linux-stable/drivers/counter/counter-sysfs.c
William Breathitt Gray 8ac33b8b68 counter: Fix use-after-free race condition for events_queue_size write
A race condition is possible when writing to events_queue_size where the
events kfifo is freed during the execution of a kfifo_in(), resulting in
a use-after-free. This patch prevents such a scenario by protecting the
events queue in operation with a spinlock and locking before performing
the events queue size adjustment.

The existing events_lock mutex is renamed to events_out_lock to reflect
that it only protects events queue out operations. Because the events
queue in operations can occur in an interrupt context, a new
events_in_lock spinlock is introduced and utilized.

Fixes: feff17a550 ("counter: Implement events_queue_size sysfs attribute")
Cc: David Lechner <david@lechnology.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Link: https://lore.kernel.org/r/20211021103540.955639-1-vilhelm.gray@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21 13:02:47 +02:00

959 lines
25 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Generic Counter sysfs interface
* Copyright (C) 2020 William Breathitt Gray
*/
#include <linux/counter.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/kfifo.h>
#include <linux/kstrtox.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/types.h>
#include "counter-sysfs.h"
/**
* struct counter_attribute - Counter sysfs attribute
* @dev_attr: device attribute for sysfs
* @l: node to add Counter attribute to attribute group list
* @comp: Counter component callbacks and data
* @scope: Counter scope of the attribute
* @parent: pointer to the parent component
*/
struct counter_attribute {
struct device_attribute dev_attr;
struct list_head l;
struct counter_comp comp;
enum counter_scope scope;
void *parent;
};
#define to_counter_attribute(_dev_attr) \
container_of(_dev_attr, struct counter_attribute, dev_attr)
/**
* struct counter_attribute_group - container for attribute group
* @name: name of the attribute group
* @attr_list: list to keep track of created attributes
* @num_attr: number of attributes
*/
struct counter_attribute_group {
const char *name;
struct list_head attr_list;
size_t num_attr;
};
static const char *const counter_function_str[] = {
[COUNTER_FUNCTION_INCREASE] = "increase",
[COUNTER_FUNCTION_DECREASE] = "decrease",
[COUNTER_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
[COUNTER_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
[COUNTER_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
[COUNTER_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
[COUNTER_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
[COUNTER_FUNCTION_QUADRATURE_X4] = "quadrature x4"
};
static const char *const counter_signal_value_str[] = {
[COUNTER_SIGNAL_LEVEL_LOW] = "low",
[COUNTER_SIGNAL_LEVEL_HIGH] = "high"
};
static const char *const counter_synapse_action_str[] = {
[COUNTER_SYNAPSE_ACTION_NONE] = "none",
[COUNTER_SYNAPSE_ACTION_RISING_EDGE] = "rising edge",
[COUNTER_SYNAPSE_ACTION_FALLING_EDGE] = "falling edge",
[COUNTER_SYNAPSE_ACTION_BOTH_EDGES] = "both edges"
};
static const char *const counter_count_direction_str[] = {
[COUNTER_COUNT_DIRECTION_FORWARD] = "forward",
[COUNTER_COUNT_DIRECTION_BACKWARD] = "backward"
};
static const char *const counter_count_mode_str[] = {
[COUNTER_COUNT_MODE_NORMAL] = "normal",
[COUNTER_COUNT_MODE_RANGE_LIMIT] = "range limit",
[COUNTER_COUNT_MODE_NON_RECYCLE] = "non-recycle",
[COUNTER_COUNT_MODE_MODULO_N] = "modulo-n"
};
