* [PATCH] ARM: ep93xx: don't use clang IAS for crunch
@ 2021-02-26 16:43 Arnd Bergmann
2021-02-26 18:00 ` Arnd Bergmann
2021-02-26 19:23 ` Alexander Sverdlin
0 siblings, 2 replies; 6+ messages in thread
From: Arnd Bergmann @ 2021-02-26 16:43 UTC (permalink / raw)
To: Hartley Sweeten, Alexander Sverdlin
Cc: Arnd Bergmann, Nick Desaulniers, Russell King, linux-kernel,
Nathan Chancellor, clang-built-linux, soc, linux-arm-kernel
From: Arnd Bergmann <arnd@arndb.de>
Randconfig builds with ep93xx fail with the clang integrated
assembler that does not understand the maverick crunch extensions:
arch/arm/mach-ep93xx/crunch-bits.S:94:2: error: invalid instruction
cfstr64 mvdx0, [r1, #0] @ save 64b registers
It is unclear if anyone is still using support for crunch: gcc-4.8 dropped
it in 2012 when it was already too broken to be used reliabled. glibc
support existed as an external patch but was never merged upstream.
We could consider removing the last bits of the kernel support as well.
Turn off the integrated assembler for this file for now.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
arch/arm/mach-ep93xx/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/mach-ep93xx/Makefile b/arch/arm/mach-ep93xx/Makefile
index 86768495f61d..f686577ba059 100644
--- a/arch/arm/mach-ep93xx/Makefile
+++ b/arch/arm/mach-ep93xx/Makefile
@@ -7,7 +7,7 @@ obj-y := core.o clock.o timer-ep93xx.o
obj-$(CONFIG_EP93XX_DMA) += dma.o
obj-$(CONFIG_CRUNCH) += crunch.o crunch-bits.o
-AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312
+AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312 $(cc-option, -fno-integrated-as)
obj-$(CONFIG_MACH_ADSSPHERE) += adssphere.o
obj-$(CONFIG_MACH_EDB93XX) += edb93xx.o
--
2.29.2
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^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] ARM: ep93xx: don't use clang IAS for crunch
2021-02-26 16:43 [PATCH] ARM: ep93xx: don't use clang IAS for crunch Arnd Bergmann
@ 2021-02-26 18:00 ` Arnd Bergmann
2021-06-03 23:27 ` Nick Desaulniers
2021-02-26 19:23 ` Alexander Sverdlin
1 sibling, 1 reply; 6+ messages in thread
From: Arnd Bergmann @ 2021-02-26 18:00 UTC (permalink / raw)
To: Hartley Sweeten, Alexander Sverdlin
Cc: Arnd Bergmann, Nick Desaulniers, Russell King,
linux-kernel@vger.kernel.org, Nathan Chancellor,
clang-built-linux, SoC Team, Linux ARM
On Fri, Feb 26, 2021 at 5:44 PM Arnd Bergmann <arnd@kernel.org> wrote:
>
> obj-$(CONFIG_CRUNCH) += crunch.o crunch-bits.o
> -AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312
> +AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312 $(cc-option, -fno-integrated-as)
I reworked that patch just before sending it out, and ended up with two typos
in there, it should be
+AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312 $(call cc-option,
-no-integrated-as)
I'll wait for others to comment before I send the fixed version.
Arnd
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] ARM: ep93xx: don't use clang IAS for crunch
2021-02-26 18:00 ` Arnd Bergmann
@ 2021-06-03 23:27 ` Nick Desaulniers
0 siblings, 0 replies; 6+ messages in thread
From: Nick Desaulniers @ 2021-06-03 23:27 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Hartley Sweeten, Alexander Sverdlin, SoC Team, Arnd Bergmann,
Russell King, Nathan Chancellor, Linux ARM,
linux-kernel@vger.kernel.org, clang-built-linux
On Fri, Feb 26, 2021 at 10:01 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> On Fri, Feb 26, 2021 at 5:44 PM Arnd Bergmann <arnd@kernel.org> wrote:
> >
> > obj-$(CONFIG_CRUNCH) += crunch.o crunch-bits.o
> > -AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312
> > +AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312 $(cc-option, -fno-integrated-as)
>
> I reworked that patch just before sending it out, and ended up with two typos
> in there, it should be
>
> +AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312 $(call cc-option,
> -no-integrated-as)
>
> I'll wait for others to comment before I send the fixed version.
Probably good for that v2?
--
Thanks,
~Nick Desaulniers
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] ARM: ep93xx: don't use clang IAS for crunch
2021-02-26 16:43 [PATCH] ARM: ep93xx: don't use clang IAS for crunch Arnd Bergmann
2021-02-26 18:00 ` Arnd Bergmann
@ 2021-02-26 19:23 ` Alexander Sverdlin
2021-02-26 19:32 ` Hartley Sweeten
1 sibling, 1 reply; 6+ messages in thread
From: Alexander Sverdlin @ 2021-02-26 19:23 UTC (permalink / raw)
To: Arnd Bergmann, Hartley Sweeten
Cc: Arnd Bergmann, Nick Desaulniers, Russell King, linux-kernel,
Nathan Chancellor, clang-built-linux, soc, linux-arm-kernel
Hi!
On Fri, 2021-02-26 at 17:43 +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> Randconfig builds with ep93xx fail with the clang integrated
> assembler that does not understand the maverick crunch extensions:
>
> arch/arm/mach-ep93xx/crunch-bits.S:94:2: error: invalid instruction
> cfstr64 mvdx0, [r1, #0] @ save 64b registers
>
> It is unclear if anyone is still using support for crunch: gcc-4.8 dropped
> it in 2012 when it was already too broken to be used reliabled. glibc
> support existed as an external patch but was never merged upstream.
