* [PATCH] x86: Remove excess calculations for heap_end_ptr
@ 2014-12-26 12:22 Alexander Kuleshov
2014-12-26 14:35 ` Jeremiah Mahler
0 siblings, 1 reply; 4+ messages in thread
From: Alexander Kuleshov @ 2014-12-26 12:22 UTC (permalink / raw)
To: H. Peter Anvin, x86; +Cc: linux-kernel, Alexander Kuleshov
heap_end_ptr default value defined as _end+STACK_SZE-512, but
STACK_SIZE is already 512.
Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
---
| 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 16ef025..c69b870 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -342,7 +342,7 @@ ramdisk_size: .long 0 # its size in bytes
bootsect_kludge:
.long 0 # obsolete
-heap_end_ptr: .word _end+STACK_SIZE-512
+heap_end_ptr: .word _end
# (Header version 0x0201 or later)
# space from here (exclusive) down to
# end of setup code can be used by setup
--
2.2.1.201.gbbcefff
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] x86: Remove excess calculations for heap_end_ptr
2014-12-26 12:22 [PATCH] x86: Remove excess calculations for heap_end_ptr Alexander Kuleshov
@ 2014-12-26 14:35 ` Jeremiah Mahler
2014-12-26 17:03 ` Alexander Kuleshov
0 siblings, 1 reply; 4+ messages in thread
From: Jeremiah Mahler @ 2014-12-26 14:35 UTC (permalink / raw)
To: Alexander Kuleshov; +Cc: H. Peter Anvin, x86, linux-kernel
Alexander,
On Fri, Dec 26, 2014 at 06:22:42PM +0600, Alexander Kuleshov wrote:
> heap_end_ptr default value defined as _end+STACK_SZE-512, but
STACK_SIZE
> STACK_SIZE is already 512.
>
> Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
> ---
> arch/x86/boot/header.S | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
> index 16ef025..c69b870 100644
> --- a/arch/x86/boot/header.S
> +++ b/arch/x86/boot/header.S
> @@ -342,7 +342,7 @@ ramdisk_size: .long 0 # its size in bytes
> bootsect_kludge:
> .long 0 # obsolete
>
> -heap_end_ptr: .word _end+STACK_SIZE-512
> +heap_end_ptr: .word _end
> # (Header version 0x0201 or later)
> # space from here (exclusive) down to
> # end of setup code can be used by setup
So right now STACK_SIZE happens to be 512 so STACK_SIZE-512 is zero.
What happens if someone changes the size of STACK_SIZE?
This change doesn't fix any problem right now and creates potential
problems in the future.
> --
> 2.2.1.201.gbbcefff
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
- Jeremiah Mahler
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86: Remove excess calculations for heap_end_ptr
2014-12-26 14:35 ` Jeremiah Mahler
@ 2014-12-26 17:03 ` Alexander Kuleshov
2014-12-26 17:04 ` H. Peter Anvin
0 siblings, 1 reply; 4+ messages in thread
From: Alexander Kuleshov @ 2014-12-26 17:03 UTC (permalink / raw)
To: Jeremiah Mahler, Alexander Kuleshov, H. Peter Anvin, x86, linux-kernel
Yes, you're right,
At first i thought that it is just typo, and right after that i
thought about this case when somebody will change STACK_SIZE
2014-12-26 20:35 GMT+06:00 Jeremiah Mahler <jmmahler@gmail.com>:
> Alexander,
>
> On Fri, Dec 26, 2014 at 06:22:42PM +0600, Alexander Kuleshov wrote:
>> heap_end_ptr default value defined as _end+STACK_SZE-512, but
> STACK_SIZE
>
>> STACK_SIZE is already 512.
>>
>> Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
>> ---
>> arch/x86/boot/header.S | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
>> index 16ef025..c69b870 100644
>> --- a/arch/x86/boot/header.S
>> +++ b/arch/x86/boot/header.S
>> @@ -342,7 +342,7 @@ ramdisk_size: .long 0 # its size in bytes
>> bootsect_kludge:
>> .long 0 # obsolete
>>
>> -heap_end_ptr: .word _end+STACK_SIZE-512
>> +heap_end_ptr: .word _end
>> # (Header version 0x0201 or later)
>> # space from here (exclusive) down to
>> # end of setup code can be used by setup
>
> So right now STACK_SIZE happens to be 512 so STACK_SIZE-512 is zero.
> What happens if someone changes the size of STACK_SIZE?
>
> This change doesn't fix any problem right now and creates potential
> problems in the future.
>
>> --
>> 2.2.1.201.gbbcefff
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at http://www.tux.org/lkml/
>
> --
> - Jeremiah Mahler
--
_________________________
0xAX
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86: Remove excess calculations for heap_end_ptr
2014-12-26 17:03 ` Alexander Kuleshov
@ 2014-12-26 17:04 ` H. Peter Anvin
0 siblings, 0 replies; 4+ messages in thread
From: H. Peter Anvin @ 2014-12-26 17:04 UTC (permalink / raw)
To: Alexander Kuleshov, Jeremiah Mahler, x86, linux-kernel
Yes, the -512 is not related to STACK_SIZE, so this patch is wrong. NAK.
On December 26, 2014 9:03:38 AM PST, Alexander Kuleshov <kuleshovmail@gmail.com> wrote:
>Yes, you're right,
>
>At first i thought that it is just typo, and right after that i
>thought about this case when somebody will change STACK_SIZE
>
>2014-12-26 20:35 GMT+06:00 Jeremiah Mahler <jmmahler@gmail.com>:
>> Alexander,
>>
>> On Fri, Dec 26, 2014 at 06:22:42PM +0600, Alexander Kuleshov wrote:
>>> heap_end_ptr default value defined as _end+STACK_SZE-512, but
>> STACK_SIZE
>>
>>> STACK_SIZE is already 512.
>>>
>>> Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
>>> ---
>>> arch/x86/boot/header.S | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
>>> index 16ef025..c69b870 100644
>>> --- a/arch/x86/boot/header.S
>>> +++ b/arch/x86/boot/header.S
>>> @@ -342,7 +342,7 @@ ramdisk_size: .long 0 # its
>size in bytes
>>> bootsect_kludge:
>>> .long 0 # obsolete
>>>
>>> -heap_end_ptr: .word _end+STACK_SIZE-512
>>> +heap_end_ptr: .word _end
>>> # (Header version 0x0201 or
>later)
>>> # space from here (exclusive)
>down to
>>> # end of setup code can be
>used by setup
>>
>> So right now STACK_SIZE happens to be 512 so STACK_SIZE-512 is zero.
>> What happens if someone changes the size of STACK_SIZE?
>>
>> This change doesn't fix any problem right now and creates potential
>> problems in the future.
>>
>>> --
>>> 2.2.1.201.gbbcefff
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe
>linux-kernel" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>> Please read the FAQ at http://www.tux.org/lkml/
>>
>> --
>> - Jeremiah Mahler
--
Sent from my mobile phone. Please pardon brevity and lack of formatting.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2014-12-26 12:22 [PATCH] x86: Remove excess calculations for heap_end_ptr Alexander Kuleshov
2014-12-26 14:35 ` Jeremiah Mahler
2014-12-26 17:03 ` Alexander Kuleshov
2014-12-26 17:04 ` H. Peter Anvin
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