From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753487Ab0FWP0b (ORCPT ); Wed, 23 Jun 2010 11:26:31 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:39437 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753358Ab0FWP03 (ORCPT ); Wed, 23 Jun 2010 11:26:29 -0400 X-Authority-Analysis: v=1.1 cv=CRXretTPUtnO3YxfLBAQPdv2BUzevxUrVWgTW+Y28TY= c=1 sm=0 a=IdOwrB8lMGEA:10 a=uEzv4HemXiYA:10 a=7U3hwN5JcxgA:10 a=Q9fys5e9bTEA:10 a=gMqfjgEr1zLu/65IO0LwxA==:17 a=20KFwNOVAAAA:8 a=VnNF1IyMAAAA:8 a=nf-zp79boe1UZuaW8YMA:9 a=JK5eNJezOygYmBU9u50A:7 a=6dPkz42Sqh1dSHIFFYHaRqvU3lUA:4 a=PUjeQqilurYA:10 a=jEp0ucaQiEUA:10 a=gMqfjgEr1zLu/65IO0LwxA==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.89.75 Subject: Re: [PATCH 10/40] tracing: add tracing support for compat syscalls From: Steven Rostedt Reply-To: rostedt@goodmis.org To: Ian Munsie Cc: linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, Jason Baron , Frederic Weisbecker , Ingo Molnar , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , "David S. Miller" , Andrew Morton , Arnd Bergmann , Lai Jiangshan , Masami Hiramatsu , Li Zefan In-Reply-To: <1277287401-28571-11-git-send-email-imunsie@au1.ibm.com> References: <1277287401-28571-1-git-send-email-imunsie@au1.ibm.com> <1277287401-28571-11-git-send-email-imunsie@au1.ibm.com> Content-Type: text/plain; charset="ISO-8859-15" Organization: Kihon Technologies Inc. Date: Wed, 23 Jun 2010 11:26:26 -0400 Message-ID: <1277306786.9181.51.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2010-06-23 at 20:02 +1000, Ian Munsie wrote: > From: Jason Baron > > Add core support to event tracing for compat syscalls. The basic idea is that we > check if we have a compat task via 'is_compat_task()'. If so, we lookup in the > new compat_syscalls_metadata table, the corresponding struct syscall_metadata, to > check syscall arguments and whether or not we are enabled. > > Signed-off-by: Jason Baron > Signed-off-by: Ian Munsie > --- > include/linux/compat.h | 2 + > include/trace/syscall.h | 4 ++ > kernel/trace/trace.h | 2 + > kernel/trace/trace_syscalls.c | 86 +++++++++++++++++++++++++++++++++++++---- > 4 files changed, 86 insertions(+), 8 deletions(-) > > diff --git a/include/linux/compat.h b/include/linux/compat.h > index ab638e9..a94f13d 100644 > --- a/include/linux/compat.h > +++ b/include/linux/compat.h > @@ -363,6 +363,8 @@ extern ssize_t compat_rw_copy_check_uvector(int type, > > #else /* CONFIG_COMPAT */ > > +#define NR_syscalls_compat 0 > + > static inline int is_compat_task(void) > { > return 0; > diff --git a/include/trace/syscall.h b/include/trace/syscall.h > index 75f3dce..67d4e64 100644 > --- a/include/trace/syscall.h > +++ b/include/trace/syscall.h > @@ -22,6 +22,7 @@ > struct syscall_metadata { > const char *name; > int syscall_nr; > + int compat_syscall_nr; This is also bloating the kernel. I don't like to add fields to the syscall_metadata lightly. You're adding 4 more bytes to this structure to handle a few items. Find a better way to do this. > int nb_args; > const char **types; > const char **args; > @@ -38,6 +39,9 @@ struct syscall_metadata { > > #ifdef CONFIG_FTRACE_SYSCALLS > extern unsigned long arch_syscall_addr(int nr); > +#ifdef CONFIG_COMPAT > +extern unsigned long arch_compat_syscall_addr(int nr); > +#endif > extern int init_syscall_trace(struct ftrace_event_call *call); > > extern int reg_event_syscall_enter(struct ftrace_event_call *call); > diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h > index 01ce088..53ace4b 100644 > --- a/kernel/trace/trace.h > +++ b/kernel/trace/trace.h > @@ -79,12 +79,14 @@ enum trace_type { > struct syscall_trace_enter { > struct trace_entry ent; > int nr; > + int compat; You're adding 4 bytes to a trace (taking up precious buffer space) for a single flag. If anything, set the 31st bit of nr if it is compat. -- Steve > unsigned long args[]; > }; > > struct syscall_trace_exit { > struct trace_entry ent; > int nr; > + int compat; > long ret; > }; >