HIGHMEM

HIGHMEM

[Hdei Nunoe]

Hi there,

Has anyone succeeded the HIGHMEM with discontiguous physical memory?
I am using kernel 2.4.18 on TX4937 with two chunks of 256Mbyte memory.
There is 256Mbyte gap in between the physical memory blocks - lower 
memory is 0x00000000 to 0x10000000, upper memory is 0x20000000 to
0x30000000.  System hungs when it create INIT process.

Cheers,
-hdei

HIGHMEM

[Hdei Nunoe]

Hi there,

Has anyone succeeded the HIGHMEM with discontiguous physical memory?
I am using kernel 2.4.18 on TX4937 with two chunks of 256Mbyte memory.
There is 256Mbyte gap in between the physical memory blocks - lower 
memory is 0x00000000 to 0x10000000, upper memory is 0x20000000 to
0x30000000.  System hungs when it create INIT process.

Cheers,
-hdei

Re: HIGHMEM

[Jan-Benedict Glaw]

[-- Attachment #1: Type: text/plain, Size: 642 bytes --]

On Tue, 2004-12-07 10:07:26 +0900, Hdei Nunoe <nunoe@co-nss.co.jp>
wrote in message <001101c4dbf9$1da02270$3ca06096@NUNOE>:

> Has anyone succeeded the HIGHMEM with discontiguous physical memory?
> I am using kernel 2.4.18 on TX4937 with two chunks of 256Mbyte memory.

2.4.18 is obsolete...

MfG, JBG

-- 
Jan-Benedict Glaw       jbglaw@lug-owl.de    . +49-172-7608481             _ O _
"Eine Freie Meinung in  einem Freien Kopf    | Gegen Zensur | Gegen Krieg  _ _ O
 fuer einen Freien Staat voll Freier Bürger" | im Internet! |   im Irak!   O O O
ret = do_actions((curr | FREE_SPEECH) & ~(NEW_COPYRIGHT_LAW | DRM | TCPA));

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 189 bytes --]

Re: HIGHMEM

[Hdei Nunoe]

Hi Jan,

Will it work on the newer version?

Cheers,
-hdei

----- Original Message ----- 
From: "Jan-Benedict Glaw" <jbglaw@lug-owl.de>
To: "Hdei Nunoe" <nunoe@co-nss.co.jp>
Cc: <linux-mips@linux-mips.org>
Sent: Tuesday, December 07, 2004 6:17 PM
Subject: Re: HIGHMEM

> Has anyone succeeded the HIGHMEM with discontiguous physical memory?
> I am using kernel 2.4.18 on TX4937 with two chunks of 256Mbyte memory.

2.4.18 is obsolete...

MfG, JBG

-- 

Re: HIGHMEM

[Hdei Nunoe]

Hi Jan,

Will it work on the newer version?

Cheers,
-hdei

----- Original Message ----- 
From: "Jan-Benedict Glaw" <jbglaw@lug-owl.de>
To: "Hdei Nunoe" <nunoe@co-nss.co.jp>
Cc: <linux-mips@linux-mips.org>
Sent: Tuesday, December 07, 2004 6:17 PM
Subject: Re: HIGHMEM

> Has anyone succeeded the HIGHMEM with discontiguous physical memory?
> I am using kernel 2.4.18 on TX4937 with two chunks of 256Mbyte memory.

2.4.18 is obsolete...

MfG, JBG

-- 

Re: HIGHMEM

[Ralf Baechle]

On Tue, Dec 07, 2004 at 10:07:26AM +0900, Hdei Nunoe wrote:

> Has anyone succeeded the HIGHMEM with discontiguous physical memory?
> I am using kernel 2.4.18 on TX4937 with two chunks of 256Mbyte memory.
> There is 256Mbyte gap in between the physical memory blocks - lower 
> memory is 0x00000000 to 0x10000000, upper memory is 0x20000000 to
> 0x30000000.  System hungs when it create INIT process.

