csky: Add support for restartable sequence
Copied and adapted from vincent's patch, but modified for csky.
ref:
https://lore.kernel.org/linux-riscv/1572919114-3886-3-git-send-email-vincent.chen@sifive.com/raw
Add calls to rseq_signal_deliver(), rseq_handle_notify_resume() and
rseq_syscall() to introduce RSEQ support.
1. Call the rseq_handle_notify_resume() function on return to userspace
if TIF_NOTIFY_RESUME thread flag is set.
2. Call the rseq_signal_deliver() function to fixup on the pre-signal
frame when a signal is delivered on top of a restartable sequence
critical section.
3. Check that system calls are not invoked from within rseq critical
sections by invoking rseq_signal() from ret_from_syscall(). With
CONFIG_DEBUG_RSEQ, such behavior results in termination of the
process with SIGSEGV.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
3 files changed