[v2] tracing: Add register read and write tracing support

diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index fd172c4..bcfc65c 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -9,6 +9,7 @@ 
 #define __ASM_IO_H
 
 #include <linux/types.h>
+#include <linux/iorw.h>
 #include <linux/pgtable.h>
 
 #include <asm/byteorder.h>
@@ -24,24 +25,28 @@ 
 #define __raw_writeb __raw_writeb
 static inline void __raw_writeb(u8 val, volatile void __iomem *addr)
 {
+	log_write_io(addr);
 	asm volatile("strb %w0, [%1]" : : "rZ" (val), "r" (addr));
 }
 
 #define __raw_writew __raw_writew
 static inline void __raw_writew(u16 val, volatile void __iomem *addr)
 {
+	log_write_io(addr);
 	asm volatile("strh %w0, [%1]" : : "rZ" (val), "r" (addr));
 }
 
 #define __raw_writel __raw_writel
 static __always_inline void __raw_writel(u32 val, volatile void __iomem *addr)
 {
+	log_write_io(addr);
 	asm volatile("str %w0, [%1]" : : "rZ" (val), "r" (addr));
 }
 
 #define __raw_writeq __raw_writeq
 static inline void __raw_writeq(u64 val, volatile void __iomem *addr)
 {
+	log_write_io(addr);
 	asm volatile("str %x0, [%1]" : : "rZ" (val), "r" (addr));
 }
 
@@ -49,6 +54,7 @@  static inline void __raw_writeq(u64 val, volatile void __iomem *addr)
 static inline u8 __raw_readb(const volatile void __iomem *addr)
 {
 	u8 val;
+	log_read_io(addr);
 	asm volatile(ALTERNATIVE("ldrb %w0, [%1]",
 				 "ldarb %w0, [%1]",
 				 ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)
@@ -61,6 +67,7 @@  static inline u16 __raw_readw(const volatile void __iomem *addr)
 {
 	u16 val;
 
+	log_read_io(addr);
 	asm volatile(ALTERNATIVE("ldrh %w0, [%1]",
 				 "ldarh %w0, [%1]",
 				 ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)
@@ -72,6 +79,7 @@  static inline u16 __raw_readw(const volatile void __iomem *addr)
 static __always_inline u32 __raw_readl(const volatile void __iomem *addr)
 {
 	u32 val;
+	log_read_io(addr);
 	asm volatile(ALTERNATIVE("ldr %w0, [%1]",
 				 "ldar %w0, [%1]",
 				 ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)
@@ -83,6 +91,7 @@  static __always_inline u32 __raw_readl(const volatile void __iomem *addr)
 static inline u64 __raw_readq(const volatile void __iomem *addr)
 {
 	u64 val;
+	log_read_io(addr);
 	asm volatile(ALTERNATIVE("ldr %0, [%1]",
 				 "ldar %0, [%1]",
 				 ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index c615b28..6a70d91 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -103,6 +103,14 @@  KVM_NVHE_ALIAS(gic_nonsecure_priorities);
 KVM_NVHE_ALIAS(__start___kvm_ex_table);
 KVM_NVHE_ALIAS(__stop___kvm_ex_table);
 
+/* raw_read/write logging */
+#if IS_ENABLED(CONFIG_TRACE_RW)
+KVM_NVHE_ALIAS(__log_write_io);
+KVM_NVHE_ALIAS(__log_read_io);
+KVM_NVHE_ALIAS(__tracepoint_rwio_read);
+KVM_NVHE_ALIAS(__tracepoint_rwio_write);
+#endif
+
 #endif /* CONFIG_KVM */
 
