Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754819Ab3JCRP2 (ORCPT ); Thu, 3 Oct 2013 13:15:28 -0400 Received: from mail-ea0-f181.google.com ([209.85.215.181]:48222 "EHLO mail-ea0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754515Ab3JCRPY (ORCPT ); Thu, 3 Oct 2013 13:15:24 -0400 Date: Thu, 3 Oct 2013 19:15:20 +0200 From: Ingo Molnar To: Mike Travis Cc: Ingo Molnar , Jason Wessel , Peter Zijlstra , Paul Mackerras , Arnaldo Carvalho de Melo , "H. Peter Anvin" , Thomas Gleixner , Andrew Morton , Dimitri Sivanich , Hedi Berriche , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] PATCH: KGDB/KDB Fix no KDB config problem. Message-ID: <20131003171520.GA5144@gmail.com> References: <20131003163824.966169920@asylum.americas.sgi.com> <20131003163825.184494258@asylum.americas.sgi.com> <20131003165122.GB32755@gmail.com> <524DA381.2050108@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <524DA381.2050108@sgi.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3749 Lines: 107 * Mike Travis wrote: > > > On 10/3/2013 9:51 AM, Ingo Molnar wrote: > > > > * Mike Travis wrote: > > > >> Some code added to the debug_core module had KDB dependencies > >> that it shouldn't have. > >> > >> Signed-off-by: Mike Travis > >> --- > >> kernel/debug/debug_core.c | 8 ++++---- > >> kernel/debug/debug_core.h | 2 ++ > >> 2 files changed, 6 insertions(+), 4 deletions(-) > >> > >> --- linux.orig/kernel/debug/debug_core.c > >> +++ linux/kernel/debug/debug_core.c > >> @@ -575,8 +575,8 @@ return_normal: > >> raw_spin_lock(&dbg_slave_lock); > >> > >> #ifdef CONFIG_SMP > >> - /* If SYSTEM_NMI, slaves are already waiting */ > >> - if (ks->err_code == KDB_REASON_SYSTEM_NMI) > >> + /* If send_ready set, slaves are already waiting */ > >> + if (ks->send_ready) > >> atomic_set(ks->send_ready, 1); > >> > >> /* Signal the other CPUs to enter kgdb_wait() */ > >> @@ -682,11 +682,11 @@ kgdb_handle_exception(int evector, int s > >> if (arch_kgdb_ops.enable_nmi) > >> arch_kgdb_ops.enable_nmi(0); > >> > >> + memset(ks, 0, sizeof(struct kgdb_state)); > >> ks->cpu = raw_smp_processor_id(); > >> ks->ex_vector = evector; > >> ks->signo = signo; > >> ks->err_code = ecode; > >> - ks->kgdb_usethreadid = 0; > >> ks->linux_regs = regs; > >> > >> if (kgdb_reenter_check(ks)) > >> @@ -750,7 +750,7 @@ int kgdb_nmicallin(int cpu, int trapnr, > >> ks->cpu = cpu; > >> ks->ex_vector = trapnr; > >> ks->signo = SIGTRAP; > >> - ks->err_code = KDB_REASON_SYSTEM_NMI; > >> + ks->err_code = KGDB_KDB_REASON_SYSTEM_NMI; > >> ks->linux_regs = regs; > >> ks->send_ready = send_ready; > >> kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); > >> --- linux.orig/kernel/debug/debug_core.h > >> +++ linux/kernel/debug/debug_core.h > >> @@ -75,11 +75,13 @@ extern int kdb_stub(struct kgdb_state *k > >> extern int kdb_parse(const char *cmdstr); > >> extern int kdb_common_init_state(struct kgdb_state *ks); > >> extern int kdb_common_deinit_state(void); > >> +#define KGDB_KDB_REASON_SYSTEM_NMI KDB_REASON_SYSTEM_NMI > >> #else /* ! CONFIG_KGDB_KDB */ > >> static inline int kdb_stub(struct kgdb_state *ks) > >> { > >> return DBG_PASS_EVENT; > >> } > >> +#define KGDB_KDB_REASON_SYSTEM_NMI 0 > >> #endif /* CONFIG_KGDB_KDB */ > >> > >> #endif /* _DEBUG_CORE_H_ */ > > > > Hm, the KGDB_KDB_REASON_SYSTEM_NMI definition is a bit ugly. I still think > > there are layering violations here and just kludging it around doesn't > > solve it - a helper function that keeps kgdb details to the kgdb code > > would. > > > > Anyway, if Jason is fine with this solution and upholds his Acked-by then > > I'll merge this into the first patch and apply the two patches. > > > > Thanks, > > > > Ingo > > > > Would you prefer a simple #ifdef CONFIG_KGDB_KDB around the assignment? An #ifdef doesn't solve the layering violation! kernel/debug/debug_core.c didn't have any serious use of #ifdef CONFIG_KGDB_KDB before (it used it to flavor a few printks) and I'm not convinced it needs one for this feature either. So if that whole chunk is kdb dependent, why not shuffle that into a nicely named function and host it somewhere appropriate in kernel/debug/kdb/? That function would turn into an empty inline function in the !CONFIG_KGDB_KDB case. But ... it's up to Jason really whether he wants to abstract that piece of code out, I'm just kibitzing here really. Thanks, Ingo -- 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/