Get system memory size

#ifndef _LINUX_KERNEL_H
#define _LINUX_KERNEL_H
 
/*
 * 'kernel.h' contains some often-used function prototypes etc
 */
 
#ifdef __KERNEL__
 
#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 <asm/byteorder.h>
#include <asm/bug.h>
 
extern const char linux_banner[];
extern const char linux_proc_banner[];
 
#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 STACK_MAGIC     0xdeadbeef
 
#define ALIGN(x,a)              __ALIGN_MASK(x,(typeof(x))(a)-1)
#define __ALIGN_MASK(x,mask)    (((x)+(mask))&~(mask))
 
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
 
#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
#define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y))
 
/**
 * 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))
 
#define KERN_EMERG      "<0>"   /* system is unusable                   */
#define KERN_ALERT      "<1>"   /* action must be taken immediately     */
#define KERN_CRIT       "<2>"   /* critical conditions                  */
#define KERN_ERR        "<3>"   /* error conditions                     */
#define KERN_WARNING    "<4>"   /* warning conditions                   */
#define KERN_NOTICE     "<5>"   /* normal but significant condition     */
#define KERN_INFO       "<6>"   /* informational                        */
#define KERN_DEBUG      "<7>"   /* debug-level messages                 */
 
extern int console_printk[];
 
#define console_loglevel (console_printk[0])
#define default_message_loglevel (console_printk[1])
#define minimum_console_loglevel (console_printk[2])
#define default_console_loglevel (console_printk[3])
 
struct completion;
struct pt_regs;
struct user;
 
/**
 * 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.
 */
#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_SPINLOCK_SLEEP
  void __might_sleep(char *file, int line);
# define might_sleep() \
        do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0)
#else
# define might_sleep() do { might_resched(); } while (0)
#endif
 
#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 
#define abs(x) ({                               \
                int __x = (x);                  \
                (__x < 0) ? -__x : __x;         \
        })
 
extern struct atomic_notifier_head panic_notifier_list;
extern long (*panic_blink)(long time);
NORET_TYPE void panic(const char * fmt, ...)
        __attribute__ ((NORET_AND format (printf, 1, 2)));
extern void oops_enter(void);
extern void oops_exit(void);
extern int oops_may_print(void);
fastcall NORET_TYPE void do_exit(long error_code)
        ATTRIB_NORET;
NORET_TYPE void complete_and_exit(struct completion *, long)
        ATTRIB_NORET;
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 sprintf(char * buf, const char * fmt, ...)
        __attribute__ ((format (printf, 2, 3)));
extern int vsprintf(char *buf, const char *, va_list)
        __attribute__ ((format (printf, 2, 0)));
extern int snprintf(char * buf, size_t size, const char * fmt, ...)
        __attribute__ ((format (printf, 3, 4)));
extern int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
        __attribute__ ((format (printf, 3, 0)));
extern int scnprintf(char * buf, size_t size, const char * fmt, ...)
        __attribute__ ((format (printf, 3, 4)));
extern int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
        __attribute__ ((format (printf, 3, 0)));
extern char *kasprintf(gfp_t gfp, const char *fmt, ...)
        __attribute__ ((format (printf, 2, 3)));
extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 
extern int sscanf(const char *, const char *, ...)
        __attribute__ ((format (scanf, 2, 3)));
extern int vsscanf(const char *, const char *, va_list)
        __attribute__ ((format (scanf, 2, 0)));
 
extern int get_option(char **str, int *pint);
extern char *get_options(const char *str, int nints, int *ints);
extern unsigned long long memparse(char *ptr, char **retptr);
 
extern int core_kernel_text(unsigned long addr);
extern int __kernel_text_address(unsigned long addr);
extern int kernel_text_address(unsigned long addr);
struct pid;
extern struct pid *session_of_pgrp(struct pid *pgrp);
 
extern void dump_thread(struct pt_regs *regs, struct user *dump);
 
#ifdef CONFIG_PRINTK
asmlinkage int vprintk(const char *fmt, va_list args)
        __attribute__ ((format (printf, 1, 0)));
asmlinkage int printk(const char * fmt, ...)
        __attribute__ ((format (printf, 1, 2)));
#else
static inline int vprintk(const char *s, va_list args)
        __attribute__ ((format (printf, 1, 0)));
static inline int vprintk(const char *s, va_list args) { return 0; }
static inline int printk(const char *s, ...)
        __attribute__ ((format (printf, 1, 2)));
static inline int printk(const char *s, ...) { return 0; }
#endif
 
unsigned long int_sqrt(unsigned long);
 
extern int printk_ratelimit(void);
extern int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst);
extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
                                unsigned int interval_msec);
 
static inline void console_silent(void)
{
        console_loglevel = 0;
}
 
static inline void console_verbose(void)
{
        if (console_loglevel)
                console_loglevel = 15;
}
 
extern void bust_spinlocks(int yes);
extern void wake_up_klogd(void);
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 tainted;
extern const char *print_tainted(void);
extern void add_taint(unsigned);
 
/* Values used for system_state */
extern enum system_states {
        SYSTEM_BOOTING,
        SYSTEM_RUNNING,
        SYSTEM_HALT,
        SYSTEM_POWER_OFF,
        SYSTEM_RESTART,
        SYSTEM_SUSPEND_DISK,
} system_state;
 
