x86/aperfmperf: Untangle Intel and AMD frequency invariance init

AMD boot CPU initialization happens late via ACPI/CPPC which prevents the
Intel parts from being marked __init.

Split out the common code and provide a dedicated interface for the AMD
initialization and mark the Intel specific code and data __init.

The remaining text size is almost cut in half:

text: 2614 -> 1350
init.text: 0 -> 786

Signed-off-by: Thomas Gleixner <[e-mail]>
Reviewed-by: Rafael J. Wysocki <[e-mail]>
Acked-by: Peter Zijlstra (Intel) <[e-mail]>
Acked-by: Paul E. McKenney <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/x86/include/asm/topology.h

···
 #define arch_scale_freq_tick arch_scale_freq_tick
 
 extern void arch_set_max_freq_ratio(bool turbo_disabled);
-extern void bp_init_freq_invariance(bool cppc_ready);
+extern void freq_invariance_set_perf_ratio(u64 ratio, bool turbo_disabled);
+extern void bp_init_freq_invariance(void);
 extern void ap_init_freq_invariance(void);
 #else
 static inline void arch_set_max_freq_ratio(bool turbo_disabled) { }
-static inline void bp_init_freq_invariance(bool cppc_ready) { }
+static inline void freq_invariance_set_perf_ratio(u64 ratio, bool turbo_disabled) { }
+static inline void bp_init_freq_invariance(void) { }
 static inline void ap_init_freq_invariance(void) { }
 #endif
 
 #ifdef CONFIG_ACPI_CPPC_LIB
 void init_freq_invariance_cppc(void);
 #define arch_init_invariance_cppc init_freq_invariance_cppc
-
-bool amd_set_max_freq_ratio(u64 *ratio);
-#else
-static inline bool amd_set_max_freq_ratio(u64 *ratio)
-{
-	return false;
-}
 #endif
 
 #endif /* _ASM_X86_TOPOLOGY_H */

arch/x86/kernel/acpi/cppc.c

···
 	return err;
 }
 
-bool amd_set_max_freq_ratio(u64 *ratio)
+static void amd_set_max_freq_ratio(void)
 {
 	struct cppc_perf_caps perf_caps;
 	u64 highest_perf, nominal_perf;
 	u64 perf_ratio;
 	int rc;
 
-	if (!ratio)
-		return false;
-
 	rc = cppc_get_perf_caps(0, &perf_caps);
 	if (rc) {
 		pr_debug("Could not retrieve perf counters (%d)\n", rc);
-		return false;
+		return;
 	}
 
 	highest_perf = amd_get_highest_perf();
···
 
 	if (!highest_perf || !nominal_perf) {
 		pr_debug("Could not retrieve highest or nominal performance\n");
-		return false;
+		return;
 	}
 
 	perf_ratio = div_u64(highest_perf * SCHED_CAPACITY_SCALE, nominal_perf);
···
 	perf_ratio = (perf_ratio + SCHED_CAPACITY_SCALE) >> 1;
 	if (!perf_ratio) {
 		pr_debug("Non-zero highest/nominal perf values led to a 0 ratio\n");
-		return false;
+		return;
 	}
 
-	*ratio = perf_ratio;
-	arch_set_max_freq_ratio(false);
-
-	return true;
+	freq_invariance_set_perf_ratio(perf_ratio, false);
 }
 
 static DEFINE_MUTEX(freq_invariance_lock);
 
 void init_freq_invariance_cppc(void)
 {
-	static bool secondary;
+	static bool init_done;
+
+	if (!cpu_feature_enabled(X86_FEATURE_APERFMPERF))
+		return;
+
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+		return;
 
 	mutex_lock(&freq_invariance_lock);
-
-	if (!secondary)
-		bp_init_freq_invariance(true);
-	secondary = true;
-
+	if (!init_done)
+		amd_set_max_freq_ratio();
+	init_done = true;
 	mutex_unlock(&freq_invariance_lock);
 }

arch/x86/kernel/cpu/aperfmperf.c

···
 }
 EXPORT_SYMBOL_GPL(arch_set_max_freq_ratio);
 
-static bool turbo_disabled(void)
+static bool __init turbo_disabled(void)
 {
 	u64 misc_en;
 	int err;
···
 	return (misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE);
 }
 
-static bool slv_set_max_freq_ratio(u64 *base_freq, u64 *turbo_freq)
+static bool __init slv_set_max_freq_ratio(u64 *base_freq, u64 *turbo_freq)
 {
 	int err;
 
