lkml.org 
[lkml]   [2011]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 4/5] x86-64: Replace vsyscall gettimeofday fallback with int 0xcc
On Sun, May 29, 2011 at 4:01 PM, Ingo Molnar <mingo@elte.hu> wrote:
>
> * Andrew Lutomirski <luto@mit.edu> wrote:
>
>> On Sun, May 29, 2011 at 3:49 PM, Ingo Molnar <mingo@elte.hu> wrote:
>> >
>> > * Andrew Lutomirski <luto@mit.edu> wrote:
>> >
>> >> > Ok, i suspect you marked it 0xCC because that's the INT3 instruction
>> >> > - not very useful for exploits?
>> >>
>> >> Exactly.
>> >>
>> >> The comments in irq_vectors.h make it sound like vectors 0x81..0xed
>> >> are used for device interrupts but AFAICT it's only 0x20..0x39 that
>> >> are used, so the precise choice of vector doesn't matter that much.
>> >
>> > No, we use almost all of the vector space for device interrupts. Why
>> > do you think only 0x20..0x39 is used?
>>
>> Possibility my inability to understand all the IRQ mapping code in
>> just half an hour of trying.
>
> Hey, you managed to find all the scattered pieces in just half an
> hour, i'm impressed ;-)

grep and an SSD are amazing. I'll add the BUG_ON just to satisfy my
paranoia. I'll also update the comment in irq_vectors.h.

--Andy


\
 
 \ /
  Last update: 2011-05-29 22:07    [from the cache]
©2003-2011 Jasper Spaans