[PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Robert Millan]

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Please consider this patch, it enables AT_PLATFORM for Loongson 2F CPU.



[-- Attachment #2: loongson-2f.diff --]
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Enable AT_PLATFORM for Loongson 2F CPU.

Signed-off-by: Robert Millan <rmh@gnu.org>

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 71620e1..504f3b1 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -614,6 +614,8 @@ static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
 	case PRID_IMP_LOONGSON2:
 		c->cputype = CPU_LOONGSON2;
 		__cpu_name[cpu] = "ICT Loongson-2";
+		if (cpu == 0)
+			__elf_platform = "loongson-2f";
 		c->isa_level = MIPS_CPU_ISA_III;
 		c->options = R4K_OPTS |
 			     MIPS_CPU_FPU | MIPS_CPU_LLSC |

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[David Daney]

On 11/04/2010 05:18 AM, Robert Millan wrote:
>
> Please consider this patch, it enables AT_PLATFORM for Loongson 2F CPU.
>
>
[...]
> diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
> index 71620e1..504f3b1 100644
> --- a/arch/mips/kernel/cpu-probe.c
> +++ b/arch/mips/kernel/cpu-probe.c
> @@ -614,6 +614,8 @@ static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
>  	case PRID_IMP_LOONGSON2:
>  		c->cputype = CPU_LOONGSON2;
>  		__cpu_name[cpu] = "ICT Loongson-2";
> +		if (cpu == 0)
> +			__elf_platform = "loongson-2f";
>  		c->isa_level = MIPS_CPU_ISA_III;
>  		c->options = R4K_OPTS |
>  			     MIPS_CPU_FPU | MIPS_CPU_LLSC |

This doesn't look right to me.

You are claiming that all loongson2 are loongson-2f.  Is that really 
true?  Or are there other types of loongson2 that are not loongson-2f?

You need to be very careful here.  This is part of the userspace ABI, so 
if you get it wrong, you are stuck with it forever.

One question you didn't address is why userspace would care that it is 
running on exactly "loongson-2f" instead of just mips4.

The __elf_platform gets converted to a directory name by ld.so, so you 
may want to choose a value without '-' in it.

My suggestion would be to set "loongson2" for the generic CPU_LOONGSON2, 
and if there is a good reason for it, "loongson2f" for the 'f' variant.

David Daney

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Aurelien Jarno]

David Daney a écrit :
> On 11/04/2010 05:18 AM, Robert Millan wrote:
>> Please consider this patch, it enables AT_PLATFORM for Loongson 2F CPU.
>>
>>
> [...]
>> diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
>> index 71620e1..504f3b1 100644
>> --- a/arch/mips/kernel/cpu-probe.c
>> +++ b/arch/mips/kernel/cpu-probe.c
>> @@ -614,6 +614,8 @@ static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
>>  	case PRID_IMP_LOONGSON2:
>>  		c->cputype = CPU_LOONGSON2;
>>  		__cpu_name[cpu] = "ICT Loongson-2";
>> +		if (cpu == 0)
>> +			__elf_platform = "loongson-2f";
>>  		c->isa_level = MIPS_CPU_ISA_III;
>>  		c->options = R4K_OPTS |
>>  			     MIPS_CPU_FPU | MIPS_CPU_LLSC |
> 
> This doesn't look right to me.
> 
> You are claiming that all loongson2 are loongson-2f.  Is that really 
> true?  Or are there other types of loongson2 that are not loongson-2f?
> 
> You need to be very careful here.  This is part of the userspace ABI, so 
> if you get it wrong, you are stuck with it forever.
> 
> One question you didn't address is why userspace would care that it is 
> running on exactly "loongson-2f" instead of just mips4.
> 
> The __elf_platform gets converted to a directory name by ld.so, so you 
> may want to choose a value without '-' in it.
> 
> My suggestion would be to set "loongson2" for the generic CPU_LOONGSON2, 
> and if there is a good reason for it, "loongson2f" for the 'f' variant.
> 

You should definitely define here loongson-2e and loongson-2f
separately. They have the same instruction set, but different opcodes
for the loongson specific instructions, hence they are not compatible.


