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[PATCH v2 4/4] x86: Stop Intel PT and save its registers when panic occurs

From Takao Indoh <indou.takao@jp.fujitsu.com>
Newsgroups linux.kernel
Subject [PATCH v2 4/4] x86: Stop Intel PT and save its registers when panic occurs
Date 2015-09-08 08:00 +0200
Message-ID <q6k6J-3KE-5@gated-at.bofh.it> (permalink)
References <q6jX3-3zi-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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 <indou.takao@jp.fujitsu.com>
---
 arch/x86/kernel/crash.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index e068d66..78deceb 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -35,6 +35,7 @@
 #include <asm/cpu.h>
 #include <asm/reboot.h>
 #include <asm/virtext.h>
+#include <asm/intel_pt_log.h>
 
 /* 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


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Thread

[PATCH v2 0/4] x86: Intel Processor Trace Logger Takao Indoh <indou.takao@jp.fujitsu.com> - 2015-09-08 07:50 +0200
  [PATCH v2 3/4] perf/x86/intel/pt: Add Intel PT logger Takao Indoh <indou.takao@jp.fujitsu.com> - 2015-09-08 08:00 +0200
    Re: [PATCH v2 3/4] perf/x86/intel/pt: Add Intel PT logger Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-09-08 11:50 +0200
      Re: [PATCH v2 3/4] perf/x86/intel/pt: Add Intel PT logger Takao Indoh <indou.takao@jp.fujitsu.com> - 2015-09-09 04:50 +0200
        Re: [PATCH v2 3/4] perf/x86/intel/pt: Add Intel PT logger Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-09-15 14:10 +0200
  [PATCH v2 4/4] x86: Stop Intel PT and save its registers when panic occurs Takao Indoh <indou.takao@jp.fujitsu.com> - 2015-09-08 08:00 +0200
  [PATCH v2 2/4] perf: Add function to enable perf events in kernel with ring buffer Takao Indoh <indou.takao@jp.fujitsu.com> - 2015-09-08 08:00 +0200
    Re: [PATCH v2 2/4] perf: Add function to enable perf events in kernel with ring buffer Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-09-08 11:40 +0200
      Re: [PATCH v2 2/4] perf: Add function to enable perf events in kernel  with ring buffer Takao Indoh <indou.takao@jp.fujitsu.com> - 2015-09-09 04:20 +0200
        Re: [PATCH v2 2/4] perf: Add function to enable perf events in kernel with ring buffer Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-09-15 14:10 +0200
  [PATCH v2 1/4] perf/trace: Add function to find event type by name Takao Indoh <indou.takao@jp.fujitsu.com> - 2015-09-08 08:00 +0200

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