[Qemu-devel] [PATCH v2] target-ppc: Eliminate redundant and incorrect function booke206_page_size_to_tlb

[Qemu-devel] [PATCH v2] target-ppc: Eliminate redundant and incorrect function booke206_page_size_to_tlb

[Aaron Larson]

Eliminate redundant and incorrect booke206_page_size_to_tlb function
from ppce500_spin.c in preference to previously existing but newly
exported definition from e500.c

Defect analysis:

The booke206_page_size_to_tlb function in e500.c was updated in commit
2bd9543 "ppc: booke206: use MAV=2.0 TSIZE definition, fix 4G pages" to
reflect a change in the definition of MAS1_TSIZE_SHIFT from 8
(corresponding to a min TLB page size of 4kb) to a value of 7 (TLB
page size 2k).  The booke206_page_size_to_tlb() function defined in
ppce500_spin.c was never updated to reflect the change in
MAS1_TSIZE_SHIFT.

In http://lists.nongnu.org/archive/html/qemu-ppc/2016-06/msg00533.html,
Scott Wood suggested this "root cause" explanation:

SW> The patch that changed MAS1_TSIZE_SHIFT from 8 to 7 was around the
SW> same time as the patch that added this code, which is probably why
SW> adjusting it got missed.  Commit 2bd9543cd3 did update the
SW> equivalent code in ppce500_mpc8544ds.c, which now resides in
SW> hw/ppc/e500.c and has been changed to not assume a power-of-2
SW> size.  The ppce500_spin version should be eliminated.

Signed-off-by: Aaron Larson <alarson@ddci.com>
---
 hw/ppc/e500.c         | 2 +-
 hw/ppc/e500.h         | 2 ++
 hw/ppc/ppce500_spin.c | 7 +------
 3 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
index ee1c60b..0cd534d 100644
--- a/hw/ppc/e500.c
+++ b/hw/ppc/e500.c
@@ -601,7 +601,7 @@ static int ppce500_prep_device_tree(MachineState *machine,
 }
 
 /* Create -kernel TLB entries for BookE.  */
-static inline hwaddr booke206_page_size_to_tlb(uint64_t size)
+hwaddr booke206_page_size_to_tlb(uint64_t size)
 {
     return 63 - clz64(size >> 10);
 }
diff --git a/hw/ppc/e500.h b/hw/ppc/e500.h
index ef224ea..70ba1d8 100644
--- a/hw/ppc/e500.h
+++ b/hw/ppc/e500.h
@@ -26,4 +26,6 @@ typedef struct PPCE500Params {
 
 void ppce500_init(MachineState *machine, PPCE500Params *params);
 
+hwaddr booke206_page_size_to_tlb(uint64_t size);
+
 #endif
diff --git a/hw/ppc/ppce500_spin.c b/hw/ppc/ppce500_spin.c
index 225177b..22c584e 100644
--- a/hw/ppc/ppce500_spin.c
+++ b/hw/ppc/ppce500_spin.c
@@ -32,6 +32,7 @@
 #include "sysemu/sysemu.h"
 #include "hw/sysbus.h"
 #include "sysemu/kvm.h"
+#include "e500.h"
 
 #define MAX_CPUS 32
 
@@ -72,12 +73,6 @@ static void spin_reset(void *opaque)
     }
 }
 
-/* Create -kernel TLB entries for BookE, linearly spanning 256MB.  */
-static inline hwaddr booke206_page_size_to_tlb(uint64_t size)
-{
-    return ctz32(size >> 10) >> 1;
-}
-
 static void mmubooke_create_initial_mapping(CPUPPCState *env,
                                      target_ulong va,
                                      hwaddr pa,
-- 
2.7.4

Re: [Qemu-devel] [PATCH v2] target-ppc: Eliminate redundant and incorrect function booke206_page_size_to_tlb

[David Gibson]

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On Tue, Jun 28, 2016 at 06:50:05AM -0700, Aaron Larson wrote:
> 
> Eliminate redundant and incorrect booke206_page_size_to_tlb function
> from ppce500_spin.c in preference to previously existing but newly
> exported definition from e500.c
> 
> Defect analysis:
> 
> The booke206_page_size_to_tlb function in e500.c was updated in commit
> 2bd9543 "ppc: booke206: use MAV=2.0 TSIZE definition, fix 4G pages" to
> reflect a change in the definition of MAS1_TSIZE_SHIFT from 8
> (corresponding to a min TLB page size of 4kb) to a value of 7 (TLB
> page size 2k).  The booke206_page_size_to_tlb() function defined in
> ppce500_spin.c was never updated to reflect the change in
> MAS1_TSIZE_SHIFT.
> 
> In http://lists.nongnu.org/archive/html/qemu-ppc/2016-06/msg00533.html,
> Scott Wood suggested this "root cause" explanation:
> 
> SW> The patch that changed MAS1_TSIZE_SHIFT from 8 to 7 was around the
> SW> same time as the patch that added this code, which is probably why
> SW> adjusting it got missed.  Commit 2bd9543cd3 did update the
> SW> equivalent code in ppce500_mpc8544ds.c, which now resides in
> SW> hw/ppc/e500.c and has been changed to not assume a power-of-2
> SW> size.  The ppce500_spin version should be eliminated.
> 
> Signed-off-by: Aaron Larson <alarson@ddci.com>

Applied to pppc-for-2.7, thanks.

