summaryrefslogtreecommitdiffstats
path: root/kernel/include/linux/kernel.h
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/include/linux/kernel.h')
-rw-r--r--kernel/include/linux/kernel.h836
1 files changed, 836 insertions, 0 deletions
diff --git a/kernel/include/linux/kernel.h b/kernel/include/linux/kernel.h
new file mode 100644
index 000000000..8ecfe3c52
--- /dev/null
+++ b/kernel/include/linux/kernel.h
@@ -0,0 +1,836 @@
+#ifndef _LINUX_KERNEL_H
+#define _LINUX_KERNEL_H
+
+
+#include <stdarg.h>
+#include <linux/linkage.h>
+#include <linux/stddef.h>
+#include <linux/types.h>
+#include <linux/compiler.h>
+#include <linux/bitops.h>
+#include <linux/log2.h>
+#include <linux/typecheck.h>
+#include <linux/printk.h>
+#include <linux/dynamic_debug.h>
+#include <asm/byteorder.h>
+#include <uapi/linux/kernel.h>
+
+#define USHRT_MAX ((u16)(~0U))
+#define SHRT_MAX ((s16)(USHRT_MAX>>1))
+#define SHRT_MIN ((s16)(-SHRT_MAX - 1))
+#define INT_MAX ((int)(~0U>>1))
+#define INT_MIN (-INT_MAX - 1)
+#define UINT_MAX (~0U)
+#define LONG_MAX ((long)(~0UL>>1))
+#define LONG_MIN (-LONG_MAX - 1)
+#define ULONG_MAX (~0UL)
+#define LLONG_MAX ((long long)(~0ULL>>1))
+#define LLONG_MIN (-LLONG_MAX - 1)
+#define ULLONG_MAX (~0ULL)
+#define SIZE_MAX (~(size_t)0)
+
+#define U8_MAX ((u8)~0U)
+#define S8_MAX ((s8)(U8_MAX>>1))
+#define S8_MIN ((s8)(-S8_MAX - 1))
+#define U16_MAX ((u16)~0U)
+#define S16_MAX ((s16)(U16_MAX>>1))
+#define S16_MIN ((s16)(-S16_MAX - 1))
+#define U32_MAX ((u32)~0U)
+#define S32_MAX ((s32)(U32_MAX>>1))
+#define S32_MIN ((s32)(-S32_MAX - 1))
+#define U64_MAX ((u64)~0ULL)
+#define S64_MAX ((s64)(U64_MAX>>1))
+#define S64_MIN ((s64)(-S64_MAX - 1))
+
+#define STACK_MAGIC 0xdeadbeef
+
+#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
+
+#define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
+#define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask))
+#define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
+#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
+
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
+
+/*
+ * This looks more complex than it should be. But we need to
+ * get the type for the ~ right in round_down (it needs to be
+ * as wide as the result!), and we want to evaluate the macro
+ * arguments just once each.
+ */
+#define __round_mask(x, y) ((__typeof__(x))((y)-1))
+#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
+#define round_down(x, y) ((x) & ~__round_mask(x, y))
+
+#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
+#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
+#define DIV_ROUND_UP_ULL(ll,d) \
+ ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
+
+#if BITS_PER_LONG == 32
+# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
+#else
+# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
+#endif
+
+/* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
+#define roundup(x, y) ( \
+{ \
+ const typeof(y) __y = y; \
+ (((x) + (__y - 1)) / __y) * __y; \
+} \
+)
+#define rounddown(x, y) ( \
+{ \
+ typeof(x) __x = (x); \
+ __x - (__x % (y)); \
+} \
+)
+
+/*
+ * Divide positive or negative dividend by positive divisor and round
+ * to closest integer. Result is undefined for negative divisors and
+ * for negative dividends if the divisor variable type is unsigned.
