File: /Users/paulross/dev/linux/linux-3.13/include/linux/kernel.h

Green shading in the line number column means the source is part of the translation unit, red means it is conditionally excluded. Highlighted line numbers link to the translation unit page. Highlighted macros link to the macro page.

       1: #ifndef _LINUX_KERNEL_H
       2: #define _LINUX_KERNEL_H
       3: 
       4: 
       5: #include <stdarg.h>
       6: #include <linux/linkage.h>
       7: #include <linux/stddef.h>
       8: #include <linux/types.h>
       9: #include <linux/compiler.h>
      10: #include <linux/bitops.h>
      11: #include <linux/log2.h>
      12: #include <linux/typecheck.h>
      13: #include <linux/printk.h>
      14: #include <linux/dynamic_debug.h>
      15: #include <asm/byteorder.h>
      16: #include <uapi/linux/kernel.h>
      17: 
      18: #define USHRT_MAX    ((u16)(~0U))
      19: #define SHRT_MAX    ((s16)(USHRT_MAX>>1))
      20: #define SHRT_MIN    ((s16)(-SHRT_MAX - 1))
      21: #define INT_MAX        ((int)(~0U>>1))
      22: #define INT_MIN        (-INT_MAX - 1)
      23: #define UINT_MAX    (~0U)
      24: #define LONG_MAX    ((long)(~0UL>>1))
      25: #define LONG_MIN    (-LONG_MAX - 1)
      26: #define ULONG_MAX    (~0UL)
      27: #define LLONG_MAX    ((long long)(~0ULL>>1))
      28: #define LLONG_MIN    (-LLONG_MAX - 1)
      29: #define ULLONG_MAX    (~0ULL)
      30: #define SIZE_MAX    (~(size_t)0)
      31: 
      32: #define STACK_MAGIC    0xdeadbeef
      33: 
      34: #define REPEAT_BYTE(x)    ((~0ul / 0xff) * (x))
      35: 
      36: #define ALIGN(x, a)        __ALIGN_KERNEL((x), (a))
      37: #define __ALIGN_MASK(x, mask)    __ALIGN_KERNEL_MASK((x), (mask))
      38: #define PTR_ALIGN(p, a)        ((typeof(p))ALIGN((unsigned long)(p), (a)))
      39: #define IS_ALIGNED(x, a)        (((x) & ((typeof(x))(a) - 1)) == 0)
      40: 
      41: #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
      42: 
      43: /*
      44:  * This looks more complex than it should be. But we need to
      45:  * get the type for the ~ right in round_down (it needs to be
      46:  * as wide as the result!), and we want to evaluate the macro
      47:  * arguments just once each.
      48:  */
      49: #define __round_mask(x, y) ((__typeof__(x))((y)-1))
      50: #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
      51: #define round_down(x, y) ((x) & ~__round_mask(x, y))
      52: 
      53: #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
      54: #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
      55: #define DIV_ROUND_UP_ULL(ll,d) \
      56:     ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
      57: 
      58: #if BITS_PER_LONG == 32
      59: # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
      60: #else
      61: # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
      62: #endif
      63: 
      64: /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
      65: #define roundup(x, y) (                    \
      66: {                            \
      67:     const typeof(y) __y = y;            \
      68:     (((x) + (__y - 1)) / __y) * __y;        \
      69: }                            \
      70: )
      71: #define rounddown(x, y) (                \
      72: {                            \
      73:     typeof(x) __x = (x);                \
      74:     __x - (__x % (y));                \
      75: }                            \
      76: )
      77: 
      78: /*
      79:  * Divide positive or negative dividend by positive divisor and round
      80:  * to closest integer. Result is undefined for negative divisors and
      81:  * for negative dividends if the divisor variable type is unsigned.
