[RFC PATCH for 4.16 07/21] powerpc: Add support for restartable sequences

* [RFC PATCH for 4.16 07/21] powerpc: Add support for restartable sequences
       [not found] <20171214161403.30643-1-mathieu.desnoyers@efficios.com>
@ 2017-12-14 16:13 ` Mathieu Desnoyers
  2017-12-14 16:13 ` [RFC PATCH for 4.16 08/21] powerpc: Wire up restartable sequences system call Mathieu Desnoyers
  2017-12-14 16:13 ` [RFC PATCH for 4.16 12/21] powerpc: Wire up cpu_opv " Mathieu Desnoyers
  2 siblings, 0 replies; 3+ messages in thread
From: Mathieu Desnoyers @ 2017-12-14 16:13 UTC (permalink / raw)
  To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
	Dave Watson
  Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton,
	Russell King, Thomas Gleixner, Ingo Molnar, H . Peter Anvin,
	Andrew Hunter, Andi Kleen, Chris Lameter, Ben Maurer,
	Steven Rostedt, Josh Triplett, Linus Torvalds, Catalin Marinas,
	Will Deacon, Michael Kerrisk, Mathieu Desnoyers,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	linuxppc-dev

From: Boqun Feng <boqun.feng@gmail.com>

Call the rseq_handle_notify_resume() function on return to userspace if
TIF_NOTIFY_RESUME thread flag is set.

Increment the event counter and perform fixup on the pre-signal when a
signal is delivered on top of a restartable sequence critical section.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: Peter Zijlstra <peterz@infradead.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/Kconfig         | 1 +
 arch/powerpc/kernel/signal.c | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c51e6ce42e7a..e9992f80819c 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -221,6 +221,7 @@ config PPC
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_VIRT_CPU_ACCOUNTING
 	select HAVE_IRQ_TIME_ACCOUNTING
+	select HAVE_RSEQ
 	select IRQ_DOMAIN
 	select IRQ_FORCED_THREADING
 	select MODULES_USE_ELF_RELA
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index 3d7539b90010..a7b95f7bcaf1 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -133,6 +133,8 @@ static void do_signal(struct task_struct *tsk)
 	/* Re-enable the breakpoints for the signal stack */
 	thread_change_pc(tsk, tsk->thread.regs);
 
+	rseq_signal_deliver(tsk->thread.regs);
+
 	if (is32) {
         	if (ksig.ka.sa.sa_flags & SA_SIGINFO)
 			ret = handle_rt_signal32(&ksig, oldset, tsk);
@@ -161,6 +163,7 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 		clear_thread_flag(TIF_NOTIFY_RESUME);
 		tracehook_notify_resume(regs);
+		rseq_handle_notify_resume(regs);
 	}
 
 	if (thread_info_flags & _TIF_PATCH_PENDING)
-- 
2.11.0

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