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 <[email protected]> Reviewed-by: James Hogan <[email protected]> Patchwork: https://patchwork.linux-mips.org/patch/19522/ Cc: Ralf Baechle <[email protected]> Cc: Mathieu Desnoyers <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: Boqun Feng <[email protected]> Cc: [email protected] Cc: [email protected]
cail · Jun 20, 2018 · 9bcf535 · 9bcf535
1 parent 9ea141a
commit 9bcf535
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S
@@ -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