Re: [PATCH] tracing: Add register read and write tracing support
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2020-09-28 14:55:06
Also in:
linux-arm-msm, lkml
On Sun, 27 Sep 2020 17:34:50 -0700 Prasad Sodagudi [off-list ref] wrote:
Add register read/write operations tracing support. ftrace events helps trace register read and write location details of memory mapped IO registers. Also add _no_log variants the writel_relaxed/readl_relaed APIs to avoid excessive logging for certain register operations.
As mentioned elsewhere, I don't see a reason for "nolog" variants if it is just to avoid logging too much. You can easily filter on the recording side.
quoted hunk ↗ jump to hunk
--- /dev/null +++ b/include/linux/iorw.h@@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * + */ +#ifndef __LOG_IORW_H__ +#define __LOG_IORW_H__ + +#include <linux/types.h> + +#if IS_ENABLED(CONFIG_TRACE_RW) +void log_write_io(volatile void __iomem *addr); +void log_read_io(const volatile void __iomem *addr);
So basically, this is always doing a function call, even when tracing is not enabled. You may want to turn this into a macro, and use the new interface I'm about to push: See https://lore.kernel.org/r/20200925211206.423598568@goodmis.org (local) Although I'm about to push a v3 (found a config that breaks msr.h) #if IS_ENABLED(CONFIG_TRACE_RW) #include <linux/atomic.h> #include <linux/tracepoint-defs.h> 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) \ if (tracepoint_enabled(rwio_write) __log_write_io(addr) #define log_read_io(addr) \ if (tracepoint_enabled(rwio_read) __log_read_io(addr)
quoted hunk ↗ jump to hunk
+#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..b829629 --- /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(raw_write,
"raw" is too generic. Call this 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(raw_read,And this "rwio_read" -- Steve
+
+ 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 */
+_______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel