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charset=UTF-8 X-Mailman-Approved-At: Tue, 20 Sep 2022 07:59:18 +1000 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: juri.lelli@redhat.com, rafael@kernel.org, catalin.marinas@arm.com, linus.walleij@linaro.org, bsegall@google.com, guoren@kernel.org, pavel@ucw.cz, agordeev@linux.ibm.com, srivatsa@csail.mit.edu, linux-arch@vger.kernel.org, vincent.guittot@linaro.org, chenhuacai@kernel.org, linux-acpi@vger.kernel.org, agross@kernel.org, geert@linux-m68k.org, linux-imx@nxp.com, vgupta@kernel.org, mattst88@gmail.com, borntraeger@linux.ibm.com, mturquette@baylibre.com, sammy@sammy.net, pmladek@suse.com, linux-pm@vger.kernel.org, Sascha Hauer , linux-um@lists.infradead.org, npiggin@gmail.com, tglx@linutronix.de, linux-omap@vger.kernel.org, dietmar.eggemann@arm.com, andreyknvl@gmail.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, senozhatsky@chromium.org, svens@linux.ibm.com, jolsa@kernel.org, tj@kernel.org, Andrew Morton , mark.rutland@arm.com, linux-ia64@vger.kernel.org, dave.hansen@linux.intel.com, vir tualization@lists.linux-foundation.org, James.Bottomley@HansenPartnership.com, jcmvbkbc@gmail.com, thierry.reding@gmail.com, kernel@xen0n.name, cl@linux.com, linux-s390@vger.kernel.org, vschneid@redhat.com, john.ogness@linutronix.de, ysato@users.sourceforge.jp, linux-sh@vger.kernel.org, festevam@gmail.com, deller@gmx.de, daniel.lezcano@linaro.org, jonathanh@nvidia.com, dennis@kernel.org, lenb@kernel.org, linux-xtensa@linux-xtensa.org, kernel@pengutronix.de, gor@linux.ibm.com, linux-arm-msm@vger.kernel.org, linux-alpha@vger.kernel.org, linux-m68k@lists.linux-m68k.org, loongarch@lists.linux.dev, shorne@gmail.com, chris@zankel.net, sboyd@kernel.org, dinguyen@kernel.org, bristot@redhat.com, alexander.shishkin@linux.intel.com, fweisbec@gmail.com, lpieralisi@kernel.org, atishp@atishpatra.org, linux@rasmusvillemoes.dk, kasan-dev@googlegroups.com, will@kernel.org, boris.ostrovsky@oracle.com, khilman@kernel.org, linux-csky@vger.kernel.org, pv-drivers@vmware.com, linux-snps-arc@lists.infradea d.org, mgorman@suse.de, jacob.jun.pan@linux.intel.com, Arnd Bergmann , ulli.kroll@googlemail.com, linux-clk@vger.kernel.org, rostedt@goodmis.org, ink@jurassic.park.msu.ru, bcain@quicinc.com, tsbogend@alpha.franken.de, linux-parisc@vger.kernel.org, ryabinin.a.a@gmail.com, sudeep.holla@arm.com, shawnguo@kernel.org, davem@davemloft.net, dalias@libc.org, tony@atomide.com, amakhalov@vmware.com, konrad.dybcio@somainline.org, bjorn.andersson@linaro.org, glider@google.com, hpa@zytor.com, sparclinux@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-riscv@lists.infradead.org, vincenzo.frascino@arm.com, anton.ivanov@cambridgegreys.com, jonas@southpole.se, yury.norov@gmail.com, richard@nod.at, x86@kernel.org, linux@armlinux.org.uk, mingo@redhat.com, aou@eecs.berkeley.edu, hca@linux.ibm.com, richard.henderson@linaro.org, stefan.kristiansson@saunalahti.fi, openrisc@lists.librecores.org, acme@kernel.org, paul.walmsley@sifive.com, linux-tegra@vger.kernel.org, namhyung@kernel.org, andriy.shevchenko@linux.intel.com, jpoimboe@kernel.org, dvyukov@google.com, jgross@suse.com, monstr@monstr.eu, linux-mips@vger.kernel.org, palmer@dabbelt.com, anup@brainfault.org, bp@alien8.de, johannes@sipsolutions.net, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" CONFIG_GENERIC_ENTRY disallows any and all tracing when RCU isn't enabled. XXX if s390 (the only other GENERIC_ENTRY user as of this writing) isn't comfortable with this, we could switch to HAVE_NOINSTR_VALIDATION which is x86_64 only atm. Signed-off-by: Peter Zijlstra (Intel) --- include/linux/tracepoint.h | 13 ++++++++++++- kernel/trace/trace.c | 3 +++ 2 files changed, 15 insertions(+), 1 deletion(-) --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -178,6 +178,16 @@ static inline struct tracepoint *tracepo #endif /* CONFIG_HAVE_STATIC_CALL */ /* + * CONFIG_GENERIC_ENTRY archs are expected to have sanitized entry and idle + * code that disallow any/all tracing/instrumentation when RCU isn't watching. + */ +#ifdef CONFIG_GENERIC_ENTRY +#define RCUIDLE_COND(rcuidle) (rcuidle) +#else +#define RCUIDLE_COND(rcuidle) (rcuidle && in_nmi()) +#endif + +/* * it_func[0] is never NULL because there is at least one element in the array * when the array itself is non NULL. */ @@ -189,7 +199,8 @@ static inline struct tracepoint *tracepo return; \ \ /* srcu can't be used from NMI */ \ - WARN_ON_ONCE(rcuidle && in_nmi()); \ + if (WARN_ON_ONCE(RCUIDLE_COND(rcuidle))) \ + return; \ \ /* keep srcu and sched-rcu usage consistent */ \ preempt_disable_notrace(); \ --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3104,6 +3104,9 @@ void __trace_stack(struct trace_array *t return; } + if (WARN_ON_ONCE(IS_ENABLED(CONFIG_GENERIC_ENTRY))) + return; + /* * When an NMI triggers, RCU is enabled via ct_nmi_enter(), * but if the above rcu_is_watching() failed, then the NMI