      82:  */
      83: #define DIV_ROUND_CLOSEST(x, divisor)(            \
      84: {                            \
      85:     typeof(x) __x = x;                \
      86:     typeof(divisor) __d = divisor;            \
      87:     (((typeof(x))-1) > 0 ||                \
      88:      ((typeof(divisor))-1) > 0 || (__x) > 0) ?    \
      89:         (((__x) + ((__d) / 2)) / (__d)) :    \
      90:         (((__x) - ((__d) / 2)) / (__d));    \
      91: }                            \
      92: )
      93: 
      94: /*
      95:  * Multiplies an integer by a fraction, while avoiding unnecessary
      96:  * overflow or loss of precision.
      97:  */
      98: #define mult_frac(x, numer, denom)(            \
      99: {                            \
     100:     typeof(x) quot = (x) / (denom);            \
     101:     typeof(x) rem  = (x) % (denom);            \
     102:     (quot * (numer)) + ((rem * (numer)) / (denom));    \
     103: }                            \
     104: )
     105: 
     106: 
     107: #define _RET_IP_        (unsigned long)__builtin_return_address(0)
     108: #define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
     109: 
     110: #ifdef CONFIG_LBDAF
     111: # include <asm/div64.h>
     112: # define sector_div(a, b) do_div(a, b)
     113: #else
     114: # define sector_div(n, b)( \
     115: { \
     116:     int _res; \
     117:     _res = (n) % (b); \
     118:     (n) /= (b); \
     119:     _res; \
     120: } \
     121: )
     122: #endif
     123: 
     124: /**
     125:  * upper_32_bits - return bits 32-63 of a number
     126:  * @n: the number we're accessing
     127:  *
     128:  * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
     129:  * the "right shift count >= width of type" warning when that quantity is
     130:  * 32-bits.
     131:  */
     132: #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
     133: 
     134: /**
     135:  * lower_32_bits - return bits 0-31 of a number
     136:  * @n: the number we're accessing
     137:  */
     138: #define lower_32_bits(n) ((u32)(n))
     139: 
     140: struct completion;
     141: struct pt_regs;
     142: struct user;
     143: 
     144: #ifdef CONFIG_PREEMPT_VOLUNTARY
     145: extern int _cond_resched(void);
     146: # define might_resched() _cond_resched()
     147: #else
     148: # define might_resched() do { } while (0)
     149: #endif
     150: 
     151: #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
     152:   void __might_sleep(const char *file, int line, int preempt_offset);
     153: /**
     154:  * might_sleep - annotation for functions that can sleep
     155:  *
     156:  * this macro will print a stack trace if it is executed in an atomic
     157:  * context (spinlock, irq-handler, ...).
     158:  *
     159:  * This is a useful debugging help to be able to catch problems early and not
     160:  * be bitten later when the calling function happens to sleep when it is not
     161:  * supposed to.
     162:  */
     163: # define might_sleep() \
     164:     do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
     165: #else
     166:   static inline void __might_sleep(const char *file, int line,
     167:                    int preempt_offset) { }
     168: # define might_sleep() do { might_resched(); } while (0)
     169: #endif
     170: 
     171: #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
     172: 
     173: /*
     174:  * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
     175:  * input types abs() returns a signed long.
     176:  * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
     177:  * for those.
     178:  */
     179: #define abs(x) ({                        \
     180:         long ret;                    \
     181:         if (sizeof(x) == sizeof(long)) {        \
     182:             long __x = (x);                \
     183:             ret = (__x < 0) ? -__x : __x;        \
     184:         } else {                    \
     185:             int __x = (x);                \
     186:             ret = (__x < 0) ? -__x : __x;        \
     187:         }                        \
     188:         ret;                        \
     189:     })
     190: 
     191: #define abs64(x) ({                \
     192:         s64 __x = (x);            \
     193:         (__x < 0) ? -__x : __x;        \
     194:     })
     195: 
     196: #if defined(CONFIG_MMU) && \
     197:     (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
     198: void might_fault(void);
     199: #else
     200: static inline void might_fault(void) { }
     201: #endif
     202: 
     203: extern struct atomic_notifier_head panic_notifier_list;
     204: extern long (*panic_blink)(int state);
     205: __printf(1, 2)
     206: void panic(const char *fmt, ...)
