[lttng-dev] [PATCH lttng-modules v2] Add support for i2c tracepoints
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Tue Oct 4 21:51:31 UTC 2016
Merged with edit, thanks!
Mathieu
----- On Oct 4, 2016, at 5:07 PM, Simon Marchi simon.marchi at ericsson.com wrote:
> New in v2:
>
> * Add module parameter (extract_sensitive_payload) to control the extraction
> of possibly sensitive data from events.
>
> This patch teaches lttng-modules about the i2c tracepoints in the Linux
> kernel.
>
> It contains the following tracepoints:
>
> * i2c_write
> * i2c_read
> * i2c_reply
> * i2c_result
>
> I translated the fields and assignments from the kernel's
> include/trace/events/i2c.h as well as I could. I also tried building
> this module against a kernel without CONFIG_I2C, and it built fine (the
> required types are unconditionally defined). So I don't think any "#if
> CONFIG_I2C" or similar are required.
>
> Signed-off-by: Simon Marchi <simon.marchi at ericsson.com>
> ---
> instrumentation/events/lttng-module/i2c.h | 124 ++++++++++++++++++++++++++++++
> probes/Kbuild | 1 +
> probes/lttng-probe-i2c.c | 54 +++++++++++++
> 3 files changed, 179 insertions(+)
> create mode 100644 instrumentation/events/lttng-module/i2c.h
> create mode 100644 probes/lttng-probe-i2c.c
>
> diff --git a/instrumentation/events/lttng-module/i2c.h
> b/instrumentation/events/lttng-module/i2c.h
> new file mode 100644
> index 0000000..8ca12f9
> --- /dev/null
> +++ b/instrumentation/events/lttng-module/i2c.h
> @@ -0,0 +1,124 @@
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM i2c
> +
> +#if !defined(LTTNG_TRACE_I2C_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define LTTNG_TRACE_I2C_H
> +
> +#include <probes/lttng-tracepoint-event.h>
> +
> +#ifndef _TRACE_I2C_DEF_
> +#define _TRACE_I2C_DEF_
> +
> +#endif /* _TRACE_I2C_DEF_ */
> +
> +/*
> + * __i2c_transfer() write request
> + */
> +LTTNG_TRACEPOINT_EVENT_CODE(i2c_write,
> +
> + TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg,
> + int num),
> +
> + TP_ARGS(adap, msg, num),
> +
> + TP_locvar(
> + int extract_sensitive_payload;
> + ),
> +
> + TP_code_pre(
> + tp_locvar->extract_sensitive_payload
> + = ACCESS_ONCE(extract_sensitive_payload);
> + ),
> +
> + TP_FIELDS(
> + ctf_integer(int, adapter_nr, adap->nr)
> + ctf_integer(__u16, msg_nr, num)
> + ctf_integer(__u16, addr, msg->addr)
> + ctf_integer(__u16, flags, msg->flags)
> + ctf_integer(__u16, len, msg->len)
> + ctf_sequence_hex(__u8, buf,
> + tp_locvar->extract_sensitive_payload ?
> + msg->buf : NULL,
> + __u16,
> + tp_locvar->extract_sensitive_payload ?
> + msg->len : 0)
> + ),
> +
> + TP_code_post()
> +)
> +
> +/*
> + * __i2c_transfer() read request
> + */
> +LTTNG_TRACEPOINT_EVENT(i2c_read,
> +
> + TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg,
> + int num),
> +
> + TP_ARGS(adap, msg, num),
> +
> + TP_FIELDS(
> + ctf_integer(int, adapter_nr, adap->nr)
> + ctf_integer(__u16, msg_nr, num)
> + ctf_integer(__u16, addr, msg->addr)
> + ctf_integer(__u16, flags, msg->flags)
> + ctf_integer(__u16, len, msg->len)
> + )
> +)
> +
> +/*
> + * __i2c_transfer() read reply
> + */
> +LTTNG_TRACEPOINT_EVENT_CODE(i2c_reply,
> +
> + TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg,
> + int num),
> +
> + TP_ARGS(adap, msg, num),
> +
> + TP_locvar(
> + int extract_sensitive_payload;
> + ),
> +
> + TP_code_pre(
> + tp_locvar->extract_sensitive_payload
> + = ACCESS_ONCE(extract_sensitive_payload);
> + ),
> +
> + TP_FIELDS(
> + ctf_integer(int, adapter_nr, adap->nr)
> + ctf_integer(__u16, msg_nr, num)
> + ctf_integer(__u16, addr, msg->addr)
> + ctf_integer(__u16, flags, msg->flags)
> + ctf_integer(__u16, len, msg->len)
> + ctf_sequence_hex(__u8, buf,
> + tp_locvar->extract_sensitive_payload ?