In 2.4 the support for CONFIG_DISCONTIG and CONFIG_NUMA are a bit tangled
with each other because IP27 is the only platform to uses these features
and it needs both.  Other than that you can also just setup your system
as 0x0 - 0x10000000 being RAM, 0x10000000 - 0x20000000 being reserved
memory and 0x20000000 - 0x30000000 being highmem.  Which works but is a
bit wasteful.

Issue #2 is that we don't support the combination of CONFIG_DISCONTIG and
CONFIG_HIGHMEM.  And highmem is a lobotomized solution for lobotomized
silicon anyway.  You have a 64-bit processor - use it's capabilities :-)

Issue #3 - As I recall the TX4937's H3 core is suffering from cache
aliases.  Handling those efficiently for highmem is not easily possible
and so we don't even try.  More recent kernels will refuse to enable
highmem on such cache configurations but something like 2.4.18 which by
now is an almost 3 year old antique doesn't know about that and will
happily crash.

I recommend you should go for a 64-bit kernel instead.  And 64-bit support
is certainly better in 2.6 than in 2.4.  Especially the area of 32-bit
binary compatibility has been improved significantly.

  Ralf

Re: HIGHMEM

[Jan-Benedict Glaw]

[-- Attachment #1: Type: text/plain, Size: 547 bytes --]

On Tue, 2004-12-07 18:56:33 +0900, Hdei Nunoe <nunoe@co-nss.co.jp>
wrote in message <002101c4dc43$08c4c7d0$3ca06096@NUNOE>:

> Will it work on the newer version?

Did you try recent 2.6.x versions?

MfG, JBG

-- 
Jan-Benedict Glaw       jbglaw@lug-owl.de    . +49-172-7608481             _ O _
"Eine Freie Meinung in  einem Freien Kopf    | Gegen Zensur | Gegen Krieg  _ _ O
 fuer einen Freien Staat voll Freier Bürger" | im Internet! |   im Irak!   O O O
ret = do_actions((curr | FREE_SPEECH) & ~(NEW_COPYRIGHT_LAW | DRM | TCPA));

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 189 bytes --]

Re: HIGHMEM

[Jon Anders Haugum]

> In 2.4 the support for CONFIG_DISCONTIG and CONFIG_NUMA are a bit tangled
> with each other because IP27 is the only platform to uses these features and
> it needs both.  Other than that you can also just setup your system as 0x0 -
> 0x10000000 being RAM, 0x10000000 - 0x20000000 being reserved memory and
> 0x20000000 - 0x30000000 being highmem.  Which works but is a bit wasteful.
>
> Issue #2 is that we don't support the combination of CONFIG_DISCONTIG and
> CONFIG_HIGHMEM.  And highmem is a lobotomized solution for lobotomized
> silicon anyway.  You have a 64-bit processor - use it's capabilities :-)
>
> Issue #3 - As I recall the TX4937's H3 core is suffering from cache aliases.
> Handling those efficiently for highmem is not easily possible and so we
> don't even try.  More recent kernels will refuse to enable highmem on such
> cache configurations but something like 2.4.18 which by now is an almost 3
> year old antique doesn't know about that and will happily crash.
>
> I recommend you should go for a 64-bit kernel instead.  And 64-bit support
> is certainly better in 2.6 than in 2.4.  Especially the area of 32-bit
> binary compatibility has been improved significantly.

What about on a processor like the AMD au1550?

I've tried the latest from 2.4 branch in cvs, and I haven't been 
successful in geting past INIT either...

Can I place all the memory from address 0x20000000 to get more than 
256Meg?