     207:     __noreturn __cold;
     208: extern void oops_enter(void);
     209: extern void oops_exit(void);
     210: void print_oops_end_marker(void);
     211: extern int oops_may_print(void);
     212: void do_exit(long error_code)
     213:     __noreturn;
     214: void complete_and_exit(struct completion *, long)
     215:     __noreturn;
     216: 
     217: /* Internal, do not use. */
     218: int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
     219: int __must_check _kstrtol(const char *s, unsigned int base, long *res);
     220: 
     221: int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
     222: int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
     223: 
     224: /**
     225:  * kstrtoul - convert a string to an unsigned long
     226:  * @s: The start of the string. The string must be null-terminated, and may also
     227:  *  include a single newline before its terminating null. The first character
     228:  *  may also be a plus sign, but not a minus sign.
     229:  * @base: The number base to use. The maximum supported base is 16. If base is
     230:  *  given as 0, then the base of the string is automatically detected with the
     231:  *  conventional semantics - If it begins with 0x the number will be parsed as a
     232:  *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
     233:  *  parsed as an octal number. Otherwise it will be parsed as a decimal.
     234:  * @res: Where to write the result of the conversion on success.
     235:  *
     236:  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
     237:  * Used as a replacement for the obsolete simple_strtoull. Return code must
     238:  * be checked.
     239: */
     240: static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
     241: {
     242:     /*
     243:      * We want to shortcut function call, but
     244:      * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
     245:      */
     246:     if (sizeof(unsigned long) == sizeof(unsigned long long) &&
     247:         __alignof__(unsigned long) == __alignof__(unsigned long long))
     248:         return kstrtoull(s, base, (unsigned long long *)res);
     249:     else
     250:         return _kstrtoul(s, base, res);
     251: }
     252: 
     253: /**
     254:  * kstrtol - convert a string to a long
     255:  * @s: The start of the string. The string must be null-terminated, and may also
     256:  *  include a single newline before its terminating null. The first character
     257:  *  may also be a plus sign or a minus sign.
     258:  * @base: The number base to use. The maximum supported base is 16. If base is
     259:  *  given as 0, then the base of the string is automatically detected with the
     260:  *  conventional semantics - If it begins with 0x the number will be parsed as a
     261:  *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
     262:  *  parsed as an octal number. Otherwise it will be parsed as a decimal.
     263:  * @res: Where to write the result of the conversion on success.
     264:  *
     265:  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
     266:  * Used as a replacement for the obsolete simple_strtoull. Return code must
     267:  * be checked.
     268:  */
     269: static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
     270: {
     271:     /*
     272:      * We want to shortcut function call, but
     273:      * __builtin_types_compatible_p(long, long long) = 0.
