--- /dev/null
+/*
+ * lib/dynamic_debug.c
+ *
+ * make pr_debug()/dev_dbg() calls runtime configurable based upon their
+ * source module.
+ *
+ * Copyright (C) 2008 Jason Baron <jbaron@redhat.com>
+ * By Greg Banks <gnb@melbourne.sgi.com>
+ * Copyright (c) 2008 Silicon Graphics Inc. All Rights Reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/kallsyms.h>
+#include <linux/version.h>
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/list.h>
+#include <linux/sysctl.h>
+#include <linux/ctype.h>
+#include <linux/uaccess.h>
+#include <linux/dynamic_debug.h>
+#include <linux/debugfs.h>
+
+extern struct _ddebug __start___verbose[];
+extern struct _ddebug __stop___verbose[];
+
+/* dynamic_debug_enabled, and dynamic_debug_enabled2 are bitmasks in which
+ * bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
+ * use independent hash functions, to reduce the chance of false positives.
+ */
+long long dynamic_debug_enabled;
+EXPORT_SYMBOL_GPL(dynamic_debug_enabled);
+long long dynamic_debug_enabled2;
+EXPORT_SYMBOL_GPL(dynamic_debug_enabled2);
+
+struct ddebug_table {
+ struct list_head link;
+ char *mod_name;
+ unsigned int num_ddebugs;
+ unsigned int num_enabled;
+ struct _ddebug *ddebugs;
+};
+
+struct ddebug_query {
+ const char *filename;
+ const char *module;
+ const char *function;
+ const char *format;
+ unsigned int first_lineno, last_lineno;
+};
+
+struct ddebug_iter {
+ struct ddebug_table *table;
+ unsigned int idx;
+};
+
+static DEFINE_MUTEX(ddebug_lock);
+static LIST_HEAD(ddebug_tables);
+static int verbose = 0;
+
+/* Return the last part of a pathname */
+static inline const char *basename(const char *path)
+{
+ const char *tail = strrchr(path, '/');
+ return tail ? tail+1 : path;
+}
+
+/* format a string into buf[] which describes the _ddebug's flags */
+static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
+ size_t maxlen)
+{
+ char *p = buf;
+
+ BUG_ON(maxlen < 4);
+ if (dp->flags & _DPRINTK_FLAGS_PRINT)
+ *p++ = 'p';
+ if (p == buf)
+ *p++ = '-';
+ *p = '\0';
+
+ return buf;
+}
+
+/*
+ * must be called with ddebug_lock held
+ */
+
+static int disabled_hash(char hash, bool first_table)
+{
+ struct ddebug_table *dt;
+ char table_hash_value;
+
+ list_for_each_entry(dt, &ddebug_tables, link) {
+ if (first_table)
+ table_hash_value = dt->ddebugs->primary_hash;
+ else
+ table_hash_value = dt->ddebugs->secondary_hash;
+ if (dt->num_enabled && (hash == table_hash_value))
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * Search the tables for _ddebug's which match the given
+ * `query' and apply the `flags' and `mask' to them. Tells
+ * the user which ddebug's were changed, or whether none
+ * were matched.
+ */
+static void ddebug_change(const struct ddebug_query *query,
+ unsigned int flags, unsigned int mask)
+{
+ int i;
+ struct ddebug_table *dt;
+ unsigned int newflags;
+ unsigned int nfound = 0;
+ char flagbuf[8];
+
+ /* search for matching ddebugs */
+ mutex_lock(&ddebug_lock);
+ list_for_each_entry(dt, &ddebug_tables, link) {
+
+ /* match against the module name */
+ if (query->module != NULL &&
+ strcmp(query->module, dt->mod_name))
+ continue;
+
+ for (i = 0 ; i < dt->num_ddebugs ; i++) {
+ struct _ddebug *dp = &dt->ddebugs[i];
+
+ /* match against the source filename */
+ if (query->filename != NULL &&
+ strcmp(query->filename, dp->filename) &&
+ strcmp(query->filename, basename(dp->filename)))
+ continue;
+
+ /* match against the function */
+ if (query->function != NULL &&
+ strcmp(query->function, dp->function))
+ continue;
+
+ /* match against the format */
+ if (query->format != NULL &&
+ strstr(dp->format, query->format) == NULL)