static ssize_t counter_comp_u8_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const struct counter_attribute *const a = to_counter_attribute(attr);
struct counter_device *const counter = dev_get_drvdata(dev);
int err;
u8 data = 0;
switch (a->scope) {
case COUNTER_SCOPE_DEVICE:
err = a->comp.device_u8_read(counter, &data);
break;
case COUNTER_SCOPE_SIGNAL:
err = a->comp.signal_u8_read(counter, a->parent, &data);
break;
case COUNTER_SCOPE_COUNT:
err = a->comp.count_u8_read(counter, a->parent, &data);
break;
default:
return -EINVAL;
}
if (err < 0)
return err;
if (a->comp.type == COUNTER_COMP_BOOL)
/* data should already be boolean but ensure just to be safe */
data = !!data;
return sysfs_emit(buf, "%u\n", (unsigned int)data);
}
static ssize_t counter_comp_u8_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
const struct counter_attribute *const a = to_counter_attribute(attr);
struct counter_device *const counter = dev_get_drvdata(dev);
int err;
bool bool_data = 0;
u8 data = 0;
if (a->comp.type == COUNTER_COMP_BOOL) {
err = kstrtobool(buf, &bool_data);
data = bool_data;
} else
err = kstrtou8(buf, 0, &data);
if (err < 0)
return err;
switch (a->scope) {
case COUNTER_SCOPE_DEVICE:
err = a->comp.device_u8_write(counter, data);
break;
case COUNTER_SCOPE_SIGNAL:
err = a->comp.signal_u8_write(counter, a->parent, data);
break;
case COUNTER_SCOPE_COUNT:
err = a->comp.count_u8_write(counter, a->parent, data);
break;
default:
return -EINVAL;
}
if (err < 0)
return err;
return len;
}
static ssize_t counter_comp_u32_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const struct counter_attribute *const a = to_counter_attribute(attr);
struct counter_device *const counter = dev_get_drvdata(dev);
const struct counter_available *const avail = a->comp.priv;
int err;
u32 data = 0;
switch (a->scope) {
case COUNTER_SCOPE_DEVICE:
err = a->comp.device_u32_read(counter, &data);
break;
case COUNTER_SCOPE_SIGNAL:
err = a->comp.signal_u32_read(counter, a->parent, &data);
break;
case COUNTER_SCOPE_COUNT:
if (a->comp.type == COUNTER_COMP_SYNAPSE_ACTION)
err = a->comp.action_read(counter, a->parent,
a->comp.priv, &data);
else
err = a->comp.count_u32_read(counter, a->parent, &data);
break;
default:
return -EINVAL;
}
if (err < 0)
return err;
switch (a->comp.type) {
case COUNTER_COMP_FUNCTION:
return sysfs_emit(buf, "%s\n", counter_function_str[data]);
case COUNTER_COMP_SIGNAL_LEVEL:
return sysfs_emit(buf, "%s\n", counter_signal_value_str[data]);
case COUNTER_COMP_SYNAPSE_ACTION:
return sysfs_emit(buf, "%s\n", counter_synapse_action_str[data]);
case COUNTER_COMP_ENUM:
return sysfs_emit(buf, "%s\n", avail->strs[data]);
case COUNTER_COMP_COUNT_DIRECTION:
return sysfs_emit(buf, "%s\n", counter_count_direction_str[data]);
case COUNTER_COMP_COUNT_MODE:
return sysfs_emit(buf, "%s\n", counter_count_mode_str[data]);
default:
return sysfs_emit(buf, "%u\n", (unsigned int)data);
}
}
static int counter_find_enum(u32 *const enum_item, const u32 *const enums,
const size_t num_enums, const char *const buf,
const char *const string_array[])
{
size_t index;
for (index = 0; index < num_enums; index++) {
*enum_item = enums[index];
if (sysfs_streq(buf, string_array[*enum_item]))
return 0;
}
return -EINVAL;
}
static ssize_t counter_comp_u32_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
const struct counter_attribute *const a = to_counter_attribute(attr);
struct counter_device *const counter = dev_get_drvdata(dev);
struct counter_count *const count = a->parent;
struct counter_synapse *const synapse = a->comp.priv;
const struct counter_available *const avail = a->comp.priv;
int err;
u32 data = 0;
switch (a->comp.type) {
case COUNTER_COMP_FUNCTION:
