From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> Copied and adapted from vincent's patch, but modified for csky. ref: https://lore.kernel.org/linux-riscv/1572919114-3886-3-git-send-email-vincent.chen@xxxxxxxxxx/raw Add calls to rseq_signal_deliver(), rseq_handle_notify_resume() and rseq_syscall() to introduce RSEQ support. 1. Call the rseq_handle_notify_resume() function on return to userspace if TIF_NOTIFY_RESUME thread flag is set. 2. Call the rseq_signal_deliver() function to fixup on the pre-signal frame when a signal is delivered on top of a restartable sequence critical section. 3. Check that system calls are not invoked from within rseq critical sections by invoking rseq_signal() from ret_from_syscall(). With CONFIG_DEBUG_RSEQ, such behavior results in termination of the process with SIGSEGV. Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> --- arch/csky/Kconfig | 1 + arch/csky/kernel/entry.S | 5 ++++- arch/csky/kernel/signal.c | 3 +++ 3 files changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig index 2dfd3fb07db9..0e9b14367fa8 100644 --- a/arch/csky/Kconfig +++ b/arch/csky/Kconfig @@ -49,6 +49,7 @@ config CSKY select HAVE_PERF_USER_STACK_DUMP select HAVE_DMA_CONTIGUOUS select HAVE_REGS_AND_STACK_ACCESS_API + select HAVE_RSEQ select HAVE_STACKPROTECTOR select HAVE_SYSCALL_TRACEPOINTS select MAY_HAVE_SPARSE_IRQ diff --git a/arch/csky/kernel/entry.S b/arch/csky/kernel/entry.S index 007706328000..0bde1d9fd277 100644 --- a/arch/csky/kernel/entry.S +++ b/arch/csky/kernel/entry.S @@ -128,7 +128,10 @@ tlbop_end 1 ENTRY(csky_systemcall) SAVE_ALL TRAP0_SIZE zero_fp - +#ifdef CONFIG_RSEQ_DEBUG + mov a0, sp + jbsr rseq_syscall +#endif psrset ee, ie lrw r11, __NR_syscalls diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c index 9b1b7c039ddf..3d6b728cbb72 100644 --- a/arch/csky/kernel/signal.c +++ b/arch/csky/kernel/signal.c @@ -175,6 +175,8 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) sigset_t *oldset = sigmask_to_save(); int ret; + rseq_signal_deliver(ksig, regs); + /* Are we from a system call? */ if (in_syscall(regs)) { /* Avoid additional syscall restarting via ret_from_exception */ @@ -258,5 +260,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, if (thread_info_flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); + rseq_handle_notify_resume(NULL, regs); } } -- 2.17.0
