Re: [PATCHv8 4/5] lib: Add register read/write tracing support
From: Sai Prakash Ranjan
Date: Mon Jan 17 2022 - 10:51:31 EST
On 1/17/2022 9:00 PM, Sai Prakash Ranjan wrote:
Hi Steve,
On 1/17/2022 8:33 PM, Steven Rostedt wrote:
On Mon, 17 Jan 2022 09:02:53 +0530
Sai Prakash Ranjan <quic_saipraka@xxxxxxxxxxx> wrote:
diff --git a/include/trace/events/rwmmio.h
b/include/trace/events/rwmmio.h
new file mode 100644
index 000000000000..798fbe1ac9f9
--- /dev/null
+++ b/include/trace/events/rwmmio.h
@@ -0,0 +1,112 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2021-2022 Qualcomm Innovation Center, Inc. All
rights reserved.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM rwmmio
+
+#if !defined(_TRACE_RWMMIO_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_RWMMIO_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(rwmmio_write,
+
+ TP_PROTO(unsigned long caller, u64 val, u8 width, volatile void
__iomem *addr),
+
+ TP_ARGS(caller, val, width, addr),
+
+ TP_STRUCT__entry(
+ __field(u64, caller)
+ __field(u64, val)
+ __field(u64, addr)
+ __field(u8, width)
+ ),
+
+ TP_fast_assign(
+ __entry->caller = caller;
+ __entry->val = val;
+ __entry->addr = (unsigned long)(void *)addr;
+ __entry->width = width;
+ ),
+
+ TP_printk("%pS width=%d val=%#llx addr=%#llx",
+ (void *)(unsigned long)__entry->caller, __entry->width,
+ __entry->val, __entry->addr)
+);
+
+TRACE_EVENT(rwmmio_post_write,
+
+ TP_PROTO(unsigned long caller, u64 val, u8 width, volatile void
__iomem *addr),
+
+ TP_ARGS(caller, val, width, addr),
+
+ TP_STRUCT__entry(
+ __field(u64, caller)
+ __field(u64, val)
+ __field(u64, addr)
+ __field(u8, width)
+ ),
+
+ TP_fast_assign(
+ __entry->caller = caller;
+ __entry->val = val;
+ __entry->addr = (unsigned long)(void *)addr;
+ __entry->width = width;
+ ),
+
+ TP_printk("%pS width=%d val=%#llx addr=%#llx",
+ (void *)(unsigned long)__entry->caller, __entry->width,
+ __entry->val, __entry->addr)
+);
+
+TRACE_EVENT(rwmmio_read,
+
+ TP_PROTO(unsigned long caller, u8 width, const volatile void
__iomem *addr),
+
+ TP_ARGS(caller, width, addr),
+
+ TP_STRUCT__entry(
+ __field(u64, caller)
+ __field(u64, addr)
+ __field(u8, width)
+ ),
+
+ TP_fast_assign(
+ __entry->caller = caller;
+ __entry->addr = (unsigned long)(void *)addr;
+ __entry->width = width;
+ ),
+
+ TP_printk("%pS width=%d addr=%#llx",
+ (void *)(unsigned long)__entry->caller, __entry->width,
__entry->addr)
+);
+
+TRACE_EVENT(rwmmio_post_read,
+
+ TP_PROTO(unsigned long caller, u64 val, u8 width, const
volatile void __iomem *addr),
+
+ TP_ARGS(caller, val, width, addr),
+
+ TP_STRUCT__entry(
+ __field(u64, caller)
+ __field(u64, val)
+ __field(u64, addr)
+ __field(u8, width)
+ ),
+
+ TP_fast_assign(
+ __entry->caller = caller;
+ __entry->val = val;
+ __entry->addr = (unsigned long)(void *)addr;
+ __entry->width = width;
+ ),
+
+ TP_printk("%pS width=%d val=%#llx addr=%#llx",
+ (void *)(unsigned long)__entry->caller, __entry->width,
+ __entry->val, __entry->addr)
+);
The above should be replaced with:
DECLARE_EVENT_CLASS(rwmmio_rw_template,
TP_PROTO(unsigned long caller, u64 val, u8 width, volatile void
__iomem *addr),
TP_ARGS(caller, val, width, addr),
TP_STRUCT__entry(
__field(u64, caller)
__field(u64, val)
__field(u64, addr)
__field(u8, width)
),
TP_fast_assign(
__entry->caller = caller;
__entry->val = val;
__entry->addr = (unsigned long)(void *)addr;
__entry->width = width;
),
TP_printk("%pS width=%d val=%#llx addr=%#llx",
(void *)(unsigned long)__entry->caller, __entry->width,
__entry->val, __entry->addr)
);
DEFINE_EVENT(rwmmio_rw_template, rwmmio_write,
TP_PROTO(unsigned long caller, u64 val, u8 width, volatile void
__iomem *addr),
TP_ARGS(caller, val, width, addr)
);
DEFINE_EVENT(rwmmio_rw_template, rwmmio_post_write,
TP_PROTO(unsigned long caller, u64 val, u8 width, volatile void
__iomem *addr),
TP_ARGS(caller, val, width, addr)
);
DEFINE_EVENT(rwmmio_rw_template, rwmmio_post_read,
TP_PROTO(unsigned long caller, u64 val, u8 width, volatile void
__iomem *addr),
TP_ARGS(caller, val, width, addr)
);
It will save around 15k in memory.
