Messages in this thread | | | From | Andrew Lutomirski <> | Date | Sun, 29 May 2011 16:04:36 -0400 | Subject | Re: [PATCH 4/5] x86-64: Replace vsyscall gettimeofday fallback with int 0xcc |
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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
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