+ */
+#define DIV_ROUND_CLOSEST(x, divisor)( \
+{ \
+ typeof(x) __x = x; \
+ typeof(divisor) __d = divisor; \
+ (((typeof(x))-1) > 0 || \
+ ((typeof(divisor))-1) > 0 || (__x) > 0) ? \
+ (((__x) + ((__d) / 2)) / (__d)) : \
+ (((__x) - ((__d) / 2)) / (__d)); \
+} \
+)
+/*
+ * Same as above but for u64 dividends. divisor must be a 32-bit
+ * number.
+ */
+#define DIV_ROUND_CLOSEST_ULL(x, divisor)( \
+{ \
+ typeof(divisor) __d = divisor; \
+ unsigned long long _tmp = (x) + (__d) / 2; \
+ do_div(_tmp, __d); \
+ _tmp; \
+} \
+)
+
+/*
+ * Multiplies an integer by a fraction, while avoiding unnecessary
+ * overflow or loss of precision.
+ */
+#define mult_frac(x, numer, denom)( \
+{ \
+ typeof(x) quot = (x) / (denom); \
+ typeof(x) rem = (x) % (denom); \
+ (quot * (numer)) + ((rem * (numer)) / (denom)); \
+} \
+)
+
+
+#define _RET_IP_ (unsigned long)__builtin_return_address(0)
+#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
+
+#ifdef CONFIG_LBDAF
+# include <asm/div64.h>
+# define sector_div(a, b) do_div(a, b)
+#else
+# define sector_div(n, b)( \
+{ \
+ int _res; \
+ _res = (n) % (b); \
+ (n) /= (b); \
+ _res; \
+} \
+)
+#endif
+
+/**
+ * upper_32_bits - return bits 32-63 of a number
+ * @n: the number we're accessing
+ *
+ * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
+ * the "right shift count >= width of type" warning when that quantity is
+ * 32-bits.
+ */
+#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
+
+/**
+ * lower_32_bits - return bits 0-31 of a number
+ * @n: the number we're accessing
+ */
+#define lower_32_bits(n) ((u32)(n))
+
+struct completion;
+struct pt_regs;
+struct user;
+
+#ifdef CONFIG_PREEMPT_VOLUNTARY
+extern int _cond_resched(void);
+# define might_resched() _cond_resched()
+#else
+# define might_resched() do { } while (0)
+#endif
+
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+ void ___might_sleep(const char *file, int line, int preempt_offset);
+ void __might_sleep(const char *file, int line, int preempt_offset);
+/**
+ * might_sleep - annotation for functions that can sleep
+ *
+ * this macro will print a stack trace if it is executed in an atomic
+ * context (spinlock, irq-handler, ...).
+ *
+ * This is a useful debugging help to be able to catch problems early and not
+ * be bitten later when the calling function happens to sleep when it is not
+ * supposed to.
+ */
+# define might_sleep() \
+ do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
+
+# define might_sleep_no_state_check() \
+ do { ___might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
+# define sched_annotate_sleep() (current->task_state_change = 0)
+#else
+ static inline void ___might_sleep(const char *file, int line,
+ int preempt_offset) { }
+ static inline void __might_sleep(const char *file, int line,
+ int preempt_offset) { }
+# define might_sleep() do { might_resched(); } while (0)
+# define might_sleep_no_state_check() do { might_resched(); } while (0)
+# define sched_annotate_sleep() do { } while (0)
+#endif
+
+#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
+
+/*
+ * abs() handles unsigned and signed longs, ints, shorts and chars. For all
+ * input types abs() returns a signed long.
+ * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
+ * for those.
+ */
+#define abs(x) ({ \
+ long ret; \
+ if (sizeof(x) == sizeof(long)) { \
+ long __x = (x); \
+ ret = (__x < 0) ? -__x : __x; \
+ } else { \
+ int __x = (x); \
+ ret = (__x < 0) ? -__x : __x; \
+ } \
+ ret; \
+ })
+
+#define abs64(x) ({ \
+ s64 __x = (x); \
+ (__x < 0) ? -__x : __x; \
+ })
+
+/**
+ * reciprocal_scale - "scale" a value into range [0, ep_ro)
+ * @val: value
+ * @ep_ro: right open interval endpoint
+ *
+ * Perform a "reciprocal multiplication" in order to "scale" a value into
+ * range [0, ep_ro), where the upper interval endpoint is right-open.