-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Robert Millan]

Hi!

David Daney a écrit :
> You are claiming that all loongson2 are loongson-2f.  Is that really
> true?  Or are there other types of loongson2 that are not loongson-2f?
>
> You need to be very careful here.  This is part of the userspace ABI, so
> if you get it wrong, you are stuck with it forever.

I'll figure out how to distinguish them and send a new patch.

> One question you didn't address is why userspace would care that it is
> running on exactly "loongson-2f" instead of just mips4.

I think Aurelien answered this.

> The __elf_platform gets converted to a directory name by ld.so, so you
> may want to choose a value without '-' in it.

Well I appreciate consistency with GCC flag names, so I'd rather keep
the dash, but then again it's not my decision to make.  In any case,
whoever commits this can adjust the name to his/her liking.

-- 
Robert Millan

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[David Daney]

On 11/04/2010 11:43 AM, Robert Millan wrote:
> Hi!
>
> David Daney a écrit :
>> You are claiming that all loongson2 are loongson-2f.  Is that really
>> true?  Or are there other types of loongson2 that are not loongson-2f?
>>
>> You need to be very careful here.  This is part of the userspace ABI, so
>> if you get it wrong, you are stuck with it forever.
>
> I'll figure out how to distinguish them and send a new patch.
>
>> One question you didn't address is why userspace would care that it is
>> running on exactly "loongson-2f" instead of just mips4.
>
> I think Aurelien answered this.
>
>> The __elf_platform gets converted to a directory name by ld.so, so you
>> may want to choose a value without '-' in it.
>
> Well I appreciate consistency with GCC flag names, so I'd rather keep
> the dash, but then again it's not my decision to make.  In any case,
> whoever commits this can adjust the name to his/her liking.

I don't like to put words into Ralf's mouth, but it is easier to work 
with patches that have been tested and are ready to go, rather than 
having to re-write everything.


Some of the strings in use are "i686", "x86_64", "octeon", "octeon2", 
"PARISC", "PARISC32", tilegx-m32", "v4l", "v3l", "v4b", and "v3b", these 
last for for ARM and they don't match the GCC -mcpu= values.

So I guess what ever you want.

David Daney

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Ralf Baechle]

On Thu, Nov 04, 2010 at 12:11:13PM -0700, David Daney wrote:

> >Well I appreciate consistency with GCC flag names, so I'd rather keep
> >the dash, but then again it's not my decision to make.  In any case,
> >whoever commits this can adjust the name to his/her liking.
> 
> I don't like to put words into Ralf's mouth, but it is easier to
> work with patches that have been tested and are ready to go, rather
> than having to re-write everything.

Indeed.  I modify lots of patches that I can't test on my hardware
collection so any change I have to do also increases of me adding bugs.
Heck, I do most of my builds on fairly modest dual core machines so I
can't even afford test builds which is how occasionally the most stupid
errors end up getting committed.

Which is why I'm increasingly asking people to do trivial changes to
patches, not because I'm lazy.

> Some of the strings in use are "i686", "x86_64", "octeon",
> "octeon2", "PARISC", "PARISC32", tilegx-m32", "v4l", "v3l", "v4b",
> and "v3b", these last for for ARM and they don't match the GCC
> -mcpu= values.
> 
> So I guess what ever you want.

It's probably reasonable if the names don't diverge too far from each
other.  Then again with the number of cpu type synonyms accepted by gcc
that may just be wishful thinking.

  Ralf

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Robert Millan]

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El 04/11/10 19:43:08, en/na Robert Millan va escriure:
> David Daney a écrit :
> > You are claiming that all loongson2 are loongson-2f.  Is that 
> > really true?  Or are there other types of loongson2 that are not
> > loongson-2f?
> 
> I'll figure out how to distinguish them and send a new patch.

