include/log.h

   1 /*
   2  * Logging support
   3  *
   4  * Copyright (c) 2017 Google, Inc
   5  * Written by Simon Glass <sjg@chromium.org>
   6  *
   7  * SPDX-License-Identifier:     GPL-2.0+
   8  */
   9
  10 #ifndef __LOG_H
  11 #define __LOG_H
  12
  13 #include <dm/uclass-id.h>
  14 #include <linux/list.h>
  15
  16 /** Log levels supported, ranging from most to least important */
  17 enum log_level_t {
  18         LOGL_EMERG = 0,         /*U-Boot is unstable */
  19         LOGL_ALERT,             /* Action must be taken immediately */
  20         LOGL_CRIT,              /* Critical conditions */
  21         LOGL_ERR,               /* Error that prevents something from working */
  22         LOGL_WARNING,           /* Warning may prevent optimial operation */
  23         LOGL_NOTICE,            /* Normal but significant condition, printf() */
  24         LOGL_INFO,              /* General information message */
  25         LOGL_DEBUG,             /* Basic debug-level message */
  26         LOGL_DEBUG_CONTENT,     /* Debug message showing full message content */
  27         LOGL_DEBUG_IO,          /* Debug message showing hardware I/O access */
  28
  29         LOGL_COUNT,
  30         LOGL_NONE,
  31
  32         LOGL_FIRST = LOGL_EMERG,
  33         LOGL_MAX = LOGL_DEBUG_IO,
  34 };
  35
  36 /**
  37  * Log categories supported. Most of these correspond to uclasses (i.e.
  38  * enum uclass_id) but there are also some more generic categories
  39  */
  40 enum log_category_t {
  41         LOGC_FIRST = 0, /* First part mirrors UCLASS_... */
  42
  43         LOGC_NONE = UCLASS_COUNT,
  44         LOGC_ARCH,
  45         LOGC_BOARD,
  46         LOGC_CORE,
  47         LOGC_DM,        /* Core driver-model */
  48         LOGC_DT,        /* Device-tree */
  49         LOGL_EFI,       /* EFI implementation */
  50
  51         LOGC_COUNT,
  52         LOGC_END,
  53 };
  54
  55 /* Helper to cast a uclass ID to a log category */
  56 static inline int log_uc_cat(enum uclass_id id)
  57 {
  58         return (enum log_category_t)id;
  59 }
  60
  61 /**
  62  * _log() - Internal function to emit a new log record
  63  *
  64  * @cat: Category of log record (indicating which subsystem generated it)
  65  * @level: Level of log record (indicating its severity)
  66  * @file: File name of file where log record was generated
  67  * @line: Line number in file where log record was generated
  68  * @func: Function where log record was generated
  69  * @fmt: printf() format string for log record
  70  * @...: Optional parameters, according to the format string @fmt
  71  * @return 0 if log record was emitted, -ve on error
  72  */
  73 int _log(enum log_category_t cat, enum log_level_t level, const char *file,
  74          int line, const char *func, const char *fmt, ...);
  75
  76 /* Define this at the top of a file to add a prefix to debug messages */
  77 #ifndef pr_fmt
  78 #define pr_fmt(fmt) fmt
  79 #endif
  80
  81 /* Use a default category if this file does not supply one */
  82 #ifndef LOG_CATEGORY
  83 #define LOG_CATEGORY LOGC_NONE
  84 #endif
  85
  86 /*
  87  * This header may be including when CONFIG_LOG is disabled, in which case
  88  * CONFIG_LOG_MAX_LEVEL is not defined. Add a check for this.
  89  */
  90 #if CONFIG_IS_ENABLED(LOG)
  91 #define _LOG_MAX_LEVEL CONFIG_VAL(LOG_MAX_LEVEL)
  92 #else
  93 #define _LOG_MAX_LEVEL LOGL_INFO
  94 #endif
  95
  96 /* Emit a log record if the level is less that the maximum */
  97 #define log(_cat, _level, _fmt, _args...) ({ \
  98         int _l = _level; \
  99         if (_l <= _LOG_MAX_LEVEL) \
 100                 _log((enum log_category_t)(_cat), _l, __FILE__, __LINE__, \
 101                       __func__, \
 102                       pr_fmt(_fmt), ##_args); \
 103         })
 104
 105 #ifdef DEBUG
 106 #define _DEBUG  1
 107 #else
 108 #define _DEBUG  0
 109 #endif
 110
 111 #ifdef CONFIG_SPL_BUILD
 112 #define _SPL_BUILD      1
 113 #else
 114 #define _SPL_BUILD      0
 115 #endif
 116
 117 #if !_DEBUG && CONFIG_IS_ENABLED(LOG)
 118
 119 #define debug_cond(cond, fmt, args...)                  \
 120         do {                                            \
 121                 if (1)                                  \
 122                         log(LOG_CATEGORY, LOGL_DEBUG, fmt, ##args); \
 123         } while (0)
 124
 125 #else /* _DEBUG */
 126
 127 /*
 128  * Output a debug text when condition "cond" is met. The "cond" should be
 129  * computed by a preprocessor in the best case, allowing for the best
 130  * optimization.
