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of: make kobject and bin_attribute support configurable

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Having device_nodes be kobjects is only needed if sysfs or OF_DYNAMIC is
enabled. Otherwise, having a kobject in struct device_node is
unnecessary bloat in minimal kernel configurations.

Likewise, bin_attribute is only needed in struct property when sysfs is
enabled, so we can make it configurable too.

Tested-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Frank Rowand <frowand.list@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Rob Herring <robh@kernel.org>
This commit is contained in:
Rob Herring 2017-10-04 14:09:40 -05:00
parent 0c3c234b95
commit b56b5528f5
7 changed files with 202 additions and 164 deletions
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4
drivers/of/Kconfig
View File

@ -46,10 +46,14 @@ config OF_EARLY_FLATTREE
config OF_PROMTREE
bool
config OF_KOBJ
def_bool SYSFS
# Hardly any platforms need this. It is safe to select, but only do so if you
# need it.
config OF_DYNAMIC
bool "Support for dynamic device trees" if OF_UNITTEST
select OF_KOBJ
help
On some platforms, the device tree can be manipulated at runtime.
While this option is selected automatically on such platforms, you

1
drivers/of/Makefile
View File

@ -1,4 +1,5 @@
obj-y = base.o device.o platform.o property.o
obj-$(CONFIG_OF_KOBJ) += kobj.o
obj-$(CONFIG_OF_DYNAMIC) += dynamic.o
obj-$(CONFIG_OF_FLATTREE) += fdt.o
obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o

130
drivers/of/base.c
View File

@ -95,105 +95,6 @@ int __weak of_node_to_nid(struct device_node *np)
}
#endif
#ifndef CONFIG_OF_DYNAMIC
static void of_node_release(struct kobject *kobj)
{
/* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
}
#endif /* CONFIG_OF_DYNAMIC */
struct kobj_type of_node_ktype = {
.release = of_node_release,
};
static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t offset, size_t count)
{
struct property *pp = container_of(bin_attr, struct property, attr);
return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
}
/* always return newly allocated name, caller must free after use */
static const char *safe_name(struct kobject *kobj, const char *orig_name)
{
const char *name = orig_name;
struct kernfs_node *kn;
int i = 0;
/* don't be a hero. After 16 tries give up */
while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
sysfs_put(kn);
if (name != orig_name)
kfree(name);
name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
}
if (name == orig_name) {
name = kstrdup(orig_name, GFP_KERNEL);
} else {
pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
kobject_name(kobj), name);
}
return name;
}
int __of_add_property_sysfs(struct device_node *np, struct property *pp)
{
int rc;
/* Important: Don't leak passwords */
bool secure = strncmp(pp->name, "security-", 9) == 0;
if (!IS_ENABLED(CONFIG_SYSFS))
return 0;
if (!of_kset || !of_node_is_attached(np))
return 0;
sysfs_bin_attr_init(&pp->attr);
pp->attr.attr.name = safe_name(&np->kobj, pp->name);
pp->attr.attr.mode = secure ? 0400 : 0444;
pp->attr.size = secure ? 0 : pp->length;
pp->attr.read = of_node_property_read;
rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
return rc;
}
int __of_attach_node_sysfs(struct device_node *np)
{
const char *name;
struct kobject *parent;
struct property *pp;
int rc;
if (!of_kset)
return 0;
np->kobj.kset = of_kset;
if (!np->parent) {
/* Nodes without parents are new top level trees */
name = safe_name(&of_kset->kobj, "base");
parent = NULL;
} else {
name = safe_name(&np->parent->kobj, kbasename(np->full_name));
parent = &np->parent->kobj;
}
if (!name)
return -ENOMEM;
rc = kobject_add(&np->kobj, parent, "%s", name);
kfree(name);
if (rc)
return rc;
for_each_property_of_node(np, pp)
__of_add_property_sysfs(np, pp);
return 0;
}
void __init of_core_init(void)
{
struct device_node *np;
@ -1501,22 +1402,6 @@ int __of_remove_property(struct device_node *np, struct property *prop)
return 0;
}
void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)
{
sysfs_remove_bin_file(&np->kobj, &prop->attr);
kfree(prop->attr.attr.name);
}
void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
{
if (!IS_ENABLED(CONFIG_SYSFS))
return;
/* at early boot, bail here and defer setup to of_init() */
if (of_kset && of_node_is_attached(np))
__of_sysfs_remove_bin_file(np, prop);
}
/**
* of_remove_property - Remove a property from a node.
*
@ -1576,21 +1461,6 @@ int __of_update_property(struct device_node *np, struct property *newprop,
return 0;
}
void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
struct property *oldprop)
{
if (!IS_ENABLED(CONFIG_SYSFS))
return;
/* At early boot, bail out and defer setup to of_init() */
if (!of_kset)
return;
if (oldprop)
__of_sysfs_remove_bin_file(np, oldprop);
__of_add_property_sysfs(np, newprop);
}
/*
* of_update_property - Update a property in a node, if the property does
* not exist, add it.

