Update the tilegx main loop and sigreturn code:
* on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
* return -TARGET_QEMU_ESIGRETURN from sigreturn rather than current R_RE
* handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
that the main loop should not touch any guest CPU state
Note that this fixes a bug where a sigreturn which happened to have
an errno value in TILEGX_R_RE would incorrectly cause TILEGX_R_ERR
to get set.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
a9175169cc