From 262e1f6e39143c2a0f559e2fb4a835069a7693a9 Mon Sep 17 00:00:00 2001 From: Chunyan Zhang Date: Mon, 21 Nov 2016 15:57:19 +0800 Subject: stm class: ftrace: Add ftrace-export-over-stm driver This patch adds a driver that models itself as an stm_source called stm_ftrace. Once the stm device and stm_ftrace have been linked via sysfs, the driver registers itself as a trace_export and everything passed to the interface from Ftrace subsystem will end up in the STM trace engine. Link: http://lkml.kernel.org/r/1479715043-6534-3-git-send-email-zhang.chunyan@linaro.org Signed-off-by: Chunyan Zhang Acked-by: Alexander Shishkin Signed-off-by: Steven Rostedt --- drivers/hwtracing/stm/Kconfig | 11 ++++++ drivers/hwtracing/stm/Makefile | 2 + drivers/hwtracing/stm/ftrace.c | 87 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 100 insertions(+) create mode 100644 drivers/hwtracing/stm/ftrace.c (limited to 'drivers/hwtracing') diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig index 847a39b35307..723e2d90083d 100644 --- a/drivers/hwtracing/stm/Kconfig +++ b/drivers/hwtracing/stm/Kconfig @@ -39,4 +39,15 @@ config STM_SOURCE_HEARTBEAT If you want to send heartbeat messages over STM devices, say Y. +config STM_SOURCE_FTRACE + tristate "Copy the output from kernel Ftrace to STM engine" + depends on FUNCTION_TRACER + help + This option can be used to copy the output from kernel Ftrace + to STM engine. Enabling this option will introduce a slight + timing effect. + + If you want to send kernel Ftrace messages over STM devices, + say Y. + endif diff --git a/drivers/hwtracing/stm/Makefile b/drivers/hwtracing/stm/Makefile index a9ce3d487e57..3abd84ce13d4 100644 --- a/drivers/hwtracing/stm/Makefile +++ b/drivers/hwtracing/stm/Makefile @@ -6,6 +6,8 @@ obj-$(CONFIG_STM_DUMMY) += dummy_stm.o obj-$(CONFIG_STM_SOURCE_CONSOLE) += stm_console.o obj-$(CONFIG_STM_SOURCE_HEARTBEAT) += stm_heartbeat.o +obj-$(CONFIG_STM_SOURCE_FTRACE) += stm_ftrace.o stm_console-y := console.o stm_heartbeat-y := heartbeat.o +stm_ftrace-y := ftrace.o diff --git a/drivers/hwtracing/stm/ftrace.c b/drivers/hwtracing/stm/ftrace.c new file mode 100644 index 000000000000..bd126a7c6da2 --- /dev/null +++ b/drivers/hwtracing/stm/ftrace.c @@ -0,0 +1,87 @@ +/* + * Simple kernel driver to link kernel Ftrace and an STM device + * Copyright (c) 2016, Linaro Ltd. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * STM Ftrace will be registered as a trace_export. + */ + +#include +#include +#include + +#define STM_FTRACE_NR_CHANNELS 1 +#define STM_FTRACE_CHAN 0 + +static int stm_ftrace_link(struct stm_source_data *data); +static void stm_ftrace_unlink(struct stm_source_data *data); + +static struct stm_ftrace { + struct stm_source_data data; + struct trace_export ftrace; +} stm_ftrace = { + .data = { + .name = "ftrace", + .nr_chans = STM_FTRACE_NR_CHANNELS, + .link = stm_ftrace_link, + .unlink = stm_ftrace_unlink, + }, +}; + +/** + * stm_ftrace_write() - write data to STM via 'stm_ftrace' source + * @buf: buffer containing the data packet + * @len: length of the data packet + */ +static void notrace +stm_ftrace_write(const void *buf, unsigned int len) +{ + stm_source_write(&stm_ftrace.data, STM_FTRACE_CHAN, buf, len); +} + +static int stm_ftrace_link(struct stm_source_data *data) +{ + struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data); + + sf->ftrace.write = stm_ftrace_write; + + return register_ftrace_export(&sf->ftrace); +} + +static void stm_ftrace_unlink(struct stm_source_data *data) +{ + struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data); + + unregister_ftrace_export(&sf->ftrace); +} + +static int __init stm_ftrace_init(void) +{ + int ret; + + ret = stm_source_register_device(NULL, &stm_ftrace.data); + if (ret) + pr_err("Failed to register stm_source - ftrace.