Messages in this thread | | | Date | Thu, 31 Jul 2003 19:37:30 +0100 | From | Jamie Lokier <> | Subject | Re: TSCs are a no-no on i386 |
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Alan Cox wrote: > > > And if the byte you are looking at was patched by another thread you've > > > blown it. Your emulation can only be so good 8) People do stuff like > > > patching instructions under software decode as a robustness check - its > > > normally pretty amusing > > > > On a uniprocessor 386, this is not a problem. Just disable preemption > > in the kernel decoder. > > Wrong again. Thats a common myth but you see I can put the instruction on a page > so that its executed from a page I just did a read() into in another process. If > I'm really bored I'll use O_DIRECT but thats mostly for makign life really bad > for non cache coherent setups 8)
I wouldn't be surprised if even real CPUs mis-decode when there's a concurrent DMA into the area they are reading instructions from! :)
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