Re: [PATCH] MIPS: use generic GCC library routines from lib/

[James Hogan]

On 18 January 2018 20:05:05 GMT+00:00, Antony Pavlov <antonynpavlov@xxxxxxxxx> wrote:
>On Wed, 17 Jan 2018 17:34:59 -0800 (PST)
>Palmer Dabbelt <palmer@xxxxxxxxxx> wrote:
>
>> Ah, thanks for reminding me -- I'd originally posted a patch set that
>converted 
>> every other port to use these routines, but I ended up dropping all
>those.  
>> Here's my original MIPS attempt
>> 
>>     https://marc.info/?l=linux-mips&m=149677651707103&w=2
>
>Now I see that I have dubbed your June 2017 patch. Sorry!
>
>Alas in June 2017 there was no chance to push your patch to linux-mips
>repo.
>Linus merged your patches in November 2017. Ralf merged your RISC-V
>changes
>into linux-mips repo AFAIR just several days ago.
>
>> Given that, I think you can also drop arch/mips/lib/libgcc.h -- if
>it's used 
>> from anywhere else, it should be possible to use
>include/linux/libgcc.h 
>> instead.
>
>I agree with you.

actually theres a patch in mips-next which implements __multi3 for mips64r6, which uses that file, and in fact extends it for 128bit types.