22
drivers/of/dynamic.c
View File

@ -48,28 +48,6 @@ void of_node_put(struct device_node *node)
}
EXPORT_SYMBOL(of_node_put);
void __of_detach_node_sysfs(struct device_node *np)
{
struct property *pp;
if (!IS_ENABLED(CONFIG_SYSFS))
return;
BUG_ON(!of_node_is_initialized(np));
if (!of_kset)
return;
/* only remove properties if on sysfs */
if (of_node_is_attached(np)) {
for_each_property_of_node(np, pp)
__of_sysfs_remove_bin_file(np, pp);
kobject_del(&np->kobj);
}
/* finally remove the kobj_init ref */
of_node_put(np);
}
static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
int of_reconfig_notifier_register(struct notifier_block *nb)

164
drivers/of/kobj.c Normal file
View File

@ -0,0 +1,164 @@
#include <linux/of.h>
#include <linux/slab.h>
#include "of_private.h"
/* true when node is initialized */
static int of_node_is_initialized(struct device_node *node)
{
return node && node->kobj.state_initialized;
}
/* true when node is attached (i.e. present on sysfs) */
int of_node_is_attached(struct device_node *node)
{
return node && node->kobj.state_in_sysfs;
}
#ifndef CONFIG_OF_DYNAMIC
static void of_node_release(struct kobject *kobj)
{
/* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
}
#endif /* CONFIG_OF_DYNAMIC */
struct kobj_type of_node_ktype = {
.release = of_node_release,
};
static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t offset, size_t count)
{
struct property *pp = container_of(bin_attr, struct property, attr);
return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
}
/* always return newly allocated name, caller must free after use */
static const char *safe_name(struct kobject *kobj, const char *orig_name)
{
const char *name = orig_name;
struct kernfs_node *kn;
int i = 0;
/* don't be a hero. After 16 tries give up */
while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
sysfs_put(kn);
if (name != orig_name)
kfree(name);
name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
}
if (name == orig_name) {
name = kstrdup(orig_name, GFP_KERNEL);
} else {
pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
kobject_name(kobj), name);
}
return name;
}
int __of_add_property_sysfs(struct device_node *np, struct property *pp)
{
int rc;
/* Important: Don't leak passwords */
bool secure = strncmp(pp->name, "security-", 9) == 0;
if (!IS_ENABLED(CONFIG_SYSFS))
return 0;
if (!of_kset || !of_node_is_attached(np))
return 0;
sysfs_bin_attr_init(&pp->attr);
pp->attr.attr.name = safe_name(&np->kobj, pp->name);
pp->attr.attr.mode = secure ? 0400 : 0444;
pp->attr.size = secure ? 0 : pp->length;
pp->attr.read = of_node_property_read;
rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
return rc;
}
void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)
{
if (!IS_ENABLED(CONFIG_SYSFS))
return;
sysfs_remove_bin_file(&np->kobj, &prop->attr);
kfree(prop->attr.attr.name);
}
void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
{
/* at early boot, bail here and defer setup to of_init() */
if (of_kset && of_node_is_attached(np))
__of_sysfs_remove_bin_file(np, prop);
}
void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
struct property *oldprop)
{
/* At early boot, bail out and defer setup to of_init() */
if (!of_kset)
return;
if (oldprop)
__of_sysfs_remove_bin_file(np, oldprop);
__of_add_property_sysfs(np, newprop);
}
int __of_attach_node_sysfs(struct device_node *np)
{
const char *name;
struct kobject *parent;
struct property *pp;
int rc;
if (!of_kset)
return 0;
np->kobj.kset = of_kset;
if (!np->parent) {
/* Nodes without parents are new top level trees */
name = safe_name(&of_kset->kobj, "base");
parent = NULL;
} else {
name = safe_name(&np->parent->kobj, kbasename(np->full_name));
parent = &np->parent->kobj;
}
if (!name)
return -ENOMEM;
rc = kobject_add(&np->kobj, parent, "%s", name);
kfree(name);
if (rc)
return rc;
for_each_property_of_node(np, pp)
__of_add_property_sysfs(np, pp);
return 0;
}
void __of_detach_node_sysfs(struct device_node *np)
{
struct property *pp;
BUG_ON(!of_node_is_initialized(np));
if (!of_kset)
return;
/* only remove properties if on sysfs */
if (of_node_is_attached(np)) {
for_each_property_of_node(np, pp)
__of_sysfs_remove_bin_file(np, pp);
kobject_del(&np->kobj);
}
/* finally remove the kobj_init ref */
of_node_put(np);
}