err = counter_find_enum(&data, count->functions_list,
count->num_functions, buf,
counter_function_str);
break;
case COUNTER_COMP_SYNAPSE_ACTION:
err = counter_find_enum(&data, synapse->actions_list,
synapse->num_actions, buf,
counter_synapse_action_str);
break;
case COUNTER_COMP_ENUM:
err = __sysfs_match_string(avail->strs, avail->num_items, buf);
data = err;
break;
case COUNTER_COMP_COUNT_MODE:
err = counter_find_enum(&data, avail->enums, avail->num_items,
buf, counter_count_mode_str);
break;
default:
err = kstrtou32(buf, 0, &data);
break;
}
if (err < 0)
return err;
switch (a->scope) {
case COUNTER_SCOPE_DEVICE:
err = a->comp.device_u32_write(counter, data);
break;
case COUNTER_SCOPE_SIGNAL:
err = a->comp.signal_u32_write(counter, a->parent, data);
break;
case COUNTER_SCOPE_COUNT:
if (a->comp.type == COUNTER_COMP_SYNAPSE_ACTION)
err = a->comp.action_write(counter, count, synapse,
data);
else
err = a->comp.count_u32_write(counter, count, data);
break;
default:
return -EINVAL;
}
if (err < 0)
return err;
return len;
}
static ssize_t counter_comp_u64_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const struct counter_attribute *const a = to_counter_attribute(attr);
struct counter_device *const counter = dev_get_drvdata(dev);
int err;
u64 data = 0;
switch (a->scope) {
case COUNTER_SCOPE_DEVICE:
err = a->comp.device_u64_read(counter, &data);
break;
case COUNTER_SCOPE_SIGNAL:
err = a->comp.signal_u64_read(counter, a->parent, &data);
break;
case COUNTER_SCOPE_COUNT:
err = a->comp.count_u64_read(counter, a->parent, &data);
break;
default:
return -EINVAL;
}
if (err < 0)
return err;
return sysfs_emit(buf, "%llu\n", (unsigned long long)data);
}
static ssize_t counter_comp_u64_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
const struct counter_attribute *const a = to_counter_attribute(attr);
struct counter_device *const counter = dev_get_drvdata(dev);
int err;
u64 data = 0;
err = kstrtou64(buf, 0, &data);
if (err < 0)
return err;
switch (a->scope) {
case COUNTER_SCOPE_DEVICE:
err = a->comp.device_u64_write(counter, data);
break;
case COUNTER_SCOPE_SIGNAL:
err = a->comp.signal_u64_write(counter, a->parent, data);
break;
case COUNTER_SCOPE_COUNT:
err = a->comp.count_u64_write(counter, a->parent, data);
break;
default:
return -EINVAL;
}
if (err < 0)
return err;
return len;
}
static ssize_t enums_available_show(const u32 *const enums,
const size_t num_enums,
const char *const strs[], char *buf)
{
size_t len = 0;
size_t index;
for (index = 0; index < num_enums; index++)
len += sysfs_emit_at(buf, len, "%s\n", strs[enums[index]]);
return len;
}
static ssize_t strs_available_show(const struct counter_available *const avail,
char *buf)
{
size_t len = 0;
size_t index;
for (index = 0; index < avail->num_items; index++)
len += sysfs_emit_at(buf, len, "%s\n", avail->strs[index]);
return len;
}
static ssize_t counter_comp_available_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
const struct counter_attribute *const a = to_counter_attribute(attr);
const struct counter_count *const count = a->parent;
const struct counter_synapse *const synapse = a->comp.priv;
const struct counter_available *const avail = a->comp.priv;
switch (a->comp.type) {
case COUNTER_COMP_FUNCTION:
return enums_available_show(count->functions_list,
count->num_functions,
counter_function_str, buf);
case COUNTER_COMP_SYNAPSE_ACTION:
return enums_available_show(synapse->actions_list,
synapse->num_actions,
counter_synapse_action_str, buf);
case COUNTER_COMP_ENUM:
return strs_available_show(avail, buf);
case COUNTER_COMP_COUNT_MODE:
