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Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions

From Arnd Bergmann <arnd@arndb.de>
Newsgroups linux.kernel
Subject Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions
Date 2015-11-22 21:00 +0100
Message-ID <qxIXM-8iK-13@gated-at.bofh.it> (permalink)
References <qx5a1-6MK-1@gated-at.bofh.it> <qxIuK-88H-7@gated-at.bofh.it> <qxIO5-8fj-5@gated-at.bofh.it>
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On Sunday 22 November 2015 19:47:05 Russell King - ARM Linux wrote:
> On Sun, Nov 22, 2015 at 08:25:27PM +0100, Arnd Bergmann wrote:
> > The question is really about Marvell Dove, MMP and Armada 370,
> > which are all based on PJ4 or PJ4B (CPU part : 0x581), so ARMv7-A
> > and report idivt support but idiva.
> 
> Well, it's pretty hard to test when binutils blocks your ability to
> write assembly using the instructions.
> 
> root@cubox:~# gcc -O2 -o idiv idiv.c -Wa,-mcpu='cortex-a9+idiv' -marm
> /tmp/cc8WPQiB.s: Assembler messages:
> /tmp/cc8WPQiB.s:32: Error: selected processor does not support ARM mode `udiv ip,r5,r4'
> root@cubox:~# gcc -O2 -o idiv idiv.c -Wa,-mcpu='cortex-a9+idiv' -mthumb
> /tmp/ccRzgAlM.s: Assembler messages:
> /tmp/ccRzgAlM.s:36: Error: selected processor does not support Thumb mode `udiv r6,r5,r4'
> root@cubox:~# gcc -O2 -o idiv idiv.c -Wa,-mcpu='marvell-pj4+idiv' -mthumb
> /tmp/cc1JYyFD.s: Assembler messages:
> /tmp/cc1JYyFD.s:36: Error: selected processor does not support Thumb mode `udiv r6,r5,r4'
> root@cubox:~# gcc -O2 -o idiv idiv.c -Wa,-mcpu='marvell-pj4+idiv' -marm
> /tmp/ccEQbQpp.s: Assembler messages:
> /tmp/ccEQbQpp.s:32: Error: selected processor does not support ARM mode `udiv ip,r5,r4'
> 
> That's binutils 2.24 and gcc 4.8.4 as found on Ubuntu 14.04.  I'm
> sorry, but I don't have spare time to work out what the opcodes
> would be.
> 

does it work with -mcpu=cortex-a15?  I've tried crosstool as versions
2.23.52.20130913, 2.24.0.20141017 and 2.25.51.20150518, and they
all seem to behave as expected, failing with -mcpu=cortex-a9 and
marvell-pj4 but succeeding with -mcpu=cortex-a15 or marvell-pj4+idiv.

I've also found some /proc/cpuinfo output to cross-reference SoCs
to their core names.

		variant	part	revision	name		features
mmp2:		0	0x581	5		PJ4		idivt
dove:		0	0x581	5		PJ4		idivt
Armada 370	1	0x581	1		PJ4B		idivt
mmp3:		2	0x584	2		PJ4-MP		idiva idivt lpae
Armada XP	2	0x584	2		PJ4-MP		idiva idivt lpae
Berlin		2	0x584	2		PJ4-MP		idiva idivt lpae

