From e37b86ed2c5aa9cae9f5c3c1c5489348323ee481 Mon Sep 17 00:00:00 2001 From: Luming Yu Date: Fri, 29 Sep 2017 22:12:59 +0800 Subject: [PATCH v1 9/9] early pt: early start intel processor trace in early boot enable intel PT to trace kernel boot && runtime Signed-off-by: Luming Yu --- arch/x86/events/intel/early_pt.c | 19 +++++++++++++------ arch/x86/kernel/smpboot.c | 2 ++ init/main.c | 2 ++ 3 files changed, 17 insertions(+), 6 deletions(-) diff --git a/arch/x86/events/intel/early_pt.c b/arch/x86/events/intel/early_pt.c index 95225d6..253aa3d 100644 --- a/arch/x86/events/intel/early_pt.c +++ b/arch/x86/events/intel/early_pt.c @@ -140,11 +140,13 @@ static int early_pt_cpuid_caps(void) } return 0; } -static int start_early_pt(void *arg) +int start_early_pt(void *arg) { u64 val, oldval; int cpu; + if (__this_cpu_read(early_pt_running)) + return 0; if (rdmsrl_safe(MSR_IA32_RTIT_CTL, &val) < 0) { pr_info("start_early_pt: failed\n"); @@ -220,6 +222,7 @@ static int start_early_pt(void *arg) __this_cpu_write(early_pt_running, true); return 0; } +EXPORT_SYMBOL(start_early_pt); static void start_pt_no_return(void *arg) { @@ -229,20 +232,24 @@ static void start_pt_no_return(void *arg) static struct miscdevice early_pt_miscdev; -static int early_pt_init(void) +int early_pt_init(void) { int err; if (!early_pt_enabled) return 0; - err = early_pt_cpuid_caps(); - if (err < 0) { - pr_info("early_pt_init: no feature available\n"); - return err; + if (!__this_cpu_read(early_pt_running)) { + err = early_pt_cpuid_caps(); + if (err < 0) { + pr_info("early_pt_init: no feature available\n"); + return err; + } } on_each_cpu(start_pt_no_return, NULL, 0); return 0; } +EXPORT_SYMBOL(early_pt_init); + static int late_pt_init(void) { int err; diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 54b9e89..fd366ed 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -220,6 +220,7 @@ static void smp_callin(void) static int cpu0_logical_apicid; static int enable_start_cpu0; +extern int start_early_pt(void *); /* * Activate a secondary processor. */ @@ -231,6 +232,7 @@ static void notrace start_secondary(void *unused) * most necessary things. */ cpu_init(); + start_early_pt(NULL); x86_cpuinit.early_percpu_clock_init(); preempt_disable(); smp_callin(); diff --git a/init/main.c b/init/main.c index c0c7cf0..7792e54 100644 --- a/init/main.c +++ b/init/main.c @@ -506,6 +506,7 @@ static void __init mm_init(void) ioremap_huge_init(); } +extern int early_pt_init(void); asmlinkage __visible void __init start_kernel(void) { char *command_line; @@ -567,6 +568,7 @@ asmlinkage __visible void __init start_kernel(void) trap_init(); mm_init(); + early_pt_init(); ftrace_init(); /* trace_printk can be enabled here */ -- 2.7.5