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Unverified Commit 9ea141ad authored by Paul Burton's avatar Paul Burton
Browse files

MIPS: Add support for restartable sequences 



Implement support for restartable sequences on MIPS, which requires 3
simple things:

  - Call rseq_handle_notify_resume() on return to userspace if
    TIF_NOTIFY_RESUME is set.

  - Call rseq_signal_deliver() to fixup the pre-signal stack frame when
    a signal is delivered whilst executing a restartable sequence
    critical section.

  - Select CONFIG_HAVE_RSEQ.

Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Reviewed-by: default avatarJames Hogan <jhogan@kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/19523/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
parent 18f3e95b

arch/mips/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ config MIPS 
	select HAVE_OPROFILE

	select HAVE_PERF_EVENTS

	select HAVE_REGS_AND_STACK_ACCESS_API

	select HAVE_RSEQ

	select HAVE_STACKPROTECTOR

	select HAVE_SYSCALL_TRACEPOINTS

	select HAVE_VIRT_CPU_ACCOUNTING_GEN if 64BIT || !SMP

arch/mips/kernel/signal.c

+3 −0
Original line number Diff line number Diff line
@@ -801,6 +801,8 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) 
		regs->regs[0] = 0;		/* Don't deal with this again.	*/

	}



	rseq_signal_deliver(regs);



	if (sig_uses_siginfo(&ksig->ka, abi))

		ret = abi->setup_rt_frame(vdso + abi->vdso->off_rt_sigreturn,

					  ksig, regs, oldset);
@@ -868,6 +870,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused, 
	if (thread_info_flags & _TIF_NOTIFY_RESUME) {

		clear_thread_flag(TIF_NOTIFY_RESUME);

		tracehook_notify_resume(regs);

		rseq_handle_notify_resume(regs);

	}



	user_enter();