+ * This is useful, e.g. for accessing a index of an array containing
+ * ep_ro elements, for example. Think of it as sort of modulus, only that
+ * the result isn't that of modulo. ;) Note that if initial input is a
+ * small value, then result will return 0.
+ *
+ * Return: a result based on val in interval [0, ep_ro).
+ */
+static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
+{
+ return (u32)(((u64) val * ep_ro) >> 32);
+}
+
+#if defined(CONFIG_MMU) && \
+ (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
+#define might_fault() __might_fault(__FILE__, __LINE__)
+void __might_fault(const char *file, int line);
+#else
+static inline void might_fault(void) { }
+#endif
+
+extern struct atomic_notifier_head panic_notifier_list;
+extern long (*panic_blink)(int state);
+__printf(1, 2)
+void panic(const char *fmt, ...)
+ __noreturn __cold;
+extern void oops_enter(void);
+extern void oops_exit(void);
+void print_oops_end_marker(void);
+extern int oops_may_print(void);
+void do_exit(long error_code)
+ __noreturn;
+void complete_and_exit(struct completion *, long)
+ __noreturn;
+
+/* Internal, do not use. */
+int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
+int __must_check _kstrtol(const char *s, unsigned int base, long *res);
+
+int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
+int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
+
+/**
+ * kstrtoul - convert a string to an unsigned long
+ * @s: The start of the string. The string must be null-terminated, and may also
+ * include a single newline before its terminating null. The first character
+ * may also be a plus sign, but not a minus sign.
+ * @base: The number base to use. The maximum supported base is 16. If base is
+ * given as 0, then the base of the string is automatically detected with the
+ * conventional semantics - If it begins with 0x the number will be parsed as a
+ * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
+ * parsed as an octal number. Otherwise it will be parsed as a decimal.
+ * @res: Where to write the result of the conversion on success.
+ *
+ * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
+ * Used as a replacement for the obsolete simple_strtoull. Return code must
+ * be checked.
+*/
+static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
+{
+ /*
+ * We want to shortcut function call, but
+ * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
+ */
+ if (sizeof(unsigned long) == sizeof(unsigned long long) &&
+ __alignof__(unsigned long) == __alignof__(unsigned long long))
+ return kstrtoull(s, base, (unsigned long long *)res);
+ else
+ return _kstrtoul(s, base, res);
+}
+
+/**
+ * kstrtol - convert a string to a long
+ * @s: The start of the string. The string must be null-terminated, and may also
+ * include a single newline before its terminating null. The first character
+ * may also be a plus sign or a minus sign.
+ * @base: The number base to use. The maximum supported base is 16. If base is
+ * given as 0, then the base of the string is automatically detected with the
+ * conventional semantics - If it begins with 0x the number will be parsed as a
+ * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
+ * parsed as an octal number. Otherwise it will be parsed as a decimal.
+ * @res: Where to write the result of the conversion on success.
+ *
+ * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
+ * Used as a replacement for the obsolete simple_strtoull. Return code must
+ * be checked.
+ */
+static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
+{
+ /*
+ * We want to shortcut function call, but
+ * __builtin_types_compatible_p(long, long long) = 0.