cheers
James

>
>> 
>> Assuming it still seems sane do to that I can go give the rest of the
>patch set 
>> another shot.  I'm a bit new to this, but I think I should do
>something like
>> 
>> Reviewed-by: Palmer Dabbelt <palmer@xxxxxxxxxx>
>
>I suppose that it's better to resurrect you patch and abandon my patch.
>
>Your original patch series
>(https://www.linux-mips.org/archives/linux-mips/2017-06/msg00148.html)
>has a disadvantage: it tries to change several architectures at once.
>
>I propose to create new short separate patch series for MIPS
>architecture.
>
>This patch series should contain two patches:
>
>   [PATCH 1/2] Add notrace to lib/ucmpdi2.c
>   [PATCH 2/2] MIPS: Use generic libgcc intrinsics
>
>
>> Thanks!
>> 
>> On Tue, 16 Jan 2018 22:51:21 PST (-0800), antonynpavlov@xxxxxxxxx
>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.
>> >
>> > This commit removes several generic GCC library
>> > routines from arch/mips/lib/ in favour of similar
>> > routines from lib/.
>> >
>> > Signed-off-by: Antony Pavlov <antonynpavlov@xxxxxxxxx>
>> > Cc: Palmer Dabbelt <palmer@xxxxxxxxxx>
>> > Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
>> > Cc: linux-mips@xxxxxxxxxxxxxx
>> > Cc: linux-kernel@xxxxxxxxxxxxxxx
>> > ---
>> >  arch/mips/Kconfig       |  5 +++++
>> >  arch/mips/lib/Makefile  |  2 +-
>> >  arch/mips/lib/ashldi3.c | 30 ------------------------------
>> >  arch/mips/lib/ashrdi3.c | 32 --------------------------------
>> >  arch/mips/lib/cmpdi2.c  | 28 ----------------------------
>> >  arch/mips/lib/lshrdi3.c | 30 ------------------------------
>> >  arch/mips/lib/ucmpdi2.c | 22 ----------------------
>> >  7 files changed, 6 insertions(+), 143 deletions(-)
>> >  delete mode 100644 arch/mips/lib/ashldi3.c
>> >  delete mode 100644 arch/mips/lib/ashrdi3.c
>> >  delete mode 100644 arch/mips/lib/cmpdi2.c
>> >  delete mode 100644 arch/mips/lib/lshrdi3.c
>> >  delete mode 100644 arch/mips/lib/ucmpdi2.c
>> >
>> > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
>> > index 350a990fc719..9cd49ee848c6 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..195ab4cb0840 100644
>> > --- a/arch/mips/lib/Makefile
>> > +++ b/arch/mips/lib/Makefile
>> > @@ -16,4 +16,4 @@ obj-$(CONFIG_CPU_R3000)		+= r3k_dump_tlb.o
>> >  obj-$(CONFIG_CPU_TX39XX)	+= r3k_dump_tlb.o
>> >
>> >  # libgcc-style stuff needed in the kernel
>> > -obj-y += ashldi3.o ashrdi3.o bswapsi.o bswapdi.o cmpdi2.o
>lshrdi3.o ucmpdi2.o
>> > +obj-y += bswapsi.o bswapdi.o
>> > diff --git a/arch/mips/lib/ashldi3.c b/arch/mips/lib/ashldi3.c
>> > deleted file mode 100644
>> > index 24cd6903e797..000000000000
>> > --- a/arch/mips/lib/ashldi3.c
>> > +++ /dev/null
>> > @@ -1,30 +0,0 @@
>> > -// SPDX-License-Identifier: GPL-2.0
>> > -#include <linux/export.h>
>> > -
>> > -#include "libgcc.h"
>> > -
>> > -long long notrace __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/mips/lib/ashrdi3.c b/arch/mips/lib/ashrdi3.c
>> > deleted file mode 100644
>> > index 23f5295af51e..000000000000
>> > --- a/arch/mips/lib/ashrdi3.c
>> > +++ /dev/null
>> > @@ -1,32 +0,0 @@
>> > -// SPDX-License-Identifier: GPL-2.0
>> > -#include <linux/export.h>
>> > -
>> > -#include "libgcc.h"
>> > -
>> > -long long notrace __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/mips/lib/cmpdi2.c b/arch/mips/lib/cmpdi2.c
>> > deleted file mode 100644
>> > index 93cfc785927d..000000000000
>> > --- a/arch/mips/lib/cmpdi2.c
>> > +++ /dev/null
>> > @@ -1,28 +0,0 @@
>> > -// SPDX-License-Identifier: GPL-2.0
>> > -#include <linux/export.h>
>> > -
>> > -#include "libgcc.h"
>> > -
>> > -word_type notrace __cmpdi2(long long a, long long b)
>> > -{
>> > -	const DWunion au = {
>> > -		.ll = a
>> > -	};
>> > -	const DWunion bu = {
>> > -		.ll = b
>> > -	};
>> > -
>> > -	if (au.s.high < bu.s.high)
>> > -		return 0;
>> > -	else if (au.s.high > bu.s.high)
>> > -		return 2;
>> > -
>> > -	if ((unsigned int) au.s.low < (unsigned int) bu.s.low)
>> > -		return 0;
>> > -	else if ((unsigned int) au.s.low > (unsigned int) bu.s.low)
>> > -		return 2;
>> > -
>> > -	return 1;
>> > -}
>> > -
>> > -EXPORT_SYMBOL(__cmpdi2);
>> > diff --git a/arch/mips/lib/lshrdi3.c b/arch/mips/lib/lshrdi3.c
>> > deleted file mode 100644
>> > index 914b971aca3b..000000000000
>> > --- a/arch/mips/lib/lshrdi3.c
>> > +++ /dev/null
>> > @@ -1,30 +0,0 @@
>> > -// SPDX-License-Identifier: GPL-2.0
>> > -#include <linux/export.h>
>> > -
>> > -#include "libgcc.h"
>> > -
>> > -long long notrace __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);
>> > diff --git a/arch/mips/lib/ucmpdi2.c b/arch/mips/lib/ucmpdi2.c
>> > deleted file mode 100644
>> > index c31c78ca4175..000000000000
>> > --- a/arch/mips/lib/ucmpdi2.c
>> > +++ /dev/null
>> > @@ -1,22 +0,0 @@
>> > -// SPDX-License-Identifier: GPL-2.0
>> > -#include <linux/export.h>
>> > -
>> > -#include "libgcc.h"
>> > -
>> > -word_type notrace __ucmpdi2(unsigned long long a, unsigned long
>long b)
>> > -{
>> > -	const DWunion au = {.ll = a};
>> > -	const DWunion bu = {.ll = b};
>> > -
>> > -	if ((unsigned int) au.s.high < (unsigned int) bu.s.high)
>> > -		return 0;
>> > -	else if ((unsigned int) au.s.high > (unsigned int) bu.s.high)
>> > -		return 2;
>> > -	if ((unsigned int) au.s.low < (unsigned int) bu.s.low)
>> > -		return 0;
>> > -	else if ((unsigned int) au.s.low > (unsigned int) bu.s.low)
>> > -		return 2;
>> > -	return 1;
>> > -}
>> > -
>> > -EXPORT_SYMBOL(__ucmpdi2);


-- 
Cheers
James Hogan