-- 
Jon Anders Haugum

Re: HIGHMEM

[Atsushi Nemoto]

>>>>> On Tue, 7 Dec 2004 10:58:37 +0100, Ralf Baechle <ralf@linux-mips.org> said:
ralf> Issue #3 - As I recall the TX4937's H3 core is suffering from
ralf> cache aliases.  Handling those efficiently for highmem is not
ralf> easily possible and so we don't even try.  More recent kernels
ralf> will refuse to enable highmem on such cache configurations but
ralf> something like 2.4.18 which by now is an almost 3 year old
ralf> antique doesn't know about that and will happily crash.

ralf> I recommend you should go for a 64-bit kernel instead.  And
ralf> 64-bit support is certainly better in 2.6 than in 2.4.
ralf> Especially the area of 32-bit binary compatibility has been
ralf> improved significantly.

And this is a small step to a 64-bit kernel for TX49XX.  Could you
apply?

--- linux-mips/arch/mips/mm/Makefile	2004-12-13 09:39:09.000000000 +0900
+++ linux/arch/mips/mm/Makefile	2004-12-13 09:52:54.000000000 +0900
@@ -49,6 +49,7 @@
 endif
 ifdef CONFIG_MIPS64
 obj-$(CONFIG_CPU_R4300)		+= tlbex64.o
+obj-$(CONFIG_CPU_TX49XX)	+= tlbex64.o
 obj-$(CONFIG_CPU_R4X00)		+= tlbex64.o
 obj-$(CONFIG_CPU_R5000)		+= tlbex64.o
 obj-$(CONFIG_CPU_NEVADA)	+= tlbex64.o

Re: HIGHMEM

[Hdei Nunoe]

Ralf,

Thanks for the info!  I still have a ocuple of question, hope you do not 
mind.

> In 2.4 the support for CONFIG_DISCONTIG and CONFIG_NUMA are a bit tangled
> with each other because IP27 is the only platform to uses these features
> and it needs both.

Is it named "sgi-ip27"?

> Other than that you can also just setup your system
> as 0x0 - 0x10000000 being RAM, 0x10000000 - 0x20000000 being reserved
> memory and 0x20000000 - 0x30000000 being highmem.  Which works but is a
> bit wasteful.

The gap in physical memory is 0x10000000 - 0x20000000, but it is 
0x90000000 -
0xC0000000 in virtual memory because there is K1 segment.  So the macros 
such
as __pa() or __va() does not work, I think.  Started to wonder it might not 
be easy
as just changing the PAGE_OFFSET value.  Do you see?

cheers,
-hdei

Re: HIGHMEM

[Hdei Nunoe]

Ralf,

Thanks for the info!  I still have a ocuple of question, hope you do not 
mind.

> In 2.4 the support for CONFIG_DISCONTIG and CONFIG_NUMA are a bit tangled
> with each other because IP27 is the only platform to uses these features
> and it needs both.

Is it named "sgi-ip27"?

> Other than that you can also just setup your system
> as 0x0 - 0x10000000 being RAM, 0x10000000 - 0x20000000 being reserved
> memory and 0x20000000 - 0x30000000 being highmem.  Which works but is a
> bit wasteful.

The gap in physical memory is 0x10000000 - 0x20000000, but it is 
0x90000000 -
0xC0000000 in virtual memory because there is K1 segment.  So the macros 
such
as __pa() or __va() does not work, I think.  Started to wonder it might not 
be easy
as just changing the PAGE_OFFSET value.  Do you see?

cheers,
-hdei

Re: HIGHMEM

[Ralf Baechle]

On Tue, Dec 14, 2004 at 01:26:55PM +0900, Hdei Nunoe wrote:

> >In 2.4 the support for CONFIG_DISCONTIG and CONFIG_NUMA are a bit tangled
> >with each other because IP27 is the only platform to uses these features
> >and it needs both.
> 
> Is it named "sgi-ip27"?

Yes, obviously :-)

> >Other than that you can also just setup your system
> >as 0x0 - 0x10000000 being RAM, 0x10000000 - 0x20000000 being reserved
> >memory and 0x20000000 - 0x30000000 being highmem.  Which works but is a
> >bit wasteful.
> 
> The gap in physical memory is 0x10000000 - 0x20000000, but it is 
> 0x90000000 -
> 0xC0000000 in virtual memory because there is K1 segment.  So the macros 
> such
> as __pa() or __va() does not work, I think.  Started to wonder it might not 
> be easy
> as just changing the PAGE_OFFSET value.  Do you see?

