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

From Christopher Covington <cov@codeaurora.org>
Newsgroups linux.kernel
Subject Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions
Date 2015-11-23 15:20 +0100
Message-ID <qy08i-2R4-15@gated-at.bofh.it> (permalink)
References <qx5a1-6MK-1@gated-at.bofh.it> <qxIXM-8iK-13@gated-at.bofh.it> <qxPcR-3ZO-1@gated-at.bofh.it> <qxUvV-7DO-17@gated-at.bofh.it>
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On 11/23/2015 03:15 AM, Arnd Bergmann wrote:
> On Sunday 22 November 2015 21:36:45 Nicolas Pitre wrote:
>> On Sun, 22 Nov 2015, Arnd Bergmann wrote:
>>
>>> I've also found some /proc/cpuinfo output to cross-reference SoCs
>>> to their core names.
>>>
>>>               variant part    revision        name            features
>>> dove:         0       0x581   5               PJ4             idivt
>>
>> I just managed to boot my dusty Dove DB and ran a quick test programon 
>> it. Its cpuinfo corresponds to the above.
>>
>> $ cat m.c
>> #include <stdio.h>
>> int mydiv(int, int);
>> int main()
>> {
>>         printf("div test\n");
>>         printf("%d\n", mydiv(12345678, 37));
>>         return 0;
>> }
>> $ cat d.c
>> int mydiv(int x, int y)
>> {
>>         return x/y;
>> }
>> $ gcc -o test m.c d.c
>> $ ./test
>> div test
>> 333666
>> $ gcc -o test m.c d.c -march=armv7ve -mthumb
>> $ ./test
>> div test
>> 333666
>> $ gcc -o test m.c d.c -march=armv7ve -marm
>> $ ./test
>> div test
>> Illegal instruction (core dumped)
>> $
> 
> Ok, thanks a lot! So the reporting in /proc/cpuinfo clearly matches
> the actual features, and we can just treat this as no LPAE / no IDIV
> for kernel compilation, as nobody ever seems to use THUMB2_KERNEL
> in practice.
> 
> PJ4-MP is like Cortex-A15/A7/A12/A17 and supports both IDIV and LPAE,
> which leaves the question whether Scorpion or Krait do the same as
> well, or whether they are outliers and need a special configuration.

LPAE is only supported in the Krait 450.

http://www.anandtech.com/show/7537/qualcomms-snapdragon-805-25ghz-128bit-memory-interface-d3d11class-graphics-more

I'm pretty sure idiv support came earlier, but I don't have the
specifics on hand.

Regards,
Christopher Covington

-- 
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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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