Bug#834844: release-notes: document that mips* arches now require a R2 CPU

[Aurelien Jarno]

On 2016-08-25 14:42, James Cowgill wrote:
> Hi,
> 
> On 25/08/16 14:17, Ed Swierk wrote:
> > This mips32r2 requirement also appears to exclude Cavium Octeon:
> > 
> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h#n50
> > 
> > If that's accurate, it would be worth mentioning in the release notes as 
> > well.
> 
> *sigh* Cavium Octeon machines do support R2 (mips32r2 is a subset of
> mips64r2) but for some reason unknown to me, don't actually expose this.
> I've adjusted the check to look for mips64r2 as well and attached a new
> patch.

Thanks for the patch, it looks fine to me.

Cheers,
Aurelien

-- 
Aurelien Jarno  GPG: 4096R/1DDD8C9B
aurel...@aurel32.net http://www.aurel32.net


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Bug#834844: release-notes: document that mips* arches now require a R2 CPU

[James Cowgill]

On 26/08/16 00:19, Aaro Koskinen wrote:
> Hi,
> 
> On Thu, Aug 25, 2016 at 12:10:09PM +0100, James Cowgill wrote:
>> +  The 32-bit MIPS support (both big and little endian) now requires a
>> +  processor supporting MIPS32 Release 2 of the MIPS instruction set.
>> +  Notably the Loongson-2E/2F and systems based on them (including the
>> +  Yeeloong laptop) are no longer supported.
> 
> So, what HW is there available today to run 32-bit MIPS Debian on?

mips32r2/mips64r2 was released in 2002. I expect the vast majority of
MIPS processors you can buy today support R2. Things that work with R2
include almost all recent routers, loongson 3 processors, cavium
processors, the ci20 ...

James



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Bug#834844: release-notes: document that mips* arches now require a R2 CPU

[Aaro Koskinen]

Hi,

On Thu, Aug 25, 2016 at 12:10:09PM +0100, James Cowgill wrote:
> +  The 32-bit MIPS support (both big and little endian) now requires a
> +  processor supporting MIPS32 Release 2 of the MIPS instruction set.
> +  Notably the Loongson-2E/2F and systems based on them (including the
> +  Yeeloong laptop) are no longer supported.

So, what HW is there available today to run 32-bit MIPS Debian on?

A.

Bug#834844: release-notes: document that mips* arches now require a R2 CPU

[David Daney]

On 08/25/2016 06:42 AM, James Cowgill wrote:

Hi,

On 25/08/16 14:17, Ed Swierk wrote:

This mips32r2 requirement also appears to exclude Cavium Octeon:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h#n50

If that's accurate, it would be worth mentioning in the release notes as well.


*sigh* Cavium Octeon machines do support R2 (mips32r2 is a subset of
mips64r2) but for some reason unknown to me, don't actually expose this.
I've adjusted the check to look for mips64r2 as well and attached a new
patch.



Yes, *all* OCTEON CPUs have always been r2 (or better).

At the time the code was written, there were good reasons not to set:

 #define cpu_has_mips32r2   0

This was discussed on the lmo mailing lists, but I forget what they were 
at this point.


David Daney


Thanks,
James


On Thu, Aug 25, 2016 at 4:10 AM, James Cowgill  wrote:

Control: tags -1 patch

On 19/08/16 22:42, Aurelien Jarno wrote:

This is something to be expected as the mips and mipsel port now
defaults to using R2 instructions set. This means the Loongson 2
CPUs are not supported anymore (this includes the Yeeloong machine).

I have asked many times to document this changes in the release notes,
but this hasn't been done yet. I am therefore reassigning the bug there,
Cc:ing debian-mips so that somone can take care of that.


How about the attached patch? It's loosely based on the i686 notes just
above.

I also changed the "human readable" mips architecture names since all
the other arches seem to have them.

James

Bug#834844: release-notes: document that mips* arches now require a R2 CPU

[Ed Swierk]

On Thu, Aug 25, 2016 at 6:42 AM, James Cowgill  wrote:
> *sigh* Cavium Octeon machines do support R2 (mips32r2 is a subset of
> mips64r2) but for some reason unknown to me, don't actually expose this.
> I've adjusted the check to look for mips64r2 as well and attached a new
> patch.

Looks good. Thanks.

--Ed

Bug#834844: release-notes: document that mips* arches now require a R2 CPU

[James Cowgill]

Hi,

On 25/08/16 14:17, Ed Swierk wrote:
> This mips32r2 requirement also appears to exclude Cavium Octeon:
> 
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h#n50
> 
> If that's accurate, it would be worth mentioning in the release notes as well.

*sigh* Cavium Octeon machines do support R2 (mips32r2 is a subset of
mips64r2) but for some reason unknown to me, don't actually expose this.
I've adjusted the check to look for mips64r2 as well and attached a new
patch.