I looked at details about CPU identification, and this
seems to be broken.

See the the notes about PRId in pages 72 and 66, respectively:
http://dev.lemote.com/files/resource/documents/Loongson/ls2f/Loongson2FUserGuide.pdf

In both 2E and 2F, the implementation field is the same (0x63).

Revision field is the same too, according to docs, and it can't
be used anyway (no garantee of consistency).

I'm sending a new patch that uses machtype instead. Yes, I know
it's a bit of a kludge, but it really seems to be the only way.

> Well I appreciate consistency with GCC flag names,

Actually, I missread GCC flag (it's dashless).  I'm using
"loongson2f" as David requested.


[-- Attachment #2: loongson2f.diff --]
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Enable AT_PLATFORM for Loongson 2F CPU.

Signed-off-by: Robert Millan <rmh@gnu.org>

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 71620e1..69905d2 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -5,6 +5,7 @@
  * Copyright (C) 1994 - 2006 Ralf Baechle
  * Copyright (C) 2003, 2004  Maciej W. Rozycki
  * Copyright (C) 2001, 2004  MIPS Inc.
+ * Copyright (C) 2010  Robert Millan
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -18,6 +19,7 @@
 #include <linux/stddef.h>
 #include <linux/module.h>
 
+#include <asm/bootinfo.h>
 #include <asm/bugs.h>
 #include <asm/cpu.h>
 #include <asm/fpu.h>
@@ -613,7 +615,30 @@ static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
 		break;
 	case PRID_IMP_LOONGSON2:
 		c->cputype = CPU_LOONGSON2;
-		__cpu_name[cpu] = "ICT Loongson-2";
+		/*
+		 * On Loongson 2, PRID doesn't specify sub-class reliably.
+		 * We use machtype info passed by bootloader, when available,
+		 * or otherwise fallback to generic "ICT Loongson-2".
+		 */
+		switch (mips_machtype) {
+		case MACH_LEMOTE_FL2E:
+			__cpu_name[cpu] = "ICT Loongson-2E";
+			if (cpu == 0)
+				__elf_platform = "loongson2e";
+			break;
+		case MACH_LEMOTE_FL2F:
+		case MACH_LEMOTE_ML2F7:
+		case MACH_LEMOTE_YL2F89:
+		case MACH_DEXXON_GDIUM2F10:
+		case MACH_LEMOTE_NAS:
+		case MACH_LEMOTE_LL2F:
+			__cpu_name[cpu] = "ICT Loongson-2F";
+			if (cpu == 0)
+				__elf_platform = "loongson2f";
+			break;
+		default:
+			__cpu_name[cpu] = "ICT Loongson-2";
+		}
 		c->isa_level = MIPS_CPU_ISA_III;
 		c->options = R4K_OPTS |
 			     MIPS_CPU_FPU | MIPS_CPU_LLSC |
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index acd3f2c..74b8c16 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -551,6 +551,14 @@ void __init setup_arch(char **cmdline_p)
 {
 	cpu_probe();
 	prom_init();
+#ifdef CONFIG_MACH_LOONGSON
+	/*
+	 * On Loongson 2, CPU detection is defective. machtype
+	 * heuristics are used instead, but they only work after
+	 * prom_init().
+	 */
+	cpu_probe();
+#endif
 
 #ifdef CONFIG_EARLY_PRINTK
 	setup_early_printk();

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[David Daney]

On 11/07/2010 04:30 AM, Robert Millan wrote:
> El 04/11/10 19:43:08, en/na Robert Millan va escriure:
>> David Daney a écrit :
>>> You are claiming that all loongson2 are loongson-2f.  Is that
>>> really true?  Or are there other types of loongson2 that are not
>>> loongson-2f?
>>
>> I'll figure out how to distinguish them and send a new patch.
>
> I looked at details about CPU identification, and this
> seems to be broken.
>
> See the the notes about PRId in pages 72 and 66, respectively:
> http://dev.lemote.com/files/resource/documents/Loongson/ls2f/Loongson2FUserGuide.pdf
>
> In both 2E and 2F, the implementation field is the same (0x63).
>
> Revision field is the same too, according to docs, and it can't
> be used anyway (no garantee of consistency).

