5f64f73957
This cleans up the /proc/device-tree representation of the Open Firmware device-tree on ppc and ppc64. It does the following things: - Workaround an issue in some Apple device-trees where a property may exist with the same name as a child node of the parent. We now simply "drop" the property instead of creating duplicate entries in /proc with random result... - Do not try to chop off the "@0" at the end of a node name whose unit address is 0. This is not useful, inconsistent, and the code was buggy and didn't always work anyway. - Do not create symlinks for the short name and unit address parts of a node. These were never really used, bloated the memory footprint of the device-tree with useless struct proc_dir_entry and their matching dentry and inode cache bloat. This results in smaller code, smaller memory footprint, and a more accurate view of the tree presented to userland. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
136 lines
3.1 KiB
C
136 lines
3.1 KiB
C
/*
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* proc_devtree.c - handles /proc/device-tree
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*
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* Copyright 1997 Paul Mackerras
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*/
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#include <linux/errno.h>
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#include <linux/time.h>
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#include <linux/proc_fs.h>
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#include <linux/stat.h>
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#include <linux/string.h>
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#include <asm/prom.h>
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#include <asm/uaccess.h>
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#ifndef HAVE_ARCH_DEVTREE_FIXUPS
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static inline void set_node_proc_entry(struct device_node *np,
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struct proc_dir_entry *de)
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{
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}
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#endif
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static struct proc_dir_entry *proc_device_tree;
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/*
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* Supply data on a read from /proc/device-tree/node/property.
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*/
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static int property_read_proc(char *page, char **start, off_t off,
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int count, int *eof, void *data)
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{
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struct property *pp = data;
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int n;
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if (off >= pp->length) {
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*eof = 1;
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return 0;
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}
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n = pp->length - off;
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if (n > count)
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n = count;
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else
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*eof = 1;
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memcpy(page, pp->value + off, n);
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*start = page;
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return n;
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}
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/*
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* For a node with a name like "gc@10", we make symlinks called "gc"
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* and "@10" to it.
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*/
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/*
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* Process a node, adding entries for its children and its properties.
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*/
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void proc_device_tree_add_node(struct device_node *np,
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struct proc_dir_entry *de)
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{
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struct property *pp;
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struct proc_dir_entry *ent;
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struct device_node *child;
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struct proc_dir_entry *list = NULL, **lastp;
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const char *p;
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set_node_proc_entry(np, de);
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lastp = &list;
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for (child = NULL; (child = of_get_next_child(np, child));) {
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p = strrchr(child->full_name, '/');
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if (!p)
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p = child->full_name;
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else
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++p;
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ent = proc_mkdir(p, de);
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if (ent == 0)
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break;
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*lastp = ent;
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ent->next = NULL;
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lastp = &ent->next;
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proc_device_tree_add_node(child, ent);
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}
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of_node_put(child);
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for (pp = np->properties; pp != 0; pp = pp->next) {
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/*
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* Yet another Apple device-tree bogosity: on some machines,
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* they have properties & nodes with the same name. Those
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* properties are quite unimportant for us though, thus we
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* simply "skip" them here, but we do have to check.
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*/
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for (ent = list; ent != NULL; ent = ent->next)
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if (!strcmp(ent->name, pp->name))
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break;
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if (ent != NULL) {
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printk(KERN_WARNING "device-tree: property \"%s\" name"
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" conflicts with node in %s\n", pp->name,
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np->full_name);
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continue;
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}
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/*
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* Unfortunately proc_register puts each new entry
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* at the beginning of the list. So we rearrange them.
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*/
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ent = create_proc_read_entry(pp->name,
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strncmp(pp->name, "security-", 9)
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? S_IRUGO : S_IRUSR, de,
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property_read_proc, pp);
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if (ent == 0)
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break;
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if (!strncmp(pp->name, "security-", 9))
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ent->size = 0; /* don't leak number of password chars */
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else
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ent->size = pp->length;
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ent->next = NULL;
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*lastp = ent;
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lastp = &ent->next;
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}
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de->subdir = list;
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}
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/*
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* Called on initialization to set up the /proc/device-tree subtree
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*/
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void proc_device_tree_init(void)
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{
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struct device_node *root;
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if ( !have_of )
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return;
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proc_device_tree = proc_mkdir("device-tree", NULL);
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if (proc_device_tree == 0)
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return;
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root = of_find_node_by_path("/");
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if (root == 0) {
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printk(KERN_ERR "/proc/device-tree: can't find root\n");
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return;
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}
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proc_device_tree_add_node(root, proc_device_tree);
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of_node_put(root);
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}
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