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lib/dynamic_debug.c
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/* * 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. |
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* Copyright (C) 2011 Bart Van Assche. All Rights Reserved. |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__ |
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#include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/kallsyms.h> |
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#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> |
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#include <linux/string.h> |
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#include <linux/uaccess.h> #include <linux/dynamic_debug.h> #include <linux/debugfs.h> |
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#include <linux/slab.h> |
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#include <linux/jump_label.h> |
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#include <linux/hardirq.h> |
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#include <linux/sched.h> |
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#include <linux/device.h> |
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#include <linux/netdevice.h> |
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extern struct _ddebug __start___verbose[]; extern struct _ddebug __stop___verbose[]; |
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struct ddebug_table { struct list_head link; char *mod_name; unsigned int num_ddebugs; |
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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; } |
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static struct { unsigned flag:8; char opt_char; } opt_array[] = { { _DPRINTK_FLAGS_PRINT, 'p' }, { _DPRINTK_FLAGS_INCL_MODNAME, 'm' }, { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' }, { _DPRINTK_FLAGS_INCL_LINENO, 'l' }, { _DPRINTK_FLAGS_INCL_TID, 't' }, }; |
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/* 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; |
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int i; |
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BUG_ON(maxlen < 4); |
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for (i = 0; i < ARRAY_SIZE(opt_array); ++i) if (dp->flags & opt_array[i].flag) *p++ = opt_array[i].opt_char; |
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if (p == buf) *p++ = '-'; *p = '\0'; return buf; } /* |
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* 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; |
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dp->flags = newflags; |
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if (newflags) dp->enabled = 1; else dp->enabled = 0; |
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if (verbose) |
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pr_info("changed %s:%d [%s]%s %s ", |
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dp->filename, dp->lineno, dt->mod_name, dp->function, ddebug_describe_flags(dp, flagbuf, sizeof(flagbuf))); } } mutex_unlock(&ddebug_lock); if (!nfound && verbose) |
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pr_info("no matches for query "); |
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} /* |
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* Split the buffer `buf' into space-separated words. |
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* Handles simple " and ' quoting, i.e. without nested, * embedded or escaped \". Return the number of words * or <0 on error. |
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*/ static int ddebug_tokenize(char *buf, char *words[], int maxwords) { int nwords = 0; |
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while (*buf) { char *end; /* Skip leading whitespace */ |
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buf = skip_spaces(buf); |
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if (!*buf) break; /* oh, it was trailing whitespace */ /* Run `end' over a word, either whitespace separated or quoted */ if (*buf == '"' || *buf == '\'') { int quote = *buf++; for (end = buf ; *end && *end != quote ; end++) ; if (!*end) return -EINVAL; /* unclosed quote */ } else { for (end = buf ; *end && !isspace(*end) ; end++) ; BUG_ON(end == buf); } /* Here `buf' is the start of the word, `end' is one past the end */ if (nwords == maxwords) return -EINVAL; /* ran out of words[] before bytes */ if (*end) *end++ = '\0'; /* terminate the word */ words[nwords++] = buf; buf = end; } |
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if (verbose) { int i; |
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pr_info("split into words:"); |
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for (i = 0 ; i < nwords ; i++) |
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pr_cont(" \"%s\"", words[i]); pr_cont(" "); |
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} 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++ = ' '; 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) |
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pr_err("unknown keyword \"%s\" ", words[i]); |
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return -EINVAL; } } if (verbose) |
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pr_info("q->function=\"%s\" q->filename=\"%s\" " "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u ", query->function, query->filename, |
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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; |
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int op = '=', i; |
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switch (*str) { case '+': case '-': case '=': op = *str++; break; default: return -EINVAL; } if (verbose) |
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pr_info("op='%c' ", op); |
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for ( ; *str ; ++str) { |
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for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) { if (*str == opt_array[i].opt_char) { flags |= opt_array[i].flag; break; } |
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} |
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if (i < 0) return -EINVAL; |
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} if (flags == 0) return -EINVAL; if (verbose) |
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pr_info("flags=0x%x ", flags); |
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/* 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) |
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pr_info("*flagsp=0x%x *maskp=0x%x ", *flagsp, *maskp); |
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return 0; } |
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static int ddebug_exec_query(char *query_string) { unsigned int flags = 0, mask = 0; struct ddebug_query query; #define MAXWORDS 9 int nwords; char *words[MAXWORDS]; nwords = ddebug_tokenize(query_string, 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); return 0; } |
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#define PREFIX_SIZE 64 static int remaining(int wrote) { if (PREFIX_SIZE - wrote > 0) return PREFIX_SIZE - wrote; return 0; } static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf) |
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{ |
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int pos_after_tid; int pos = 0; |
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pos += snprintf(buf + pos, remaining(pos), "%s", KERN_DEBUG); if (desc->flags & _DPRINTK_FLAGS_INCL_TID) { |
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if (in_interrupt()) |
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pos += snprintf(buf + pos, remaining(pos), "%s ", "<intr>"); |
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else |
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pos += snprintf(buf + pos, remaining(pos), "[%d] ", task_pid_vnr(current)); |
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} |