return enums_available_show(avail->enums, avail->num_items,
counter_count_mode_str, buf);
default:
return -EINVAL;
}
}
static int counter_avail_attr_create(struct device *const dev,
struct counter_attribute_group *const group,
const struct counter_comp *const comp, void *const parent)
{
struct counter_attribute *counter_attr;
struct device_attribute *dev_attr;
counter_attr = devm_kzalloc(dev, sizeof(*counter_attr), GFP_KERNEL);
if (!counter_attr)
return -ENOMEM;
/* Configure Counter attribute */
counter_attr->comp.type = comp->type;
counter_attr->comp.priv = comp->priv;
counter_attr->parent = parent;
/* Initialize sysfs attribute */
dev_attr = &counter_attr->dev_attr;
sysfs_attr_init(&dev_attr->attr);
/* Configure device attribute */
dev_attr->attr.name = devm_kasprintf(dev, GFP_KERNEL, "%s_available",
comp->name);
if (!dev_attr->attr.name)
return -ENOMEM;
dev_attr->attr.mode = 0444;
dev_attr->show = counter_comp_available_show;
/* Store list node */
list_add(&counter_attr->l, &group->attr_list);
group->num_attr++;
return 0;
}
static int counter_attr_create(struct device *const dev,
struct counter_attribute_group *const group,
const struct counter_comp *const comp,
const enum counter_scope scope,
void *const parent)
{
struct counter_attribute *counter_attr;
struct device_attribute *dev_attr;
counter_attr = devm_kzalloc(dev, sizeof(*counter_attr), GFP_KERNEL);
if (!counter_attr)
return -ENOMEM;
/* Configure Counter attribute */
counter_attr->comp = *comp;
counter_attr->scope = scope;
counter_attr->parent = parent;
/* Configure device attribute */
dev_attr = &counter_attr->dev_attr;
sysfs_attr_init(&dev_attr->attr);
dev_attr->attr.name = comp->name;
switch (comp->type) {
case COUNTER_COMP_U8:
case COUNTER_COMP_BOOL:
if (comp->device_u8_read) {
dev_attr->attr.mode |= 0444;
dev_attr->show = counter_comp_u8_show;
}
if (comp->device_u8_write) {
dev_attr->attr.mode |= 0200;
dev_attr->store = counter_comp_u8_store;
}
break;
case COUNTER_COMP_SIGNAL_LEVEL:
case COUNTER_COMP_FUNCTION:
case COUNTER_COMP_SYNAPSE_ACTION:
case COUNTER_COMP_ENUM:
case COUNTER_COMP_COUNT_DIRECTION:
case COUNTER_COMP_COUNT_MODE:
if (comp->device_u32_read) {
dev_attr->attr.mode |= 0444;
dev_attr->show = counter_comp_u32_show;
}
if (comp->device_u32_write) {
dev_attr->attr.mode |= 0200;
dev_attr->store = counter_comp_u32_store;
}
break;
case COUNTER_COMP_U64:
if (comp->device_u64_read) {
dev_attr->attr.mode |= 0444;
dev_attr->show = counter_comp_u64_show;
}
if (comp->device_u64_write) {
dev_attr->attr.mode |= 0200;
dev_attr->store = counter_comp_u64_store;
}
break;
default:
return -EINVAL;
}
/* Store list node */
list_add(&counter_attr->l, &group->attr_list);
group->num_attr++;
/* Create "*_available" attribute if needed */
switch (comp->type) {
case COUNTER_COMP_FUNCTION:
case COUNTER_COMP_SYNAPSE_ACTION:
case COUNTER_COMP_ENUM:
case COUNTER_COMP_COUNT_MODE:
return counter_avail_attr_create(dev, group, comp, parent);
default:
return 0;
}
}
static ssize_t counter_comp_name_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%s\n", to_counter_attribute(attr)->comp.name);
}
static int counter_name_attr_create(struct device *const dev,
struct counter_attribute_group *const group,
const char *const name)
{
struct counter_attribute *counter_attr;
counter_attr = devm_kzalloc(dev, sizeof(*counter_attr), GFP_KERNEL);
if (!counter_attr)
return -ENOMEM;
/* Configure Counter attribute */
counter_attr->comp.name = name;
/* Configure device attribute */
sysfs_attr_init(&counter_attr->dev_attr.attr);
counter_attr->dev_attr.attr.name = "name";
counter_attr->dev_attr.attr.mode = 0444;