	Arnd
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[RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Stephen Boyd <sboyd@codeaurora.org> - 2015-11-21 02:30 +0100
  [RFC/PATCH 2/3] recordmcount: Record locations of __aeabi_{u}idiv() calls on ARM Stephen Boyd <sboyd@codeaurora.org> - 2015-11-21 02:30 +0100
    Re: [RFC/PATCH 2/3] recordmcount: Record locations of  __aeabi_{u}idiv() calls on ARM Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-21 11:20 +0100
      Re: [RFC/PATCH 2/3] recordmcount: Record locations of  __aeabi_{u}idiv() calls on ARM Steven Rostedt <rostedt@goodmis.org> - 2015-11-23 22:00 +0100
      Re: [RFC/PATCH 2/3] recordmcount: Record locations of  __aeabi_{u}idiv() calls on ARM Stephen Boyd <sboyd@codeaurora.org> - 2015-11-23 22:00 +0100
        Re: [RFC/PATCH 2/3] recordmcount: Record locations of  __aeabi_{u}idiv() calls on ARM Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-23 22:10 +0100
          Re: [RFC/PATCH 2/3] recordmcount: Record locations of  __aeabi_{u}idiv() calls on ARM Stephen Boyd <sboyd@codeaurora.org> - 2015-11-23 22:20 +0100
            Re: [RFC/PATCH 2/3] recordmcount: Record locations of  __aeabi_{u}idiv() calls on ARM Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-23 22:40 +0100
              Re: [RFC/PATCH 2/3] recordmcount: Record locations of  __aeabi_{u}idiv() calls on ARM Stephen Boyd <sboyd@codeaurora.org> - 2015-11-24 02:10 +0100
  [RFC/PATCH 1/3] scripts: Allow recordmcount to be used without tracing enabled Stephen Boyd <sboyd@codeaurora.org> - 2015-11-21 02:30 +0100
  [RFC/PATCH 3/3] ARM: Replace calls to __aeabi_{u}idiv with udiv/sdiv instructions Stephen Boyd <sboyd@codeaurora.org> - 2015-11-21 02:30 +0100
    Re: [RFC/PATCH 3/3] ARM: Replace calls to __aeabi_{u}idiv with udiv/sdiv instructions Måns Rullgård <mans@mansr.com> - 2015-11-21 13:00 +0100
      Re: [RFC/PATCH 3/3] ARM: Replace calls to __aeabi_{u}idiv with  udiv/sdiv instructions Stephen Boyd <sboyd@codeaurora.org> - 2015-11-23 22:00 +0100
        Re: [RFC/PATCH 3/3] ARM: Replace calls to __aeabi_{u}idiv with udiv/sdiv instructions Måns Rullgård <mans@mansr.com> - 2015-11-23 22:00 +0100
          Re: [RFC/PATCH 3/3] ARM: Replace calls to __aeabi_{u}idiv with  udiv/sdiv instructions Stephen Boyd <sboyd@codeaurora.org> - 2015-11-23 22:20 +0100
  Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Måns Rullgård <mans@mansr.com> - 2015-11-21 21:50 +0100
    Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-21 22:10 +0100
      Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Måns Rullgård <mans@mansr.com> - 2015-11-21 23:20 +0100
        Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-22 00:20 +0100
          Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-22 00:30 +0100
            Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Peter Maydell <peter.maydell@linaro.org> - 2015-11-22 14:40 +0100
              Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-22 20:30 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Måns Rullgård <mans@mansr.com> - 2015-11-22 20:40 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-22 20:50 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-22 21:00 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-22 21:10 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-22 21:40 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Måns Rullgård <mans@mansr.com> - 2015-11-22 21:50 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-22 22:20 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Nicolas Pitre <nicolas.pitre@linaro.org> - 2015-11-23 03:40 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-23 09:20 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv  library functions Christopher Covington <cov@codeaurora.org> - 2015-11-23 15:20 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-23 16:40 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Stephen Boyd <sboyd@codeaurora.org> - 2015-11-23 21:40 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-23 22:30 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Stephen Boyd <sboyd@codeaurora.org> - 2015-11-23 22:40 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-23 23:00 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Stephen Boyd <sboyd@codeaurora.org> - 2015-11-24 00:20 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-24 11:20 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Måns Rullgård <mans@mansr.com> - 2015-11-24 13:20 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-24 14:50 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Stephen Boyd <sboyd@codeaurora.org> - 2015-11-25 03:00 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-25 08:30 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Stephen Boyd <sboyd@codeaurora.org> - 2015-11-24 01:20 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Stephen Boyd <sboyd@codeaurora.org> - 2015-11-24 10:00 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-24 11:40 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-24 11:50 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Måns Rullgård <mans@mansr.com> - 2015-11-24 13:20 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Måns Rullgård <mans@mansr.com> - 2015-11-24 13:30 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Måns Rullgård <mans@mansr.com> - 2015-11-24 15:10 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-24 15:10 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-24 13:30 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-24 11:50 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Stephen Boyd <sboyd@codeaurora.org> - 2015-11-24 21:10 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-24 21:40 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-24 22:20 +0100
                Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library  functions Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-24 11:40 +0100
  Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions Arnd Bergmann <arnd@arndb.de> - 2015-11-21 21:50 +0100

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