 131  */
 132 #define debug_cond(cond, fmt, args...)                  \
 133         do {                                            \
 134                 if (cond)                               \
 135                         printf(pr_fmt(fmt), ##args);    \
 136         } while (0)
 137
 138 #endif /* _DEBUG */
 139
 140 /* Show a message if DEBUG is defined in a file */
 141 #define debug(fmt, args...)                     \
 142         debug_cond(_DEBUG, fmt, ##args)
 143
 144 /* Show a message if not in SPL */
 145 #define warn_non_spl(fmt, args...)                      \
 146         debug_cond(!_SPL_BUILD, fmt, ##args)
 147
 148 /*
 149  * An assertion is run-time check done in debug mode only. If DEBUG is not
 150  * defined then it is skipped. If DEBUG is defined and the assertion fails,
 151  * then it calls panic*( which may or may not reset/halt U-Boot (see
 152  * CONFIG_PANIC_HANG), It is hoped that all failing assertions are found
 153  * before release, and after release it is hoped that they don't matter. But
 154  * in any case these failing assertions cannot be fixed with a reset (which
 155  * may just do the same assertion again).
 156  */
 157 void __assert_fail(const char *assertion, const char *file, unsigned int line,
 158                    const char *function);
 159 #define assert(x) \
 160         ({ if (!(x) && _DEBUG) \
 161                 __assert_fail(#x, __FILE__, __LINE__, __func__); })
 162
 163 #ifdef CONFIG_LOG_ERROR_RETURN
 164 #define log_ret(_ret) ({ \
 165         int __ret = (_ret); \
 166         if (__ret < 0) \
 167                 log(LOG_CATEGORY, LOGL_ERR, "returning err=%d\n", __ret); \
 168         __ret; \
 169         })
 170 #else
 171 #define log_ret(_ret) (_ret)
 172 #endif
 173
 174 /**
 175  * struct log_rec - a single log record
 176  *
 177  * Holds information about a single record in the log
 178  *
 179  * Members marked as 'not allocated' are stored as pointers and the caller is
 180  * responsible for making sure that the data pointed to is not overwritten.
 181  * Memebers marked as 'allocated' are allocated (e.g. via strdup()) by the log
 182  * system.
 183  *
 184  * @cat: Category, representing a uclass or part of U-Boot
 185  * @level: Severity level, less severe is higher
 186  * @file: Name of file where the log record was generated (not allocated)
 187  * @line: Line number where the log record was generated
 188  * @func: Function where the log record was generated (not allocated)
 189  * @msg: Log message (allocated)
 190  */
 191 struct log_rec {
 192         enum log_category_t cat;
 193         enum log_level_t level;
 194         const char *file;
 195         int line;
 196         const char *func;
 197         const char *msg;
 198 };
 199
 200 struct log_device;
 201
 202 /**
 203  * struct log_driver - a driver which accepts and processes log records
 204  *
 205  * @name: Name of driver
 206  */
 207 struct log_driver {
 208         const char *name;
 209         /**
 210          * emit() - emit a log record
 211          *
 212          * Called by the log system to pass a log record to a particular driver
 213          * for processing. The filter is checked before calling this function.
 214          */
 215         int (*emit)(struct log_device *ldev, struct log_rec *rec);
 216 };
 217
 218 /**
 219  * struct log_device - an instance of a log driver
 220  *
 221  * Since drivers are set up at build-time we need to have a separate device for
 222  * the run-time aspects of drivers (currently just a list of filters to apply
 223  * to records send to this device).
 224  *
 225  * @next_filter_num: Seqence number of next filter filter added (0=no filters
 226  *      yet). This increments with each new filter on the device, but never
 227  *      decrements
 228  * @drv: Pointer to driver for this device
 229  * @filter_head: List of filters for this device
 230  * @sibling_node: Next device in the list of all devices
 231  */
 232 struct log_device {
 233         int next_filter_num;
 234         struct log_driver *drv;
 235         struct list_head filter_head;
 236         struct list_head sibling_node;
 237 };
 238
 239 enum {
 240         LOGF_MAX_CATEGORIES = 5,        /* maximum categories per filter */
 241 };
 242
 243 enum log_filter_flags {
 244         LOGFF_HAS_CAT           = 1 << 0,       /* Filter has a category list */
 245 };
 246
 247 /**
 248  * struct log_filter - criterial to filter out log messages
 249  *
 250  * @filter_num: Sequence number of this filter.  This is returned when adding a
 251  *      new filter, and must be provided when removing a previously added
 252  *      filter.
