From 9bcf53598dfe1bd8caaf8e03738d3cc51d45904e Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Thu, 14 Jun 2018 10:20:54 -0700 Subject: [PATCH] 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 Reviewed-by: James Hogan Patchwork: https://patchwork.linux-mips.org/patch/19522/ Cc: Ralf Baechle Cc: Mathieu Desnoyers Cc: Peter Zijlstra Cc: Paul E. McKenney Cc: Boqun Feng Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org --- arch/mips/kernel/entry.S | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S index 38a3029..d7de8ad 100644 --- 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 -- 2.7.4