     274:      */
     275:     if (sizeof(long) == sizeof(long long) &&
     276:         __alignof__(long) == __alignof__(long long))
     277:         return kstrtoll(s, base, (long long *)res);
     278:     else
     279:         return _kstrtol(s, base, res);
     280: }
     281: 
     282: int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
     283: int __must_check kstrtoint(const char *s, unsigned int base, int *res);
     284: 
     285: static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
     286: {
     287:     return kstrtoull(s, base, res);
     288: }
     289: 
     290: static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
     291: {
     292:     return kstrtoll(s, base, res);
     293: }
     294: 
     295: static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
     296: {
     297:     return kstrtouint(s, base, res);
     298: }
     299: 
     300: static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
     301: {
     302:     return kstrtoint(s, base, res);
     303: }
     304: 
     305: int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
     306: int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
     307: int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
     308: int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
     309: 
     310: int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
     311: int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
     312: int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
     313: int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
     314: int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
     315: int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
     316: int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
     317: int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
     318: int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
     319: int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
     320: 
     321: static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
     322: {
     323:     return kstrtoull_from_user(s, count, base, res);
     324: }
     325: 
     326: static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
     327: {
     328:     return kstrtoll_from_user(s, count, base, res);
     329: }
     330: 
     331: static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
     332: {
     333:     return kstrtouint_from_user(s, count, base, res);
     334: }
     335: 
     336: static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
     337: {
     338:     return kstrtoint_from_user(s, count, base, res);
     339: }
     340: 
     341: /* Obsolete, do not use.  Use kstrto<foo> instead */
     342: 
     343: extern unsigned long simple_strtoul(const char *,char **,unsigned int);
     344: extern long simple_strtol(const char *,char **,unsigned int);
     345: extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
     346: extern long long simple_strtoll(const char *,char **,unsigned int);
     347: #define strict_strtoul    kstrtoul
     348: #define strict_strtol    kstrtol
     349: #define strict_strtoull    kstrtoull
     350: #define strict_strtoll    kstrtoll
     351: 
     352: extern int num_to_str(char *buf, int size, unsigned long long num);
     353: 
     354: /* lib/printf utilities */
     355: 
     356: extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
     357: extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
     358: extern __printf(3, 4)
     359: int snprintf(char *buf, size_t size, const char *fmt, ...);
     360: extern __printf(3, 0)
     361: int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
     362: extern __printf(3, 4)
     363: int scnprintf(char *buf, size_t size, const char *fmt, ...);
     364: extern __printf(3, 0)
     365: int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
     366: extern __printf(2, 3)
     367: char *kasprintf(gfp_t gfp, const char *fmt, ...);
     368: extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
     369: 
     370: extern __scanf(2, 3)
     371: int sscanf(const char *, const char *, ...);
     372: extern __scanf(2, 0)
     373: int vsscanf(const char *, const char *, va_list);
     374: 
     375: extern int get_option(char **str, int *pint);
     376: extern char *get_options(const char *str, int nints, int *ints);
     377: extern unsigned long long memparse(const char *ptr, char **retptr);
     378: 
     379: extern int core_kernel_text(unsigned long addr);
     380: extern int core_kernel_data(unsigned long addr);
     381: extern int __kernel_text_address(unsigned long addr);
     382: extern int kernel_text_address(unsigned long addr);
     383: extern int func_ptr_is_kernel_text(void *ptr);
     384: 
     385: struct pid;