counter_attr->dev_attr.show = counter_comp_name_show;
/* Store list node */
list_add(&counter_attr->l, &group->attr_list);
group->num_attr++;
return 0;
}
static ssize_t counter_comp_id_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const size_t id = (size_t)to_counter_attribute(attr)->comp.priv;
return sysfs_emit(buf, "%zu\n", id);
}
static int counter_comp_id_attr_create(struct device *const dev,
struct counter_attribute_group *const group,
const char *name, const size_t id)
{
struct counter_attribute *counter_attr;
/* Allocate Counter attribute */
counter_attr = devm_kzalloc(dev, sizeof(*counter_attr), GFP_KERNEL);
if (!counter_attr)
return -ENOMEM;
/* Generate component ID name */
name = devm_kasprintf(dev, GFP_KERNEL, "%s_component_id", name);
if (!name)
return -ENOMEM;
/* Configure Counter attribute */
counter_attr->comp.priv = (void *)id;
/* Configure device attribute */
sysfs_attr_init(&counter_attr->dev_attr.attr);
counter_attr->dev_attr.attr.name = name;
counter_attr->dev_attr.attr.mode = 0444;
counter_attr->dev_attr.show = counter_comp_id_show;
/* Store list node */
list_add(&counter_attr->l, &group->attr_list);
group->num_attr++;
return 0;
}
static struct counter_comp counter_signal_comp = {
.type = COUNTER_COMP_SIGNAL_LEVEL,
.name = "signal",
};
static int counter_signal_attrs_create(struct counter_device *const counter,
struct counter_attribute_group *const cattr_group,
struct counter_signal *const signal)
{
const enum counter_scope scope = COUNTER_SCOPE_SIGNAL;
struct device *const dev = &counter->dev;
int err;
struct counter_comp comp;
size_t i;
struct counter_comp *ext;
/* Create main Signal attribute */
comp = counter_signal_comp;
comp.signal_u32_read = counter->ops->signal_read;
err = counter_attr_create(dev, cattr_group, &comp, scope, signal);
if (err < 0)
return err;
/* Create Signal name attribute */
err = counter_name_attr_create(dev, cattr_group, signal->name);
if (err < 0)
return err;
/* Create an attribute for each extension */
for (i = 0; i < signal->num_ext; i++) {
ext = &signal->ext[i];
err = counter_attr_create(dev, cattr_group, ext, scope, signal);
if (err < 0)
return err;
err = counter_comp_id_attr_create(dev, cattr_group, ext->name,
i);
if (err < 0)
return err;
}
return 0;
}
static int counter_sysfs_signals_add(struct counter_device *const counter,
struct counter_attribute_group *const groups)
{
size_t i;
int err;
/* Add each Signal */
for (i = 0; i < counter->num_signals; i++) {
/* Generate Signal attribute directory name */
groups[i].name = devm_kasprintf(&counter->dev, GFP_KERNEL,
"signal%zu", i);
if (!groups[i].name)
return -ENOMEM;
/* Create all attributes associated with Signal */
err = counter_signal_attrs_create(counter, groups + i,
counter->signals + i);
if (err < 0)
return err;
}
return 0;
}
static int counter_sysfs_synapses_add(struct counter_device *const counter,
struct counter_attribute_group *const group,
struct counter_count *const count)
{
size_t i;
/* Add each Synapse */
for (i = 0; i < count->num_synapses; i++) {
struct device *const dev = &counter->dev;
struct counter_synapse *synapse;
size_t id;
struct counter_comp comp;
int err;
synapse = count->synapses + i;
/* Generate Synapse action name */
id = synapse->signal - counter->signals;
comp.name = devm_kasprintf(dev, GFP_KERNEL, "signal%zu_action",
id);
if (!comp.name)
return -ENOMEM;
/* Create action attribute */
comp.type = COUNTER_COMP_SYNAPSE_ACTION;
comp.action_read = counter->ops->action_read;
comp.action_write = counter->ops->action_write;
comp.priv = synapse;
err = counter_attr_create(dev, group, &comp,
COUNTER_SCOPE_COUNT, count);
