lkml.org 
[lkml]   [2008]   [May]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Make LIST_POISON less deadly
Ingo Molnar wrote:
>
>> +/*
>> + * Define LIST_POISON[12] as pointers that cannot be dereferenced.
>> + */
>> +#ifdef CONFIG_X86_84
>> +# undef LIST_POISON1
>> +# undef LIST_POISON2
>> +# define LIST_POISON1 ((void *)0x8001000100010001L)
>> +# define LIST_POISON2 ((void *)0x8002000200020002L)
>> +#endif
>>
>
> i'd suggest to add an ARCH_ILLEGAL_POINTER define instead, which
> defaults to zero and gets added to pointer-ish poison values. That makes
> it both simpler and also it does not need any include/asm changes
> because ARCH_ILLEGAL_POINTER can be set from the Kconfig space.
>

Right.

How much unmapped space do we have on i386 or other archs? The deltas
added to ARCH_ILLEGAL_POINTER will have to be limited to that.

Maybe have ARCH_ILLEGAL_POINTER_BASE and ARCH_ILLEGAL_POINTER_RANGE,
defaulting to 0 and (say) 4MB, and use the range to mask the deltas to
avoid overflows into legal pointer range.

--
error compiling committee.c: too many arguments to function



\
 
 \ /
  Last update: 2008-05-19 15:29    [W:0.138 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site