     386: extern struct pid *session_of_pgrp(struct pid *pgrp);
     387: 
     388: unsigned long int_sqrt(unsigned long);
     389: 
     390: extern void bust_spinlocks(int yes);
     391: extern int oops_in_progress;        /* If set, an oops, panic(), BUG() or die() is in progress */
     392: extern int panic_timeout;
     393: extern int panic_on_oops;
     394: extern int panic_on_unrecovered_nmi;
     395: extern int panic_on_io_nmi;
     396: extern int sysctl_panic_on_stackoverflow;
     397: extern const char *print_tainted(void);
     398: enum lockdep_ok {
     399:     LOCKDEP_STILL_OK,
     400:     LOCKDEP_NOW_UNRELIABLE
     401: };
     402: extern void add_taint(unsigned flag, enum lockdep_ok);
     403: extern int test_taint(unsigned flag);
     404: extern unsigned long get_taint(void);
     405: extern int root_mountflags;
     406: 
     407: extern bool early_boot_irqs_disabled;
     408: 
     409: /* Values used for system_state */
     410: extern enum system_states {
     411:     SYSTEM_BOOTING,
     412:     SYSTEM_RUNNING,
     413:     SYSTEM_HALT,
     414:     SYSTEM_POWER_OFF,
     415:     SYSTEM_RESTART,
     416: } system_state;
     417: 
     418: #define TAINT_PROPRIETARY_MODULE    0
     419: #define TAINT_FORCED_MODULE        1
     420: #define TAINT_UNSAFE_SMP        2
     421: #define TAINT_FORCED_RMMOD        3
     422: #define TAINT_MACHINE_CHECK        4
     423: #define TAINT_BAD_PAGE            5
     424: #define TAINT_USER            6
     425: #define TAINT_DIE            7
     426: #define TAINT_OVERRIDDEN_ACPI_TABLE    8
     427: #define TAINT_WARN            9
     428: #define TAINT_CRAP            10
     429: #define TAINT_FIRMWARE_WORKAROUND    11
     430: #define TAINT_OOT_MODULE        12
     431: 
     432: extern const char hex_asc[];
     433: #define hex_asc_lo(x)    hex_asc[((x) & 0x0f)]
     434: #define hex_asc_hi(x)    hex_asc[((x) & 0xf0) >> 4]
     435: 
     436: static inline char *hex_byte_pack(char *buf, u8 byte)
     437: {
     438:     *buf++ = hex_asc_hi(byte);
     439:     *buf++ = hex_asc_lo(byte);
     440:     return buf;
     441: }
     442: 
     443: extern const char hex_asc_upper[];
     444: #define hex_asc_upper_lo(x)    hex_asc_upper[((x) & 0x0f)]
     445: #define hex_asc_upper_hi(x)    hex_asc_upper[((x) & 0xf0) >> 4]
     446: 
     447: static inline char *hex_byte_pack_upper(char *buf, u8 byte)
     448: {
     449:     *buf++ = hex_asc_upper_hi(byte);
     450:     *buf++ = hex_asc_upper_lo(byte);
     451:     return buf;
     452: }
     453: 
     454: static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
     455: {
     456:     return hex_byte_pack(buf, byte);
     457: }
     458: 
     459: extern int hex_to_bin(char ch);
     460: extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
     461: 
     462: int mac_pton(const char *s, u8 *mac);
     463: 
     464: /*
     465:  * General tracing related utility functions - trace_printk(),
     466:  * tracing_on/tracing_off and tracing_start()/tracing_stop
     467:  *
     468:  * Use tracing_on/tracing_off when you want to quickly turn on or off
     469:  * tracing. It simply enables or disables the recording of the trace events.
     470:  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
     471:  * file, which gives a means for the kernel and userspace to interact.
     472:  * Place a tracing_off() in the kernel where you want tracing to end.
     473:  * From user space, examine the trace, and then echo 1 > tracing_on
     474:  * to continue tracing.
     475:  *
     476:  * tracing_stop/tracing_start has slightly more overhead. It is used
     477:  * by things like suspend to ram where disabling the recording of the
     478:  * trace is not enough, but tracing must actually stop because things
     479:  * like calling smp_processor_id() may crash the system.
     480:  *
     481:  * Most likely, you want to use tracing_on/tracing_off.
     482:  */
     483: #ifdef CONFIG_RING_BUFFER
     484: /* trace_off_permanent stops recording with no way to bring it back */
     485: void tracing_off_permanent(void);
     486: #else
     487: static inline void tracing_off_permanent(void) { }
     488: #endif
     489: 
     490: enum ftrace_dump_mode {
     491:     DUMP_NONE,
     492:     DUMP_ALL,
     493:     DUMP_ORIG,
     494: };
     495: 
     496: #ifdef CONFIG_TRACING
     497: void tracing_on(void);
     498: void tracing_off(void);
     499: int tracing_is_on(void);
     500: void tracing_snapshot(void);
     501: void tracing_snapshot_alloc(void);
     502: 
     503: extern void tracing_start(void);
     504: extern void tracing_stop(void);
     505: 
     506: static inline __printf(1, 2)
     507: void ____trace_printk_check_format(const char *fmt, ...)