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pos_after_tid = pos; if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME) pos += snprintf(buf + pos, remaining(pos), "%s:", desc->modname); if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME) pos += snprintf(buf + pos, remaining(pos), "%s:", desc->function); if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO) pos += snprintf(buf + pos, remaining(pos), "%d:", desc->lineno); if (pos - pos_after_tid) pos += snprintf(buf + pos, remaining(pos), " "); if (pos >= PREFIX_SIZE) buf[PREFIX_SIZE - 1] = '\0'; |
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return buf; |
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} |
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int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...) { va_list args; int res; |
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struct va_format vaf; char buf[PREFIX_SIZE]; |
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BUG_ON(!descriptor); BUG_ON(!fmt); va_start(args, fmt); |
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vaf.fmt = fmt; vaf.va = &args; res = printk("%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf); |
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va_end(args); return res; } EXPORT_SYMBOL(__dynamic_pr_debug); |
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int __dynamic_dev_dbg(struct _ddebug *descriptor, const struct device *dev, const char *fmt, ...) { struct va_format vaf; va_list args; int res; |
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char buf[PREFIX_SIZE]; |
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BUG_ON(!descriptor); BUG_ON(!fmt); va_start(args, fmt); |
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vaf.fmt = fmt; vaf.va = &args; |
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res = __dev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf); |
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va_end(args); return res; } EXPORT_SYMBOL(__dynamic_dev_dbg); |
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#ifdef CONFIG_NET |
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int __dynamic_netdev_dbg(struct _ddebug *descriptor, const struct net_device *dev, const char *fmt, ...) { struct va_format vaf; va_list args; int res; |
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char buf[PREFIX_SIZE]; |
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BUG_ON(!descriptor); BUG_ON(!fmt); va_start(args, fmt); |
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vaf.fmt = fmt; vaf.va = &args; |
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res = __netdev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf); |
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va_end(args); return res; } EXPORT_SYMBOL(__dynamic_netdev_dbg); |
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#endif |
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static __initdata char ddebug_setup_string[1024]; static __init int ddebug_setup_query(char *str) { if (strlen(str) >= 1024) { |
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pr_warn("ddebug boot param string too large "); |
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return 0; } strcpy(ddebug_setup_string, str); return 1; } __setup("ddebug_query=", ddebug_setup_query); |
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/* * 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) { |
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char tmpbuf[256]; |
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int ret; |
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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) |
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pr_info("read %d bytes from userspace ", (int)len); |
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ret = ddebug_exec_query(tmpbuf); if (ret) return ret; |
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*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) |
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pr_info("called m=%p *pos=%lld ", m, (unsigned long long)*pos); |
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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) |
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pr_info("called m=%p p=%p *pos=%lld ", m, p, (unsigned long long)*pos); |
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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) |
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pr_info("called m=%p p=%p ", m, p); |
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if (p == SEQ_START_TOKEN) { seq_puts(m, "# filename:lineno [module]function flags format "); 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 \""); seq_puts(m, "\" "); 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) |
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pr_info("called m=%p p=%p ", m, p); |
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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) |
4ad275e5c dynamic_debug: Co... |
725 726 |
pr_info("called "); |
e9d376f0f dynamic debug: co... |
727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 |
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; |
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dt->ddebugs = tab; mutex_lock(&ddebug_lock); list_add_tail(&dt->link, &ddebug_tables); mutex_unlock(&ddebug_lock); if (verbose) |
4ad275e5c dynamic_debug: Co... |
777 778 |
pr_info("%u debug prints in module %s ", n, dt->mod_name); |
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779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 |
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. */ |
ff49d74ad module: initializ... |
794 |
int ddebug_remove_module(const char *mod_name) |
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{ struct ddebug_table *dt, *nextdt; int ret = -ENOENT; if (verbose) |
4ad275e5c dynamic_debug: Co... |
800 801 |
pr_info("removing module \"%s\" ", mod_name); |
e9d376f0f dynamic debug: co... |
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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); } |
6a5c083de Dynamic Debug: In... |
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static __initdata int ddebug_init_success; static int __init dynamic_debug_init_debugfs(void) |
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{ struct dentry *dir, *file; |
6a5c083de Dynamic Debug: In... |
831 832 833 |
if (!ddebug_init_success) return -ENODEV; |
e9d376f0f dynamic debug: co... |
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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; } |
6a5c083de Dynamic Debug: In... |
844 845 846 847 848 849 850 851 852 |
return 0; } static int __init dynamic_debug_init(void) { struct _ddebug *iter, *iter_start; const char *modname = NULL; int ret = 0; int n = 0; |
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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); } |
a648ec05b Dynamic Debug: In... |
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/* ddebug_query boot param got passed -> set it up */ if (ddebug_setup_string[0] != '\0') { ret = ddebug_exec_query(ddebug_setup_string); if (ret) |
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pr_warn("Invalid ddebug boot param %s", ddebug_setup_string); |
a648ec05b Dynamic Debug: In... |
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else pr_info("ddebug initialized with string %s", ddebug_setup_string); } |
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out_free: |
6a5c083de Dynamic Debug: In... |
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if (ret) |
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ddebug_remove_all_tables(); |
6a5c083de Dynamic Debug: In... |
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else ddebug_init_success = 1; |
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return 0; } |
6a5c083de Dynamic Debug: In... |
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/* Allow early initialization for boot messages via boot param */ arch_initcall(dynamic_debug_init); /* Debugfs setup must be done later */ module_init(dynamic_debug_init_debugfs); |