On Wed, Aug 19, 2015 at 05:35:05PM +0100, Catalin Marinas wrote: > On Wed, Aug 19, 2015 at 05:23:59PM +0100, Will Deacon wrote: > > On Wed, Aug 19, 2015 at 05:03:20PM +0100, Catalin Marinas wrote: > > > There is another str x0 in __sys_trace_return which I think we could > > > remove. > > > > Hmm, I don't think we can remove that. It's needed on the slowpath to > > update the pt_regs with either -ENOSYS (for __ni_sys_trace) or the > > syscall return value from the blr in __sys_trace. > > > > What we can do instead is change the branch above to branch to > > __sys_trace_return_skipped. Patch below. > > > > Will > > > > --->8 > > > > diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S > > index 2a5e64ccc991..088322ff1ba0 100644 > > --- a/arch/arm64/kernel/entry.S > > +++ b/arch/arm64/kernel/entry.S > > @@ -619,7 +619,7 @@ ret_fast_syscall: > > kernel_exit 0 > > ret_fast_syscall_trace: > > enable_irq // enable interrupts > > - b __sys_trace_return > > + b __sys_trace_return_skipped // we already saved x0 > > That would do. With this added: > > Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx> > > (or I can take it for 4.2 but I'd like more testing like LTP) Yeah, I'll run some tests overnight and see how it holds up. Will -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html