+ */
+ if (sizeof(long) == sizeof(long long) &&
+ __alignof__(long) == __alignof__(long long))
+ return kstrtoll(s, base, (long long *)res);
+ else
+ return _kstrtol(s, base, res);
+}
+
+int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
+int __must_check kstrtoint(const char *s, unsigned int base, int *res);
+
+static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
+{
+ return kstrtoull(s, base, res);
+}
+
+static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
+{
+ return kstrtoll(s, base, res);
+}
+
+static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
+{
+ return kstrtouint(s, base, res);
+}
+
+static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
+{
+ return kstrtoint(s, base, res);
+}
+
+int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
+int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
+int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
+int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
+
+int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
+int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
+int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
+int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
+int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
+int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
+int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
+int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
+int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
+int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
+
+static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
+{
+ return kstrtoull_from_user(s, count, base, res);
+}
+
+static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
+{
+ return kstrtoll_from_user(s, count, base, res);
+}
+
+static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
+{
+ return kstrtouint_from_user(s, count, base, res);
+}
+
+static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
+{
+ return kstrtoint_from_user(s, count, base, res);
+}
+
+/* Obsolete, do not use. Use kstrto<foo> instead */
+
+extern unsigned long simple_strtoul(const char *,char **,unsigned int);
+extern long simple_strtol(const char *,char **,unsigned int);
+extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
+extern long long simple_strtoll(const char *,char **,unsigned int);
+
+extern int num_to_str(char *buf, int size, unsigned long long num);
+
+/* lib/printf utilities */
+
+extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
+extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
+extern __printf(3, 4)
+int snprintf(char *buf, size_t size, const char *fmt, ...);
+extern __printf(3, 0)
+int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
+extern __printf(3, 4)
+int scnprintf(char *buf, size_t size, const char *fmt, ...);
+extern __printf(3, 0)
+int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
+extern __printf(2, 3)
+char *kasprintf(gfp_t gfp, const char *fmt, ...);
+extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
+
+extern __scanf(2, 3)
+int sscanf(const char *, const char *, ...);
+extern __scanf(2, 0)
+int vsscanf(const char *, const char *, va_list);
+
+extern int get_option(char **str, int *pint);
+extern char *get_options(const char *str, int nints, int *ints);
+extern unsigned long long memparse(const char *ptr, char **retptr);
+extern bool parse_option_str(const char *str, const char *option);
+
+extern int core_kernel_text(unsigned long addr);
+extern int core_kernel_data(unsigned long addr);
+extern int __kernel_text_address(unsigned long addr);
+extern int kernel_text_address(unsigned long addr);
+extern int func_ptr_is_kernel_text(void *ptr);
+
+unsigned long int_sqrt(unsigned long);
+
+extern void bust_spinlocks(int yes);
+extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
+extern int panic_timeout;
+extern int panic_on_oops;
+extern int panic_on_unrecovered_nmi;
+extern int panic_on_io_nmi;
+extern int panic_on_warn;
+extern int sysctl_panic_on_stackoverflow;
+/*
+ * Only to be used by arch init code. If the user over-wrote the default
+ * CONFIG_PANIC_TIMEOUT, honor it.
+ */
+static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
+{
+ if (panic_timeout == arch_default_timeout)
+ panic_timeout = timeout;
+}
+extern const char *print_tainted(void);
+enum lockdep_ok {
+ LOCKDEP_STILL_OK,
+ LOCKDEP_NOW_UNRELIABLE
+};
+extern void add_taint(unsigned flag, enum lockdep_ok);
+extern int test_taint(unsigned flag);
+extern unsigned long get_taint(void);
+extern int root_mountflags;
+