#define TAINT_PROPRIETARY_MODULE        (1<<0)
#define TAINT_FORCED_MODULE             (1<<1)
#define TAINT_UNSAFE_SMP                (1<<2)
#define TAINT_FORCED_RMMOD              (1<<3)
#define TAINT_MACHINE_CHECK             (1<<4)
#define TAINT_BAD_PAGE                  (1<<5)
#define TAINT_USER                      (1<<6)
 
extern void dump_stack(void);
 
enum {
        DUMP_PREFIX_NONE,
        DUMP_PREFIX_ADDRESS,
        DUMP_PREFIX_OFFSET
};
extern void hex_dump_to_buffer(const void *buf, size_t len,
                                int rowsize, int groupsize,
                                char *linebuf, size_t linebuflen, bool ascii);
extern void print_hex_dump(const char *level, const char *prefix_str,
                                int prefix_type, int rowsize, int groupsize,
                                void *buf, size_t len, bool ascii);
extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
                        void *buf, size_t len);
#define hex_asc(x)      "0123456789abcdef"[x]
 
#ifdef DEBUG
/* If you are writing a driver, please use dev_dbg instead */
#define pr_debug(fmt,arg...) \
        printk(KERN_DEBUG fmt,##arg)
#else
static inline int __attribute__ ((format (printf, 1, 2))) pr_debug(const char * fmt, ...)
{
        return 0;
}
#endif
 
#define pr_info(fmt,arg...) \
        printk(KERN_INFO fmt,##arg)
 
/*
 *      Display an IP address in readable format.
 */
 
#define NIPQUAD(addr) \
        ((unsigned char *)&addr)[0], \
        ((unsigned char *)&addr)[1], \
        ((unsigned char *)&addr)[2], \
        ((unsigned char *)&addr)[3]
#define NIPQUAD_FMT "%u.%u.%u.%u"
 
#define NIP6(addr) \
        ntohs((addr).s6_addr16[0]), \
        ntohs((addr).s6_addr16[1]), \
        ntohs((addr).s6_addr16[2]), \
        ntohs((addr).s6_addr16[3]), \
        ntohs((addr).s6_addr16[4]), \
        ntohs((addr).s6_addr16[5]), \
        ntohs((addr).s6_addr16[6]), \
        ntohs((addr).s6_addr16[7])
#define NIP6_FMT "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x"
#define NIP6_SEQFMT "%04x%04x%04x%04x%04x%04x%04x%04x"
 
#if defined(__LITTLE_ENDIAN)
#define HIPQUAD(addr) \
        ((unsigned char *)&addr)[3], \
        ((unsigned char *)&addr)[2], \
        ((unsigned char *)&addr)[1], \
        ((unsigned char *)&addr)[0]
#elif defined(__BIG_ENDIAN)
#define HIPQUAD NIPQUAD
#else
#error "Please fix asm/byteorder.h"
#endif /* __LITTLE_ENDIAN */
 
/*
 * min()/max() macros that also do
 * strict type-checking.. See the
 * "unnecessary" pointer comparison.
 */
#define min(x,y) ({ \
        typeof(x) _x = (x);     \
        typeof(y) _y = (y);     \
        (void) (&_x == &_y);            \
        _x < _y ? _x : _y; })
 
#define max(x,y) ({ \
        typeof(x) _x = (x);     \
        typeof(y) _y = (y);     \
        (void) (&_x == &_y);            \
        _x > _y ? _x : _y; })
 
/*
 * ..and if you can't take the strict
 * types, you can specify one yourself.
 *
 * Or not use min/max at all, of course.
 */
#define min_t(type,x,y) \
        ({ type __x = (x); type __y = (y); __x < __y ? __x: __y; })
#define max_t(type,x,y) \
        ({ type __x = (x); type __y = (y); __x > __y ? __x: __y; })
 
 
/**
 * 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) );})
 
/*
 * Check at compile time that something is of a particular type.
 * Always evaluates to 1 so you may use it easily in comparisons.
 */
#define typecheck(type,x) \
({      type __dummy; \
        typeof(x) __dummy2; \
        (void)(&__dummy == &__dummy2); \
        1; \
})
 
/*
 * Check at compile time that 'function' is a certain type, or is a pointer
 * to that type (needs to use typedef for the function type.)
 */
#define typecheck_fn(type,function) \
({      typeof(type) __tmp = function; \
        (void)__tmp; \
})
 
struct sysinfo;
extern int do_sysinfo(struct sysinfo *info);
 
#endif /* __KERNEL__ */
 
#define SI_LOAD_SHIFT   16
struct sysinfo {
        long uptime;                    /* Seconds since boot */
        unsigned long loads[3];         /* 1, 5, and 15 minute load averages */
        unsigned long totalram;         /* Total usable main memory size */
        unsigned long freeram;          /* Available memory size */
        unsigned long sharedram;        /* Amount of shared memory */
        unsigned long bufferram;        /* Memory used by buffers */
        unsigned long totalswap;        /* Total swap space size */
        unsigned long freeswap;         /* swap space still available */
        unsigned short procs;           /* Number of current processes */
        unsigned short pad;             /* explicit padding for m68k */
        unsigned long totalhigh;        /* Total high memory size */
        unsigned long freehigh;         /* Available high memory size */
        unsigned int mem_unit;          /* Memory unit size in bytes */
        char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
};
 
/* Force a compilation error if condition is true */
#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 
/* Force a compilation error if condition is true, but also produce a
   result (of value 0 and type size_t), so the expression can be used
   e.g. in a structure initializer (or where-ever else comma expressions
   aren't permitted). */
#define BUILD_BUG_ON_ZERO(e) (sizeof(char[1 - 2 * !!(e)]) - 1)
 
/* Trap pasters of __FUNCTION__ at compile-time */
#define __FUNCTION__ (__func__)
 
/* This helps us to avoid #ifdef CONFIG_NUMA */
#ifdef CONFIG_NUMA
#define NUMA_BUILD 1
#else
#define NUMA_BUILD 0
#endif
 
#endif