| Message ID | ac8e77881212e18d117059a698affd6afc2607af.1711113657.git.hodges.daniel.scott@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | leds: trigger: Add led trigger for bpf | expand |
On Fri, Mar 22, 2024 at 7:08 AM Daniel Hodges <hodges.daniel.scott@gmail.com> wrote: > > This patch adds a led trigger that interfaces with the bpf subsystem. It > allows for BPF programs to control LED activity through calling bpf > kfuncs. This functionality is useful in giving users a physical > indication that a BPF program has performed an operation such as > handling a packet or probe point. > > Signed-off-by: Daniel Hodges <hodges.daniel.scott@gmail.com> > --- > drivers/leds/trigger/Kconfig | 10 +++++ > drivers/leds/trigger/Makefile | 1 + > drivers/leds/trigger/ledtrig-bpf.c | 72 ++++++++++++++++++++++++++++++ > 3 files changed, 83 insertions(+) > create mode 100644 drivers/leds/trigger/ledtrig-bpf.c > > diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig > index d11d80176fc0..30b0fd3847be 100644 > --- a/drivers/leds/trigger/Kconfig > +++ b/drivers/leds/trigger/Kconfig > @@ -152,4 +152,14 @@ config LEDS_TRIGGER_TTY > > When build as a module this driver will be called ledtrig-tty. > > +config LEDS_TRIGGER_BPF > + tristate "LED BPF Trigger" > + depends on BPF > + depends on BPF_SYSCALL > + help > + This allows LEDs to be controlled by the BPF subsystem. This trigger > + must be used with a loaded BPF program in order to control LED state. > + BPF programs can control LED state with kfuncs. > + If unsure, say N. > + > endif # LEDS_TRIGGERS > diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile > index 25c4db97cdd4..ac47128d406c 100644 > --- a/drivers/leds/trigger/Makefile > +++ b/drivers/leds/trigger/Makefile > @@ -16,3 +16,4 @@ obj-$(CONFIG_LEDS_TRIGGER_NETDEV) += ledtrig-netdev.o > obj-$(CONFIG_LEDS_TRIGGER_PATTERN) += ledtrig-pattern.o > obj-$(CONFIG_LEDS_TRIGGER_AUDIO) += ledtrig-audio.o > obj-$(CONFIG_LEDS_TRIGGER_TTY) += ledtrig-tty.o > +obj-$(CONFIG_LEDS_TRIGGER_BPF) += ledtrig-bpf.o > diff --git a/drivers/leds/trigger/ledtrig-bpf.c b/drivers/leds/trigger/ledtrig-bpf.c > new file mode 100644 > index 000000000000..e3b0b8281b70 > --- /dev/null > +++ b/drivers/leds/trigger/ledtrig-bpf.c > @@ -0,0 +1,72 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * LED BPF Trigger > + * > + * Author: Daniel Hodges <hodges.daniel.scott@gmail.com> > + */ > + > +#include <linux/bpf.h> > +#include <linux/btf.h> > +#include <linux/btf_ids.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/init.h> > +#include <linux/leds.h> > + > + > +DEFINE_LED_TRIGGER(ledtrig_bpf); > + > +__bpf_hook_start() > + > +__bpf_kfunc void bpf_ledtrig_blink(unsigned long delay_on, unsigned long delay_off, int invert) > +{ > + led_trigger_blink_oneshot(ledtrig_bpf, delay_on, delay_off, invert); A new kernel module just to call this helper? Feels like overkill. Can it be a part of generic led bits? btw, have you looked at net/netfilter/xt_LED.c ? netfilter had the ability to blink led for a long time. I'm curious whether folks found it useful. It can also do led_trigger_event(). Should that be another kfunc?