PAGE_OFFSET is the difference of a ZONE_NORMAL's virtual address and it's
physical address.  Once there is no more 1:1 mapping between physical and
virtual addresses such as in your suggestion PAGE_OFFSET can no longer be
used, that is you need to rewrite all users of this function.

  Ralf

Re: HIGHMEM

[Ralf Baechle]

On Mon, Dec 13, 2004 at 01:34:09PM +0900, Atsushi Nemoto wrote:

> And this is a small step to a 64-bit kernel for TX49XX.  Could you
> apply?

Sure, done.

  Ralf

Re: HIGHMEM

[Ralf Baechle]

On Tue, Dec 07, 2004 at 11:29:04AM +0100, Jon Anders Haugum wrote:

> What about on a processor like the AMD au1550?
> 
> I've tried the latest from 2.4 branch in cvs, and I haven't been 
> successful in geting past INIT either...
> 
> Can I place all the memory from address 0x20000000 to get more than 
> 256Meg?

Yes, that should just work on Alchemy.

  Ralf

Re: HIGHMEM

[Atsushi Nemoto]

>>>>> On Wed, 15 Dec 2004 15:16:13 +0100, Ralf Baechle <ralf@linux-mips.org> said:

>> And this is a small step to a 64-bit kernel for TX49XX.  Could you
>> apply?

ralf> Sure, done.

Thanks.  And this is next step.  Could you apply too?

diff -u linux-mips/include/asm-mips/addrspace.h linux/include/asm-mips/addrspace.h 
--- linux-mips/include/asm-mips/addrspace.h	Sun Sep 26 21:31:45 2004
+++ linux/include/asm-mips/addrspace.h	Sat Dec 18 21:21:01 2004
@@ -126,6 +126,7 @@
     || defined (CONFIG_CPU_R4X00)					\
     || defined (CONFIG_CPU_R5000)					\
     || defined (CONFIG_CPU_NEVADA)					\
+    || defined (CONFIG_CPU_TX49XX)					\
     || defined (CONFIG_CPU_MIPS64)
 #define	KUSIZE			0x0000010000000000	/* 2^^40 */
 #define	KUSIZE_64		0x0000010000000000	/* 2^^40 */

MIPS32 -> MIPS64

[Hdei Nunoe]

Hello,

Could anyone tell how significant the migration from MIPS32 to MIPS64 is?
Is it just re-building with the MIPS64 toolchain? 
Or is it like another architecture porting?

Regards,
-hdei

MIPS32 -> MIPS64

[Hdei Nunoe]

Hello,

Could anyone tell how significant the migration from MIPS32 to MIPS64 is?
Is it just re-building with the MIPS64 toolchain? 
Or is it like another architecture porting?

Regards,
-hdei

Re: MIPS32 -> MIPS64

[Atsushi Nemoto]

>>>>> On Wed, 22 Dec 2004 08:51:58 +0900, "Hdei Nunoe" <nunoe@co-nss.co.jp> said:
nunoe> Could anyone tell how significant the migration from MIPS32 to
nunoe> MIPS64 is?  Is it just re-building with the MIPS64 toolchain?
nunoe> Or is it like another architecture porting?

Just rebuilding will not be enough, but the migration will not be so
hard.

Most of you have to do is using correct integer data types ('long' is
64bit and 'int' is 32bit in mips64 kernel).

---
Atsushi Nemoto

Re: HIGHMEM

[Hdei Nunoe]

Ralf,

It worked fine with small changes!!   Comment and Criticism are welcome.

>> >Other than that you can also just setup your system
>> >as 0x0 - 0x10000000 being RAM, 0x10000000 - 0x20000000 being reserved
>> >memory and 0x20000000 - 0x30000000 being highmem.  Which works but is a
>> >bit wasteful.