\n"); + + return ret; +} + +static void __exit stm_ftrace_exit(void) +{ + stm_source_unregister_device(&stm_ftrace.data); +} + +module_init(stm_ftrace_init); +module_exit(stm_ftrace_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("stm_ftrace driver"); +MODULE_AUTHOR("Chunyan Zhang "); -- cgit v1.2.3 From dea5d0e1fcac657ea0d699afb1595e52cb051d46 Mon Sep 17 00:00:00 2001 From: Chunyan Zhang Date: Mon, 21 Nov 2016 15:57:20 +0800 Subject: coresight: Mark stm_generic_packet() with notrace If CONFIG_STM_SOURCE_FTRACE is selected, Function trace data can be writen to sink via STM, all functions that related to writing data packets to STM should be marked 'notrace' to avoid being traced by Ftrace, otherwise the program would stall into an endless loop. Link: http://lkml.kernel.org/r/1479715043-6534-4-git-send-email-zhang.chunyan@linaro.org Signed-off-by: Chunyan Zhang Acked-by: Alexander Shishkin Signed-off-by: Steven Rostedt --- drivers/hwtracing/coresight/coresight-stm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/hwtracing') diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c index 49e0f1b925a5..b7543bd19c9e 100644 --- a/drivers/hwtracing/coresight/coresight-stm.c +++ b/drivers/hwtracing/coresight/coresight-stm.c @@ -406,7 +406,7 @@ static long stm_generic_set_options(struct stm_data *stm_data, return 0; } -static ssize_t stm_generic_packet(struct stm_data *stm_data, +static ssize_t notrace stm_generic_packet(struct stm_data *stm_data, unsigned int master, unsigned int channel, unsigned int packet, -- cgit v1.2.3 From 22975be20f40616420dc4b26e8c1fe84e9f68427 Mon Sep 17 00:00:00 2001 From: Chunyan Zhang Date: Mon, 21 Nov 2016 15:57:21 +0800 Subject: intel_th: Mark sth_stm_packet() with notrace If CONFIG_STM_SOURCE_FTRACE is selected, Function trace data can be writen to sink via STM, all functions that related to writing data packets to STM should be marked 'notrace' to avoid being traced by Ftrace, otherwise the program would stall into an endless loop. Link: http://lkml.kernel.org/r/1479715043-6534-5-git-send-email-zhang.chunyan@linaro.org Signed-off-by: Chunyan Zhang Acked-by: Alexander Shishkin Signed-off-by: Steven Rostedt --- drivers/hwtracing/intel_th/sth.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'drivers/hwtracing') diff --git a/drivers/hwtracing/intel_th/sth.c b/drivers/hwtracing/intel_th/sth.c index e1aee61dd7b3..b03444624648 100644 --- a/drivers/hwtracing/intel_th/sth.c +++ b/drivers/hwtracing/intel_th/sth.c @@ -67,10 +67,13 @@ static void sth_iowrite(void __iomem *dest, const unsigned char *payload, } } -static ssize_t sth_stm_packet(struct stm_data *stm_data, unsigned int master, - unsigned int channel, unsigned int packet, - unsigned int flags, unsigned int size, - const unsigned char *payload) +static ssize_t notrace sth_stm_packet(struct stm_data *stm_data, + unsigned int master, + unsigned int channel, + unsigned int packet, + unsigned int flags, + unsigned int size, + const unsigned char *payload) { struct sth_device *sth = container_of(stm_data, struct sth_device, stm); struct intel_th_channel __iomem *out = -- cgit v1.2.3 From 9b5e3ff6b9baa77548c6cb832780162055733c67 