> ---
>  hw/ppc/e500.c         | 2 +-
>  hw/ppc/e500.h         | 2 ++
>  hw/ppc/ppce500_spin.c | 7 +------
>  3 files changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
> index ee1c60b..0cd534d 100644
> --- a/hw/ppc/e500.c
> +++ b/hw/ppc/e500.c
> @@ -601,7 +601,7 @@ static int ppce500_prep_device_tree(MachineState *machine,
>  }
>  
>  /* Create -kernel TLB entries for BookE.  */
> -static inline hwaddr booke206_page_size_to_tlb(uint64_t size)
> +hwaddr booke206_page_size_to_tlb(uint64_t size)
>  {
>      return 63 - clz64(size >> 10);
>  }
> diff --git a/hw/ppc/e500.h b/hw/ppc/e500.h
> index ef224ea..70ba1d8 100644
> --- a/hw/ppc/e500.h
> +++ b/hw/ppc/e500.h
> @@ -26,4 +26,6 @@ typedef struct PPCE500Params {
>  
>  void ppce500_init(MachineState *machine, PPCE500Params *params);
>  
> +hwaddr booke206_page_size_to_tlb(uint64_t size);
> +
>  #endif
> diff --git a/hw/ppc/ppce500_spin.c b/hw/ppc/ppce500_spin.c
> index 225177b..22c584e 100644
> --- a/hw/ppc/ppce500_spin.c
> +++ b/hw/ppc/ppce500_spin.c
> @@ -32,6 +32,7 @@
>  #include "sysemu/sysemu.h"
>  #include "hw/sysbus.h"
>  #include "sysemu/kvm.h"
> +#include "e500.h"
>  
>  #define MAX_CPUS 32
>  
> @@ -72,12 +73,6 @@ static void spin_reset(void *opaque)
>      }
>  }
>  
> -/* Create -kernel TLB entries for BookE, linearly spanning 256MB.  */
> -static inline hwaddr booke206_page_size_to_tlb(uint64_t size)
> -{
> -    return ctz32(size >> 10) >> 1;
> -}
> -
>  static void mmubooke_create_initial_mapping(CPUPPCState *env,
>                                       target_ulong va,
>                                       hwaddr pa,

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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Re: [Qemu-devel] [PATCH v2] target-ppc: Eliminate redundant and incorrect function booke206_page_size_to_tlb

[alarson]

David Gibson <david@gibson.dropbear.id.au> wrote on 06/28/2016 08:42:01 
PM:

> On Tue, Jun 28, 2016 at 06:50:05AM -0700, Aaron Larson wrote:
> > 
> > Eliminate redundant and incorrect booke206_page_size_to_tlb function
> > from ppce500_spin.c in preference to previously existing but newly
> > exported definition from e500.c
> > ...
> > Signed-off-by: Aaron Larson <alarson@ddci.com>
> 
> Applied to pppc-for-2.7, thanks.

I had previously created a bug for this at: 
https://bugs.launchpad.net/qemu/+bug/1587535

Do you want me to do anything with that bug?

Re: [Qemu-devel] [PATCH v2] target-ppc: Eliminate redundant and incorrect function booke206_page_size_to_tlb

[Thomas Huth]

On 29.06.2016 17:14, alarson@ddci.com wrote:
> David Gibson <david@gibson.dropbear.id.au> wrote on 06/28/2016 08:42:01 
> PM:
> 
>> On Tue, Jun 28, 2016 at 06:50:05AM -0700, Aaron Larson wrote:
>>>
>>> Eliminate redundant and incorrect booke206_page_size_to_tlb function
>>> from ppce500_spin.c in preference to previously existing but newly
>>> exported definition from e500.c
>>> ...
>>> Signed-off-by: Aaron Larson <alarson@ddci.com>
>>
>> Applied to pppc-for-2.7, thanks.
> 
> I had previously created a bug for this at: 
> https://bugs.launchpad.net/qemu/+bug/1587535
> 
> Do you want me to do anything with that bug?

Please add a comment with the title of your patch there, stating that it
has been accepted, and set the status of the bug to "Fix committed".

 Thanks!
  Thomas