In some cases the printf() mechanism is too heavy and can't be used. For example, when debugging a race condition involving devres API. When CONFIG_DEBUG_DEVRES is enabled I can't reproduce an issue, and otherwise it's quite visible with a useful information being collected.
Enable trace events for devres part of the driver core. Signed-off-by: Andy Shevchenko <[email protected]> --- v2: fixed compilation error (lkp), elaborate commit message (Greg) drivers/base/Makefile | 3 +++ drivers/base/devres.c | 23 +++++++++++------- drivers/base/trace.c | 10 ++++++++ drivers/base/trace.h | 56 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 83 insertions(+), 9 deletions(-) create mode 100644 drivers/base/trace.c create mode 100644 drivers/base/trace.h diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 8b93a7f291ec..ef8e44a7d288 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -30,3 +30,6 @@ obj-y += test/ ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG +# define_trace.h needs to know how to find our header +CFLAGS_trace.o := -I$(src) +obj-$(CONFIG_TRACING) += trace.o diff --git a/drivers/base/devres.c b/drivers/base/devres.c index db1f3137fc81..a0850bd1eab7 100644 --- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -14,14 +14,13 @@ #include <asm/sections.h> #include "base.h" +#include "trace.h" struct devres_node { struct list_head entry; dr_release_t release; -#ifdef CONFIG_DEBUG_DEVRES const char *name; size_t size; -#endif }; struct devres { @@ -43,10 +42,6 @@ struct devres_group { /* -- 8 pointers */ }; -#ifdef CONFIG_DEBUG_DEVRES -static int log_devres = 0; -module_param_named(log, log_devres, int, S_IRUGO | S_IWUSR); - static void set_node_dbginfo(struct devres_node *node, const char *name, size_t size) { @@ -54,7 +49,11 @@ static void set_node_dbginfo(struct devres_node *node, const char *name, node->size = size; } -static void devres_log(struct device *dev, struct devres_node *node, +#ifdef CONFIG_DEBUG_DEVRES +static int log_devres = 0; +module_param_named(log, log_devres, int, S_IRUGO | S_IWUSR); + +static void devres_dbg(struct device *dev, struct devres_node *node, const char *op) { if (unlikely(log_devres)) @@ -62,10 +61,16 @@ static void devres_log(struct device *dev, struct devres_node *node, op, node, node->name, node->size); } #else /* CONFIG_DEBUG_DEVRES */ -#define set_node_dbginfo(node, n, s) do {} while (0) -#define devres_log(dev, node, op) do {} while (0) +#define devres_dbg(dev, node, op) do {} while (0) #endif /* CONFIG_DEBUG_DEVRES */ +static void devres_log(struct device *dev, struct devres_node *node, + const char *op) +{ + trace_devres_log(dev, op, node, node->name, node->size); + devres_dbg(dev, node, op); +} + /* * Release functions for devres group. These callbacks are used only * for identification. diff --git a/drivers/base/trace.c b/drivers/base/trace.c new file mode 100644 index 000000000000..b24b0a309c4a --- /dev/null +++ b/drivers/base/trace.c @@ -0,0 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Device core Trace Support + * Copyright (C) 2021, Intel Corporation + * + * Author: Andy Shevchenko <[email protected]> + */ + +#define CREATE_TRACE_POINTS +#include "trace.h" diff --git a/drivers/base/trace.h b/drivers/base/trace.h new file mode 100644 index 000000000000..3192e18f877e --- /dev/null +++ b/drivers/base/trace.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Device core Trace Support + * Copyright (C) 2021, Intel Corporation + * + * Author: Andy Shevchenko <[email protected]> + */ + +#undef TRACE_SYSTEM +#define TRACE_SYSTEM dev + +#if !defined(__DEV_TRACE_H) || defined(TRACE_HEADER_MULTI_READ) +#define __DEV_TRACE_H + +#include <linux/device.h> +#include <linux/tracepoint.h> +#include <linux/types.h> + +DECLARE_EVENT_CLASS(devres, + TP_PROTO(struct device *dev, const char *op, void *node, const char *name, size_t size), + TP_ARGS(dev, op, node, name, size), + TP_STRUCT__entry( + __string(devname, dev_name(dev)) + __field(struct device *, dev) + __field(const char *, op) + __field(void *, node) + __field(const char *, name) + __field(size_t, size) + ), + TP_fast_assign( + __assign_str(devname, dev_name(dev)); + __entry->op = op; + __entry->node = node; + __entry->name = name; + __entry->size = size; + ), + TP_printk("%s %3s %p %s (%zu bytes)", __get_str(devname), + __entry->op, __entry->node, __entry->name, __entry->size) +); + +DEFINE_EVENT(devres, devres_log, + TP_PROTO(struct device *dev, const char *op, void *node, const char *name, size_t size), + TP_ARGS(dev, op, node, name, size) +); + +#endif /* __DEV_TRACE_H */ + +/* this part has to be here */ + +#undef TRACE_INCLUDE_PATH +#define TRACE_INCLUDE_PATH . + +#undef TRACE_INCLUDE_FILE +#define TRACE_INCLUDE_FILE trace + +#include <trace/define_trace.h> -- 2.30.2