 253  * @flags: Flags for this filter (LOGFF_...)
 254  * @cat_list: List of categories to allow (terminated by LOGC_none). If empty
 255  *      then all categories are permitted. Up to LOGF_MAX_CATEGORIES entries
 256  *      can be provided
 257  * @max_level: Maximum log level to allow
 258  * @file_list: List of files to allow, separated by comma. If NULL then all
 259  *      files are permitted
 260  * @sibling_node: Next filter in the list of filters for this log device
 261  */
 262 struct log_filter {
 263         int filter_num;
 264         int flags;
 265         enum log_category_t cat_list[LOGF_MAX_CATEGORIES];
 266         enum log_level_t max_level;
 267         const char *file_list;
 268         struct list_head sibling_node;
 269 };
 270
 271 #define LOG_DRIVER(_name) \
 272         ll_entry_declare(struct log_driver, _name, log_driver)
 273
 274 /**
 275  * log_get_cat_name() - Get the name of a category
 276  *
 277  * @cat: Category to look up
 278  * @return category name (which may be a uclass driver name)
 279  */
 280 const char *log_get_cat_name(enum log_category_t cat);
 281
 282 /**
 283  * log_get_cat_by_name() - Look up a category by name
 284  *
 285  * @name: Name to look up
 286  * @return category ID, or LOGC_NONE if not found
 287  */
 288 enum log_category_t log_get_cat_by_name(const char *name);
 289
 290 /**
 291  * log_get_level_name() - Get the name of a log level
 292  *
 293  * @level: Log level to look up
 294  * @return log level name (in ALL CAPS)
 295  */
 296 const char *log_get_level_name(enum log_level_t level);
 297
 298 /**
 299  * log_get_level_by_name() - Look up a log level by name
 300  *
 301  * @name: Name to look up
 302  * @return log level ID, or LOGL_NONE if not found
 303  */
 304 enum log_level_t log_get_level_by_name(const char *name);
 305
 306 /* Log format flags (bit numbers) for gd->log_fmt. See log_fmt_chars */
 307 enum log_fmt {
 308         LOGF_CAT        = 0,
 309         LOGF_LEVEL,
 310         LOGF_FILE,
 311         LOGF_LINE,
 312         LOGF_FUNC,
 313         LOGF_MSG,
 314
 315         LOGF_COUNT,
 316         LOGF_DEFAULT = (1 << LOGF_FUNC) | (1 << LOGF_MSG),
 317         LOGF_ALL = 0x3f,
 318 };
 319
 320 /* Handle the 'log test' command */
 321 int do_log_test(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[]);
 322
 323 /**
 324  * log_add_filter() - Add a new filter to a log device
 325  *
 326  * @drv_name: Driver name to add the filter to (since each driver only has a
 327  *      single device)
 328  * @cat_list: List of categories to allow (terminated by LOGC_none). If empty
 329  *      then all categories are permitted. Up to LOGF_MAX_CATEGORIES entries
 330  *      can be provided
 331  * @max_level: Maximum log level to allow
 332  * @file_list: List of files to allow, separated by comma. If NULL then all
 333  *      files are permitted
 334  * @return the sequence number of the new filter (>=0) if the filter was added,
 335  *      or a -ve value on error
 336  */
 337 int log_add_filter(const char *drv_name, enum log_category_t cat_list[],
 338                    enum log_level_t max_level, const char *file_list);
 339
 340 /**
 341  * log_remove_filter() - Remove a filter from a log device
 342  *
 343  * @drv_name: Driver name to remove the filter from (since each driver only has
 344  *      a single device)
 345  * @filter_num: Filter number to remove (as returned by log_add_filter())
 346  * @return 0 if the filter was removed, -ENOENT if either the driver or the
 347  *      filter number was not found
 348  */
 349 int log_remove_filter(const char *drv_name, int filter_num);
 350
 351 #if CONFIG_IS_ENABLED(LOG)
 352 /**
 353  * log_init() - Set up the log system ready for use
 354  *
 355  * @return 0 if OK, -ENOMEM if out of memory
 356  */
 357 int log_init(void);
 358 #else
 359 static inline int log_init(void)
 360 {
 361         return 0;
 362 }
 363 #endif
 364
 365 #endif