+ continue;
+
+ /* match against the line number range */
+ if (query->first_lineno &&
+ dp->lineno < query->first_lineno)
+ continue;
+ if (query->last_lineno &&
+ dp->lineno > query->last_lineno)
+ continue;
+
+ nfound++;
+
+ newflags = (dp->flags & mask) | flags;
+ if (newflags == dp->flags)
+ continue;
+
+ if (!newflags)
+ dt->num_enabled--;
+ else if (!dp-flags)
+ dt->num_enabled++;
+ dp->flags = newflags;
+ if (newflags) {
+ dynamic_debug_enabled |=
+ (1LL << dp->primary_hash);
+ dynamic_debug_enabled2 |=
+ (1LL << dp->secondary_hash);
+ } else {
+ if (disabled_hash(dp->primary_hash, true))
+ dynamic_debug_enabled &=
+ ~(1LL << dp->primary_hash);
+ if (disabled_hash(dp->secondary_hash, false))
+ dynamic_debug_enabled2 &=
+ ~(1LL << dp->secondary_hash);
+ }
+ if (verbose)
+ printk(KERN_INFO
+ "ddebug: changed %s:%d [%s]%s %s\n",
+ dp->filename, dp->lineno,
+ dt->mod_name, dp->function,
+ ddebug_describe_flags(dp, flagbuf,
+ sizeof(flagbuf)));
+ }
+ }
+ mutex_unlock(&ddebug_lock);
+
+ if (!nfound && verbose)
+ printk(KERN_INFO "ddebug: no matches for query\n");
+}
+
+/*
+ * Wrapper around strsep() to collapse the multiple empty tokens
+ * that it returns when fed sequences of separator characters.
+ * Now, if we had strtok_r()...
+ */
+static inline char *nearly_strtok_r(char **p, const char *sep)
+{
+ char *r;
+
+ while ((r = strsep(p, sep)) != NULL && *r == '\0')
+ ;
+ return r;
+}
+
+/*
+ * Split the buffer `buf' into space-separated words.
+ * Return the number of such words or <0 on error.
+ */
+static int ddebug_tokenize(char *buf, char *words[], int maxwords)
+{
+ int nwords = 0;
+
+ while (nwords < maxwords &&
+ (words[nwords] = nearly_strtok_r(&buf, " \t\r\n")) != NULL)
+ nwords++;
+ if (buf)
+ return -EINVAL; /* ran out of words[] before bytes */
+
+ if (verbose) {
+ int i;
+ printk(KERN_INFO "%s: split into words:", __func__);
+ for (i = 0 ; i < nwords ; i++)
+ printk(" \"%s\"", words[i]);
+ printk("\n");
+ }
+
+ return nwords;
+}
+
+/*
+ * Parse a single line number. Note that the empty string ""
+ * is treated as a special case and converted to zero, which
+ * is later treated as a "don't care" value.
+ */
+static inline int parse_lineno(const char *str, unsigned int *val)
+{
+ char *end = NULL;
+ BUG_ON(str == NULL);
+ if (*str == '\0') {
+ *val = 0;
+ return 0;
+ }
+ *val = simple_strtoul(str, &end, 10);
+ return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
+}
+
+/*
+ * Undo octal escaping in a string, inplace. This is useful to
+ * allow the user to express a query which matches a format
+ * containing embedded spaces.
+ */
+#define isodigit(c) ((c) >= '0' && (c) <= '7')
+static char *unescape(char *str)
+{
+ char *in = str;
+ char *out = str;
+
+ while (*in) {
+ if (*in == '\\') {
+ if (in[1] == '\\') {
+ *out++ = '\\';
+ in += 2;
+ continue;
+ } else if (in[1] == 't') {
+ *out++ = '\t';
+ in += 2;
+ continue;
+ } else if (in[1] == 'n') {
+ *out++ = '\n';
+ in += 2;
+ continue;
+ } else if (isodigit(in[1]) &&
+ isodigit(in[2]) &&
+ isodigit(in[3])) {
+ *out++ = ((in[1] - '0')<<6) |
+ ((in[2] - '0')<<3) |
+ (in[3] - '0');
+ in += 4;
+ continue;
+ }
+ }
+ *out++ = *in++;
+ }
+ *out = '\0';
+
+ return str;
+}
+
+/*
+ * Parse words[] as a ddebug query specification, which is a series
+ * of (keyword, value) pairs chosen from these possibilities:
+ *
+ * func <function-name>
+ * file <full-pathname>
+ * file <base-filename>
+ * module <module-name>
+ * format <escaped-string-to-find-in-format>
+ * line <lineno>
+ * line <first-lineno>-<last-lineno> // where either may be empty
+ */
+static int ddebug_parse_query(char *words[], int nwords,