Mon Sep 17 00:00:00 2001 From: Chunyan Zhang Date: Mon, 21 Nov 2016 15:57:22 +0800 Subject: stm dummy: Mark dummy_stm_packet() with notrace If CONFIG_STM_SOURCE_FTRACE is selected, Function trace data can be writen to sink via STM, all functions that related to writing data packets to STM should be marked 'notrace' to avoid being traced by Ftrace, otherwise the program would stall into an endless loop. Link: http://lkml.kernel.org/r/1479715043-6534-6-git-send-email-zhang.chunyan@linaro.org Signed-off-by: Chunyan Zhang Acked-by: Alexander Shishkin Signed-off-by: Steven Rostedt --- drivers/hwtracing/stm/dummy_stm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/hwtracing') diff --git a/drivers/hwtracing/stm/dummy_stm.c b/drivers/hwtracing/stm/dummy_stm.c index a86612d989f9..c5f94ca31c4d 100644 --- a/drivers/hwtracing/stm/dummy_stm.c +++ b/drivers/hwtracing/stm/dummy_stm.c @@ -21,7 +21,7 @@ #include #include -static ssize_t +static ssize_t notrace dummy_stm_packet(struct stm_data *stm_data, unsigned int master, unsigned int channel, unsigned int packet, unsigned int flags, unsigned int size, const unsigned char *payload) -- cgit v1.2.3 From 9dfed80d87ca2c365cd1004a91ef4ed716c8e44e Mon Sep 17 00:00:00 2001 From: Chunyan Zhang Date: Mon, 21 Nov 2016 15:57:23 +0800 Subject: stm: Mark the functions of writing STM with notrace If CONFIG_STM_SOURCE_FTRACE is selected, Function trace data can be writen to sink via STM, all functions that related to writing data packets to STM should be marked 'notrace' to avoid being traced by Ftrace, otherwise the program would stall into an endless loop. Link: http://lkml.kernel.org/r/1479715043-6534-7-git-send-email-zhang.chunyan@linaro.org Signed-off-by: Chunyan Zhang Acked-by: Alexander Shishkin Signed-off-by: Steven Rostedt --- drivers/hwtracing/stm/core.c | 7 ++++--- include/linux/stm.h | 4 ++-- 2 files changed, 6 insertions(+), 5 deletions(-) (limited to 'drivers/hwtracing') diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c index 51f81d64ca37..37d3bcbd2534 100644 --- a/drivers/hwtracing/stm/core.c +++ b/drivers/hwtracing/stm/core.c @@ -425,7 +425,7 @@ static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width) return ret; } -static ssize_t stm_write(struct stm_data *data, unsigned int master, +static ssize_t notrace stm_write(struct stm_data *data, unsigned int master, unsigned int channel, const char *buf, size_t count) { unsigned int flags = STP_PACKET_TIMESTAMPED; @@ -1121,8 +1121,9 @@ void stm_source_unregister_device(struct stm_source_data *data) } EXPORT_SYMBOL_GPL(stm_source_unregister_device); -int stm_source_write(struct stm_source_data *data, unsigned int chan, - const char *buf, size_t count) +int notrace stm_source_write(struct stm_source_data *data, + unsigned int chan, + const char *buf, size_t count) { struct stm_source_device *src = data->src; struct stm_device *stm; diff --git a/include/linux/stm.h b/include/linux/stm.h index 8369d8a8cabd..210ff2292361 100644 --- a/include/linux/stm.h +++ b/include/linux/stm.h @@ -133,7 +133,7 @@ int stm_source_register_device(struct device *parent, struct stm_source_data *data); void stm_source_unregister_device(struct stm_source_data *data); -int stm_source_write(struct stm_source_data *data, unsigned int chan, - const char *buf, size_t count); +int notrace stm_source_write(struct stm_source_data *data, unsigned int chan, + const char *buf, size_t count); #endif /* _STM_H_ */ -- cgit v1.2.3