I have set up my system as following :
- 0x00000000 - 0x10000000 RAM
- 0x10000000 - 0x40000000 RESERVED
- 0x40000000 - 0x50000000 RAM
So that the gap in physical address space and one in virtual address space 
becomes equal.
It is 0x40000000 in this case (0x10000000 - 0x40000000 vs 0x90000000 - 
0xc0000000).
That means no physical <-> virtual macro change are needed.  hehe...
And the MMU mapping to the upper 256MB is fixed with the CP0 wired register.

Changes are pretty small as follows :
--- tlb-r4k.c ---
381c381
<       write_32bit_cp0_register(CP0_WIRED, 0);
---
>       write_32bit_cp0_register(CP0_WIRED, 8 /* XXX 0 */);

--- pgtable.h ---
123c123
< #define VMALLOC_START     KSEG2
---
> #define VMALLOC_START     KSEG3               /* XXX KSEG2 */

--- page.h ---
148c148
< #define HIGHMEM_START 0x20000000UL
---
> #define HIGHMEM_START 0x50000000UL    /* XXX 0x20000000UL */

--- prom.c ---
>       add_memory_region(0, (256*1024*1024), BOOT_MEM_RAM);
>       add_memory_region(0x10000000, (256*1024*1024), BOOT_MEM_RESERVED);
>       add_memory_region(0x20000000, (512*1024*1024), BOOT_MEM_RESERVED);
>       add_memory_region(0x40000000, (256*1024*1024), BOOT_MEM_RAM);
>
>       {
>           TLB_TBL32 tlb;
>           unsigned int nTlb = 48;             /* max TLB entry */
>           unsigned int size = 0x02000000;     /* 32MB boundary */
>           unsigned int vadr = 0xc0000000;     /* virtual address */
>           unsigned int padr = 0x40000000;     /* physical address */
>
>           printk ("memory map started.\n");
>             for (i=0; i<8; i++)
>               {
>               tlb.mask = 0x01ffe000;          /* 16M bit[24-13] */
>               tlb.hi  = vadr + (i*size);
>               tlb.lo1 = (padr >> 6) | ((i*size + (size/2)) >> 6) | 0x1f;
>               tlb.lo0 = (padr >> 6) | ((i*size) >> 6) | 0x1f;
>               setTLB32 (i, &tlb);
>               }
>             for (i=8; i<nTlb; i++)
>               {
>               tlb.mask = 0x0;
>               tlb.hi  = 0x80000000;
>               tlb.lo1 = 0;
>               tlb.lo0 = 0;
>               setTLB32 (i, &tlb);
>               }
>             for (i=0; i<nTlb; i++)
>               {
>               getTLB32 (i, &tlb);
>               printk ("get: mask=0x%08x hi=0x%08x lo0=0x%08x 
> lo1=0x%08x.\n",
>                       tlb.mask, tlb.hi, tlb.lo0, tlb.lo1);
>               }
>       }

Cheers,
-hdei

Re: HIGHMEM

[Hdei Nunoe]

Ralf,

It worked fine with small changes!!   Comment and Criticism are welcome.

>> >Other than that you can also just setup your system
>> >as 0x0 - 0x10000000 being RAM, 0x10000000 - 0x20000000 being reserved
>> >memory and 0x20000000 - 0x30000000 being highmem.  Which works but is a
>> >bit wasteful.

I have set up my system as following :
- 0x00000000 - 0x10000000 RAM
- 0x10000000 - 0x40000000 RESERVED
- 0x40000000 - 0x50000000 RAM
So that the gap in physical address space and one in virtual address space 
becomes equal.
It is 0x40000000 in this case (0x10000000 - 0x40000000 vs 0x90000000 - 
0xc0000000).
That means no physical <-> virtual macro change are needed.  hehe...
And the MMU mapping to the upper 256MB is fixed with the CP0 wired register.

