On 04/12/2018 04:02 AM, Peter Maydell wrote: > AArch64 stack frames include a 'frame record' which holds a pointer > to the next frame record in the chain and the LR on entry to the > function. The procedure calling standard doesn't mandate where > exactly this frame record is in the stack frame, but for signal > frames the kernel puts it right at the top. We used to put it > there too, but in commit 7f0f4208b3a96f22 we accidentally put > the "enlarge to the 4K reserved space minimum" check after the > "allow for the frame record" code, rather than before it, with > the effect that the frame record would be inside the reserved > space and immediately after the last used part of it. > > Move the frame record back out of the reserved space to where > we used to put it. > > This bug shouldn't break any sensible guest code, but test > programs that deliberately look at the internal details > of the signal frame layout will not find what they are > expecting to see. > > Fixes: 7f0f4208b3a96f22 > Signed-off-by: Peter Maydell <[email protected]>
Reviewed-by: Richard Henderson <[email protected]> > I'm marking this as for-2.12 on the basis that it puts our frame > layout back to exactly what 2.11 had, and so seems safest. > No sensible guest code should really care, though, so this is > in the "only if we're doing an rc4" bucket; but I think that the > softfloat fixes deserve an rc4 anyway. Granted. r~