+extern bool early_boot_irqs_disabled;
+
+/* Values used for system_state */
+extern enum system_states {
+ SYSTEM_BOOTING,
+ SYSTEM_RUNNING,
+ SYSTEM_HALT,
+ SYSTEM_POWER_OFF,
+ SYSTEM_RESTART,
+ SYSTEM_SUSPEND,
+} system_state;
+
+#define TAINT_PROPRIETARY_MODULE 0
+#define TAINT_FORCED_MODULE 1
+#define TAINT_CPU_OUT_OF_SPEC 2
+#define TAINT_FORCED_RMMOD 3
+#define TAINT_MACHINE_CHECK 4
+#define TAINT_BAD_PAGE 5
+#define TAINT_USER 6
+#define TAINT_DIE 7
+#define TAINT_OVERRIDDEN_ACPI_TABLE 8
+#define TAINT_WARN 9
+#define TAINT_CRAP 10
+#define TAINT_FIRMWARE_WORKAROUND 11
+#define TAINT_OOT_MODULE 12
+#define TAINT_UNSIGNED_MODULE 13
+#define TAINT_SOFTLOCKUP 14
+#define TAINT_LIVEPATCH 15
+
+extern const char hex_asc[];
+#define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
+#define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
+
+static inline char *hex_byte_pack(char *buf, u8 byte)
+{
+ *buf++ = hex_asc_hi(byte);
+ *buf++ = hex_asc_lo(byte);
+ return buf;
+}
+
+extern const char hex_asc_upper[];
+#define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)]
+#define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4]
+
+static inline char *hex_byte_pack_upper(char *buf, u8 byte)
+{
+ *buf++ = hex_asc_upper_hi(byte);
+ *buf++ = hex_asc_upper_lo(byte);
+ return buf;
+}
+
+extern int hex_to_bin(char ch);
+extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
+extern char *bin2hex(char *dst, const void *src, size_t count);
+
+bool mac_pton(const char *s, u8 *mac);
+
+/*
+ * General tracing related utility functions - trace_printk(),
+ * tracing_on/tracing_off and tracing_start()/tracing_stop
+ *
+ * Use tracing_on/tracing_off when you want to quickly turn on or off
+ * tracing. It simply enables or disables the recording of the trace events.
+ * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
+ * file, which gives a means for the kernel and userspace to interact.
+ * Place a tracing_off() in the kernel where you want tracing to end.
+ * From user space, examine the trace, and then echo 1 > tracing_on
+ * to continue tracing.
+ *
+ * tracing_stop/tracing_start has slightly more overhead. It is used
+ * by things like suspend to ram where disabling the recording of the
+ * trace is not enough, but tracing must actually stop because things
+ * like calling smp_processor_id() may crash the system.
+ *
+ * Most likely, you want to use tracing_on/tracing_off.
+ */
+#ifdef CONFIG_RING_BUFFER
+/* trace_off_permanent stops recording with no way to bring it back */
+void tracing_off_permanent(void);
+#else
+static inline void tracing_off_permanent(void) { }
+#endif
+
+enum ftrace_dump_mode {
+ DUMP_NONE,
+ DUMP_ALL,
+ DUMP_ORIG,
+};
+
+#ifdef CONFIG_TRACING
+void tracing_on(void);
+void tracing_off(void);
+int tracing_is_on(void);
+void tracing_snapshot(void);
+void tracing_snapshot_alloc(void);
+
+extern void tracing_start(void);
+extern void tracing_stop(void);
+
+static inline __printf(1, 2)
+void ____trace_printk_check_format(const char *fmt, ...)
+{
+}
+#define __trace_printk_check_format(fmt, args...) \
+do { \
+ if (0) \
+ ____trace_printk_check_format(fmt, ##args); \
+} while (0)
+
+/**
+ * trace_printk - printf formatting in the ftrace buffer
+ * @fmt: the printf format for printing
+ *
+ * Note: __trace_printk is an internal function for trace_printk and
+ * the @ip is passed in via the trace_printk macro.
+ *
+ * This function allows a kernel developer to debug fast path sections
+ * that printk is not appropriate for. By scattering in various
+ * printk like tracing in the code, a developer can quickly see
+ * where problems are occurring.
+ *
+ * This is intended as a debugging tool for the developer only.
+ * Please refrain from leaving trace_printks scattered around in
+ * your code. (Extra memory is used for special buffers that are
+ * allocated when trace_printk() is used)
+ *
+ * A little optization trick is done here. If there's only one
+ * argument, there's no need to scan the string for printf formats.
+ * The trace_puts() will suffice. But how can we take advantage of
+ * using trace_puts() when trace_printk() has only one argument?
+ * By stringifying the args and checking the size we can tell
+ * whether or not there are args. __stringify((__VA_ARGS__)) will
+ * turn into "()\0" with a size of 3 when there are no args, anything
+ * else will be bigger. All we need to do is define a string to this,
+ * and then take its size and compare to 3. If it's bigger, use
+ * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
+ * let gcc optimize the rest.
