System page: an in-memory data structure which stores the information about the system, e.g. processor type, the location and size of available system RAM.

  • the system page is initialized by the startup program.
  • the kernel as well as applications can access this information as a read-only data structure.
  • struct syspage_entry is defined in <sys/syspage.h>

struct syspage_entry {
uint16_t size;
uint16_t total_size;
uint16_t type;          // ARM, MIPS, PPC, SH4, or X86
uint16_t num_cpu;
syspage_entry_info system_private;
syspage_entry_info asinfo;
syspage_entry_info hwinfo;
syspage_entry_info cpuinfo; //  CPU type, speed, capabilities, performance, and cache sizes, etc
syspage_entry_info cacheattr;
syspage_entry_info qtime;  // get a timestamp via: SYSPAGE_ENTRY(qtime)->nsec
syspage_entry_info callout; // allow you to “hook into” the kernel and gain control when a given event occurs.
syspage_entry_info callin;
syspage_entry_info typed_strings;
syspage_entry_info strings;
syspage_entry_info intrinfo;  // information about the interrupt system
syspage_entry_info smp;
syspage_entry_info pminfo;
union {
struct x86_syspage_entry x86;
struct ppc_syspage_entry ppc;
struct mips_syspage_entry mips;
struct arm_syspage_entry arm;
struct sh_syspage_entry sh; }}



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