Unverified Commit 9bcf5359 authored Jun 14, 2018 by Paul Burton

MIPS: Add syscall detection for restartable sequences



Syscalls are not allowed inside restartable sequences, so add a call to
rseq_syscall() at the very beginning of the system call exit path when
CONFIG_DEBUG_RSEQ=y. This will help us to detect whether there is a
syscall issued erroneously inside a restartable sequence.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Reviewed-by: James Hogan <jhogan@kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/19522/
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 9ea141ad

arch/mips/kernel/entry.S

+8 −0

Original line number	Diff line number	Diff line
		@@ -79,6 +79,10 @@ FEXPORT(ret_from_fork)
		jal schedule_tail # a0 = struct task_struct *prev

		FEXPORT(syscall_exit)
		#ifdef CONFIG_DEBUG_RSEQ
		move a0, sp
		jal rseq_syscall
		#endif
		local_irq_disable # make sure need_resched and
		# signals dont change between
		# sampling and return
		@@ -141,6 +145,10 @@ work_notifysig: # deal with pending signals and
		j resume_userspace_check

		FEXPORT(syscall_exit_partial)
		#ifdef CONFIG_DEBUG_RSEQ
		move a0, sp
		jal rseq_syscall
		#endif
		local_irq_disable # make sure need_resched doesn't
		# change between and return
		LONG_L a2, TI_FLAGS($28) # current->work

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