else {
> -		const unsigned int carries = (unsigned int) uu.s.low >> bm;
> -
> -		w.s.low = (unsigned int) uu.s.low << b;
> -		w.s.high = ((unsigned int) uu.s.high << b) | carries;
> -	}
> -
> -	return w.ll;
> -}
> -
> -EXPORT_SYMBOL(__ashldi3);
> diff --git a/arch/sh/lib/ashrdi3.c b/arch/sh/lib/ashrdi3.c
> deleted file mode 100644
> index ae263fbf25383b70..0000000000000000
> --- a/arch/sh/lib/ashrdi3.c
> +++ /dev/null
> @@ -1,32 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -#include <linux/module.h>
> -
> -#include "libgcc.h"
> -
> -long long __ashrdi3(long long u, word_type b)
> -{
> -	DWunion uu, w;
> -	word_type bm;
> -
> -	if (b == 0)
> -		return u;
> -
> -	uu.ll = u;
> -	bm = 32 - b;
> -
> -	if (bm <= 0) {
> -		/* w.s.high = 1..1 or 0..0 */
> -		w.s.high =
> -		    uu.s.high >> 31;
> -		w.s.low = uu.s.high >> -bm;
> -	} else {
> -		const unsigned int carries = (unsigned int) uu.s.high << bm;
> -
> -		w.s.high = uu.s.high >> b;
> -		w.s.low = ((unsigned int) uu.s.low >> b) | carries;
> -	}
> -
> -	return w.ll;
> -}
> -
> -EXPORT_SYMBOL(__ashrdi3);
> diff --git a/arch/sh/lib/lshrdi3.c b/arch/sh/lib/lshrdi3.c
> deleted file mode 100644
> index 33eaa1edbc3c0656..0000000000000000
> --- a/arch/sh/lib/lshrdi3.c
> +++ /dev/null
> @@ -1,30 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -#include <linux/module.h>
> -
> -#include "libgcc.h"
> -
> -long long __lshrdi3(long long u, word_type b)
> -{
> -	DWunion uu, w;
> -	word_type bm;
> -
> -	if (b == 0)
> -		return u;
> -
> -	uu.ll = u;
> -	bm = 32 - b;
> -
> -	if (bm <= 0) {
> -		w.s.high = 0;
> -		w.s.low = (unsigned int) uu.s.high >> -bm;
> -	} else {
> -		const unsigned int carries = (unsigned int) uu.s.high << bm;
> -
> -		w.s.high = (unsigned int) uu.s.high >> b;
> -		w.s.low = ((unsigned int) uu.s.low >> b) | carries;
> -	}
> -
> -	return w.ll;
> -}
> -
> -EXPORT_SYMBOL(__lshrdi3);

Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>

-- 
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