And since rwmmio_read doesn't have a val field, it can stay a
TRACE_EVENT.
TRACE_EVENT(rwmmio_read,
TP_PROTO(unsigned long caller, u8 width, const volatile void
__iomem *addr),
TP_ARGS(caller, width, addr),
TP_STRUCT__entry(
__field(u64, caller)
__field(u64, addr)
__field(u8, width)
),
TP_fast_assign(
__entry->caller = caller;
__entry->addr = (unsigned long)(void *)addr;
__entry->width = width;
),
TP_printk("%pS width=%d addr=%#llx",
(void *)(unsigned long)__entry->caller, __entry->width,
__entry->addr)
);
-- Steve
Thanks for the review, will add these changes in next version.
Just one note that I need to keep rwmmio_post_read also as TRACE_EVENT
because
of const qualifier in post_read resulting in compiler warnings,
lib/trace_readwrite.c:43:50: warning: passing argument 4 of
‘trace_rwmmio_post_read’ discards ‘const’ qualifier from pointer target
type [-Wdiscarded-qualifiers]
Thanks,
Sai
+
+#endif /* _TRACE_RWMMIO_H */
+
+#include <trace/define_trace.h>
diff --git a/lib/Kconfig b/lib/Kconfig
index c80fde816a7e..ea520c315c0f 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -119,6 +119,13 @@ config INDIRECT_IOMEM_FALLBACK
mmio accesses when the IO memory address is not a registered
emulated region.
+config TRACE_MMIO_ACCESS
+ bool "Register read/write tracing"
+ depends on TRACING && ARCH_HAVE_TRACE_MMIO_ACCESS
+ help
+ Create tracepoints for MMIO read/write operations. These
trace events
+ can be used for logging all MMIO read/write operations.
+
source "lib/crypto/Kconfig"
config CRC_CCITT
diff --git a/lib/Makefile b/lib/Makefile
index 300f569c626b..43813b0061cd 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -152,6 +152,8 @@ lib-y += logic_pio.o
lib-$(CONFIG_INDIRECT_IOMEM) += logic_iomem.o
+obj-$(CONFIG_TRACE_MMIO_ACCESS) += trace_readwrite.o
+
obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
obj-$(CONFIG_BTREE) += btree.o
diff --git a/lib/trace_readwrite.c b/lib/trace_readwrite.c
new file mode 100644
index 000000000000..88637038b30c
--- /dev/null
+++ b/lib/trace_readwrite.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Register read and write tracepoints
+ *
+ * Copyright (c) 2021-2022 Qualcomm Innovation Center, Inc. All
rights reserved.
+ */
+
+#include <linux/ftrace.h>
+#include <linux/module.h>
+#include <asm-generic/io.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/rwmmio.h>
+
+#ifdef CONFIG_TRACE_MMIO_ACCESS
+void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr,
+ unsigned long caller_addr)
+{
+ trace_rwmmio_write(caller_addr, val, width, addr);
+}
+EXPORT_SYMBOL_GPL(log_write_mmio);
+EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_write);
+
+void log_post_write_mmio(u64 val, u8 width, volatile void __iomem
*addr,
+ unsigned long caller_addr)
+{
+ trace_rwmmio_post_write(caller_addr, val, width, addr);
+}
+EXPORT_SYMBOL_GPL(log_post_write_mmio);
+EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_post_write);
+
+void log_read_mmio(u8 width, const volatile void __iomem *addr,
+ unsigned long caller_addr)
+{
+ trace_rwmmio_read(caller_addr, width, addr);
+}
+EXPORT_SYMBOL_GPL(log_read_mmio);
+EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_read);
+
+void log_post_read_mmio(u64 val, u8 width, const volatile void
__iomem *addr,
+ unsigned long caller_addr)
+{
+ trace_rwmmio_post_read(caller_addr, val, width, addr);
+}
+EXPORT_SYMBOL_GPL(log_post_read_mmio);
+EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_post_read);
+#endif /* CONFIG_TRACE_MMIO_ACCESS */