I seems weird to me that you cannot get this information from the PRId 
register.  Perhaps the documentation is defective.

The Chinese version of the Loongson2E user guide seems to say something 
about the two lower nibbles of the PRId, but being a non-chinese reader, 
I have no idea if it would be relevant.

I would think that the low order bits of the register can reliably 
differentiate these two parts.

David Daney



>
> I'm sending a new patch that uses machtype instead. Yes, I know
> it's a bit of a kludge, but it really seems to be the only way.
>
>> Well I appreciate consistency with GCC flag names,
>
> Actually, I missread GCC flag (it's dashless).  I'm using
> "loongson2f" as David requested.
>

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Robert Millan]

2010/11/8 David Daney <ddaney@caviumnetworks.com>:
> I seems weird to me that you cannot get this information from the PRId
> register.  Perhaps the documentation is defective.

Yes, I agree it's really shortsighted of them, but I don't
see any way around it.

> The Chinese version of the Loongson2E user guide seems to say something
> about the two lower nibbles of the PRId, but being a non-chinese reader, I
> have no idea if it would be relevant.
>
> I would think that the low order bits of the register can reliably
> differentiate these two parts.

There are English versions for both 2E and 2F.  See page 66
of the Loongson 2F document:

http://dev.lemote.com/files/resource/documents/Loongson/ls2f/Loongson2FUserGuide.pdf

<quote>
The revision number can distinguish some chip revisions, however there
is no guarantee
that changes to the chip will necessarily be reflected in the PRId
register, or that changes to
the revision number necessarily reflect real chip changes. For this
reason, software should
not rely on the revision number in the PRId register to characterize the chip.
</quote>

Page 72 of the Loongson 2E document
(http://www.lemote.com/upfiles/godson2e-user-manual-V0.6.pdf) has the
same text.

In both documents, the lower byte is defined as "Revision number",
and its value is 0x02 (for both 2E and 2F).

If you'd rather not assume the docs are correct, I can test if
my Yeeloong (Loongson 2F) has 0x02, but then in case it's
something higher, would you be willing to assume:

  rev <= 0x02  -->  2E
  rev > 0x02  --> 2F

or similar logic?  This seems risky if we take into account
that there's no guarantee from the vendor.

-- 
Robert Millan

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[David Daney]

On 11/08/2010 02:27 PM, Robert Millan wrote:
> 2010/11/8 David Daney<ddaney@caviumnetworks.com>:
>> I seems weird to me that you cannot get this information from the PRId
>> register.  Perhaps the documentation is defective.
>
> Yes, I agree it's really shortsighted of them, but I don't
> see any way around it.
>
>> The Chinese version of the Loongson2E user guide seems to say something
>> about the two lower nibbles of the PRId, but being a non-chinese reader, I
>> have no idea if it would be relevant.
>>
>> I would think that the low order bits of the register can reliably
>> differentiate these two parts.
>
> There are English versions for both 2E and 2F.  See page 66
> of the Loongson 2F document:
>
> http://dev.lemote.com/files/resource/documents/Loongson/ls2f/Loongson2FUserGuide.pdf
>
> <quote>
> The revision number can distinguish some chip revisions, however there
> is no guarantee
> that changes to the chip will necessarily be reflected in the PRId
> register, or that changes to
> the revision number necessarily reflect real chip changes. For this
> reason, software should
> not rely on the revision number in the PRId register to characterize the chip.
> </quote>
>
> Page 72 of the Loongson 2E document
> (http://www.lemote.com/upfiles/godson2e-user-manual-V0.6.pdf) has the
> same text.
>
> In both documents, the lower byte is defined as "Revision number",
> and its value is 0x02 (for both 2E and 2F).
>
> If you'd rather not assume the docs are correct, I can test if
> my Yeeloong (Loongson 2F) has 0x02, but then in case it's
> something higher, would you be willing to assume:
>
>    rev<= 0x02  -->   2E
>    rev>  0x02  -->  2F
>

No, I refuse to assume that.