23
drivers/of/of_private.h
View File

@ -49,6 +49,29 @@ static inline int of_property_notify(int action, struct device_node *np,
}
#endif /* CONFIG_OF_DYNAMIC */
#if defined(CONFIG_OF_KOBJ)
int of_node_is_attached(struct device_node *node);
int __of_add_property_sysfs(struct device_node *np, struct property *pp);
void __of_remove_property_sysfs(struct device_node *np, struct property *prop);
void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
struct property *oldprop);
int __of_attach_node_sysfs(struct device_node *np);
void __of_detach_node_sysfs(struct device_node *np);
#else
static inline int __of_add_property_sysfs(struct device_node *np, struct property *pp)
{
return 0;
}
static inline void __of_remove_property_sysfs(struct device_node *np, struct property *prop) {}
static inline void __of_update_property_sysfs(struct device_node *np,
struct property *newprop, struct property *oldprop) {}
static inline int __of_attach_node_sysfs(struct device_node *np)
{
return 0;
}
static inline void __of_detach_node_sysfs(struct device_node *np) {}
#endif
#if defined(CONFIG_OF_UNITTEST) && defined(CONFIG_OF_OVERLAY)
extern void __init unittest_unflatten_overlay_base(void);
#else

22
include/linux/of.h
View File

@ -43,7 +43,9 @@ struct property {
#if defined(CONFIG_OF_PROMTREE)
unsigned int unique_id;
#endif
#if defined(CONFIG_OF_KOBJ)
struct bin_attribute attr;
#endif
};
#if defined(CONFIG_SPARC)
@ -62,7 +64,9 @@ struct device_node {
struct device_node *parent;
struct device_node *child;
struct device_node *sibling;
#if defined(CONFIG_OF_KOBJ)
struct kobject kobj;
#endif
unsigned long _flags;
void *data;
#if defined(CONFIG_SPARC)
@ -107,23 +111,17 @@ extern struct kobj_type of_node_ktype;
extern const struct fwnode_operations of_fwnode_ops;
static inline void of_node_init(struct device_node *node)
{
#if defined(CONFIG_OF_KOBJ)
kobject_init(&node->kobj, &of_node_ktype);
#endif
node->fwnode.ops = &of_fwnode_ops;
}
#if defined(CONFIG_OF_KOBJ)
#define of_node_kobj(n) (&(n)->kobj)
/* true when node is initialized */
static inline int of_node_is_initialized(struct device_node *node)
{
return node && node->kobj.state_initialized;
}
/* true when node is attached (i.e. present on sysfs) */
static inline int of_node_is_attached(struct device_node *node)
{
return node && node->kobj.state_in_sysfs;
}
#else
#define of_node_kobj(n) NULL
#endif
#ifdef CONFIG_OF_DYNAMIC
extern struct device_node *of_node_get(struct device_node *node);