Hello all,
Sparse is reporting a couple warnings in mm/memblock.c:
warning: cast truncates bits from constant value (9f911029d74e35b becomes 9d74e35b)
The warnings are due to the cast of RED_INACTIVE in memblock_analyze():
/* Check marker in the unused last array entry */
WARN_ON(memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS].base
!= (phys_addr_t)RED_INACTIVE);
WARN_ON(memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS].base
!= (phys_addr_t)RED_INACTIVE);
And in memblock_init():
/* Write a marker in the unused last array entry */
memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
Could this cause any problems? If not, is there anyway to quiet the sparse noise?
Regards,
Hartley
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On Tue, 14 Jun 2011 19:47:19 -0500
H Hartley Sweeten <[email protected]> wrote:
> Hello all,
>
> Sparse is reporting a couple warnings in mm/memblock.c:
>
> warning: cast truncates bits from constant value (9f911029d74e35b becomes 9d74e35b)
>
> The warnings are due to the cast of RED_INACTIVE in memblock_analyze():
>
> /* Check marker in the unused last array entry */
> WARN_ON(memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS].base
> != (phys_addr_t)RED_INACTIVE);
> WARN_ON(memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS].base
> != (phys_addr_t)RED_INACTIVE);
>
> And in memblock_init():
>
> /* Write a marker in the unused last array entry */
> memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
> memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
>
> Could this cause any problems? If not, is there anyway to quiet the sparse noise?
>
It's all just a debugging check and that check will continue to work OK
despite this bug.
But yes, it's ugly and should be fixed.
I don't think that mm/memblock.c should have reused RED_INACTIVE.
That's a slab thing and wedging it into a phys_addr_t was
inappropriate.
In fact I don't think RED_INACTIVE should exist. It's just inviting
other subsystems to (ab)use it. It should be replaced by a
slab-specific SLAB_RED_INACTIVE, as slub did with SLUB_RED_INACTIVE.
I'd suggest something like the below, which I didn't test. Feel free to
send it back at me, or ignore it ;)
diff -puN include/linux/poison.h~a include/linux/poison.h
--- a/include/linux/poison.h~a
+++ a/include/linux/poison.h
@@ -40,6 +40,12 @@
#define RED_INACTIVE 0x09F911029D74E35BULL /* when obj is inactive */
#define RED_ACTIVE 0xD84156C5635688C0ULL /* when obj is active */
+#ifdef CONFIG_PHYS_ADDR_T_64BIT
+#define MEMBLOCK_INACTIVE 0x3a84fb0144c9e71bULL
+#else
+#define MEMBLOCK_INACTIVE 0x44c9e71bUL
+#endif
+
#define SLUB_RED_INACTIVE 0xbb
#define SLUB_RED_ACTIVE 0xcc
diff -puN mm/memblock.c~a mm/memblock.c
--- a/mm/memblock.c~a
+++ a/mm/memblock.c
@@ -758,9 +758,9 @@ void __init memblock_analyze(void)
/* Check marker in the unused last array entry */
WARN_ON(memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS].base
- != (phys_addr_t)RED_INACTIVE);
+ != MEMBLOCK_INACTIVE);
WARN_ON(memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS].base
- != (phys_addr_t)RED_INACTIVE);
+ != MEMBLOCK_INACTIVE);
memblock.memory_size = 0;
@@ -786,8 +786,8 @@ void __init memblock_init(void)
memblock.reserved.max = INIT_MEMBLOCK_REGIONS;
/* Write a marker in the unused last array entry */
- memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
- memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
+ memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = MEMBLOCK_INACTIVE;
+ memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = MEMBLOCK_INACTIVE;
/* Create a dummy zero size MEMBLOCK which will get coalesced away later.
* This simplifies the memblock_add() code below...
_
On Monday, June 20, 2011 5:03 PM, Andrew Morton wrote:
> On Tue, 14 Jun 2011 19:47:19 -0500 H Hartley Sweeten wrote:
>
>> Hello all,
>>
>> Sparse is reporting a couple warnings in mm/memblock.c:
>>
>> warning: cast truncates bits from constant value (9f911029d74e35b becomes 9d74e35b)
>>
>> The warnings are due to the cast of RED_INACTIVE in memblock_analyze():
>>
>> /* Check marker in the unused last array entry */
>> WARN_ON(memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS].base
>> != (phys_addr_t)RED_INACTIVE);
>> WARN_ON(memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS].base
>> != (phys_addr_t)RED_INACTIVE);
>>
>> And in memblock_init():
>>
>> /* Write a marker in the unused last array entry */
>> memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
>> memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
>>
>> Could this cause any problems? If not, is there anyway to quiet the sparse noise?
>>
>
> It's all just a debugging check and that check will continue to work OK
> despite this bug.
>
> But yes, it's ugly and should be fixed.
>
> I don't think that mm/memblock.c should have reused RED_INACTIVE.
> That's a slab thing and wedging it into a phys_addr_t was
> inappropriate.
>
> In fact I don't think RED_INACTIVE should exist. It's just inviting
> other subsystems to (ab)use it. It should be replaced by a
> slab-specific SLAB_RED_INACTIVE, as slub did with SLUB_RED_INACTIVE.