     508: {
     509: }
     510: #define __trace_printk_check_format(fmt, args...)            \
     511: do {                                    \
     512:     if (0)                                \
     513:         ____trace_printk_check_format(fmt, ##args);        \
     514: } while (0)
     515: 
     516: /**
     517:  * trace_printk - printf formatting in the ftrace buffer
     518:  * @fmt: the printf format for printing
     519:  *
     520:  * Note: __trace_printk is an internal function for trace_printk and
     521:  *       the @ip is passed in via the trace_printk macro.
     522:  *
     523:  * This function allows a kernel developer to debug fast path sections
     524:  * that printk is not appropriate for. By scattering in various
     525:  * printk like tracing in the code, a developer can quickly see
     526:  * where problems are occurring.
     527:  *
     528:  * This is intended as a debugging tool for the developer only.
     529:  * Please refrain from leaving trace_printks scattered around in
     530:  * your code. (Extra memory is used for special buffers that are
     531:  * allocated when trace_printk() is used)
     532:  *
     533:  * A little optization trick is done here. If there's only one
     534:  * argument, there's no need to scan the string for printf formats.
     535:  * The trace_puts() will suffice. But how can we take advantage of
     536:  * using trace_puts() when trace_printk() has only one argument?
     537:  * By stringifying the args and checking the size we can tell
     538:  * whether or not there are args. __stringify((__VA_ARGS__)) will
     539:  * turn into "()\0" with a size of 3 when there are no args, anything
     540:  * else will be bigger. All we need to do is define a string to this,
     541:  * and then take its size and compare to 3. If it's bigger, use
     542:  * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
     543:  * let gcc optimize the rest.
     544:  */
     545: 
     546: #define trace_printk(fmt, ...)                \
     547: do {                            \
     548:     char _______STR[] = __stringify((__VA_ARGS__));    \
     549:     if (sizeof(_______STR) > 3)            \
     550:         do_trace_printk(fmt, ##__VA_ARGS__);    \
     551:     else                        \
     552:         trace_puts(fmt);            \
     553: } while (0)
     554: 
     555: #define do_trace_printk(fmt, args...)                    \
     556: do {                                    \
     557:     static const char *trace_printk_fmt                \
     558:         __attribute__((section("__trace_printk_fmt"))) =    \
     559:         __builtin_constant_p(fmt) ? fmt : NULL;            \
     560:                                     \
     561:     __trace_printk_check_format(fmt, ##args);            \
     562:                                     \
     563:     if (__builtin_constant_p(fmt))                    \
     564:         __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);    \
     565:     else                                \
     566:         __trace_printk(_THIS_IP_, fmt, ##args);            \
     567: } while (0)
     568: 
     569: extern __printf(2, 3)
     570: int __trace_bprintk(unsigned long ip, const char *fmt, ...);
     571: 
     572: extern __printf(2, 3)
     573: int __trace_printk(unsigned long ip, const char *fmt, ...);
     574: 
     575: /**
     576:  * trace_puts - write a string into the ftrace buffer
     577:  * @str: the string to record
     578:  *
     579:  * Note: __trace_bputs is an internal function for trace_puts and
     580:  *       the @ip is passed in via the trace_puts macro.
     581:  *
     582:  * This is similar to trace_printk() but is made for those really fast
     583:  * paths that a developer wants the least amount of "Heisenbug" affects,
     584:  * where the processing of the print format is still too much.
     585:  *
     586:  * This function allows a kernel developer to debug fast path sections
     587:  * that printk is not appropriate for. By scattering in various
     588:  * printk like tracing in the code, a developer can quickly see
     589:  * where problems are occurring.
     590:  *
     591:  * This is intended as a debugging tool for the developer only.
     592:  * Please refrain from leaving trace_puts scattered around in
     593:  * your code. (Extra memory is used for special buffers that are
     594:  * allocated when trace_puts() is used)
     595:  *
     596:  * Returns: 0 if nothing was written, positive # if string was.