+ struct ddebug_query *query)
+{
+ unsigned int i;
+
+ /* check we have an even number of words */
+ if (nwords % 2 != 0)
+ return -EINVAL;
+ memset(query, 0, sizeof(*query));
+
+ for (i = 0 ; i < nwords ; i += 2) {
+ if (!strcmp(words[i], "func"))
+ query->function = words[i+1];
+ else if (!strcmp(words[i], "file"))
+ query->filename = words[i+1];
+ else if (!strcmp(words[i], "module"))
+ query->module = words[i+1];
+ else if (!strcmp(words[i], "format"))
+ query->format = unescape(words[i+1]);
+ else if (!strcmp(words[i], "line")) {
+ char *first = words[i+1];
+ char *last = strchr(first, '-');
+ if (last)
+ *last++ = '\0';
+ if (parse_lineno(first, &query->first_lineno) < 0)
+ return -EINVAL;
+ if (last != NULL) {
+ /* range <first>-<last> */
+ if (parse_lineno(last, &query->last_lineno) < 0)
+ return -EINVAL;
+ } else {
+ query->last_lineno = query->first_lineno;
+ }
+ } else {
+ if (verbose)
+ printk(KERN_ERR "%s: unknown keyword \"%s\"\n",
+ __func__, words[i]);
+ return -EINVAL;
+ }
+ }
+
+ if (verbose)
+ printk(KERN_INFO "%s: q->function=\"%s\" q->filename=\"%s\" "
+ "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
+ __func__, query->function, query->filename,
+ query->module, query->format, query->first_lineno,
+ query->last_lineno);
+
+ return 0;
+}
+
+/*
+ * Parse `str' as a flags specification, format [-+=][p]+.
+ * Sets up *maskp and *flagsp to be used when changing the
+ * flags fields of matched _ddebug's. Returns 0 on success
+ * or <0 on error.
+ */
+static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
+ unsigned int *maskp)
+{
+ unsigned flags = 0;
+ int op = '=';
+
+ switch (*str) {
+ case '+':
+ case '-':
+ case '=':
+ op = *str++;
+ break;
+ default:
+ return -EINVAL;
+ }
+ if (verbose)
+ printk(KERN_INFO "%s: op='%c'\n", __func__, op);
+
+ for ( ; *str ; ++str) {
+ switch (*str) {
+ case 'p':
+ flags |= _DPRINTK_FLAGS_PRINT;
+ break;
+ default:
+ return -EINVAL;
+ }
+ }
+ if (flags == 0)
+ return -EINVAL;
+ if (verbose)
+ printk(KERN_INFO "%s: flags=0x%x\n", __func__, flags);
+
+ /* calculate final *flagsp, *maskp according to mask and op */
+ switch (op) {
+ case '=':
+ *maskp = 0;
+ *flagsp = flags;
+ break;
+ case '+':
+ *maskp = ~0U;
+ *flagsp = flags;
+ break;
+ case '-':
+ *maskp = ~flags;
+ *flagsp = 0;
+ break;
+ }
+ if (verbose)
+ printk(KERN_INFO "%s: *flagsp=0x%x *maskp=0x%x\n",
+ __func__, *flagsp, *maskp);
+ return 0;
+}
+
+/*
+ * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
+ * command text from userspace, parses and executes it.
+ */
+static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
+ size_t len, loff_t *offp)
+{
+ unsigned int flags = 0, mask = 0;
+ struct ddebug_query query;
+#define MAXWORDS 9
+ int nwords;
+ char *words[MAXWORDS];
+ char tmpbuf[256];
+
+ if (len == 0)
+ return 0;
+ /* we don't check *offp -- multiple writes() are allowed */
+ if (len > sizeof(tmpbuf)-1)
+ return -E2BIG;
+ if (copy_from_user(tmpbuf, ubuf, len))
+ return -EFAULT;
+ tmpbuf[len] = '\0';
+ if (verbose)
+ printk(KERN_INFO "%s: read %d bytes from userspace\n",
+ __func__, (int)len);
+
+ nwords = ddebug_tokenize(tmpbuf, words, MAXWORDS);
+ if (nwords < 0)
+ return -EINVAL;
+ if (ddebug_parse_query(words, nwords-1, &query))
+ return -EINVAL;
+ if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
+ return -EINVAL;
+
+ /* actually go and implement the change */
+ ddebug_change(&query, flags, mask);
+
+ *offp += len;
+ return len;
+}
+
+/*
+ * Set the iterator to point to the first _ddebug object
+ * and return a pointer to that first object. Returns
+ * NULL if there are no _ddebugs at all.