Look at the description of the register in this document:

http://dev.lemote.com/files/resource/documents/Loongson/ls2e/godson2e.user.manual.pdf

On page 49, it says that bits 0-3 contain the minor version number and 
bits 4-7 are the major version number (according to a workmate that 
reads Chinese).

I don't know for certain, but it seems plausible that the 2E and 2F will 
differ in bits 4-7, and bits 0-3 can be ignored.



> or similar logic?  This seems risky if we take into account
> that there's no guarantee from the vendor.
>

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Robert Millan]

2010/11/8 David Daney <ddaney@caviumnetworks.com>:
> Look at the description of the register in this document:
>
> http://dev.lemote.com/files/resource/documents/Loongson/ls2e/godson2e.user.manual.pdf
>
> On page 49, it says that bits 0-3 contain the minor version number and bits
> 4-7 are the major version number (according to a workmate that reads
> Chinese).
>
> I don't know for certain, but it seems plausible that the 2E and 2F will
> differ in bits 4-7, and bits 0-3 can be ignored.

Thanks for investigating, but ignoring bits 0-3 doesn't
really change anything.  Our problem was that bits 0-7
are the same on 2E and 2F (0x02).  If we ignore bits 0-3,
then our problem is that bits 4-7 are the same on 2E
and 2F (0x2).

-- 
Robert Millan

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[wu zhangjin]

Hi, Robert

On Tue, Nov 9, 2010 at 7:02 AM, Robert Millan <rmh@gnu.org> wrote:
> 2010/11/8 David Daney <ddaney@caviumnetworks.com>:
>> Look at the description of the register in this document:
>>
>> http://dev.lemote.com/files/resource/documents/Loongson/ls2e/godson2e.user.manual.pdf
>>
>> On page 49, it says that bits 0-3 contain the minor version number and bits
>> 4-7 are the major version number (according to a workmate that reads
>> Chinese).
>>
>> I don't know for certain, but it seems plausible that the 2E and 2F will
>> differ in bits 4-7, and bits 0-3 can be ignored.
>
> Thanks for investigating, but ignoring bits 0-3 doesn't
> really change anything.  Our problem was that bits 0-7
> are the same on 2E and 2F (0x02).  If we ignore bits 0-3,
> then our problem is that bits 4-7 are the same on 2E
> and 2F (0x2).

Just rechecked this with a friend from Lemote, in reality, the
revision id of Loongson-2F is 0x3, so, my old code should be a
reference for you:

arch/mips/loongson/common/platform.c

PRID_REV_LOONGSON2F and PRID_REV_LOONGSON2E has already been defined
in arch/mips/include/asm/cpu.h

So, the manual is buggy, perhaps the editors of the manuals did copy
and paste for I have found the title of the 2F manual is the same as
the 2E manual ;-)

Best Regards,
Wu Zhangjin

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Robert Millan]

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El 09/11/10 10:48:34, en/na wu zhangjin va escriure:
> Just rechecked this with a friend from Lemote, in reality, the
> revision id of Loongson-2F is 0x3, so, my old code should be a
> reference for you:
> 
> arch/mips/loongson/common/platform.c
> 
> PRID_REV_LOONGSON2F and PRID_REV_LOONGSON2E has already been defined
> in arch/mips/include/asm/cpu.h
> 
> So, the manual is buggy, perhaps the editors of the manuals did copy
> and paste for I have found the title of the 2F manual is the same as
> the 2E manual ;-)

Thank you!  Then I suppose this will do it.


