From: Grant Likely <grant.likely@xxxxxxxxxxxx> Device tree nodes are already treated as objects, and we already want to expose them to userspace which is done using the /proc filesystem today. Right now the kernel has to do a lot of work to keep the /proc view in sync with the in-kernel representation. If device_nodes are switched to be kobjects then the device tree code can be a whole lot simpler. It also turns out that switching to using /sysfs from /proc results in smaller code and data size, and the userspace ABI won't change if /proc/device-tree symlinks to /sys/firmware/devicetree/base. v6: Add __of_add_property() early init fixes from Pantelis v5: Rename firmware/ofw to firmware/devicetree Fix updating property values in sysfs v4: Fixed build error on Powerpc Fixed handling of dynamic nodes on powerpc v3: Fixed handling of duplicate attribute and child node names v2: switch to using sysfs bin_attributes which solve the problem of reporting incorrect property size. Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxxxx> Tested-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> Cc: Rob Herring <rob.herring@xxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: David S. Miller <davem@xxxxxxxxxxxxx> Cc: Nathan Fontenot <nfont@xxxxxxxxxxxxxxxxxx> Cc: Pantelis Antoniou <panto@xxxxxxxxxxxxxxxxxxxxxxx> --- I'm not sending the whole series this time. Only the first patch. This version fixes some early boot breakage. g. Documentation/ABI/testing/sysfs-firmware-ofw | 28 +++++ arch/arm/boot/dts/testcases/tests-phandle.dtsi | 3 + arch/powerpc/platforms/pseries/dlpar.c | 1 - arch/powerpc/platforms/pseries/reconfig.c | 2 - arch/powerpc/sysdev/msi_bitmap.c | 2 +- drivers/of/base.c | 165 +++++++++++++++++++++++-- drivers/of/fdt.c | 3 +- drivers/of/pdt.c | 4 +- include/linux/of.h | 9 +- 9 files changed, 201 insertions(+), 16 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-firmware-ofw diff --git a/Documentation/ABI/testing/sysfs-firmware-ofw b/Documentation/ABI/testing/sysfs-firmware-ofw new file mode 100644 index 000000000000..f562b188e71d --- /dev/null +++ b/Documentation/ABI/testing/sysfs-firmware-ofw @@ -0,0 +1,28 @@ +What: /sys/firmware/devicetree/* +Date: November 2013 +Contact: Grant Likely <grant.likely@xxxxxxxxxx> +Description: + When using OpenFirmware or a Flattened Device Tree to enumerate + hardware, the device tree structure will be exposed in this + directory. + + It is possible for multiple device-tree directories to exist. + Some device drivers use a separate detached device tree which + have no attachment to the system tree and will appear in a + different subdirectory under /sys/firmware/devicetree. + + Userspace must not use the /sys/firmware/devicetree/base + path directly, but instead should follow /proc/device-tree + symlink. It is possible that the absolute path will change + in the future, but the symlink is the stable ABI. + + The /proc/device-tree symlink replaces the devicetree /proc + filesystem support, and has largely the same semantics and + should be compatible with existing userspace. + + The contents of /sys/firmware/devicetree/ is a + hierarchy of directories, one per device tree node. The + directory name is the resolved path component name (node + name plus address). Properties are represented as files + in the directory. The contents of each file is the exact + binary data from the device tree. diff --git a/arch/arm/boot/dts/testcases/tests-phandle.dtsi b/arch/arm/boot/dts/testcases/tests-phandle.dtsi index 0007d3cd7dc2..788a4c24b8f5 100644 --- a/arch/arm/boot/dts/testcases/tests-phandle.dtsi +++ b/arch/arm/boot/dts/testcases/tests-phandle.dtsi @@ -1,6 +1,9 @@ / { testcase-data { + security-password = "password"; + duplicate-name = "duplicate"; + duplicate-name { }; phandle-tests { provider0: provider0 { #phandle-cells = <0>; diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c index a8fe5aa3d34f..397661de19ec 100644 --- a/arch/powerpc/platforms/pseries/dlpar.c +++ b/arch/powerpc/platforms/pseries/dlpar.c @@ -11,7 +11,6 @@ */ #include <linux/kernel.h> -#include <linux/kref.h> #include <linux/notifier.h> #include <linux/spinlock.h> #include <linux/cpu.h> diff --git a/arch/powerpc/platforms/pseries/reconfig.c b/arch/powerpc/platforms/pseries/reconfig.c index f93cdf55628c..0435bb65d0aa 100644 --- a/arch/powerpc/platforms/pseries/reconfig.c +++ b/arch/powerpc/platforms/pseries/reconfig.c @@ -12,7 +12,6 @@ */ #include <linux/kernel.h> -#include <linux/kref.h> #include <linux/notifier.h> #include <linux/proc_fs.h> #include <linux/slab.h> @@ -70,7 +69,6 @@ static int pSeries_reconfig_add_node(const char *path, struct property *proplist np->properties = proplist; of_node_set_flag(np, OF_DYNAMIC); - kref_init(&np->kref); np->parent = derive_parent(path); if (IS_ERR(np->parent)) { diff --git a/arch/powerpc/sysdev/msi_bitmap.c b/arch/powerpc/sysdev/msi_bitmap.c index 0968b66b4cf9..8ba60424be95 100644 --- a/arch/powerpc/sysdev/msi_bitmap.c +++ b/arch/powerpc/sysdev/msi_bitmap.c @@ -202,7 +202,7 @@ void __init test_of_node(void) /* There should really be a struct device_node allocator */ memset(&of_node, 0, sizeof(of_node)); - kref_init(&of_node.kref); + kref_init(&of_node.kobj.kref); of_node.full_name = node_name; check(0 == msi_bitmap_alloc(&bmp, size, &of_node)); diff --git a/drivers/of/base.c b/drivers/of/base.c index 967b3209907a..5f5eb1563f4f 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -23,6 +23,7 @@ #include <linux/of.h> #include <linux/spinlock.h> #include <linux/slab.h> +#include <linux/string.h> #include <linux/proc_fs.h> #include "of_private.h" @@ -35,6 +36,12 @@ struct device_node *of_chosen; struct device_node *of_aliases; static struct device_node *of_stdout; +static struct kset *of_kset; + +/* + * Used to protect the of_aliases; but also overloaded to hold off addition of + * nodes to sysfs + */ DEFINE_MUTEX(of_aliases_mutex); /* use when traversing tree through the allnext, child, sibling, @@ -92,14 +99,14 @@ int __weak of_node_to_nid(struct device_node *np) struct device_node *of_node_get(struct device_node *node) { if (node) - kref_get(&node->kref); + kobject_get(&node->kobj); return node; } EXPORT_SYMBOL(of_node_get); -static inline struct device_node *kref_to_device_node(struct kref *kref) +static inline struct device_node *kobj_to_device_node(struct kobject *kobj) { - return container_of(kref, struct device_node, kref); + return container_of(kobj, struct device_node, kobj); } /** @@ -109,16 +116,15 @@ static inline struct device_node *kref_to_device_node(struct kref *kref) * In of_node_put() this function is passed to kref_put() * as the destructor. */ -static void of_node_release(struct kref *kref) +static void of_node_release(struct kobject *kobj) { - struct device_node *node = kref_to_device_node(kref); + struct device_node *node = kobj_to_device_node(kobj); struct property *prop = node->properties; /* We should never be releasing nodes that haven't been detached. */ if (!of_node_check_flag(node, OF_DETACHED)) { pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name); dump_stack(); - kref_init(&node->kref); return; } @@ -151,11 +157,138 @@ static void of_node_release(struct kref *kref) void of_node_put(struct device_node *node) { if (node) - kref_put(&node->kref, of_node_release); + kobject_put(&node->kobj); } EXPORT_SYMBOL(of_node_put); +#else +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); +} + +static const char *safe_name(struct kobject *kobj, const char *orig_name) +{ + const char *name = orig_name; + struct sysfs_dirent *sd; + int i = 0; + + /* don't be a hero. After 16 tries give up */ + while (i < 16 && (sd = sysfs_get_dirent(kobj->sd, name))) { + sysfs_put(sd); + if (name != orig_name) + kfree(name); + name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i); + } + + if (name != orig_name) + pr_warn("device-tree: Duplicate name in %s, renamed to \"%s\"\n", + kobject_name(kobj), name); + return name; +} + +static int __of_add_property(struct device_node *np, struct property *pp) +{ + int rc; + + /* Important: Don't leak passwords */ + bool secure = strncmp(pp->name, "security-", 9) == 0; + + pp->attr.attr.name = safe_name(&np->kobj, pp->name); + pp->attr.attr.mode = secure ? S_IRUSR : S_IRUGO; + 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 %s\n", pp->name, np->full_name); + return rc; +} + +static int __of_node_add(struct device_node *np) +{ + const char *name; + struct property *pp; + int rc; + + np->kobj.kset = of_kset; + if (!np->parent) { + /* Nodes without parents are new top level trees */ + rc = kobject_add(&np->kobj, NULL, safe_name(&of_kset->kobj, "base")); + } else { + name = safe_name(&np->parent->kobj, kbasename(np->full_name)); + if (!name || !name[0]) + return -EINVAL; + + rc = kobject_add(&np->kobj, &np->parent->kobj, "%s", name); + } + if (rc) + return rc; + + for_each_property_of_node(np, pp) + __of_add_property(np, pp); + + return 0; +} + +int of_node_add(struct device_node *np) +{ + int rc = 0; + kobject_init(&np->kobj, &of_node_ktype); + mutex_lock(&of_aliases_mutex); + if (of_kset) + rc = __of_node_add(np); + mutex_unlock(&of_aliases_mutex); + return rc; +} + +#if defined(CONFIG_OF_DYNAMIC) +static void of_node_remove(struct device_node *np) +{ + struct property *pp; + + for_each_property_of_node(np, pp) + sysfs_remove_bin_file(&np->kobj, &pp->attr); + + kobject_del(&np->kobj); +} +#endif + +static int __init of_init(void) +{ + struct device_node *np; + + of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj); + if (!of_kset) + return -ENOMEM; + + /* Make sure all nodes added before this time get added to sysfs */ + mutex_lock(&of_aliases_mutex); + for_each_of_allnodes(np) + __of_node_add(np); + mutex_unlock(&of_aliases_mutex); + +#if !defined(CONFIG_PROC_DEVICETREE) + /* Symlink to the new tree when PROC_DEVICETREE is disabled */ + if (of_allnodes) + proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base"); +#endif /* CONFIG_PROC_DEVICETREE */ + + return 0; +} +core_initcall(of_init); + static struct property *__of_find_property(const struct device_node *np, const char *name, int *lenp) { @@ -1495,6 +1628,12 @@ int of_add_property(struct device_node *np, struct property *prop) *next = prop; raw_spin_unlock_irqrestore(&devtree_lock, flags); + /* at early boot, bail hear and defer setup to of_init() */ + if (!of_kset) + return 0; + + __of_add_property(np, prop); + #ifdef CONFIG_PROC_DEVICETREE /* try to add to proc as well if it was initialized */ if (np->pde) @@ -1541,6 +1680,12 @@ int of_remove_property(struct device_node *np, struct property *prop) if (!found) return -ENODEV; + /* at early boot, bail hear and defer setup to of_init() */ + if (!of_kset) + return 0; + + sysfs_remove_bin_file(&np->kobj, &prop->attr); + #ifdef CONFIG_PROC_DEVICETREE /* try to remove the proc node as well */ if (np->pde) @@ -1595,6 +1740,10 @@ int of_update_property(struct device_node *np, struct property *newprop) if (!found) return -ENODEV; + /* Update the sysfs attribute */ + sysfs_remove_bin_file(&np->kobj, &oldprop->attr); + __of_add_property(np, newprop); + #ifdef CONFIG_PROC_DEVICETREE /* try to add to proc as well if it was initialized */ if (np->pde) @@ -1671,6 +1820,7 @@ int of_attach_node(struct device_node *np) of_node_clear_flag(np, OF_DETACHED); raw_spin_unlock_irqrestore(&devtree_lock, flags); + of_node_add(np); of_add_proc_dt_entry(np); return 0; } @@ -1743,6 +1893,7 @@ int of_detach_node(struct device_node *np) raw_spin_unlock_irqrestore(&devtree_lock, flags); of_remove_proc_dt_entry(np); + of_node_remove(np); return rc; } #endif /* defined(CONFIG_OF_DYNAMIC) */ diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index 2fa024b97c43..d5d62cd5680f 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -232,7 +232,6 @@ static void * unflatten_dt_node(struct boot_param_header *blob, dad->next->sibling = np; dad->next = np; } - kref_init(&np->kref); } /* process properties */ while (1) { @@ -327,6 +326,8 @@ static void * unflatten_dt_node(struct boot_param_header *blob, np->name = "<NULL>"; if (!np->type) np->type = "<NULL>"; + + of_node_add(np); } while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) { if (tag == OF_DT_NOP) diff --git a/drivers/of/pdt.c b/drivers/of/pdt.c index 7b666736c168..e64fa3d3da5f 100644 --- a/drivers/of/pdt.c +++ b/drivers/of/pdt.c @@ -179,8 +179,6 @@ static struct device_node * __init of_pdt_create_node(phandle node, of_pdt_incr_unique_id(dp); dp->parent = parent; - kref_init(&dp->kref); - dp->name = of_pdt_get_one_property(node, "name"); dp->type = of_pdt_get_one_property(node, "device_type"); dp->phandle = node; @@ -215,6 +213,7 @@ static struct device_node * __init of_pdt_build_tree(struct device_node *parent, *nextp = &dp->allnext; dp->full_name = of_pdt_build_full_name(dp); + of_node_add(dp); dp->child = of_pdt_build_tree(dp, of_pdt_prom_ops->getchild(node), nextp); @@ -245,6 +244,7 @@ void __init of_pdt_build_devicetree(phandle root_node, struct of_pdt_ops *ops) of_allnodes->path_component_name = ""; #endif of_allnodes->full_name = "/"; + of_node_add(of_allnodes); nextp = &of_allnodes->allnext; of_allnodes->child = of_pdt_build_tree(of_allnodes, diff --git a/include/linux/of.h b/include/linux/of.h index a4b7fdf17044..c899a89de9a8 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -18,7 +18,7 @@ #include <linux/types.h> #include <linux/bitops.h> #include <linux/errno.h> -#include <linux/kref.h> +#include <linux/kobject.h> #include <linux/mod_devicetable.h> #include <linux/spinlock.h> #include <linux/topology.h> @@ -37,6 +37,7 @@ struct property { struct property *next; unsigned long _flags; unsigned int unique_id; + struct bin_attribute attr; }; #if defined(CONFIG_SPARC) @@ -57,7 +58,7 @@ struct device_node { struct device_node *next; /* next device of same type */ struct device_node *allnext; /* next in list of all nodes */ struct proc_dir_entry *pde; /* this node's proc directory */ - struct kref kref; + struct kobject kobj; unsigned long _flags; void *data; #if defined(CONFIG_SPARC) @@ -74,6 +75,8 @@ struct of_phandle_args { uint32_t args[MAX_PHANDLE_ARGS]; }; +extern int of_node_add(struct device_node *node); + #ifdef CONFIG_OF_DYNAMIC extern struct device_node *of_node_get(struct device_node *node); extern void of_node_put(struct device_node *node); @@ -187,6 +190,8 @@ static inline const char *of_node_full_name(const struct device_node *np) return np ? np->full_name : "<no-node>"; } +#define for_each_of_allnodes(dn) \ + for (dn = of_allnodes; dn; dn = dn->allnext) extern struct device_node *of_find_node_by_name(struct device_node *from, const char *name); #define for_each_node_by_name(dn, name) \ -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html