if (err < 0)
return err;
/* Create Synapse component ID attribute */
err = counter_comp_id_attr_create(dev, group, comp.name, i);
if (err < 0)
return err;
}
return 0;
}
static struct counter_comp counter_count_comp =
COUNTER_COMP_COUNT_U64("count", NULL, NULL);
static struct counter_comp counter_function_comp = {
.type = COUNTER_COMP_FUNCTION,
.name = "function",
};
static int counter_count_attrs_create(struct counter_device *const counter,
struct counter_attribute_group *const cattr_group,
struct counter_count *const count)
{
const enum counter_scope scope = COUNTER_SCOPE_COUNT;
struct device *const dev = &counter->dev;
int err;
struct counter_comp comp;
size_t i;
struct counter_comp *ext;
/* Create main Count attribute */
comp = counter_count_comp;
comp.count_u64_read = counter->ops->count_read;
comp.count_u64_write = counter->ops->count_write;
err = counter_attr_create(dev, cattr_group, &comp, scope, count);
if (err < 0)
return err;
/* Create Count name attribute */
err = counter_name_attr_create(dev, cattr_group, count->name);
if (err < 0)
return err;
/* Create Count function attribute */
comp = counter_function_comp;
comp.count_u32_read = counter->ops->function_read;
comp.count_u32_write = counter->ops->function_write;
err = counter_attr_create(dev, cattr_group, &comp, scope, count);
if (err < 0)
return err;
/* Create an attribute for each extension */
for (i = 0; i < count->num_ext; i++) {
ext = &count->ext[i];
err = counter_attr_create(dev, cattr_group, ext, scope, count);
if (err < 0)
return err;
err = counter_comp_id_attr_create(dev, cattr_group, ext->name,
i);
if (err < 0)
return err;
}
return 0;
}
static int counter_sysfs_counts_add(struct counter_device *const counter,
struct counter_attribute_group *const groups)
{
size_t i;
struct counter_count *count;
int err;
/* Add each Count */
for (i = 0; i < counter->num_counts; i++) {
count = counter->counts + i;
/* Generate Count attribute directory name */
groups[i].name = devm_kasprintf(&counter->dev, GFP_KERNEL,
"count%zu", i);
if (!groups[i].name)
return -ENOMEM;
/* Add sysfs attributes of the Synapses */
err = counter_sysfs_synapses_add(counter, groups + i, count);
if (err < 0)
return err;
/* Create all attributes associated with Count */
err = counter_count_attrs_create(counter, groups + i, count);
if (err < 0)
return err;
}
return 0;
}
static int counter_num_signals_read(struct counter_device *counter, u8 *val)
{
*val = counter->num_signals;
return 0;
}
static int counter_num_counts_read(struct counter_device *counter, u8 *val)
{
*val = counter->num_counts;
return 0;
}
static int counter_events_queue_size_read(struct counter_device *counter,
u64 *val)
{
*val = kfifo_size(&counter->events);
return 0;
}
static int counter_events_queue_size_write(struct counter_device *counter,
u64 val)
{
DECLARE_KFIFO_PTR(events, struct counter_event);
int err;
unsigned long flags;
/* Allocate new events queue */
err = kfifo_alloc(&events, val, GFP_KERNEL);
if (err)
return err;
/* Swap in new events queue */
mutex_lock(&counter->events_out_lock);
spin_lock_irqsave(&counter->events_in_lock, flags);
kfifo_free(&counter->events);
counter->events.kfifo = events.kfifo;
spin_unlock_irqrestore(&counter->events_in_lock, flags);
mutex_unlock(&counter->events_out_lock);
return 0;
}
static struct counter_comp counter_num_signals_comp =
COUNTER_COMP_DEVICE_U8("num_signals", counter_num_signals_read, NULL);
static struct counter_comp counter_num_counts_comp =
COUNTER_COMP_DEVICE_U8("num_counts", counter_num_counts_read, NULL);
static struct counter_comp counter_events_queue_size_comp =
