Cc: Andi Kleen <andi@...>, Vegard Nossum <vegard.nossum@...>, Bart Van Assche <bart.vanassche@...>, Pekka Enberg <penberg@...>, Linux Kernel Mailing List <linux-kernel@...>, Ingo Molnar <mingo@...>, Peter Zijlstra <a.p.zijlstra@...>, Paul E. McKenney <paulmck@...>, Christoph Lameter <clameter@...>, Daniel Walker <dwalker@...>, Randy Dunlap <randy.dunlap@...>, Josh Aune <luken@...>, Pekka Paalanen <pq@...>
Hm, I never particularly liked that approach because unless you do the
whole thing in assembly it was never certain that there wasn't a
basic-block break between them (ie, atomic with respect to valgrind).
For the kernel that may be possible, but I was thinking of the general
case where you might want to use setjmp or something.
Matter of taste really, but I tend to disagree. If you say something
like "addresses A-B, C-D, E-F are stacks", then the stack pointer
changing from the range A-B to C-D is a pretty clear indication of stack
switch, regardless of the mechanism you use to do it. Of course, an
explicit hint prevents an accidental push/pop of 32k onto an 8K stack
from being considered a stack switch, but unless you actually know where
the stacks are, you can't warn about it or prevent it from
validating/invalidating a pile of innocent memory.
J
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