> We could consider removing the last bits of the kernel support as well.
This was my impression already in 2006, that Cirrus is not going to work
on Crunch support. From my PoV it's OK to remove the support in the
kernel completely.
> Turn off the integrated assembler for this file for now.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> arch/arm/mach-ep93xx/Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/mach-ep93xx/Makefile b/arch/arm/mach-ep93xx/Makefile
> index 86768495f61d..f686577ba059 100644
> --- a/arch/arm/mach-ep93xx/Makefile
> +++ b/arch/arm/mach-ep93xx/Makefile
> @@ -7,7 +7,7 @@ obj-y := core.o clock.o timer-ep93xx.o
> obj-$(CONFIG_EP93XX_DMA) += dma.o
>
> obj-$(CONFIG_CRUNCH) += crunch.o crunch-bits.o
> -AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312
> +AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312 $(cc-option, -fno-integrated-as)
>
> obj-$(CONFIG_MACH_ADSSPHERE) += adssphere.o
> obj-$(CONFIG_MACH_EDB93XX) += edb93xx.o
--
Alexander Sverdlin.
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: [PATCH] ARM: ep93xx: don't use clang IAS for crunch
2021-02-26 19:23 ` Alexander Sverdlin
@ 2021-02-26 19:32 ` Hartley Sweeten
2021-02-26 20:47 ` Nick Desaulniers
0 siblings, 1 reply; 6+ messages in thread
From: Hartley Sweeten @ 2021-02-26 19:32 UTC (permalink / raw)
To: Alexander Sverdlin, Arnd Bergmann
Cc: Arnd Bergmann, Nick Desaulniers, Russell King,
linux-kernel@vger.kernel.org, Nathan Chancellor,
clang-built-linux@googlegroups.com, soc@kernel.org,
linux-arm-kernel@lists.infradead.org
On Friday, February 26, 2021 12:23 PM, Alexander Sverdlin wrote:
> On Fri, 2021-02-26 at 17:43 +0100, Arnd Bergmann wrote:
>> Randconfig builds with ep93xx fail with the clang integrated assembler
>> that does not understand the maverick crunch extensions:
>>
>> arch/arm/mach-ep93xx/crunch-bits.S:94:2: error: invalid instruction
>> cfstr64 mvdx0, [r1, #0] @ save 64b registers
>>
>> It is unclear if anyone is still using support for crunch: gcc-4.8
>> dropped it in 2012 when it was already too broken to be used
>> reliabled. glibc support existed as an external patch but was never merged upstream.
>> We could consider removing the last bits of the kernel support as well.
>
> This was my impression already in 2006, that Cirrus is not going to work on Crunch support. From my PoV it's OK to remove the support in the kernel completely.
Martin Guy did a lot of work trying to get the maverick crunch working but I was never able to successfully use it for anything. It "kind" of works but depending on the EP93xx silicon revision there are still a number of hardware bugs that either give imprecise or garbage results.
I have no problem with removing the kernel support for the maverick crunch.
Hartley
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] ARM: ep93xx: don't use clang IAS for crunch
2021-02-26 19:32 ` Hartley Sweeten
@ 2021-02-26 20:47 ` Nick Desaulniers
0 siblings, 0 replies; 6+ messages in thread
From: Nick Desaulniers @ 2021-02-26 20:47 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Arnd Bergmann, Russell King, linux-kernel@vger.kernel.org,
Nathan Chancellor, clang-built-linux@googlegroups.com,
soc@kernel.org, Hartley Sweeten, Alexander Sverdlin,
linux-arm-kernel@lists.infradead.org
On Fri, Feb 26, 2021 at 11:32 AM Hartley Sweeten
<HartleyS@visionengravers.com> wrote:
>
> On Friday, February 26, 2021 12:23 PM, Alexander Sverdlin wrote:
> > On Fri, 2021-02-26 at 17:43 +0100, Arnd Bergmann wrote:
> >> Randconfig builds with ep93xx fail with the clang integrated assembler
> >> that does not understand the maverick crunch extensions:
> >>
> >> arch/arm/mach-ep93xx/crunch-bits.S:94:2: error: invalid instruction
> >> cfstr64 mvdx0, [r1, #0] @ save 64b registers
> >>
> >> It is unclear if anyone is still using support for crunch: gcc-4.8
> >> dropped it in 2012 when it was already too broken to be used
> >> reliabled. glibc support existed as an external patch but was never merged upstream.
> >> We could consider removing the last bits of the kernel support as well.
> >
> > This was my impression already in 2006, that Cirrus is not going to work on Crunch support. From my PoV it's OK to remove the support in the kernel completely.
>
> Martin Guy did a lot of work trying to get the maverick crunch working but I was never able to successfully use it for anything. It "kind" of works but depending on the EP93xx silicon revision there are still a number of hardware bugs that either give imprecise or garbage results.
>
> I have no problem with removing the kernel support for the maverick crunch.
Either way, please consider adding a
Link: https://github.com/ClangBuiltLinux/linux/issues/1272
tag. That will help us notice when/where this lands in order to close
out the issue. Thanks for the patch.
(if we go with this rather than removing the driver:)
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
(I'm also fine with removing the driver; my ack is not conditional on
one way or the other).
--
Thanks,
~Nick Desaulniers
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^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-02-26 16:43 [PATCH] ARM: ep93xx: don't use clang IAS for crunch Arnd Bergmann
2021-02-26 18:00 ` Arnd Bergmann
2021-06-03 23:27 ` Nick Desaulniers
2021-02-26 19:23 ` Alexander Sverdlin
2021-02-26 19:32 ` Hartley Sweeten
2021-02-26 20:47 ` Nick Desaulniers
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