Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752078AbbG2Ew1 (ORCPT ); Wed, 29 Jul 2015 00:52:27 -0400 Received: from mgwkm04.jp.fujitsu.com ([202.219.69.171]:56303 "EHLO mgwkm04.jp.fujitsu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751676AbbG2EwY (ORCPT ); Wed, 29 Jul 2015 00:52:24 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v2.2.3 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20140219-2 From: Takao Indoh To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Peter Zijlstra , Arnaldo Carvalho de Melo , Alexander Shishkin , Vivek Goyal CC: , Subject: [PATCH RFC 3/3] x86: Stop Intel PT and save its registers when panic occurs Date: Wed, 29 Jul 2015 13:51:36 +0900 Message-ID: <1438145496-5932-4-git-send-email-indou.takao@jp.fujitsu.com> X-Mailer: git-send-email 2.4.5 In-Reply-To: <1438145496-5932-1-git-send-email-indou.takao@jp.fujitsu.com> References: <1438145496-5932-1-git-send-email-indou.takao@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain X-SecurityPolicyCheck-GC: OK by FENCE-Mail X-TM-AS-MML: disable Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2009 Lines: 65 When panic occurs, Intel PT logging is stopped to prevent it from overwrite its log buffer. The registers of Intel PT are saved in the memory on panic, they are needed for debugger to find the last position where Intel PT wrote data. Signed-off-by: Takao Indoh --- arch/x86/include/asm/intel_pt.h | 2 ++ arch/x86/kernel/crash.c | 9 +++++++++ 2 files changed, 11 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/intel_pt.h b/arch/x86/include/asm/intel_pt.h index 7cb16e1..71bcd8d 100644 --- a/arch/x86/include/asm/intel_pt.h +++ b/arch/x86/include/asm/intel_pt.h @@ -79,4 +79,6 @@ u32 pt_cap_get(enum pt_capabilities cap); const char *pt_cap_name(enum pt_capabilities cap); int pt_cap_num(void); +void save_intel_pt_registers(void); + #endif /* __INTEL_PT_H__ */ diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index e068d66..953c086 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -35,6 +35,7 @@ #include #include #include +#include /* Alignment required for elf header segment */ #define ELF_CORE_HEADER_ALIGN 4096 @@ -127,6 +128,10 @@ static void kdump_nmi_callback(int cpu, struct pt_regs *regs) cpu_emergency_vmxoff(); cpu_emergency_svm_disable(); +#ifdef CONFIG_X86_INTEL_PT_LOG + save_intel_pt_registers(); +#endif + disable_local_APIC(); } @@ -172,6 +177,10 @@ void native_machine_crash_shutdown(struct pt_regs *regs) cpu_emergency_vmxoff(); cpu_emergency_svm_disable(); +#ifdef CONFIG_X86_INTEL_PT_LOG + save_intel_pt_registers(); +#endif + #ifdef CONFIG_X86_IO_APIC /* Prevent crash_kexec() from deadlocking on ioapic_lock. */ ioapic_zap_locks(); -- 1.7.1 -- 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/