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Unverified Commit 9bcf5359 authored by Paul Burton's avatar Paul Burton
Browse files

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: default avatarPaul Burton <paul.burton@mips.com>
Reviewed-by: default avatarJames 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