Commit ca46ebff authored by Stafford Horne's avatar Stafford Horne
Browse files

openrisc: Add support for restartable sequences 



Implement support for restartable sequences on OpenRISC by doing:
 - Select HAVE_RSEQ in Kconfig
 - Call rseq_syscall() on return to userspace when CONFIG_DEBUG_RSEQ
   is enabled.
 - Call rseq_signal_deliver() to fixup the pre-signal stack frame when a
   signal is delivered on top of a restartable sequence critical section

Cc: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: default avatarStafford Horne <shorne@gmail.com>
parent 7ce8716e

arch/openrisc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ config OPENRISC 
	select HAVE_UID16

	select HAVE_PAGE_SIZE_8KB

	select HAVE_REGS_AND_STACK_ACCESS_API

	select HAVE_RSEQ

	select GENERIC_ATOMIC64

	select GENERIC_CLOCKEVENTS_BROADCAST

	select GENERIC_SMP_IDLE_THREAD

arch/openrisc/kernel/entry.S

+4 −0
Original line number Diff line number Diff line
@@ -714,6 +714,10 @@ _syscall_check_trace_leave: 
 * interrupts that set NEED_RESCHED or SIGNALPENDING... really true? */



_syscall_check_work:

#ifdef CONFIG_DEBUG_RSEQ

	l.jal	rseq_syscall

	 l.ori	r3,r1,0

#endif

	/* Here we need to disable interrupts */

	DISABLE_INTERRUPTS(r27,r29)

	TRACE_IRQS_OFF

arch/openrisc/kernel/signal.c

+2 −0
Original line number Diff line number Diff line
@@ -244,6 +244,8 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs) 
{

	int ret;



	rseq_signal_deliver(ksig, regs);



	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);



	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));