[-- Attachment #2: loongson2f.diff --]
[-- Type: text/x-patch, Size: 931 bytes --]


Signed-off-by: Robert Millan <rmh@gnu.org>

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 71620e1..4341950 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -613,7 +613,20 @@ static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
 		break;
 	case PRID_IMP_LOONGSON2:
 		c->cputype = CPU_LOONGSON2;
-		__cpu_name[cpu] = "ICT Loongson-2";
+		switch (c->processor_id & PRID_REV_MASK) {
+		case PRID_REV_LOONGSON2E:
+			__cpu_name[cpu] = "ICT Loongson-2E";
+			if (cpu == 0)
+				__elf_platform = "loongson2e";
+			break;
+		case PRID_REV_LOONGSON2F:
+			__cpu_name[cpu] = "ICT Loongson-2F";
+			if (cpu == 0)
+				__elf_platform = "loongson2f";
+			break;
+		default:
+			__cpu_name[cpu] = "ICT Loongson-2";
+		}
 		c->isa_level = MIPS_CPU_ISA_III;
 		c->options = R4K_OPTS |
 			     MIPS_CPU_FPU | MIPS_CPU_LLSC |

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Ralf Baechle]

On Tue, Nov 09, 2010 at 01:24:02PM +0100, Robert Millan wrote:

> El 09/11/10 10:48:34, en/na wu zhangjin va escriure:
> > Just rechecked this with a friend from Lemote, in reality, the
> > revision id of Loongson-2F is 0x3, so, my old code should be a
> > reference for you:
> > 
> > arch/mips/loongson/common/platform.c
> > 
> > PRID_REV_LOONGSON2F and PRID_REV_LOONGSON2E has already been defined
> > in arch/mips/include/asm/cpu.h
> > 
> > So, the manual is buggy, perhaps the editors of the manuals did copy
> > and paste for I have found the title of the 2F manual is the same as
> > the 2E manual ;-)
> 
> Thank you!  Then I suppose this will do it.

Looks technically ok; I just have a more stylistic problem with the patch:

> +			if (cpu == 0)
> +				__elf_platform = "loongson2e";

Cavium introduced this idion first.  Now your patch is repeating it and I'm
sure other SMP platforms will soon use it.   I don't want a thousand
if (cpu == 0) in that file, so can you cook a patch that introduces a
helper, something like

static void set_elf_platform(const char *plat)
{
	if (cpu == 0)
		__elf_platform = plat;
}

Then use that for all assignments to __elf_platform?  Thanks.

  Ralf

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Robert Millan]

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El 09/11/10 16:40:55, en/na Ralf Baechle va escriure:
> Cavium introduced this idion first.  Now your patch is repeating it
> and I'm
> sure other SMP platforms will soon use it.   I don't want a thousand
> if (cpu == 0) in that file, so can you cook a patch that introduces a
> helper, something like
> 
> static void set_elf_platform(const char *plat)
> {
> 	if (cpu == 0)
> 		__elf_platform = plat;
> }
> 
> Then use that for all assignments to __elf_platform?  Thanks.

Here.


[-- Attachment #2: loongson2f.diff --]
[-- Type: text/x-patch, Size: 2010 bytes --]


Signed-off-by: Robert Millan <rmh@gnu.org>

diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
index fd1d39e..58844f6 100644
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -344,6 +344,12 @@ extern int dump_task_fpu(struct task_struct *, elf_fpregset_t *);
 #define ELF_PLATFORM  __elf_platform
 extern const char *__elf_platform;
 