     597:  *  (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
     598:  */
     599: 
     600: #define trace_puts(str) ({                        \
     601:     static const char *trace_printk_fmt                \
     602:         __attribute__((section("__trace_printk_fmt"))) =    \
     603:         __builtin_constant_p(str) ? str : NULL;            \
     604:                                     \
     605:     if (__builtin_constant_p(str))                    \
     606:         __trace_bputs(_THIS_IP_, trace_printk_fmt);        \
     607:     else                                \
     608:         __trace_puts(_THIS_IP_, str, strlen(str));        \
     609: })
     610: extern int __trace_bputs(unsigned long ip, const char *str);
     611: extern int __trace_puts(unsigned long ip, const char *str, int size);
     612: 
     613: extern void trace_dump_stack(int skip);
     614: 
     615: /*
     616:  * The double __builtin_constant_p is because gcc will give us an error
     617:  * if we try to allocate the static variable to fmt if it is not a
     618:  * constant. Even with the outer if statement.
     619:  */
     620: #define ftrace_vprintk(fmt, vargs)                    \
     621: do {                                    \
     622:     if (__builtin_constant_p(fmt)) {                \
     623:         static const char *trace_printk_fmt            \
     624:           __attribute__((section("__trace_printk_fmt"))) =    \
     625:             __builtin_constant_p(fmt) ? fmt : NULL;        \
     626:                                     \
     627:         __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);    \
     628:     } else                                \
     629:         __ftrace_vprintk(_THIS_IP_, fmt, vargs);        \
     630: } while (0)
     631: 
     632: extern int
     633: __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
     634: 
     635: extern int
     636: __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
     637: 
     638: extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
     639: #else
     640: static inline void tracing_start(void) { }
     641: static inline void tracing_stop(void) { }
     642: static inline void trace_dump_stack(int skip) { }
     643: 
     644: static inline void tracing_on(void) { }
     645: static inline void tracing_off(void) { }
     646: static inline int tracing_is_on(void) { return 0; }
     647: static inline void tracing_snapshot(void) { }
     648: static inline void tracing_snapshot_alloc(void) { }
     649: 
     650: static inline __printf(1, 2)
     651: int trace_printk(const char *fmt, ...)
     652: {
     653:     return 0;
     654: }
     655: static inline int
     656: ftrace_vprintk(const char *fmt, va_list ap)
     657: {
     658:     return 0;
     659: }
     660: static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
     661: #endif /* CONFIG_TRACING */
     662: 
     663: /*
     664:  * min()/max()/clamp() macros that also do
     665:  * strict type-checking.. See the
     666:  * "unnecessary" pointer comparison.
     667:  */
     668: #define min(x, y) ({                \
     669:     typeof(x) _min1 = (x);            \
     670:     typeof(y) _min2 = (y);            \
     671:     (void) (&_min1 == &_min2);        \
     672:     _min1 < _min2 ? _min1 : _min2; })
     673: 
     674: #define max(x, y) ({                \
     675:     typeof(x) _max1 = (x);            \
     676:     typeof(y) _max2 = (y);            \
     677:     (void) (&_max1 == &_max2);        \
     678:     _max1 > _max2 ? _max1 : _max2; })
     679: 
     680: #define min3(x, y, z) ({            \
     681:     typeof(x) _min1 = (x);            \
     682:     typeof(y) _min2 = (y);            \
     683:     typeof(z) _min3 = (z);            \
     684:     (void) (&_min1 == &_min2);        \
     685:     (void) (&_min1 == &_min3);        \
     686:     _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
     687:         (_min2 < _min3 ? _min2 : _min3); })
     688: 
     689: #define max3(x, y, z) ({            \
     690:     typeof(x) _max1 = (x);            \
     691:     typeof(y) _max2 = (y);            \
     692:     typeof(z) _max3 = (z);            \
     693:     (void) (&_max1 == &_max2);        \
     694:     (void) (&_max1 == &_max3);        \
     695:     _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
     696:         (_max2 > _max3 ? _max2 : _max3); })
     697: 
     698: /**
     699:  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
     700:  * @x: value1
     701:  * @y: value2
     702:  */
     703: #define min_not_zero(x, y) ({            \
     704:     typeof(x) __x = (x);            \
     705:     typeof(y) __y = (y);            \
     706:     __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
     707: 
     708: /**
     709:  * clamp - return a value clamped to a given range with strict typechecking
     710:  * @val: current value
     711:  * @min: minimum allowable value
     712:  * @max: maximum allowable value
     713:  *
     714:  * This macro does strict typechecking of min/max to make sure they are of the
     715:  * same type as val.  See the unnecessary pointer comparisons.
