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    SubjectRe: [PATCH v12 12/17] tools/counter: Create Counter tools
    On Mon,  5 Jul 2021 17:19:00 +0900
    William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

    > This creates an example Counter program under tools/counter/*
    > to exemplify the Counter character device interface.
    >
    > Cc: Pavel Machek <pavel@ucw.cz>
    > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
    > ---
    > MAINTAINERS | 1 +
    > tools/Makefile | 13 ++---
    > tools/counter/Build | 1 +
    > tools/counter/Makefile | 53 ++++++++++++++++++
    > tools/counter/counter_example.c | 95 +++++++++++++++++++++++++++++++++
    > 5 files changed, 157 insertions(+), 6 deletions(-)
    > create mode 100644 tools/counter/Build
    > create mode 100644 tools/counter/Makefile
    > create mode 100644 tools/counter/counter_example.c
    >
    > diff --git a/MAINTAINERS b/MAINTAINERS
    > index 5de4d2164844..e96797f57f04 100644
    > --- a/MAINTAINERS
    > +++ b/MAINTAINERS
    > @@ -4688,6 +4688,7 @@ F: Documentation/driver-api/generic-counter.rst
    > F: drivers/counter/
    > F: include/linux/counter.h
    > F: include/uapi/linux/counter.h
    > +F: tools/counter/
    >
    > CP2615 I2C DRIVER
    > M: Bence Csókás <bence98@sch.bme.hu>
    > diff --git a/tools/Makefile b/tools/Makefile
    > index 7e9d34ddd74c..4c26400ffc03 100644
    > --- a/tools/Makefile
    > +++ b/tools/Makefile
    > @@ -12,6 +12,7 @@ help:
    > @echo ' acpi - ACPI tools'
    > @echo ' bpf - misc BPF tools'
    > @echo ' cgroup - cgroup tools'
    > + @echo ' counter - Counter tools'
    > @echo ' cpupower - a tool for all things x86 CPU power'
    > @echo ' debugging - tools for debugging'
    > @echo ' firewire - the userspace part of nosy, an IEEE-1394 traffic sniffer'
    > @@ -65,7 +66,7 @@ acpi: FORCE
    > cpupower: FORCE
    > $(call descend,power/$@)
    >
    > -cgroup firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
    > +cgroup counter firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
    > $(call descend,$@)
    >
    > bpf/%: FORCE
    > @@ -100,7 +101,7 @@ freefall: FORCE
    > kvm_stat: FORCE
    > $(call descend,kvm/$@)
    >
    > -all: acpi cgroup cpupower gpio hv firewire liblockdep \
    > +all: acpi cgroup counter cpupower gpio hv firewire liblockdep \
    > perf selftests bootconfig spi turbostat usb \
    > virtio vm bpf x86_energy_perf_policy \
    > tmon freefall iio objtool kvm_stat wmi \
    > @@ -112,7 +113,7 @@ acpi_install:
    > cpupower_install:
    > $(call descend,power/$(@:_install=),install)
    >
    > -cgroup_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install vm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
    > +cgroup_install counter_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install vm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
    > $(call descend,$(@:_install=),install)
    >
    > liblockdep_install:
    > @@ -133,7 +134,7 @@ freefall_install:
    > kvm_stat_install:
    > $(call descend,kvm/$(@:_install=),install)
    >
    > -install: acpi_install cgroup_install cpupower_install gpio_install \
    > +install: acpi_install cgroup_install counter_install cpupower_install gpio_install \
    > hv_install firewire_install iio_install liblockdep_install \
    > perf_install selftests_install turbostat_install usb_install \
    > virtio_install vm_install bpf_install x86_energy_perf_policy_install \
    > @@ -147,7 +148,7 @@ acpi_clean:
    > cpupower_clean:
    > $(call descend,power/cpupower,clean)
    >
    > -cgroup_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean vm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
    > +cgroup_clean counter_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean vm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
    > $(call descend,$(@:_clean=),clean)
    >
    > liblockdep_clean:
    > @@ -181,7 +182,7 @@ freefall_clean:
    > build_clean:
    > $(call descend,build,clean)
    >
    > -clean: acpi_clean cgroup_clean cpupower_clean hv_clean firewire_clean \
    > +clean: acpi_clean cgroup_clean counter_clean cpupower_clean hv_clean firewire_clean \
    > perf_clean selftests_clean turbostat_clean bootconfig_clean spi_clean usb_clean virtio_clean \
    > vm_clean bpf_clean iio_clean x86_energy_perf_policy_clean tmon_clean \
    > freefall_clean build_clean libbpf_clean libsubcmd_clean liblockdep_clean \
    > diff --git a/tools/counter/Build b/tools/counter/Build
    > new file mode 100644
    > index 000000000000..33f4a51d715e
    > --- /dev/null
    > +++ b/tools/counter/Build
    > @@ -0,0 +1 @@
    > +counter_example-y += counter_example.o
    > diff --git a/tools/counter/Makefile b/tools/counter/Makefile
    > new file mode 100644
    > index 000000000000..5ebc195fd9c0
    > --- /dev/null
    > +++ b/tools/counter/Makefile
    > @@ -0,0 +1,53 @@
    > +# SPDX-License-Identifier: GPL-2.0
    > +include ../scripts/Makefile.include
    > +
    > +bindir ?= /usr/bin
    > +
    > +ifeq ($(srctree),)
    > +srctree := $(patsubst %/,%,$(dir $(CURDIR)))
    > +srctree := $(patsubst %/,%,$(dir $(srctree)))
    > +endif
    > +
    > +# Do not use make's built-in rules
    > +# (this improves performance and avoids hard-to-debug behaviour);
    > +MAKEFLAGS += -r
    > +
    > +override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
    > +
    > +ALL_TARGETS := counter_example
    > +ALL_PROGRAMS := $(patsubst %,$(OUTPUT)%,$(ALL_TARGETS))
    > +
    > +all: $(ALL_PROGRAMS)
    > +
    > +export srctree OUTPUT CC LD CFLAGS
    > +include $(srctree)/tools/build/Makefile.include
    > +
    > +#
    > +# We need the following to be outside of kernel tree
    > +#
    > +$(OUTPUT)include/linux/counter.h: ../../include/uapi/linux/counter.h
    > + mkdir -p $(OUTPUT)include/linux 2>&1 || true
    > + ln -sf $(CURDIR)/../../include/uapi/linux/counter.h $@
    > +
    > +prepare: $(OUTPUT)include/linux/counter.h
    > +
    > +COUNTER_EXAMPLE := $(OUTPUT)counter_example.o
    > +$(COUNTER_EXAMPLE): prepare FORCE
    > + $(Q)$(MAKE) $(build)=counter_example
    > +$(OUTPUT)counter_example: $(COUNTER_EXAMPLE)
    > + $(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
    > +
    > +clean:
    > + rm -f $(ALL_PROGRAMS)
    > + rm -rf $(OUTPUT)include/linux/counter.h
    > + find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
    > +
    > +install: $(ALL_PROGRAMS)
    > + install -d -m 755 $(DESTDIR)$(bindir); \
    > + for program in $(ALL_PROGRAMS); do \
    > + install $$program $(DESTDIR)$(bindir); \
    > + done
    > +
    > +FORCE:
    > +
    > +.PHONY: all install clean FORCE prepare
    > diff --git a/tools/counter/counter_example.c b/tools/counter/counter_example.c
    > new file mode 100644
    > index 000000000000..71dfec673c11
    > --- /dev/null
    > +++ b/tools/counter/counter_example.c
    > @@ -0,0 +1,95 @@
    > +// SPDX-License-Identifier: GPL-2.0-only
    > +/* Counter - example userspace application
    > + *
    > + * The userspace application opens /dev/counter0, configures the
    > + * COUNTER_EVENT_INDEX event channel 0 to gather Count 0 count and Count
    > + * 1 count, and prints out the data as it becomes available on the
    > + * character device node.
    > + *
    > + * Copyright (C) 2021 William Breathitt Gray
    > + */
    > +#include <errno.h>
    > +#include <fcntl.h>
    > +#include <linux/counter.h>
    > +#include <stdio.h>
    > +#include <string.h>
    > +#include <sys/ioctl.h>
    > +#include <unistd.h>
    > +
    > +struct counter_watch watches[2] = {
    > + {
    > + /* Component data: Count 0 count */
    > + .component.type = COUNTER_COMPONENT_COUNT,
    > + .component.scope = COUNTER_SCOPE_COUNT,
    > + .component.parent = 0,
    > + /* Event type: Index */
    > + .event = COUNTER_EVENT_INDEX,
    > + /* Device event channel 0 */
    > + .channel = 0,
    > + },
    > + {
    > + /* Component data: Count 1 count */
    > + .component.type = COUNTER_COMPONENT_COUNT,
    > + .component.scope = COUNTER_SCOPE_COUNT,
    > + .component.parent = 1,
    > + /* Event type: Index */
    > + .event = COUNTER_EVENT_INDEX,
    > + /* Device event channel 0 */
    > + .channel = 0,
    > + },
    > +};
    > +
    > +int main(void)
    > +{
    > + int fd;
    > + int ret;
    > + struct counter_event event_data[2];
    > +
    > + fd = open("/dev/counter0", O_RDWR);
    > + if (fd == -1) {
    > + perror("Unable to open /dev/counter0");
    > + return -errno;
    > + }
    > +
    > + ret = ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches);
    > + if (ret == -1) {
    > + perror("Error adding watches[0]");
    > + return -errno;
    > + }
    > + ret = ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches + 1);
    > + if (ret == -1) {
    > + perror("Error adding watches[1]");
    > + return -errno;
    > + }
    > + ret = ioctl(fd, COUNTER_ENABLE_EVENTS_IOCTL);
    > + if (ret == -1) {
    > + perror("Error enabling events");
    > + return -errno;
    > + }
    > +
    > + for (;;) {
    > + ret = read(fd, event_data, sizeof(event_data));
    > + if (ret == -1) {
    > + perror("Failed to read event data");
    > + return -errno;
    > + }
    > +
    > + if (ret != sizeof(event_data)) {
    > + fprintf(stderr, "Failed to read event data\n");
    > + return -EIO;
    > + }
    > +
    > + printf("Timestamp 0: %llu\tCount 0: %llu\n"
    > + "Error Message 0: %s\n"
    > + "Timestamp 1: %llu\tCount 1: %llu\n"
    > + "Error Message 1: %s\n",
    > + (unsigned long long)event_data[0].timestamp,

    I think there should be no need to cast this one. __aligned_u64 is always
    going to be of type llu anyway.


    > + (unsigned long long)event_data[0].value,
    > + strerror(event_data[0].status),
    > + (unsigned long long)event_data[1].timestamp,
    > + (unsigned long long)event_data[1].value,
    > + strerror(event_data[1].status));
    > + }
    > +
    > + return 0;
    > +}

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