+static inline void set_elf_platform(int cpu, const char *plat)
+{
+	if (cpu == 0)
+		__elf_platform = plat;
+}
+
 /*
  * See comments in asm-alpha/elf.h, this is the same thing
  * on the MIPS.
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 71620e1..7e547ca 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -613,7 +613,18 @@ static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
 		break;
 	case PRID_IMP_LOONGSON2:
 		c->cputype = CPU_LOONGSON2;
-		__cpu_name[cpu] = "ICT Loongson-2";
+		switch (c->processor_id & PRID_REV_MASK) {
+		case PRID_REV_LOONGSON2E:
+			__cpu_name[cpu] = "ICT Loongson-2E";
+			set_elf_platform(cpu, "loongson2e");
+			break;
+		case PRID_REV_LOONGSON2F:
+			__cpu_name[cpu] = "ICT Loongson-2F";
+			set_elf_platform(cpu, "loongson2f");
+			break;
+		default:
+			__cpu_name[cpu] = "ICT Loongson-2";
+		}
 		c->isa_level = MIPS_CPU_ISA_III;
 		c->options = R4K_OPTS |
 			     MIPS_CPU_FPU | MIPS_CPU_LLSC |
@@ -957,14 +968,12 @@ static inline void cpu_probe_cavium(struct cpuinfo_mips *c, unsigned int cpu)
 		c->cputype = CPU_CAVIUM_OCTEON_PLUS;
 		__cpu_name[cpu] = "Cavium Octeon+";
 platform:
-		if (cpu == 0)
-			__elf_platform = "octeon";
+		set_elf_platform(cpu, "octeon");
 		break;
 	case PRID_IMP_CAVIUM_CN63XX:
 		c->cputype = CPU_CAVIUM_OCTEON2;
 		__cpu_name[cpu] = "Cavium Octeon II";
-		if (cpu == 0)
-			__elf_platform = "octeon2";
+		set_elf_platform(cpu, "octeon2");
 		break;
 	default:
 		printk(KERN_INFO "Unknown Octeon chip!\n");

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Robert Millan]

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El 11/11/10 15:47:35, en/na Robert Millan va escriure:
> -		__cpu_name[cpu] = "ICT Loongson-2";
> +		switch (c->processor_id & PRID_REV_MASK) {
> +		case PRID_REV_LOONGSON2E:
> +			__cpu_name[cpu] = "ICT Loongson-2E";

Actually, the V0.2 / V0.3 that follows in cpuinfo output
already indicates revision.  And I noticed that appending
the 'E' or 'F' breaks GCC's -march=native option (which
works by parsing /proc/cpuinfo).

Please use this patch instead.


[-- Attachment #2: loongson2f.diff --]
[-- Type: text/x-patch, Size: 1861 bytes --]


Signed-off-by: Robert Millan <rmh@gnu.org>

diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
index fd1d39e..58844f6 100644
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -344,6 +344,12 @@ extern int dump_task_fpu(struct task_struct *, elf_fpregset_t *);
 #define ELF_PLATFORM  __elf_platform
 extern const char *__elf_platform;
 
+static inline void set_elf_platform(int cpu, const char *plat)
+{
+	if (cpu == 0)
+		__elf_platform = plat;
+}
+
 /*
  * See comments in asm-alpha/elf.h, this is the same thing
  * on the MIPS.
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 71620e1..accde65 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -614,6 +614,14 @@ static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
 	case PRID_IMP_LOONGSON2:
 		c->cputype = CPU_LOONGSON2;
 		__cpu_name[cpu] = "ICT Loongson-2";
+		switch (c->processor_id & PRID_REV_MASK) {
+		case PRID_REV_LOONGSON2E:
+			set_elf_platform(cpu, "loongson2e");
+			break;
+		case PRID_REV_LOONGSON2F:
+			set_elf_platform(cpu, "loongson2f");
+			break;
+		}
 		c->isa_level = MIPS_CPU_ISA_III;
 		c->options = R4K_OPTS |
 			     MIPS_CPU_FPU | MIPS_CPU_LLSC |
@@ -957,14 +965,12 @@ static inline void cpu_probe_cavium(struct cpuinfo_mips *c, unsigned int cpu)
 		c->cputype = CPU_CAVIUM_OCTEON_PLUS;
 		__cpu_name[cpu] = "Cavium Octeon+";
 platform:
-		if (cpu == 0)
-			__elf_platform = "octeon";
+		set_elf_platform(cpu, "octeon");
 		break;
 	case PRID_IMP_CAVIUM_CN63XX:
 		c->cputype = CPU_CAVIUM_OCTEON2;
 		__cpu_name[cpu] = "Cavium Octeon II";
-		if (cpu == 0)
-			__elf_platform = "octeon2";
+		set_elf_platform(cpu, "octeon2");
 		break;
 	default:
 		printk(KERN_INFO "Unknown Octeon chip!\n");

