From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756038AbZHYTET (ORCPT ); Tue, 25 Aug 2009 15:04:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755805AbZHYTES (ORCPT ); Tue, 25 Aug 2009 15:04:18 -0400 Received: from tomts16.bellnexxia.net ([209.226.175.4]:41081 "EHLO tomts16-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755662AbZHYTEQ (ORCPT ); Tue, 25 Aug 2009 15:04:16 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AigFAAfSk0pMROOX/2dsb2JhbACBU9dQhBoF Date: Tue, 25 Aug 2009 15:04:15 -0400 From: Mathieu Desnoyers To: Jason Baron Cc: Steven Rostedt , Frederic Weisbecker , linux-kernel@vger.kernel.org, x86@kernel.org, lethal@linux-sh.org, mingo@elte.hu, laijs@cn.fujitsu.com, peterz@infradead.org, jiayingz@google.com, mbligh@google.com, lizf@cn.fujitsu.com, jistone@redhat.com, tglx@linutronix.de, hpa@zytor.com Subject: Re: [PATCH 2/4] Add NR_syscalls for x86_64 Message-ID: <20090825190415.GB8474@Krystal> References: <233dfaa6fadd5aa2fa7ac8511ed9ab98a5f2619c.1251146513.git.jbaron@redhat.com> <20090824221447.GA5124@nowhere> <20090825134005.GB2656@redhat.com> <20090825184734.GE2656@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <20090825184734.GE2656@redhat.com> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.27.31-grsec (i686) X-Uptime: 14:56:12 up 7 days, 5:45, 2 users, load average: 0.81, 0.44, 0.35 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jason Baron (jbaron@redhat.com) wrote: > On Tue, Aug 25, 2009 at 09:40:05AM -0400, Jason Baron wrote: > > > > On Mon, Aug 24, 2009 at 05:40:18PM -0400, Jason Baron wrote: > > > > > Add a dynamic definition of NR_syscalls for x86_64. This is used in the > > > > > syscall events tracing code. > > > > > > > > > > Signed-off-by: Jason Baron > > > > > > > > > > --- > > > > > include/linux/ftrace.h | 5 +++++ > > > > > 1 files changed, 5 insertions(+), 0 deletions(-) > > > > > > > > > > diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h > > > > > index dc3b132..3bd94ee 100644 > > > > > --- a/include/linux/ftrace.h > > > > > +++ b/include/linux/ftrace.h > > > > > @@ -14,6 +14,11 @@ > > > > > > > > > > #include > > > > > > > > > > +#ifdef CONFIG_X86_64 > > > > > +#include > > > > > +#define NR_syscalls (__NR_syscall_max + 1) > > > > > +#endif > > > > > + > > > > > > > > > > > > I'd rather see this in arch/x86/include/unistd_64.h, since > > > > NR_syscalls seems to be the defined in unistd.h in all archs. > > > > > > > > That also makes a unified way to retrieve this number for > > > > other users. > > > > > > > > > > Yes, NR_syscalls should be included there. > > > > > > -- Steve > > > > right, for x86_64, unistd.h is included to generate __NR_syscall_max > > which is then used for NR_syscalls. So I did initially try it there, but > > there were dependency problems. I'll see what I can come up with... > > > > thanks, > > > > -Jason > > ok, since unistd_64.h is used to generate offsets.c, which eventually > generates, asm/asm-offsets.h, which defines, __NR_syscall_max, we can't > just put #define of NR_syscalls in unistd_64.h. However, it seems the > only point in time that unistd_64.h can not depend upon __NR_syscall_max, > is before asm/asm-offsets.h is defined. Thus, the patch below passes in > a '-DCREATE_OFFSETS' during the creation of asm/asm-offsets.h, so that > we do not include it before it exists. The patch is hacky but works. > thoughts? Ugh! My eyes hurt! What you are doing here is to basically put back the hardcoded NR_syscalls rather that using the build infrastructure already in place. If my memory serves me well, unistd_64.h generates __NR_syscall_max automatically by being included multiples times. Can we generalize this and make the information generated available in an automaticaly generated header instead ? It is saved in ams-offsets.h currently as "__NR_syscall_max". We could also save it somewhere else meant to be included by C code. Mathieu > > Signed-off-by: Jason Baron > > --- > > Kbuild | 2 +- > arch/x86/include/asm/unistd_64.h | 6 ++++++ > scripts/Makefile.build | 4 ++++ > 3 files changed, 11 insertions(+), 1 deletions(-) > > > diff --git a/Kbuild b/Kbuild > index f056b4f..5f43d4d 100644 > --- a/Kbuild > +++ b/Kbuild > @@ -78,7 +78,7 @@ endef > arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \ > $(obj)/$(bounds-file) FORCE > $(Q)mkdir -p $(dir $@) > - $(call if_changed_dep,cc_s_c) > + $(call if_changed_dep,cc_s_c_define_offset) > > $(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s Kbuild > $(call cmd,offsets) > diff --git a/arch/x86/include/asm/unistd_64.h b/arch/x86/include/asm/unistd_64.h > index 900e161..70c0c3d 100644 > --- a/arch/x86/include/asm/unistd_64.h > +++ b/arch/x86/include/asm/unistd_64.h > @@ -688,6 +688,12 @@ __SYSCALL(__NR_perf_counter_open, sys_perf_counter_open) > #endif /* __NO_STUBS */ > > #ifdef __KERNEL__ > + > +#ifndef CREATE_OFFSETS > +#include > +#define NR_syscalls (__NR_syscall_max + 1) > +#endif > + > /* > * "Conditional" syscalls > * > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index 5c4b7a4..4177858 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -145,6 +145,10 @@ $(multi-objs-y:.o=.lst) : modname = $(modname-multi) > quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ > cmd_cc_s_c = $(CC) $(c_flags) -fverbose-asm -S -o $@ $< > > +quiet_cmd_cc_s_c_define_offset = CC $(quiet_modtag) $@ > +cmd_cc_s_c_define_offset = $(CC) $(c_flags) -DCREATE_OFFSETS \ > + -fverbose-asm -S -o $@ $< > + > $(obj)/%.s: $(src)/%.c FORCE > $(call if_changed_dep,cc_s_c) > > > > > -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68