Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752767AbbF3MVW (ORCPT ); Tue, 30 Jun 2015 08:21:22 -0400 Received: from mail.skyhub.de ([78.46.96.112]:56494 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753074AbbF3MVJ (ORCPT ); Tue, 30 Jun 2015 08:21:09 -0400 Date: Tue, 30 Jun 2015 14:20:47 +0200 From: Borislav Petkov To: Andy Lutomirski Cc: x86@kernel.org, linux-kernel@vger.kernel.org, =?utf-8?B?RnLDqWTDqXJpYw==?= Weisbecker , Rik van Riel , Oleg Nesterov , Denys Vlasenko , Kees Cook , Brian Gerst , paulmck@linux.vnet.ibm.com Subject: Re: [PATCH v4 04/17] context_tracking: Add ct_state and CT_WARN_ON Message-ID: <20150630122047.GD23297@pd.tnic> References: <5da41fb2ceb29eac671f427c67040401ba2a1fa0.1435602481.git.luto@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <5da41fb2ceb29eac671f427c67040401ba2a1fa0.1435602481.git.luto@kernel.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2763 Lines: 85 On Mon, Jun 29, 2015 at 12:33:36PM -0700, Andy Lutomirski wrote: > This will let us sprinkle sanity checks around the kernel without > making too much of a mess. > > Signed-off-by: Andy Lutomirski > --- > include/linux/context_tracking.h | 15 +++++++++++++++ > include/linux/context_tracking_state.h | 1 + > 2 files changed, 16 insertions(+) > > diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h > index b96bd299966f..008fc67d0d96 100644 > --- a/include/linux/context_tracking.h > +++ b/include/linux/context_tracking.h > @@ -49,13 +49,28 @@ static inline void exception_exit(enum ctx_state prev_ctx) > } > } > > + > +/** > + * ct_state() - return the current context tracking state if known > + * > + * Returns the current cpu's context tracking state if context tracking CPU's > + * is enabled. If context tracking is disabled, returns > + * CONTEXT_DISABLED. This should be used primarily for debugging. > + */ > +static inline enum ctx_state ct_state(void) > +{ > + return context_tracking_is_enabled() ? > + this_cpu_read(context_tracking.state) : CONTEXT_DISABLED; > +} > #else > static inline void user_enter(void) { } > static inline void user_exit(void) { } > static inline enum ctx_state exception_enter(void) { return 0; } > static inline void exception_exit(enum ctx_state prev_ctx) { } > +static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; } > #endif /* !CONFIG_CONTEXT_TRACKING */ > > +#define CT_WARN_ON(cond) WARN_ON(context_tracking_is_enabled() && (cond)) Btw, that "CT_" prefix makes this look like it is the software controlling this thing: https://upload.wikimedia.org/wikipedia/commons/thumb/2/27/UPMCEast_CTscan.jpg/1280px-UPMCEast_CTscan.jpg :-) Other kernel code uses "cxt" or "ctxt" abbreviations. Maybe CTXT_WARN_ON(cond) ... > #ifdef CONFIG_CONTEXT_TRACKING_FORCE > extern void context_tracking_init(void); > diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h > index 678ecdf90cf6..ee956c528fab 100644 > --- a/include/linux/context_tracking_state.h > +++ b/include/linux/context_tracking_state.h > @@ -14,6 +14,7 @@ struct context_tracking { > bool active; > int recursion; > enum ctx_state { > + CONTEXT_DISABLED = -1, /* returned by ct_state() if unknown */ > CONTEXT_KERNEL = 0, > CONTEXT_USER, > CONTEXT_GUEST, And those then CTXT_* -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/