If you grab http://landley.net/aboriginal/bin/qemu-system-sh4.tar.bz2 extract it and ./run-emulator.sh (which is a fairly straightforward qemu-system-sh4 invocation on the included kernel image and squashfs root filesystem), older qemu versions would run it just fine, and ctrl-C would pass through to the shell. But current qemu, ctrl-C kills the emulator.
I bisected this to commit 02c4bdf1d2ca, although that's between commit a9e8aeb3755b (which broke the sh4 pci bus) and b23ea25f5098 (which made it boot again), so you have to either revert the first or apply the second in order to test that the reverted commit fixes it. Rob