> + msg->buf : NULL,
> + __u16,
> + tp_locvar->extract_sensitive_payload ?
> + msg->len : 0)
> + ),
> +
> + TP_code_post()
> +)
> +
> +/*
> + * __i2c_transfer() result
> + */
> +LTTNG_TRACEPOINT_EVENT(i2c_result,
> +
> + TP_PROTO(const struct i2c_adapter *adap, int num, int ret),
> +
> + TP_ARGS(adap, num, ret),
> +
> + TP_FIELDS(
> + ctf_integer(int, adapter_nr, adap->nr)
> + ctf_integer(__u16, nr_msgs, num)
> + ctf_integer(__s16, ret, ret)
> + )
> +)
> +
> +#endif /* LTTNG_TRACE_I2C_H */
> +
> +/* This part must be outside protection */
> +#include <probes/define_trace.h>
> diff --git a/probes/Kbuild b/probes/Kbuild
> index 8ae9a6b..ca7c0b1 100644
> --- a/probes/Kbuild
> +++ b/probes/Kbuild
> @@ -5,6 +5,7 @@ include $(TOP_LTTNG_MODULES_DIR)/Makefile.ABI.workarounds
> ccflags-y += -I$(TOP_LTTNG_MODULES_DIR)
>
> obj-$(CONFIG_LTTNG) += lttng-probe-sched.o
> +obj-$(CONFIG_LTTNG) += lttng-probe-i2c.o
> obj-$(CONFIG_LTTNG) += lttng-probe-irq.o
> obj-$(CONFIG_LTTNG) += lttng-probe-timer.o
> obj-$(CONFIG_LTTNG) += lttng-probe-kmem.o
> diff --git a/probes/lttng-probe-i2c.c b/probes/lttng-probe-i2c.c
> new file mode 100644
> index 0000000..a14d91c
> --- /dev/null
> +++ b/probes/lttng-probe-i2c.c
> @@ -0,0 +1,54 @@
> +/*
> + * probes/lttng-probe-i2c.c
> + *
> + * LTTng i2c probes.
> + *
> + * Copyright (C) 2012 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; only
> + * version 2.1 of the License.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <lttng-tracer.h>
> +
> +/*
> + * Create the tracepoint static inlines from the kernel to validate that our
> + * trace event macros match the kernel we run on.
> + */
> +#include <trace/events/i2c.h>
> +
> +/*
> + * Create LTTng tracepoint probes.
> + */
> +#define LTTNG_PACKAGE_BUILD
> +#define CREATE_TRACE_POINTS
> +#define TRACE_INCLUDE_PATH instrumentation/events/lttng-module
> +
> +static int extract_sensitive_payload = 0;
> +module_param(extract_sensitive_payload, int, 0644);
> +MODULE_PARM_DESC(extract_sensitive_payload,
> + "Whether to extract possibly sensitive data from events (i2c "
> + "buffer contents) or not (1 or 0, default: 0).");
> +
> +#include <instrumentation/events/lttng-module/i2c.h>
> +
> +MODULE_LICENSE("GPL and additional rights");
> +MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers at efficios.com>");
> +MODULE_DESCRIPTION("LTTng i2c probes");
> +MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
> + __stringify(LTTNG_MODULES_MINOR_VERSION) "."
> + __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
> + LTTNG_MODULES_EXTRAVERSION);
> --
> 2.10.1
>
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--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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