+ */
+
+#define trace_printk(fmt, ...) \
+do { \
+ char _______STR[] = __stringify((__VA_ARGS__)); \
+ if (sizeof(_______STR) > 3) \
+ do_trace_printk(fmt, ##__VA_ARGS__); \
+ else \
+ trace_puts(fmt); \
+} while (0)
+
+#define do_trace_printk(fmt, args...) \
+do { \
+ static const char *trace_printk_fmt \
+ __attribute__((section("__trace_printk_fmt"))) = \
+ __builtin_constant_p(fmt) ? fmt : NULL; \
+ \
+ __trace_printk_check_format(fmt, ##args); \
+ \
+ if (__builtin_constant_p(fmt)) \
+ __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
+ else \
+ __trace_printk(_THIS_IP_, fmt, ##args); \
+} while (0)
+
+extern __printf(2, 3)
+int __trace_bprintk(unsigned long ip, const char *fmt, ...);
+
+extern __printf(2, 3)
+int __trace_printk(unsigned long ip, const char *fmt, ...);
+
+/**
+ * trace_puts - write a string into the ftrace buffer
+ * @str: the string to record
+ *
+ * Note: __trace_bputs is an internal function for trace_puts and
+ * the @ip is passed in via the trace_puts macro.
+ *
+ * This is similar to trace_printk() but is made for those really fast
+ * paths that a developer wants the least amount of "Heisenbug" affects,
+ * where the processing of the print format is still too much.
+ *
+ * This function allows a kernel developer to debug fast path sections
+ * that printk is not appropriate for. By scattering in various
+ * printk like tracing in the code, a developer can quickly see
+ * where problems are occurring.
+ *
+ * This is intended as a debugging tool for the developer only.
+ * Please refrain from leaving trace_puts scattered around in
+ * your code. (Extra memory is used for special buffers that are
+ * allocated when trace_puts() is used)
+ *
+ * Returns: 0 if nothing was written, positive # if string was.
+ * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
+ */
+
+#define trace_puts(str) ({ \
+ static const char *trace_printk_fmt \
+ __attribute__((section("__trace_printk_fmt"))) = \
+ __builtin_constant_p(str) ? str : NULL; \
+ \
+ if (__builtin_constant_p(str)) \
+ __trace_bputs(_THIS_IP_, trace_printk_fmt); \
+ else \
+ __trace_puts(_THIS_IP_, str, strlen(str)); \
+})
+extern int __trace_bputs(unsigned long ip, const char *str);
+extern int __trace_puts(unsigned long ip, const char *str, int size);
+
+extern void trace_dump_stack(int skip);
+
+/*
+ * The double __builtin_constant_p is because gcc will give us an error
+ * if we try to allocate the static variable to fmt if it is not a
+ * constant. Even with the outer if statement.
+ */
+#define ftrace_vprintk(fmt, vargs) \
+do { \
+ if (__builtin_constant_p(fmt)) { \
+ static const char *trace_printk_fmt \
+ __attribute__((section("__trace_printk_fmt"))) = \
+ __builtin_constant_p(fmt) ? fmt : NULL; \
+ \
+ __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
+ } else \
+ __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
+} while (0)
+
+extern int
+__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
+
+extern int
+__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
+
+extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
+#else
+static inline void tracing_start(void) { }
+static inline void tracing_stop(void) { }
+static inline void trace_dump_stack(int skip) { }
+
+static inline void tracing_on(void) { }
+static inline void tracing_off(void) { }
+static inline int tracing_is_on(void) { return 0; }
+static inline void tracing_snapshot(void) { }
+static inline void tracing_snapshot_alloc(void) { }
+
+static inline __printf(1, 2)
+int trace_printk(const char *fmt, ...)