Changes are pretty small as follows :
--- tlb-r4k.c ---
381c381
<       write_32bit_cp0_register(CP0_WIRED, 0);
---
>       write_32bit_cp0_register(CP0_WIRED, 8 /* XXX 0 */);

--- pgtable.h ---
123c123
< #define VMALLOC_START     KSEG2
---
> #define VMALLOC_START     KSEG3               /* XXX KSEG2 */

--- page.h ---
148c148
< #define HIGHMEM_START 0x20000000UL
---
> #define HIGHMEM_START 0x50000000UL    /* XXX 0x20000000UL */

--- prom.c ---
>       add_memory_region(0, (256*1024*1024), BOOT_MEM_RAM);
>       add_memory_region(0x10000000, (256*1024*1024), BOOT_MEM_RESERVED);
>       add_memory_region(0x20000000, (512*1024*1024), BOOT_MEM_RESERVED);
>       add_memory_region(0x40000000, (256*1024*1024), BOOT_MEM_RAM);
>
>       {
>           TLB_TBL32 tlb;
>           unsigned int nTlb = 48;             /* max TLB entry */
>           unsigned int size = 0x02000000;     /* 32MB boundary */
>           unsigned int vadr = 0xc0000000;     /* virtual address */
>           unsigned int padr = 0x40000000;     /* physical address */
>
>           printk ("memory map started.\n");
>             for (i=0; i<8; i++)
>               {
>               tlb.mask = 0x01ffe000;          /* 16M bit[24-13] */
>               tlb.hi  = vadr + (i*size);
>               tlb.lo1 = (padr >> 6) | ((i*size + (size/2)) >> 6) | 0x1f;
>               tlb.lo0 = (padr >> 6) | ((i*size) >> 6) | 0x1f;
>               setTLB32 (i, &tlb);
>               }
>             for (i=8; i<nTlb; i++)
>               {
>               tlb.mask = 0x0;
>               tlb.hi  = 0x80000000;
>               tlb.lo1 = 0;
>               tlb.lo0 = 0;
>               setTLB32 (i, &tlb);
>               }
>             for (i=0; i<nTlb; i++)
>               {
>               getTLB32 (i, &tlb);
>               printk ("get: mask=0x%08x hi=0x%08x lo0=0x%08x 
> lo1=0x%08x.\n",
>                       tlb.mask, tlb.hi, tlb.lo0, tlb.lo1);
>               }
>       }

Cheers,
-hdei

Re: HIGHMEM

[Ralf Baechle]

On Tue, Jan 11, 2005 at 11:33:51AM +0900, Hdei Nunoe wrote:

> I have set up my system as following :
> - 0x00000000 - 0x10000000 RAM
> - 0x10000000 - 0x40000000 RESERVED
> - 0x40000000 - 0x50000000 RAM

Your setup may work it's pretty wasteful; you're burning 12MB memory for
unused kernel data structures.

  Ralf

Re: HIGHMEM

[Geert Uytterhoeven]

On Tue, 11 Jan 2005, Ralf Baechle wrote:
> On Tue, Jan 11, 2005 at 11:33:51AM +0900, Hdei Nunoe wrote:
> > I have set up my system as following :
> > - 0x00000000 - 0x10000000 RAM
> > - 0x10000000 - 0x40000000 RESERVED
> > - 0x40000000 - 0x50000000 RAM
> 
> Your setup may work it's pretty wasteful; you're burning 12MB memory for
> unused kernel data structures.

Time to start using virtually contiguous memory, like m68k does? ;-)
(no, it's not in mainline)

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

Re: HIGHMEM

[Ralf Baechle]

On Tue, Jan 11, 2005 at 11:38:59AM +0100, Geert Uytterhoeven wrote:

> Time to start using virtually contiguous memory, like m68k does? ;-)
> (no, it's not in mainline)

Won't work for MIPS; there's the KSEG1 address gap.

  Ralf