···
 	X86_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 6,		\
 		INTEL_FAM6_##model, X86_FEATURE_APERFMPERF, NULL)
 
-static const struct x86_cpu_id has_knl_turbo_ratio_limits[] = {
+static const struct x86_cpu_id has_knl_turbo_ratio_limits[] __initconst = {
 	X86_MATCH(XEON_PHI_KNL),
 	X86_MATCH(XEON_PHI_KNM),
 	{}
 };
 
-static const struct x86_cpu_id has_skx_turbo_ratio_limits[] = {
+static const struct x86_cpu_id has_skx_turbo_ratio_limits[] __initconst = {
 	X86_MATCH(SKYLAKE_X),
 	{}
 };
 
-static const struct x86_cpu_id has_glm_turbo_ratio_limits[] = {
+static const struct x86_cpu_id has_glm_turbo_ratio_limits[] __initconst = {
 	X86_MATCH(ATOM_GOLDMONT),
 	X86_MATCH(ATOM_GOLDMONT_D),
 	X86_MATCH(ATOM_GOLDMONT_PLUS),
 	{}
 };
 
-static bool knl_set_max_freq_ratio(u64 *base_freq, u64 *turbo_freq,
-				int num_delta_fratio)
+static bool __init knl_set_max_freq_ratio(u64 *base_freq, u64 *turbo_freq,
+					  int num_delta_fratio)
 {
 	int fratio, delta_fratio, found;
 	int err, i;
···
 	return true;
 }
 
-static bool skx_set_max_freq_ratio(u64 *base_freq, u64 *turbo_freq, int size)
+static bool __init skx_set_max_freq_ratio(u64 *base_freq, u64 *turbo_freq, int size)
 {
 	u64 ratios, counts;
 	u32 group_size;
···
 	return false;
 }
 
-static bool core_set_max_freq_ratio(u64 *base_freq, u64 *turbo_freq)
+static bool __init core_set_max_freq_ratio(u64 *base_freq, u64 *turbo_freq)
 {
 	u64 msr;
 	int err;
···
 	return true;
 }
 
-static bool intel_set_max_freq_ratio(void)
+static bool __init intel_set_max_freq_ratio(void)
 {
 	u64 base_freq, turbo_freq;
 	u64 turbo_ratio;
···
 
 static void register_freq_invariance_syscore_ops(void)
 {
-	/* Bail out if registered already. */
-	if (freq_invariance_syscore_ops.node.prev)
-		return;
-
 	register_syscore_ops(&freq_invariance_syscore_ops);
 }
 #else
 static inline void register_freq_invariance_syscore_ops(void) {}
 #endif
 
-void bp_init_freq_invariance(bool cppc_ready)
+static void freq_invariance_enable(void)
 {
-	bool ret;
+	if (static_branch_unlikely(&arch_scale_freq_key)) {
+		WARN_ON_ONCE(1);
+		return;
+	}
+	static_branch_enable(&arch_scale_freq_key);
+	register_freq_invariance_syscore_ops();
+	pr_info("Estimated ratio of average max frequency by base frequency (times 1024): %llu\n", arch_max_freq_ratio);
+}
 
+void freq_invariance_set_perf_ratio(u64 ratio, bool turbo_disabled)
+{
+	arch_turbo_freq_ratio = ratio;
+	arch_set_max_freq_ratio(turbo_disabled);
+	freq_invariance_enable();
+}
+
+void __init bp_init_freq_invariance(void)
+{
 	if (!cpu_feature_enabled(X86_FEATURE_APERFMPERF))
 		return;
 
 	init_counter_refs();
 
-	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
-		ret = intel_set_max_freq_ratio();
-	else if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
-		if (!cppc_ready)
-			return;
-		ret = amd_set_max_freq_ratio(&arch_turbo_freq_ratio);
-	}
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
+		return;
 
-	if (ret) {
-		static_branch_enable(&arch_scale_freq_key);
-		register_freq_invariance_syscore_ops();
-		pr_info("Estimated ratio of average max frequency by base frequency (times 1024): %llu\n", arch_max_freq_ratio);
-	} else {
-		pr_debug("Couldn't determine max cpu frequency, necessary for scale-invariant accounting.\n");
-	}
+	if (intel_set_max_freq_ratio())
+		freq_invariance_enable();
 }
 
 void ap_init_freq_invariance(void)

arch/x86/kernel/smpboot.c

···
 {
 	smp_prepare_cpus_common();
 
-	bp_init_freq_invariance(false);
+	bp_init_freq_invariance();
 	smp_sanity_check();
 
 	switch (apic_intr_mode) {