COUNTER_COMP_DEVICE_U64("events_queue_size",
counter_events_queue_size_read,
counter_events_queue_size_write);
static int counter_sysfs_attr_add(struct counter_device *const counter,
struct counter_attribute_group *cattr_group)
{
const enum counter_scope scope = COUNTER_SCOPE_DEVICE;
struct device *const dev = &counter->dev;
int err;
size_t i;
struct counter_comp *ext;
/* Add Signals sysfs attributes */
err = counter_sysfs_signals_add(counter, cattr_group);
if (err < 0)
return err;
cattr_group += counter->num_signals;
/* Add Counts sysfs attributes */
err = counter_sysfs_counts_add(counter, cattr_group);
if (err < 0)
return err;
cattr_group += counter->num_counts;
/* Create name attribute */
err = counter_name_attr_create(dev, cattr_group, counter->name);
if (err < 0)
return err;
/* Create num_signals attribute */
err = counter_attr_create(dev, cattr_group, &counter_num_signals_comp,
scope, NULL);
if (err < 0)
return err;
/* Create num_counts attribute */
err = counter_attr_create(dev, cattr_group, &counter_num_counts_comp,
scope, NULL);
if (err < 0)
return err;
/* Create events_queue_size attribute */
err = counter_attr_create(dev, cattr_group,
&counter_events_queue_size_comp, scope, NULL);
if (err < 0)
return err;
/* Create an attribute for each extension */
for (i = 0; i < counter->num_ext; i++) {
ext = &counter->ext[i];
err = counter_attr_create(dev, cattr_group, ext, scope, NULL);
if (err < 0)
return err;
err = counter_comp_id_attr_create(dev, cattr_group, ext->name,
i);
if (err < 0)
return err;
}
return 0;
}
/**
* counter_sysfs_add - Adds Counter sysfs attributes to the device structure
* @counter: Pointer to the Counter device structure
*
* Counter sysfs attributes are created and added to the respective device
* structure for later registration to the system. Resource-managed memory
* allocation is performed by this function, and this memory should be freed
* when no longer needed (automatically by a device_unregister call, or
* manually by a devres_release_all call).
*/
int counter_sysfs_add(struct counter_device *const counter)
{
struct device *const dev = &counter->dev;
const size_t num_groups = counter->num_signals + counter->num_counts + 1;
struct counter_attribute_group *cattr_groups;
size_t i, j;
int err;
struct attribute_group *groups;
struct counter_attribute *p;
/* Allocate space for attribute groups (signals, counts, and ext) */
cattr_groups = devm_kcalloc(dev, num_groups, sizeof(*cattr_groups),
GFP_KERNEL);
if (!cattr_groups)
return -ENOMEM;
/* Initialize attribute lists */
for (i = 0; i < num_groups; i++)
INIT_LIST_HEAD(&cattr_groups[i].attr_list);
/* Add Counter device sysfs attributes */
err = counter_sysfs_attr_add(counter, cattr_groups);
if (err < 0)
return err;
/* Allocate attribute group pointers for association with device */
dev->groups = devm_kcalloc(dev, num_groups + 1, sizeof(*dev->groups),
GFP_KERNEL);
if (!dev->groups)
return -ENOMEM;
/* Allocate space for attribute groups */
groups = devm_kcalloc(dev, num_groups, sizeof(*groups), GFP_KERNEL);
if (!groups)
return -ENOMEM;
/* Prepare each group of attributes for association */
for (i = 0; i < num_groups; i++) {
groups[i].name = cattr_groups[i].name;
/* Allocate space for attribute pointers */
groups[i].attrs = devm_kcalloc(dev,
cattr_groups[i].num_attr + 1,
sizeof(*groups[i].attrs),
GFP_KERNEL);
if (!groups[i].attrs)
return -ENOMEM;
/* Add attribute pointers to attribute group */
j = 0;
list_for_each_entry(p, &cattr_groups[i].attr_list, l)
groups[i].attrs[j++] = &p->dev_attr.attr;
/* Associate attribute group */
dev->groups[i] = &groups[i];
}
return 0;
}