 #endif /* __ARM64_KERNEL_IMAGE_VARS_H */
diff --git a/include/linux/iorw.h b/include/linux/iorw.h
new file mode 100644
index 0000000..6b571b4
--- /dev/null
+++ b/include/linux/iorw.h
@@ -0,0 +1,38 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *
+ */
+#ifndef __LOG_IORW_H__
+#define __LOG_IORW_H__
+
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include <linux/tracepoint-defs.h>
+
+#if IS_ENABLED(CONFIG_TRACE_RW)
+DECLARE_TRACEPOINT(rwio_write);
+DECLARE_TRACEPOINT(rwio_read);
+
+void __log_write_io(volatile void __iomem *addr);
+void __log_read_io(const volatile void __iomem *addr);
+
+#define log_write_io(addr)			\
+do {						\
+	if (tracepoint_enabled(rwio_write))	\
+		__log_write_io(addr);		\
+} while (0)
+
+#define log_read_io(addr)			\
+do {						\
+	if (tracepoint_enabled(rwio_read))	\
+		__log_read_io(addr);		\
+} while (0)
+
+#else
+static inline void log_write_io(volatile void __iomem *addr)
+{ }
+static inline void log_read_io(const volatile void __iomem *addr)
+{ }
+#endif /* CONFIG_TRACE_RW */
+
+#endif /* __LOG_IORW_H__  */
diff --git a/include/trace/events/rwio.h b/include/trace/events/rwio.h
new file mode 100644
index 0000000..b26bcaf
--- /dev/null
+++ b/include/trace/events/rwio.h
@@ -0,0 +1,51 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM rwio
+
+#if !defined(_TRACE_RWIO_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_RWIO_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(rwio_write,
+
+	TP_PROTO(unsigned long fn, volatile void __iomem *addr),
+
+	TP_ARGS(fn, addr),
+
+	TP_STRUCT__entry(
+		__field(u64, fn)
+		__field(u64, addr)
+	),
+
+	TP_fast_assign(
+		__entry->fn = fn;
+		__entry->addr = (u64)addr;
+	),
+
+	TP_printk("%pS write addr=%p\n", __entry->fn, __entry->addr)
+);
+
+TRACE_EVENT(rwio_read,
+
+	TP_PROTO(unsigned long fn, const volatile void __iomem *addr),
+
+	TP_ARGS(fn, addr),
+
+	TP_STRUCT__entry(
+		__field(u64, fn)
+		__field(u64, addr)
+	),
+
+	TP_fast_assign(
+		__entry->fn = fn;
+		__entry->addr = (u64)addr;
+	),
+
+	TP_printk("%pS read addr=%p\n", __entry->fn, __entry->addr)
+);
+
+#endif /* _TRACE_PREEMPTIRQ_H */
+
+#include <trace/define_trace.h>
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index a4020c0..f0408f9 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -81,6 +81,17 @@  config RING_BUFFER_ALLOW_SWAP
 	 Allow the use of ring_buffer_swap_cpu.
 	 Adds a very slight overhead to tracing when enabled.
 
+config TRACE_RW
+	bool "Register read/write tracing"
+	select TRACING
+	depends on ARM64
+	help
+	  Create tracepoints for IO read/write operations, so that
+	  modules can register hooks to use them.
+
+	  Disable this option, when there is support from corresponding
+	  architecture.
+
 config PREEMPTIRQ_TRACEPOINTS
 	bool
 	depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index e153be3..69edfe50 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -92,6 +92,7 @@  obj-$(CONFIG_DYNAMIC_EVENTS) += trace_dynevent.o
 obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o
 obj-$(CONFIG_UPROBE_EVENTS) += trace_uprobe.o
 obj-$(CONFIG_BOOTTIME_TRACING) += trace_boot.o
+obj-$(CONFIG_TRACE_RW) += trace_readwrite.o
 
 obj-$(CONFIG_TRACEPOINT_BENCHMARK) += trace_benchmark.o
 
diff --git a/kernel/trace/trace_readwrite.c b/kernel/trace/trace_readwrite.c
new file mode 100644
index 0000000..d107134
--- /dev/null
+++ b/kernel/trace/trace_readwrite.c
@@ -0,0 +1,31 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Register read and write tracepoints
+ *
+ * Copyright (c) 2020, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/iorw.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/rwio.h>
+
+#ifdef CONFIG_TRACEPOINTS
+void __log_write_io(volatile void __iomem *addr)
+{
+	trace_rwio_write(CALLER_ADDR0, addr);
+}
+EXPORT_SYMBOL_GPL(__log_write_io);
+EXPORT_TRACEPOINT_SYMBOL_GPL(rwio_write);
+
+void __log_read_io(const volatile void __iomem *addr)
+{
+	trace_rwio_read(CALLER_ADDR0, addr);
+}
+EXPORT_SYMBOL_GPL(__log_read_io);
+EXPORT_TRACEPOINT_SYMBOL_GPL(rwio_read);
+#endif