From 5d74509b2d2fd6afbf3b2df31541b71ba55514c0 Mon Sep 17 00:00:00 2001
From: Martin Stein <martin.stein@genode-labs.com>
Date: Mon, 16 Aug 2021 11:23:57 +0200
Subject: [PATCH] base-hw: get rid of static perf counter object

It is not necessary to have a class, an object, and a generic header for the
perfomance counter. The kernel merely enables the counter using cpu registers
('msr' instructions, no MMIO) on arm_v6 and arm_v7 only. Therefore this commit
makes the header arm-specific and replaces class and global static object with
a function for enabling the counter.

Fixes #4217
---
 repos/base-hw/src/core/spec/arm/kernel/cpu.cc    |  3 +--
 .../core/{ => spec/arm}/kernel/perf_counter.h    | 16 +---------------
 .../base-hw/src/core/spec/arm_v6/perf_counter.cc |  9 +--------
 .../base-hw/src/core/spec/arm_v7/perf_counter.cc |  9 +--------
 4 files changed, 4 insertions(+), 33 deletions(-)
 rename repos/base-hw/src/core/{ => spec/arm}/kernel/perf_counter.h (72%)

diff --git a/repos/base-hw/src/core/spec/arm/kernel/cpu.cc b/repos/base-hw/src/core/spec/arm/kernel/cpu.cc
index f4f8edd2b1..da9c280536 100644
--- a/repos/base-hw/src/core/spec/arm/kernel/cpu.cc
+++ b/repos/base-hw/src/core/spec/arm/kernel/cpu.cc
@@ -19,8 +19,7 @@
 
 void Kernel::Cpu::_arch_init()
 {
-	/* enable performance counter */
-	perf_counter()->enable();
+	enable_performance_counter();
 
 	/* enable timer interrupt */
 	_pic.unmask(_timer.interrupt_id(), id());
diff --git a/repos/base-hw/src/core/kernel/perf_counter.h b/repos/base-hw/src/core/spec/arm/kernel/perf_counter.h
similarity index 72%
rename from repos/base-hw/src/core/kernel/perf_counter.h
rename to repos/base-hw/src/core/spec/arm/kernel/perf_counter.h
index fc0f5e1957..ca53093bfa 100644
--- a/repos/base-hw/src/core/kernel/perf_counter.h
+++ b/repos/base-hw/src/core/spec/arm/kernel/perf_counter.h
@@ -16,21 +16,7 @@
 
 namespace Kernel {
 
-	/**
-	 * Performance counter
-	 */
-	class Perf_counter
-	{
-		public:
-
-			/**
-			 * Enable counting
-			 */
-			void enable();
-	};
-
-
-	extern Perf_counter * perf_counter();
+	void enable_performance_counter();
 }
 
 #endif /* _CORE__KERNEL__PERF_COUNTER_H_ */
diff --git a/repos/base-hw/src/core/spec/arm_v6/perf_counter.cc b/repos/base-hw/src/core/spec/arm_v6/perf_counter.cc
index 8f9515b288..cd9ac1c4a7 100644
--- a/repos/base-hw/src/core/spec/arm_v6/perf_counter.cc
+++ b/repos/base-hw/src/core/spec/arm_v6/perf_counter.cc
@@ -93,7 +93,7 @@ struct Accvalctlr : Register<32>
 };
 
 
-void Kernel::Perf_counter::enable()
+void Kernel::enable_performance_counter()
 {
 	/* enable counters and disable overflow interrupt. */
 	Pmcr::access_t v = Pmcr::enable_and_reset();
@@ -105,10 +105,3 @@ void Kernel::Perf_counter::enable()
 	/* enable user-mode access */
 	Accvalctlr::write(Accvalctlr::enable_user_access());
 }
-
-
-Kernel::Perf_counter* Kernel::perf_counter()
-{
-	static Kernel::Perf_counter inst;
-	return &inst;
-}
diff --git a/repos/base-hw/src/core/spec/arm_v7/perf_counter.cc b/repos/base-hw/src/core/spec/arm_v7/perf_counter.cc
index 85ed68bf62..0e4eb5a8b2 100644
--- a/repos/base-hw/src/core/spec/arm_v7/perf_counter.cc
+++ b/repos/base-hw/src/core/spec/arm_v7/perf_counter.cc
@@ -168,7 +168,7 @@ struct Pmuseren : Register<32>
 };
 
 
-void Kernel::Perf_counter::enable()
+void Kernel::enable_performance_counter()
 {
 	/* program PMU and enable all counters */
 	Pmcr::write(Pmcr::enable_and_reset());
@@ -179,10 +179,3 @@ void Kernel::Perf_counter::enable()
 	Pmuseren::write(Pmuseren::enable());
 	Pmintenclr::write(Pmintenclr::disable_overflow_intr());
 }
-
-
-Kernel::Perf_counter* Kernel::perf_counter()
-{
-	static Kernel::Perf_counter inst;
-	return &inst;
-}