     716:  */
     717: #define clamp(val, min, max) ({            \
     718:     typeof(val) __val = (val);        \
     719:     typeof(min) __min = (min);        \
     720:     typeof(max) __max = (max);        \
     721:     (void) (&__val == &__min);        \
     722:     (void) (&__val == &__max);        \
     723:     __val = __val < __min ? __min: __val;    \
     724:     __val > __max ? __max: __val; })
     725: 
     726: /*
     727:  * ..and if you can't take the strict
     728:  * types, you can specify one yourself.
     729:  *
     730:  * Or not use min/max/clamp at all, of course.
     731:  */
     732: #define min_t(type, x, y) ({            \
     733:     type __min1 = (x);            \
     734:     type __min2 = (y);            \
     735:     __min1 < __min2 ? __min1: __min2; })
     736: 
     737: #define max_t(type, x, y) ({            \
     738:     type __max1 = (x);            \
     739:     type __max2 = (y);            \
     740:     __max1 > __max2 ? __max1: __max2; })
     741: 
     742: /**
     743:  * clamp_t - return a value clamped to a given range using a given type
     744:  * @type: the type of variable to use
     745:  * @val: current value
     746:  * @min: minimum allowable value
     747:  * @max: maximum allowable value
     748:  *
     749:  * This macro does no typechecking and uses temporary variables of type
     750:  * 'type' to make all the comparisons.
     751:  */
     752: #define clamp_t(type, val, min, max) ({        \
     753:     type __val = (val);            \
     754:     type __min = (min);            \
     755:     type __max = (max);            \
     756:     __val = __val < __min ? __min: __val;    \
     757:     __val > __max ? __max: __val; })
     758: 
     759: /**
     760:  * clamp_val - return a value clamped to a given range using val's type
     761:  * @val: current value
     762:  * @min: minimum allowable value
     763:  * @max: maximum allowable value
     764:  *
     765:  * This macro does no typechecking and uses temporary variables of whatever
     766:  * type the input argument 'val' is.  This is useful when val is an unsigned
     767:  * type and min and max are literals that will otherwise be assigned a signed
     768:  * integer type.
     769:  */
     770: #define clamp_val(val, min, max) ({        \
     771:     typeof(val) __val = (val);        \
     772:     typeof(val) __min = (min);        \
     773:     typeof(val) __max = (max);        \
     774:     __val = __val < __min ? __min: __val;    \
     775:     __val > __max ? __max: __val; })
     776: 
     777: 
     778: /*
     779:  * swap - swap value of @a and @b
     780:  */
     781: #define swap(a, b) \
     782:     do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
     783: 
     784: /**
     785:  * container_of - cast a member of a structure out to the containing structure
     786:  * @ptr:    the pointer to the member.
     787:  * @type:    the type of the container struct this is embedded in.
     788:  * @member:    the name of the member within the struct.
     789:  *
     790:  */
     791: #define container_of(ptr, type, member) ({            \
     792:     const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
     793:     (type *)( (char *)__mptr - offsetof(type,member) );})
     794: 
     795: /* Trap pasters of __FUNCTION__ at compile-time */
     796: #define __FUNCTION__ (__func__)
     797: 
     798: /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
     799: #ifdef CONFIG_FTRACE_MCOUNT_RECORD
     800: # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
     801: #endif
     802: 
     803: #endif
     804: