From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH v4 05/27] x86: Replace ist_enter() with nmi_enter() Date: Wed, 26 Feb 2020 11:25:09 +0100 Message-ID: <20200226102509.GU18400@hirez.programming.kicks-ass.net> References: <20200221133416.777099322@infradead.org> <20200221134215.328642621@infradead.org> <20200221202246.GA14897@hirez.programming.kicks-ass.net> <20200224104346.GJ14946@hirez.programming.kicks-ass.net> <20200224112708.4f307ba3@gandalf.local.home> <20200224163409.GJ18400@hirez.programming.kicks-ass.net> <20200224114754.0fb798c1@gandalf.local.home> <20200224213139.GO11457@worktop.programming.kicks-ass.net> <20200224170231.3807931d@gandalf.local.home> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from bombadil.infradead.org ([198.137.202.133]:41234 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726057AbgBZKZq (ORCPT ); Wed, 26 Feb 2020 05:25:46 -0500 Content-Disposition: inline In-Reply-To: <20200224170231.3807931d@gandalf.local.home> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Steven Rostedt Cc: Andy Lutomirski , LKML , linux-arch , Ingo Molnar , Joel Fernandes , Greg KH , gustavo@embeddedor.com, Thomas Gleixner , paulmck@kernel.org, Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Tony Luck , Frederic Weisbecker , Dan Carpenter , Masami Hiramatsu On Mon, Feb 24, 2020 at 05:02:31PM -0500, Steven Rostedt wrote: > On Mon, 24 Feb 2020 22:31:39 +0100 > Peter Zijlstra wrote: > > > > Just want to confirm that printk_nmi_enter(), lockdep_off(), > > > and ftrace_nmi_enter() are all marked fully with NOKPROBE. > > > > *sigh*, right you are, I only looked at notrace, not nokprobe. > > > > In particular the ftrace one is a bit off a mess, let me sort through > > that. > > ftrace_nmi_enter() has two purposes. One, for archs that need to deal with > NMIs while they still use stop machine. Although, it appears sh is the only > arch that does that. I can look to see if it can be ripped out. Already done :-) --- Subject: sh/ftrace: Move arch_ftrace_nmi_{enter,exit} into nmi exception From: Peter Zijlstra Date: Mon Feb 24 22:26:21 CET 2020 SuperH is the last remaining user of arch_ftrace_nmi_{enter,exit}(), remove it from the generic code and into the SuperH code. Signed-off-by: Peter Zijlstra (Intel) --- Documentation/trace/ftrace-design.rst | 8 -------- arch/sh/Kconfig | 1 - arch/sh/kernel/traps.c | 12 ++++++++++++ include/linux/ftrace_irq.h | 11 ----------- kernel/trace/Kconfig | 10 ---------- 5 files changed, 12 insertions(+), 30 deletions(-) --- a/Documentation/trace/ftrace-design.rst +++ b/Documentation/trace/ftrace-design.rst @@ -229,14 +229,6 @@ Adding support for it is easy: just defi pass the return address pointer as the 'retp' argument to ftrace_push_return_trace(). -HAVE_FTRACE_NMI_ENTER ---------------------- - -If you can't trace NMI functions, then skip this option. - -
- - HAVE_SYSCALL_TRACEPOINTS ------------------------ --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -71,7 +71,6 @@ config SUPERH32 select HAVE_FUNCTION_TRACER select HAVE_FTRACE_MCOUNT_RECORD select HAVE_DYNAMIC_FTRACE - select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE select ARCH_WANT_IPC_PARSE_VERSION select HAVE_FUNCTION_GRAPH_TRACER select HAVE_ARCH_KGDB --- a/arch/sh/kernel/traps.c +++ b/arch/sh/kernel/traps.c @@ -170,11 +170,21 @@ BUILD_TRAP_HANDLER(bug) force_sig(SIGTRAP); } +#ifdef CONFIG_HAVE_DYNAMIC_FTRACE +extern void arch_ftrace_nmi_enter(void); +extern void arch_ftrace_nmi_exit(void); +#else +static inline void arch_ftrace_nmi_enter(void) { } +static inline void arch_ftrace_nmi_exit(void) { } +#endif + BUILD_TRAP_HANDLER(nmi) { unsigned int cpu = smp_processor_id(); TRAP_HANDLER_DECL; + arch_ftrace_nmi_enter(); + nmi_enter(); nmi_count(cpu)++; @@ -190,4 +200,6 @@ BUILD_TRAP_HANDLER(nmi) } nmi_exit(); + + arch_ftrace_nmi_exit(); } --- a/include/linux/ftrace_irq.h +++ b/include/linux/ftrace_irq.h @@ -2,15 +2,6 @@ #ifndef _LINUX_FTRACE_IRQ_H #define _LINUX_FTRACE_IRQ_H - -#ifdef CONFIG_FTRACE_NMI_ENTER -extern void arch_ftrace_nmi_enter(void); -extern void arch_ftrace_nmi_exit(void); -#else -static inline void arch_ftrace_nmi_enter(void) { } -static inline void arch_ftrace_nmi_exit(void) { } -#endif - #ifdef CONFIG_HWLAT_TRACER extern bool trace_hwlat_callback_enabled; extern void trace_hwlat_callback(bool enter); @@ -22,12 +13,10 @@ static inline void ftrace_nmi_enter(void if (trace_hwlat_callback_enabled) trace_hwlat_callback(true); #endif - arch_ftrace_nmi_enter(); } static inline void ftrace_nmi_exit(void) { - arch_ftrace_nmi_exit(); #ifdef CONFIG_HWLAT_TRACER if (trace_hwlat_callback_enabled) trace_hwlat_callback(false); --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -10,11 +10,6 @@ config USER_STACKTRACE_SUPPORT config NOP_TRACER bool -config HAVE_FTRACE_NMI_ENTER - bool - help - See Documentation/trace/ftrace-design.rst - config HAVE_FUNCTION_TRACER bool help @@ -72,11 +67,6 @@ config RING_BUFFER select TRACE_CLOCK select IRQ_WORK -config FTRACE_NMI_ENTER - bool - depends on HAVE_FTRACE_NMI_ENTER - default y - config EVENT_TRACING select CONTEXT_SWITCH_TRACER select GLOB