oprofile, x86: Add kernel parameter oprofile.cpu_type=timer

We need this to better test x86 NMI timer mode. Otherwise it is very hard to setup systems with NMI timer enabled, but we have this e.g. in virtual machine environments. Signed-off-by: Robert Richter <robert.richter@amd.com>

oprofile, x86: Add kernel parameter oprofile.cpu_type=timer
We need this to better test x86 NMI timer mode. Otherwise it is very hard to setup systems with NMI timer enabled, but we have this e.g. in virtual machine environments. Signed-off-by: Robert Richter <robert.richter@amd.com>
Robert Richter
1 parent 97f7f8189f
Showing 2 changed files with 24 additions and 6 deletions Side-by-side Diff
Documentation/kernel-parameters.txt
arch/x86/oprofile/nmi_int.c
@@ -1848,6 +1848,9 @@
 			arch_perfmon: [X86] Force use of architectural
 				perfmon on Intel CPUs instead of the
 				CPU specific event set.
+			timer: [X86] Force use of architectural NMI
+				timer mode (see also oprofile.timer
+				for generic hr timer mode)
  
 	oops=panic	Always panic on oopses. Default is to just kill the
 			process, but there is a small probability of
@@ -613,24 +613,36 @@
 	return 0;
 }
  
-static int force_arch_perfmon;
-static int force_cpu_type(const char *str, struct kernel_param *kp)
+enum __force_cpu_type {
+	reserved = 0,		/* do not force */
+	timer,
+	arch_perfmon,
+};
+
+static int force_cpu_type;
+
+static int set_cpu_type(const char *str, struct kernel_param *kp)
 {
-	if (!strcmp(str, "arch_perfmon")) {
-		force_arch_perfmon = 1;
+	if (!strcmp(str, "timer")) {
+		force_cpu_type = timer;
+		printk(KERN_INFO "oprofile: forcing NMI timer mode\n");
+	} else if (!strcmp(str, "arch_perfmon")) {
+		force_cpu_type = arch_perfmon;
 		printk(KERN_INFO "oprofile: forcing architectural perfmon\n");
+	} else {
+		force_cpu_type = 0;
 	}
  
 	return 0;
 }
-module_param_call(cpu_type, force_cpu_type, NULL, NULL, 0);
+module_param_call(cpu_type, set_cpu_type, NULL, NULL, 0);
  
 static int __init ppro_init(char **cpu_type)
 {
 	__u8 cpu_model = boot_cpu_data.x86_model;
 	struct op_x86_model_spec *spec = &op_ppro_spec;	/* default */
  
-	if (force_arch_perfmon && cpu_has_arch_perfmon)
+	if (force_cpu_type == arch_perfmon && cpu_has_arch_perfmon)
 		return 0;
  
 	/*
@@ -695,6 +707,9 @@
 	int ret = 0;
  
 	if (!cpu_has_apic)
+		return -ENODEV;
+
+	if (force_cpu_type == timer)
 		return -ENODEV;
  
 	switch (vendor) {
...	...	@@ -1848,6 +1848,9 @@
1848	1848	arch_perfmon: [X86] Force use of architectural
1849	1849	perfmon on Intel CPUs instead of the
1850	1850	CPU specific event set.
	1851	+ timer: [X86] Force use of architectural NMI
	1852	+ timer mode (see also oprofile.timer
	1853	+ for generic hr timer mode)
1851	1854
1852	1855	oops=panic Always panic on oopses. Default is to just kill the
1853	1856	process, but there is a small probability of
...	...	@@ -613,24 +613,36 @@
613	613	return 0;
614	614	}
615	615
616		-static int force_arch_perfmon;
617		-static int force_cpu_type(const char str, struct kernel_param kp)
	616	+enum __force_cpu_type {
	617	+ reserved = 0, /* do not force */
	618	+ timer,
	619	+ arch_perfmon,
	620	+};
	621	+
	622	+static int force_cpu_type;
	623	+
	624	+static int set_cpu_type(const char str, struct kernel_param kp)
618	625	{
619		- if (!strcmp(str, "arch_perfmon")) {
620		- force_arch_perfmon = 1;
	626	+ if (!strcmp(str, "timer")) {
	627	+ force_cpu_type = timer;
	628	+ printk(KERN_INFO "oprofile: forcing NMI timer mode\n");
	629	+ } else if (!strcmp(str, "arch_perfmon")) {
	630	+ force_cpu_type = arch_perfmon;
621	631	printk(KERN_INFO "oprofile: forcing architectural perfmon\n");
	632	+ } else {
	633	+ force_cpu_type = 0;
622	634	}
623	635
624	636	return 0;
625	637	}
626		-module_param_call(cpu_type, force_cpu_type, NULL, NULL, 0);
	638	+module_param_call(cpu_type, set_cpu_type, NULL, NULL, 0);
627	639
628	640	static int __init ppro_init(char **cpu_type)
629	641	{
630	642	__u8 cpu_model = boot_cpu_data.x86_model;
631	643	struct op_x86_model_spec spec = &op_ppro_spec; / default */
632	644
633		- if (force_arch_perfmon && cpu_has_arch_perfmon)
	645	+ if (force_cpu_type == arch_perfmon && cpu_has_arch_perfmon)
634	646	return 0;
635	647
636	648	/*
...	...	@@ -695,6 +707,9 @@
695	707	int ret = 0;
696	708
697	709	if (!cpu_has_apic)
	710	+ return -ENODEV;
	711	+
	712	+ if (force_cpu_type == timer)
698	713	return -ENODEV;
699	714
700	715	switch (vendor) {