+{
+ return 0;
+}
+static inline int
+ftrace_vprintk(const char *fmt, va_list ap)
+{
+ return 0;
+}
+static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
+#endif /* CONFIG_TRACING */
+
+/*
+ * min()/max()/clamp() macros that also do
+ * strict type-checking.. See the
+ * "unnecessary" pointer comparison.
+ */
+#define min(x, y) ({ \
+ typeof(x) _min1 = (x); \
+ typeof(y) _min2 = (y); \
+ (void) (&_min1 == &_min2); \
+ _min1 < _min2 ? _min1 : _min2; })
+
+#define max(x, y) ({ \
+ typeof(x) _max1 = (x); \
+ typeof(y) _max2 = (y); \
+ (void) (&_max1 == &_max2); \
+ _max1 > _max2 ? _max1 : _max2; })
+
+#define min3(x, y, z) min((typeof(x))min(x, y), z)
+#define max3(x, y, z) max((typeof(x))max(x, y), z)
+
+/**
+ * min_not_zero - return the minimum that is _not_ zero, unless both are zero
+ * @x: value1
+ * @y: value2
+ */
+#define min_not_zero(x, y) ({ \
+ typeof(x) __x = (x); \
+ typeof(y) __y = (y); \
+ __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
+
+/**
+ * clamp - return a value clamped to a given range with strict typechecking
+ * @val: current value
+ * @lo: lowest allowable value
+ * @hi: highest allowable value
+ *
+ * This macro does strict typechecking of lo/hi to make sure they are of the
+ * same type as val. See the unnecessary pointer comparisons.
+ */
+#define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
+
+/*
+ * ..and if you can't take the strict
+ * types, you can specify one yourself.
+ *
+ * Or not use min/max/clamp at all, of course.
+ */
+#define min_t(type, x, y) ({ \
+ type __min1 = (x); \
+ type __min2 = (y); \
+ __min1 < __min2 ? __min1: __min2; })
+
+#define max_t(type, x, y) ({ \
+ type __max1 = (x); \
+ type __max2 = (y); \
+ __max1 > __max2 ? __max1: __max2; })
+
+/**
+ * clamp_t - return a value clamped to a given range using a given type
+ * @type: the type of variable to use
+ * @val: current value
+ * @lo: minimum allowable value
+ * @hi: maximum allowable value
+ *
+ * This macro does no typechecking and uses temporary variables of type
+ * 'type' to make all the comparisons.
+ */
+#define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
+
+/**
+ * clamp_val - return a value clamped to a given range using val's type
+ * @val: current value
+ * @lo: minimum allowable value
+ * @hi: maximum allowable value
+ *
+ * This macro does no typechecking and uses temporary variables of whatever
+ * type the input argument 'val' is. This is useful when val is an unsigned
+ * type and min and max are literals that will otherwise be assigned a signed
+ * integer type.
+ */
+#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
+
+
+/*
+ * swap - swap value of @a and @b
+ */
+#define swap(a, b) \
+ do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
+
+/**
+ * container_of - cast a member of a structure out to the containing structure
+ * @ptr: the pointer to the member.
+ * @type: the type of the container struct this is embedded in.
+ * @member: the name of the member within the struct.
+ *
+ */
+#define container_of(ptr, type, member) ({ \
+ const typeof( ((type *)0)->member ) *__mptr = (ptr); \
+ (type *)( (char *)__mptr - offsetof(type,member) );})
+
+/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
+#endif
+
+/* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
+#define VERIFY_OCTAL_PERMISSIONS(perms) \
+ (BUILD_BUG_ON_ZERO((perms) < 0) + \
+ BUILD_BUG_ON_ZERO((perms) > 0777) + \
+ /* User perms >= group perms >= other perms */ \
+ BUILD_BUG_ON_ZERO(((perms) >> 6) < (((perms) >> 3) & 7)) + \
+ BUILD_BUG_ON_ZERO((((perms) >> 3) & 7) < ((perms) & 7)) + \
+ /* Other writable? Generally considered a bad idea. */ \
+ BUILD_BUG_ON_ZERO((perms) & 2) + \
+ (perms))
+#endif