> A new kernel module just to call this helper? > Feels like overkill. Can it be a part of generic led bits? > btw, have you looked at net/netfilter/xt_LED.c ? > netfilter had the ability to blink led for a long time. > I'm curious whether folks found it useful. This might become more useful now that we have support for PHY & MAC LEDs. You can use the netdev trigger for the usual things an RJ45 LED shows: link, rx/tx activity, link speed etc. But they are just Linux LEDs, you can also use them for heartbeat, disc IO, tty IO, or xt_LED. xt_LED would actually make sense for an LED in a RJ45 socket. Andrew
From: Andrew Lunn <andrew@lunn.ch> On Fri, Mar 22, 2024 at 10:08:14AM -0400, Daniel Hodges wrote: > This patch adds a led trigger that interfaces with the bpf subsystem. It > allows for BPF programs to control LED activity through calling bpf > kfuncs. This functionality is useful in giving users a physical > indication that a BPF program has performed an operation such as > handling a packet or probe point. Don't you want a mechanism to say which LED it should blink? Say you have a BPF IR receiver, a BPF kernel scheduler and a BPF firewall. All sharing the same LED is probably not what you want. Each probably wants its own LED. Andrew
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig index d11d80176fc0..30b0fd3847be 100644 --- a/drivers/leds/trigger/Kconfig +++ b/drivers/leds/trigger/Kconfig @@ -152,4 +152,14 @@ config LEDS_TRIGGER_TTY When build as a module this driver will be called ledtrig-tty. +config LEDS_TRIGGER_BPF + tristate "LED BPF Trigger" + depends on BPF + depends on BPF_SYSCALL + help + This allows LEDs to be controlled by the BPF subsystem. This trigger + must be used with a loaded BPF program in order to control LED state. + BPF programs can control LED state with kfuncs. + If unsure, say N. + endif # LEDS_TRIGGERS diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile index 25c4db97cdd4..ac47128d406c 100644 --- a/drivers/leds/trigger/Makefile +++ b/drivers/leds/trigger/Makefile @@ -16,3 +16,4 @@ obj-$(CONFIG_LEDS_TRIGGER_NETDEV) += ledtrig-netdev.o obj-$(CONFIG_LEDS_TRIGGER_PATTERN) += ledtrig-pattern.o obj-$(CONFIG_LEDS_TRIGGER_AUDIO) += ledtrig-audio.o obj-$(CONFIG_LEDS_TRIGGER_TTY) += ledtrig-tty.o +obj-$(CONFIG_LEDS_TRIGGER_BPF) += ledtrig-bpf.o diff --git a/drivers/leds/trigger/ledtrig-bpf.c b/drivers/leds/trigger/ledtrig-bpf.c new file mode 100644 index 000000000000..e3b0b8281b70 --- /dev/null +++ b/drivers/leds/trigger/ledtrig-bpf.c @@ -0,0 +1,72 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * LED BPF Trigger + * + * Author: Daniel Hodges <hodges.daniel.scott@gmail.com> + */ + +#include <linux/bpf.h> +#include <linux/btf.h> +#include <linux/btf_ids.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/leds.h> + + +DEFINE_LED_TRIGGER(ledtrig_bpf); + +__bpf_hook_start() + +__bpf_kfunc void bpf_ledtrig_blink(unsigned long delay_on, unsigned long delay_off, int invert) +{ + led_trigger_blink_oneshot(ledtrig_bpf, delay_on, delay_off, invert); +} +__bpf_hook_end(); + +BTF_SET8_START(ledtrig_bpf_kfunc_ids) +BTF_ID_FLAGS(func, bpf_ledtrig_blink) +BTF_SET8_END(ledtrig_bpf_kfunc_ids) + +static const struct btf_kfunc_id_set ledtrig_bpf_kfunc_set = { + .owner = THIS_MODULE, + .set = &ledtrig_bpf_kfunc_ids, +}; + +static int init_bpf(void) +{ + int ret; + + ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, + &ledtrig_bpf_kfunc_set); + ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, + &ledtrig_bpf_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, + &ledtrig_bpf_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SK_SKB, + &ledtrig_bpf_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, + &ledtrig_bpf_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_ACT, + &ledtrig_bpf_kfunc_set); + return ret; +} + +static int ledtrig_bpf_init(void) +{ + led_trigger_register_simple("bpf", &ledtrig_bpf); + + return init_bpf(); +} + +static void __exit ledtrig_bpf_exit(void) +{ + led_trigger_unregister_simple(ledtrig_bpf); +} + +module_init(ledtrig_bpf_init); +module_exit(ledtrig_bpf_exit); + +MODULE_AUTHOR("Daniel Hodges <hodges.daniel.scott@gmail.com>"); +MODULE_DESCRIPTION("BPF LED trigger"); +MODULE_LICENSE("GPL v2");
This patch adds a led trigger that interfaces with the bpf subsystem. It allows for BPF programs to control LED activity through calling bpf kfuncs. This functionality is useful in giving users a physical indication that a BPF program has performed an operation such as handling a packet or probe point. Signed-off-by: Daniel Hodges <hodges.daniel.scott@gmail.com> --- drivers/leds/trigger/Kconfig | 10 +++++ drivers/leds/trigger/Makefile | 1 + drivers/leds/trigger/ledtrig-bpf.c | 72 ++++++++++++++++++++++++++++++ 3 files changed, 83 insertions(+) create mode 100644 drivers/leds/trigger/ledtrig-bpf.c