>
>
> I'd suggest something like the below, which I didn't test. Feel free to
> send it back at me, or ignore it ;)
>
>
> diff -puN include/linux/poison.h~a include/linux/poison.h
> --- a/include/linux/poison.h~a
> +++ a/include/linux/poison.h
> @@ -40,6 +40,12 @@
> #define RED_INACTIVE 0x09F911029D74E35BULL /* when obj is inactive */
> #define RED_ACTIVE 0xD84156C5635688C0ULL /* when obj is active */
>
> +#ifdef CONFIG_PHYS_ADDR_T_64BIT
> +#define MEMBLOCK_INACTIVE 0x3a84fb0144c9e71bULL
> +#else
> +#define MEMBLOCK_INACTIVE 0x44c9e71bUL
> +#endif
> +
> #define SLUB_RED_INACTIVE 0xbb
> #define SLUB_RED_ACTIVE 0xcc
>
> diff -puN mm/memblock.c~a mm/memblock.c
> --- a/mm/memblock.c~a
> +++ a/mm/memblock.c
> @@ -758,9 +758,9 @@ void __init memblock_analyze(void)
>
> /* Check marker in the unused last array entry */
> WARN_ON(memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS].base
> - != (phys_addr_t)RED_INACTIVE);
> + != MEMBLOCK_INACTIVE);
> WARN_ON(memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS].base
> - != (phys_addr_t)RED_INACTIVE);
> + != MEMBLOCK_INACTIVE);
>
> memblock.memory_size = 0;
>
> @@ -786,8 +786,8 @@ void __init memblock_init(void)
> memblock.reserved.max = INIT_MEMBLOCK_REGIONS;
>
> /* Write a marker in the unused last array entry */
> - memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
> - memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
> + memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = MEMBLOCK_INACTIVE;
> + memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = MEMBLOCK_INACTIVE;
>
> /* Create a dummy zero size MEMBLOCK which will get coalesced away later.
> * This simplifies the memblock_add() code below...
FWIW, your patch above quiet's the sparse warnings on my system (arm ep93xx) and
the system boots and runs fine.
If you want it..
Tested-by: H Hartley Sweeten <[email protected]>
On 6/21/11 3:31 AM, H Hartley Sweeten wrote:
> On Monday, June 20, 2011 5:03 PM, Andrew Morton wrote:
>> On Tue, 14 Jun 2011 19:47:19 -0500 H Hartley Sweeten wrote:
>>
>>> Hello all,
>>>
>>> Sparse is reporting a couple warnings in mm/memblock.c:
>>>
>>> warning: cast truncates bits from constant value (9f911029d74e35b becomes 9d74e35b)
>>>
>>> The warnings are due to the cast of RED_INACTIVE in memblock_analyze():
>>>
>>> /* Check marker in the unused last array entry */
>>> WARN_ON(memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS].base
>>> != (phys_addr_t)RED_INACTIVE);
>>> WARN_ON(memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS].base
>>> != (phys_addr_t)RED_INACTIVE);
>>>
>>> And in memblock_init():
>>>
>>> /* Write a marker in the unused last array entry */
>>> memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
>>> memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
>>>
>>> Could this cause any problems? If not, is there anyway to quiet the sparse noise?
>>>
>>
>> It's all just a debugging check and that check will continue to work OK
>> despite this bug.
>>
>> But yes, it's ugly and should be fixed.
>>
>> I don't think that mm/memblock.c should have reused RED_INACTIVE.
>> That's a slab thing and wedging it into a phys_addr_t was
>> inappropriate.
>>
>> In fact I don't think RED_INACTIVE should exist. It's just inviting
>> other subsystems to (ab)use it. It should be replaced by a
>> slab-specific SLAB_RED_INACTIVE, as slub did with SLUB_RED_INACTIVE.
>>
>>
>> I'd suggest something like the below, which I didn't test. Feel free to
>> send it back at me, or ignore it ;)
>>
>>
>> diff -puN include/linux/poison.h~a include/linux/poison.h
>> --- a/include/linux/poison.h~a
>> +++ a/include/linux/poison.h
>> @@ -40,6 +40,12 @@
>> #define RED_INACTIVE 0x09F911029D74E35BULL /* when obj is inactive */
>> #define RED_ACTIVE 0xD84156C5635688C0ULL /* when obj is active */
>>
>> +#ifdef CONFIG_PHYS_ADDR_T_64BIT
>> +#define MEMBLOCK_INACTIVE 0x3a84fb0144c9e71bULL
>> +#else
>> +#define MEMBLOCK_INACTIVE 0x44c9e71bUL
>> +#endif
>> +
>> #define SLUB_RED_INACTIVE 0xbb
>> #define SLUB_RED_ACTIVE 0xcc
>>
>> diff -puN mm/memblock.c~a mm/memblock.c
>> --- a/mm/memblock.c~a
>> +++ a/mm/memblock.c
>> @@ -758,9 +758,9 @@ void __init memblock_analyze(void)
>>
>> /* Check marker in the unused last array entry */
>> WARN_ON(memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS].base
>> - != (phys_addr_t)RED_INACTIVE);
>> + != MEMBLOCK_INACTIVE);
>> WARN_ON(memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS].base
>> - != (phys_addr_t)RED_INACTIVE);
>> + != MEMBLOCK_INACTIVE);
>>
>> memblock.memory_size = 0;
>>
>> @@ -786,8 +786,8 @@ void __init memblock_init(void)
>> memblock.reserved.max = INIT_MEMBLOCK_REGIONS;
>>
>> /* Write a marker in the unused last array entry */
>> - memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
>> - memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
>> + memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = MEMBLOCK_INACTIVE;
>> + memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = MEMBLOCK_INACTIVE;
>>
>> /* Create a dummy zero size MEMBLOCK which will get coalesced away later.
>> * This simplifies the memblock_add() code below...
>
> FWIW, your patch above quiet's the sparse warnings on my system (arm ep93xx) and
> the system boots and runs fine.
>
> If you want it..
>
> Tested-by: H Hartley Sweeten<[email protected]>
Acked-by: Pekka Enberg <[email protected]>