+ */
+static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
+{
+ if (list_empty(&ddebug_tables)) {
+ iter->table = NULL;
+ iter->idx = 0;
+ return NULL;
+ }
+ iter->table = list_entry(ddebug_tables.next,
+ struct ddebug_table, link);
+ iter->idx = 0;
+ return &iter->table->ddebugs[iter->idx];
+}
+
+/*
+ * Advance the iterator to point to the next _ddebug
+ * object from the one the iterator currently points at,
+ * and returns a pointer to the new _ddebug. Returns
+ * NULL if the iterator has seen all the _ddebugs.
+ */
+static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
+{
+ if (iter->table == NULL)
+ return NULL;
+ if (++iter->idx == iter->table->num_ddebugs) {
+ /* iterate to next table */
+ iter->idx = 0;
+ if (list_is_last(&iter->table->link, &ddebug_tables)) {
+ iter->table = NULL;
+ return NULL;
+ }
+ iter->table = list_entry(iter->table->link.next,
+ struct ddebug_table, link);
+ }
+ return &iter->table->ddebugs[iter->idx];
+}
+
+/*
+ * Seq_ops start method. Called at the start of every
+ * read() call from userspace. Takes the ddebug_lock and
+ * seeks the seq_file's iterator to the given position.
+ */
+static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
+{
+ struct ddebug_iter *iter = m->private;
+ struct _ddebug *dp;
+ int n = *pos;
+
+ if (verbose)
+ printk(KERN_INFO "%s: called m=%p *pos=%lld\n",
+ __func__, m, (unsigned long long)*pos);
+
+ mutex_lock(&ddebug_lock);
+
+ if (!n)
+ return SEQ_START_TOKEN;
+ if (n < 0)
+ return NULL;
+ dp = ddebug_iter_first(iter);
+ while (dp != NULL && --n > 0)
+ dp = ddebug_iter_next(iter);
+ return dp;
+}
+
+/*
+ * Seq_ops next method. Called several times within a read()
+ * call from userspace, with ddebug_lock held. Walks to the
+ * next _ddebug object with a special case for the header line.
+ */
+static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
+{
+ struct ddebug_iter *iter = m->private;
+ struct _ddebug *dp;
+
+ if (verbose)
+ printk(KERN_INFO "%s: called m=%p p=%p *pos=%lld\n",
+ __func__, m, p, (unsigned long long)*pos);
+
+ if (p == SEQ_START_TOKEN)
+ dp = ddebug_iter_first(iter);
+ else
+ dp = ddebug_iter_next(iter);
+ ++*pos;
+ return dp;
+}
+
+/*
+ * Seq_ops show method. Called several times within a read()
+ * call from userspace, with ddebug_lock held. Formats the
+ * current _ddebug as a single human-readable line, with a
+ * special case for the header line.
+ */
+static int ddebug_proc_show(struct seq_file *m, void *p)
+{
+ struct ddebug_iter *iter = m->private;
+ struct _ddebug *dp = p;
+ char flagsbuf[8];
+
+ if (verbose)
+ printk(KERN_INFO "%s: called m=%p p=%p\n",
+ __func__, m, p);
+
+ if (p == SEQ_START_TOKEN) {
+ seq_puts(m,
+ "# filename:lineno [module]function flags format\n");
+ return 0;
+ }
+
+ seq_printf(m, "%s:%u [%s]%s %s \"",
+ dp->filename, dp->lineno,
+ iter->table->mod_name, dp->function,
+ ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
+ seq_escape(m, dp->format, "\t\r\n\"");
+ seq_puts(m, "\"\n");
+
+ return 0;
+}
+
+/*
+ * Seq_ops stop method. Called at the end of each read()
+ * call from userspace. Drops ddebug_lock.
+ */
+static void ddebug_proc_stop(struct seq_file *m, void *p)
+{
+ if (verbose)
+ printk(KERN_INFO "%s: called m=%p p=%p\n",
+ __func__, m, p);
+ mutex_unlock(&ddebug_lock);
+}
+
+static const struct seq_operations ddebug_proc_seqops = {
+ .start = ddebug_proc_start,
+ .next = ddebug_proc_next,
+ .show = ddebug_proc_show,
+ .stop = ddebug_proc_stop
+};
+
+/*
+ * File_ops->open method for <debugfs>/dynamic_debug/control. Does the seq_file
+ * setup dance, and also creates an iterator to walk the _ddebugs.
+ * Note that we create a seq_file always, even for O_WRONLY files
+ * where it's not needed, as doing so simplifies the ->release method.
+ */
+static int ddebug_proc_open(struct inode *inode, struct file *file)
+{
+ struct ddebug_iter *iter;
+ int err;
+
+ if (verbose)
+ printk(KERN_INFO "%s: called\n", __func__);
+
+ iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+ if (iter == NULL)
+ return -ENOMEM;
+
+ err = seq_open(file, &ddebug_proc_seqops);
+ if (err) {
+ kfree(iter);
+ return err;
+ }
+ ((struct seq_file *) file->private_data)->private = iter;
+ return 0;
+}
+
+static const struct file_operations ddebug_proc_fops = {
+ .owner = THIS_MODULE,
+ .open = ddebug_proc_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release_private,
+ .write = ddebug_proc_write
+};
+
+/*
+ * Allocate a new ddebug_table for the given module
+ * and add it to the global list.
+ */
+int ddebug_add_module(struct _ddebug *tab, unsigned int n,
+ const char *name)
+{
+ struct ddebug_table *dt;
+ char *new_name;
+
+ dt = kzalloc(sizeof(*dt), GFP_KERNEL);
+ if (dt == NULL)
+ return -ENOMEM;
+ new_name = kstrdup(name, GFP_KERNEL);
+ if (new_name == NULL) {
+ kfree(dt);
+ return -ENOMEM;
+ }
+ dt->mod_name = new_name;
+ dt->num_ddebugs = n;
+ dt->num_enabled = 0;
+ dt->ddebugs = tab;
+
+ mutex_lock(&ddebug_lock);
+ list_add_tail(&dt->link, &ddebug_tables);
+ mutex_unlock(&ddebug_lock);
+
+ if (verbose)
+ printk(KERN_INFO "%u debug prints in module %s\n",
+ n, dt->mod_name);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ddebug_add_module);
+
+static void ddebug_table_free(struct ddebug_table *dt)
+{
+ list_del_init(&dt->link);
+ kfree(dt->mod_name);
+ kfree(dt);
+}
+
+/*
+ * Called in response to a module being unloaded. Removes
+ * any ddebug_table's which point at the module.
+ */
+int ddebug_remove_module(char *mod_name)
+{
+ struct ddebug_table *dt, *nextdt;
+ int ret = -ENOENT;
+
+ if (verbose)
+ printk(KERN_INFO "%s: removing module \"%s\"\n",
+ __func__, mod_name);
+
+ mutex_lock(&ddebug_lock);
+ list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
+ if (!strcmp(dt->mod_name, mod_name)) {
+ ddebug_table_free(dt);
+ ret = 0;
+ }
+ }
+ mutex_unlock(&ddebug_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ddebug_remove_module);
+
+static void ddebug_remove_all_tables(void)
+{
+ mutex_lock(&ddebug_lock);
+ while (!list_empty(&ddebug_tables)) {
+ struct ddebug_table *dt = list_entry(ddebug_tables.next,
+ struct ddebug_table,
+ link);
+ ddebug_table_free(dt);
+ }
+ mutex_unlock(&ddebug_lock);
+}
+
+static int __init dynamic_debug_init(void)
+{
+ struct dentry *dir, *file;
+ struct _ddebug *iter, *iter_start;
+ const char *modname = NULL;
+ int ret = 0;
+ int n = 0;
+
+ dir = debugfs_create_dir("dynamic_debug", NULL);
+ if (!dir)
+ return -ENOMEM;
+ file = debugfs_create_file("control", 0644, dir, NULL,
+ &ddebug_proc_fops);
+ if (!file) {
+ debugfs_remove(dir);
+ return -ENOMEM;
+ }
+ if (__start___verbose != __stop___verbose) {
+ iter = __start___verbose;
+ modname = iter->modname;
+ iter_start = iter;
+ for (; iter < __stop___verbose; iter++) {
+ if (strcmp(modname, iter->modname)) {
+ ret = ddebug_add_module(iter_start, n, modname);
+ if (ret)
+ goto out_free;
+ n = 0;
+ modname = iter->modname;
+ iter_start = iter;
+ }
+ n++;
+ }
+ ret = ddebug_add_module(iter_start, n, modname);
+ }
+out_free:
+ if (ret) {
+ ddebug_remove_all_tables();
+ debugfs_remove(dir);
+ debugfs_remove(file);
+ }
+ return 0;
+}
+module_init(dynamic_debug_init);
projects / linux-2.6-omap-h63xx.git / blobdiff