From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932701Ab2GMKTQ (ORCPT ); Fri, 13 Jul 2012 06:19:16 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:50565 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932482Ab2GMKTL (ORCPT ); Fri, 13 Jul 2012 06:19:11 -0400 From: Anton Vorontsov To: Russell King , Jason Wessel Cc: =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= , Colin Cross , John Stultz , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linaro-kernel@lists.linaro.org, patches@linaro.org, kernel-team@android.com, kgdb-bugreport@lists.sourceforge.net Subject: [PATCH 2/8] kernel/debug: Mask KGDB NMI upon entry Date: Fri, 13 Jul 2012 03:16:42 -0700 Message-Id: <1342174608-22407-2-git-send-email-anton.vorontsov@linaro.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <20120713101605.GA16139@lizard> References: <20120713101605.GA16139@lizard> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The new arch callback should manage NMIs that usually cause KGDB to enter. That is, not all NMIs should be enabled/disabled, but only those that issue kgdb_handle_exception(). We must mask it as serial-line interrupt can be used as an NMI, so if the original KGDB-entry cause was say a breakpoint, then every input to KDB console will cause KGDB to reenter, which we don't want. Signed-off-by: Anton Vorontsov --- include/linux/kgdb.h | 9 +++++++++ kernel/debug/debug_core.c | 12 +++++++++++- 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h index c4d2fc1..47e739e 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -221,6 +221,15 @@ extern int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt); */ extern void kgdb_arch_late(void); +/** + * kgdb_arch_enable_nmi - Enable or disable KGDB-entry NMI + * @on: Flag to either enable or disable an NMI + * + * This function manages NMIs that usually cause KGDB to enter. That is, + * not all NMIs should be enabled or disabled, but only those that issue + * kgdb_handle_exception(). + */ +extern void kgdb_arch_enable_nmi(bool on); /** * struct kgdb_arch - Describe architecture specific values. diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 0557f24..e285600 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -214,6 +214,10 @@ int __weak kgdb_skipexception(int exception, struct pt_regs *regs) return 0; } +void __weak kgdb_arch_enable_nmi(bool on) +{ +} + /* * Some architectures need cache flushes when we set/clear a * breakpoint: @@ -672,6 +676,9 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) { struct kgdb_state kgdb_var; struct kgdb_state *ks = &kgdb_var; + int ret; + + kgdb_arch_enable_nmi(0); ks->cpu = raw_smp_processor_id(); ks->ex_vector = evector; @@ -685,7 +692,10 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) if (kgdb_info[ks->cpu].enter_kgdb != 0) return 0; - return kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); + ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); + + kgdb_arch_enable_nmi(1); + return ret; } int kgdb_nmicallback(int cpu, void *regs) -- 1.7.10.4