[PATCH kernel-3.0] arm:cache-l2x0: Fix L2 Cache size calculation.

From: Srinivas Kandagatla <redacted>

This patch fixes L2 Cache size calculations for L2C-210, L2C-310 and
PL310, by changing the L2X0_AUX_CTRL_WAY_SIZE_MASK from 2 bits to 3
bits.

The Auxiliary Control Register for L2C-210, L2C-310 and PL310 has 3bits
[19:17] for Way size, however the existing code only uses 2 bits to
get this value. This results in incorrect cachesize calculations.

I should say this bug does not result in issue but, its just prints
incorrect values.

Signed-off-by: Srinivas Kandagatla <redacted>
---
Hi All,
I found an bug in L2 Cache size calculation in cache-l2x0 code.

According to ARM TRM for L2C-210, L2C-310 and PL310, the Auxiliary
Control Register has 3bits [19:17] allocated for Way size,however
the existing code only uses 2 bits to get this value from Aux 
control register. This results in incorrect cache size calculations.

thanks, 
srini


 arch/arm/include/asm/hardware/cache-l2x0.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/arm/include/asm/hardware/cache-l2x0.h b/arch/arm/include/asm/hardware/cache-l2x0.h
index 16bd480..bfa706f 100644
--- a/arch/arm/include/asm/hardware/cache-l2x0.h
+++ b/arch/arm/include/asm/hardware/cache-l2x0.h

@@ -64,7 +64,7 @@
 #define L2X0_AUX_CTRL_MASK			0xc0000fff
 #define L2X0_AUX_CTRL_ASSOCIATIVITY_SHIFT	16
 #define L2X0_AUX_CTRL_WAY_SIZE_SHIFT		17
-#define L2X0_AUX_CTRL_WAY_SIZE_MASK		(0x3 << 17)
+#define L2X0_AUX_CTRL_WAY_SIZE_MASK		(0x7 << 17)
 #define L2X0_AUX_CTRL_SHARE_OVERRIDE_SHIFT	22
 #define L2X0_AUX_CTRL_NS_LOCKDOWN_SHIFT		26
 #define L2X0_AUX_CTRL_NS_INT_CTRL_SHIFT		27

-- 
1.6.3.3

On Fri, Aug 12, 2011 at 10:45:27AM +0100, Srinivas KANDAGATLA wrote:

From: Srinivas Kandagatla <redacted>

This patch fixes L2 Cache size calculations for L2C-210, L2C-310 and
PL310, by changing the L2X0_AUX_CTRL_WAY_SIZE_MASK from 2 bits to 3
bits.

The Auxiliary Control Register for L2C-210, L2C-310 and PL310 has 3bits
[19:17] for Way size, however the existing code only uses 2 bits to
get this value. This results in incorrect cachesize calculations.

I should say this bug does not result in issue but, its just prints
incorrect values.

It also results in performing operations on the whole cache when we
erroneously decide that the range is big enough (due to l2x0_size being
too small).

Signed-off-by: Srinivas Kandagatla <redacted>

Acked-by: Will Deacon <redacted>

Please can you CC stable on this too?

Will

On Fri, Aug 12, 2011 at 11:20:20AM +0100, Will Deacon wrote:

On Fri, Aug 12, 2011 at 10:45:27AM +0100, Srinivas KANDAGATLA wrote:

quoted

From: Srinivas Kandagatla <redacted>

This patch fixes L2 Cache size calculations for L2C-210, L2C-310 and
PL310, by changing the L2X0_AUX_CTRL_WAY_SIZE_MASK from 2 bits to 3
bits.

The Auxiliary Control Register for L2C-210, L2C-310 and PL310 has 3bits
[19:17] for Way size, however the existing code only uses 2 bits to
get this value. This results in incorrect cachesize calculations.

I should say this bug does not result in issue but, its just prints
incorrect values.

It also results in performing operations on the whole cache when we
erroneously decide that the range is big enough (due to l2x0_size being
too small).

quoted

Signed-off-by: Srinivas Kandagatla <redacted>

Acked-by: Will Deacon <redacted>

Please can you CC stable on this too?