Thanks,
James

> On Thu, Aug 25, 2016 at 4:10 AM, James Cowgill  wrote:
>> Control: tags -1 patch
>>
>> On 19/08/16 22:42, Aurelien Jarno wrote:
>>> This is something to be expected as the mips and mipsel port now
>>> defaults to using R2 instructions set. This means the Loongson 2
>>> CPUs are not supported anymore (this includes the Yeeloong machine).
>>>
>>> I have asked many times to document this changes in the release notes,
>>> but this hasn't been done yet. I am therefore reassigning the bug there,
>>> Cc:ing debian-mips so that somone can take care of that.
>>
>> How about the attached patch? It's loosely based on the i686 notes just
>> above.
>>
>> I also changed the "human readable" mips architecture names since all
>> the other arches seem to have them.
>>
>> James

Index: en/issues.dbk
===
--- en/issues.dbk	(revision 11283)
+++ en/issues.dbk	(working copy)
@@ -118,6 +118,31 @@
   to i686 for the Debian i386 architecture.
 
   
+  
+
+32-bit MIPS now requires an R2 processor
+
+  The 32-bit MIPS support (both big and little endian) now requires a
+  processor supporting MIPS32 Release 2 of the MIPS instruction set.
+  Notably the Loongson-2E/2F and systems based on them (including the
+  Yeeloong laptop) are no longer supported.
+
+
+  The following shell script can be used to indicate if your machine
+  supports R2 (assuming only one type of processor is present). Note that
+  Loongson-3 processors are supported even though they only claim to
+  support MIPS32 Release 1.
+
+
+if grep -E -q '^isa.*\bmips(32|64)r2\b' /proc/cpuinfo; then
+	echo "OK (R2 supported)"
+elif grep -q '^cpu model.*\bICT Loongson-3\b' /proc/cpuinfo; then
+	echo "OK (Loongson 3)"
+else
+	echo "NOT OK: R2 not supported"
+fi
+
+  
 
 
 
Index: release-notes.ent
===
--- release-notes.ent	(revision 11283)
+++ release-notes.ent	(working copy)
@@ -87,8 +87,8 @@
 		  -->ARM EABIARMv7 (EABI hard-float ABI)32-bit PCMipsMipsel32-bit MIPS (big endian)32-bit MIPS (little endian)PowerPC64-bit little-endian 

Bug#834844: release-notes: document that mips* arches now require a R2 CPU

[Ed Swierk]

This mips32r2 requirement also appears to exclude Cavium Octeon:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h#n50

If that's accurate, it would be worth mentioning in the release notes as well.


On Thu, Aug 25, 2016 at 4:10 AM, James Cowgill  wrote:
> Control: tags -1 patch
>
> On 19/08/16 22:42, Aurelien Jarno wrote:
>> This is something to be expected as the mips and mipsel port now
>> defaults to using R2 instructions set. This means the Loongson 2
>> CPUs are not supported anymore (this includes the Yeeloong machine).
>>
>> I have asked many times to document this changes in the release notes,
>> but this hasn't been done yet. I am therefore reassigning the bug there,
>> Cc:ing debian-mips so that somone can take care of that.
>
> How about the attached patch? It's loosely based on the i686 notes just
> above.
>
> I also changed the "human readable" mips architecture names since all
> the other arches seem to have them.
>
> James

Bug#834844: release-notes: document that mips* arches now require a R2 CPU

[James Cowgill]

Control: tags -1 patch

On 19/08/16 22:42, Aurelien Jarno wrote:
> This is something to be expected as the mips and mipsel port now
> defaults to using R2 instructions set. This means the Loongson 2
> CPUs are not supported anymore (this includes the Yeeloong machine).
> 
> I have asked many times to document this changes in the release notes,
> but this hasn't been done yet. I am therefore reassigning the bug there,
> Cc:ing debian-mips so that somone can take care of that.

How about the attached patch? It's loosely based on the i686 notes just
above.

I also changed the "human readable" mips architecture names since all
the other arches seem to have them.

James
Index: en/issues.dbk
===
--- en/issues.dbk	(revision 11283)
+++ en/issues.dbk	(working copy)
@@ -118,6 +118,31 @@
   to i686 for the Debian i386 architecture.
 
   
+  
+
+32-bit MIPS now requires an R2 processor
+
+  The 32-bit MIPS support (both big and little endian) now requires a
+  processor supporting MIPS32 Release 2 of the MIPS instruction set.
+  Notably the Loongson-2E/2F and systems based on them (including the
+  Yeeloong laptop) are no longer supported.
+
+
+  The following shell script can be used to indicate if your machine
+  supports R2 (assuming only one type of processor is present). Note that
+  Loongson-3 processors are supported even though they only claim to
+  support MIPS32 Release 1.
+
+
+if grep -q '^isa.*\bmips32r2\b' /proc/cpuinfo; then
+	echo "OK (R2 supported)"
+elif grep -q '^cpu model.*\bICT Loongson-3\b' /proc/cpuinfo; then
+	echo "OK (Loongson 3)"
+else
+	echo "NOT OK: R2 not supported"
+fi
+
+  
 
 
 
Index: release-notes.ent
===
--- release-notes.ent	(revision 11283)
+++ release-notes.ent	(working copy)
@@ -87,8 +87,8 @@
 		  -->ARM EABIARMv7 (EABI hard-float ABI)32-bit PCMipsMipsel32-bit MIPS (big endian)32-bit MIPS (little endian)PowerPC64-bit little-endian