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[David Daney]

On 11/15/2010 03:50 PM, Robert Millan wrote:
> El 11/11/10 15:47:35, en/na Robert Millan va escriure:
>> >  -		__cpu_name[cpu] = "ICT Loongson-2";
>> >  +		switch (c->processor_id&  PRID_REV_MASK) {
>> >  +		case PRID_REV_LOONGSON2E:
>> >  +			__cpu_name[cpu] = "ICT Loongson-2E";
> Actually, the V0.2 / V0.3 that follows in cpuinfo output
> already indicates revision.  And I noticed that appending
> the 'E' or 'F' breaks GCC's -march=native option (which
> works by parsing /proc/cpuinfo).
>

Good catch, this is true, __cpu_name for better or worse is part of the 
kernel/user ABI.  GCC parses this in gcc/config/mips/driver-native.c


> Please use this patch instead.
>
>
>
> loongson2f.diff
>
>
>
> Signed-off-by: Robert Millan<rmh@gnu.org>
>

Acked-by: David Daney <ddaney@caviumnetworks.com>


> diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
> index fd1d39e..58844f6 100644
> --- a/arch/mips/include/asm/elf.h
> +++ b/arch/mips/include/asm/elf.h
> @@ -344,6 +344,12 @@ extern int dump_task_fpu(struct task_struct *, elf_fpregset_t *);
>   #define ELF_PLATFORM  __elf_platform
>   extern const char *__elf_platform;
>
> +static inline void set_elf_platform(int cpu, const char *plat)
> +{
> +	if (cpu == 0)
> +		__elf_platform = plat;
> +}
> +
>   /*
>    * See comments in asm-alpha/elf.h, this is the same thing
>    * on the MIPS.
> diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
> index 71620e1..accde65 100644
> --- a/arch/mips/kernel/cpu-probe.c
> +++ b/arch/mips/kernel/cpu-probe.c
> @@ -614,6 +614,14 @@ static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
>   	case PRID_IMP_LOONGSON2:
>   		c->cputype = CPU_LOONGSON2;
>   		__cpu_name[cpu] = "ICT Loongson-2";
> +		switch (c->processor_id&  PRID_REV_MASK) {
> +		case PRID_REV_LOONGSON2E:
> +			set_elf_platform(cpu, "loongson2e");
> +			break;
> +		case PRID_REV_LOONGSON2F:
> +			set_elf_platform(cpu, "loongson2f");
> +			break;
> +		}
>   		c->isa_level = MIPS_CPU_ISA_III;
>   		c->options = R4K_OPTS |
>   			     MIPS_CPU_FPU | MIPS_CPU_LLSC |
> @@ -957,14 +965,12 @@ static inline void cpu_probe_cavium(struct cpuinfo_mips *c, unsigned int cpu)
>   		c->cputype = CPU_CAVIUM_OCTEON_PLUS;
>   		__cpu_name[cpu] = "Cavium Octeon+";
>   platform:
> -		if (cpu == 0)
> -			__elf_platform = "octeon";
> +		set_elf_platform(cpu, "octeon");
>   		break;
>   	case PRID_IMP_CAVIUM_CN63XX:
>   		c->cputype = CPU_CAVIUM_OCTEON2;
>   		__cpu_name[cpu] = "Cavium Octeon II";
> -		if (cpu == 0)
> -			__elf_platform = "octeon2";
> +		set_elf_platform(cpu, "octeon2");
>   		break;
>   	default:
>   		printk(KERN_INFO "Unknown Octeon chip!\n");
>

Re: [PATCH] Enable AT_PLATFORM for Loongson 2F CPU

[Robert Millan]

> Acked-by: David Daney <ddaney@caviumnetworks.com>

Any news about this one? Is it good already?

-- 
Robert Millan