It's probably better to ask people to add a Cc: line to the _attributations_
rather than telling them to CC the stable tree with their email, and then
get a whinge from the stable maintainers about how that's not how to submit
patches for stable trees.

Hi Russell,

On Sat, Aug 13, 2011 at 09:41:29AM +0100, Russell King - ARM Linux wrote:

On Fri, Aug 12, 2011 at 11:20:20AM +0100, Will Deacon wrote:

quoted

On Fri, Aug 12, 2011 at 10:45:27AM +0100, Srinivas KANDAGATLA wrote:

quoted

From: Srinivas Kandagatla <redacted>

This patch fixes L2 Cache size calculations for L2C-210, L2C-310 and
PL310, by changing the L2X0_AUX_CTRL_WAY_SIZE_MASK from 2 bits to 3
bits.

[...]

quoted

Please can you CC stable on this too?

It's probably better to ask people to add a Cc: line to the _attributations_
rather than telling them to CC the stable tree with their email, and then
get a whinge from the stable maintainers about how that's not how to submit
patches for stable trees.

Of course, that's what I intended but unfortunately my choice of words
was ambiguous.

Srinivas: can you add the CC stable line to your patch please and put it
into Russell's patch system?

Thanks,

Will

Resending the patch with Acked by and CC lines in patch...

Thanks,
--srini

Will Deacon wrote:

Hi Russell,

On Sat, Aug 13, 2011 at 09:41:29AM +0100, Russell King - ARM Linux wrote:
  

quoted

On Fri, Aug 12, 2011 at 11:20:20AM +0100, Will Deacon wrote:
    

quoted

On Fri, Aug 12, 2011 at 10:45:27AM +0100, Srinivas KANDAGATLA wrote:
      

quoted

From: Srinivas Kandagatla <redacted>

This patch fixes L2 Cache size calculations for L2C-210, L2C-310 and
PL310, by changing the L2X0_AUX_CTRL_WAY_SIZE_MASK from 2 bits to 3
bits.
        

[...]

  

quoted

quoted

Please can you CC stable on this too?
      

It's probably better to ask people to add a Cc: line to the _attributations_
rather than telling them to CC the stable tree with their email, and then
get a whinge from the stable maintainers about how that's not how to submit
patches for stable trees.
    

Of course, that's what I intended but unfortunately my choice of words
was ambiguous.

Srinivas: can you add the CC stable line to your patch please and put it
into Russell's patch system?

Thanks,

Will
  

Srinivas,

On Mon, Aug 15, 2011 at 08:49:20AM +0100, Srinivas KANDAGATLA wrote:

Resending the patch with Acked by and CC lines in patch...

As described here:

http://www.arm.linux.org.uk/developer/patches/info.php

You need to use Russell's patch system to submit this patch. If you're using
git, the easiest way to do this is:

(0) Sign up to Russell's patch system (not sure if this required):
    http://www.arm.linux.org.uk/developer/patches/add.php

(1) Add an additional KernelVersion: 3.1-rc2 tag to your patch.

(2) Email it to patches at arm.linux.org.uk using git send-email
    --suppress-cc=all.

Thanks,

Will

On Mon, Aug 15, 2011 at 09:58:07AM +0100, Will Deacon wrote:

Srinivas,

On Mon, Aug 15, 2011 at 08:49:20AM +0100, Srinivas KANDAGATLA wrote:

quoted

Resending the patch with Acked by and CC lines in patch...

As described here:

http://www.arm.linux.org.uk/developer/patches/info.php

You need to use Russell's patch system to submit this patch. If you're using
git, the easiest way to do this is:

(0) Sign up to Russell's patch system (not sure if this required):
    http://www.arm.linux.org.uk/developer/patches/add.php

(0) is not needed if sending email.

(1) Add an additional KernelVersion: 3.1-rc2 tag to your patch.

(2) Email it to patches at arm.linux.org.uk using git send-email
    --suppress-cc=all.