startケネル関数

スタート地点ケネル()では、一連の初期化関数を呼び出して、ケネル自体の設定を完了します.これらの動作は公共的なものもあれば、配置が必要なものがあります.
スタントにケネル関数では、
Linuxバージョン情報を出力します.
システム構造に関する環境(setupuarch()を設定します.
ページ表構造初期化(pagiguinit())
「arch/alpha/kersnel/entry.S」の入口点設定システムを使用して、ノッチ入口(trapuuinit()
アルファを使うmv構造とentry.S入り口初期化システムIRQ(inituIRQ()
コアプロセススケジューラ初期化(いくつかのデフォルトのBottom-halfを初期化することを含む)
時間、タイマー初期化(CMOSクロックの読み取り、マスタ周波数の推定、初期化タイマの中断などを含む、timeyit()
コア起動パラメータを抽出して分析します(環境変数からパラメータを読み出し、該当フラグビット待ち処理を設定します.(パーrseuoptions()
コンソール初期化(PCI初期化よりも先に情報を出力するために、consolueuinit())
解析器データ構造初期化(profufferとprofulen変数)
コアCache初期化(Cache情報を記述するCache,kmemucache uinit()
ディレイキャリブレーション(クロックジffiesとCPUメイン周波数ticksの遅延を取得し、calibrate udelay()
メモリ初期化(メモリ上下界とページ項目初期値設定、memuuinit()
内部および汎用cache(「slabucache」,kmemucache()を作成して設定します.
uid taskycount SLAB cacheを作成します.
文書cacheを作成します.
ディレクトリcacheを作成します.
虚存に関するcacheを作成します.
ブロックデバイス読み書きバッファ初期化(同時に「バfferuhead」cacheを作成し、ユーザーの加速アクセス、バfferuuinit()
ページcacheを作成します(メモリページhashテーブル初期化、pagecacheuinit()
信号列cacheを作成します.
初期化メモリinodeテーブル(inodeuinit()
メモリファイルの説明書を作成します.
システム構造の脆弱性をチェックします.この関数は空です.checkubugs()
SMPマシンの他のCPU(現在のブートCPUを除く)初期化(SMPを構成していないカーネルに対しては、この関数は空であり、spuuinit())
initプロセスを起動します.(最初のコアスレッドを作成し、init()関数を呼び出します.元の実行シーケンスはcpuguidle()を呼び出してスケジュールを待っています.init()
これでstartukeernelが終わり、基本的な核心環境ができました.

 
asmlinkage void __init start_kernel(void)
{
 char * command_line;
 unsigned long mempages;
 extern char saved_command_line[];
/*
 * Interrupts are still disabled. Do necessary setups, then
 * enable them
 */
 /*   */
 lock_kernel();
 /*             */
 printk(linux_banner);
 /*                        */
 setup_arch(&command_line); 
 /*       */
 printk("Kernel command line: %s
", saved_command_line);
 /*             0            */
 parse_options(command_line);
 /*    ，      */
 trap_init();
 /*         */
 init_IRQ();
 /*                */
 sched_init();
 /*     */
 time_init();
 /*   tasklet   */
 softirq_init();
 /*
 * HACK ALERT! This is early. We're enabling the console before
 * we've done PCI setups etc, and console_init() must be aware of
 * this. But we do want output early, in case something goes wrong.
 */
 /*     */
 console_init();
#ifdef CONFIG_MODULES
 /*     symbol   */
 init_modules();
#endif
 if (prof_shift) {
 unsigned int size;
 /* only text is profiled */
 prof_len = (unsigned long) &_etext - (unsigned long) &_stext;
 prof_len >>= prof_shift;
 
 size = prof_len * sizeof(unsigned int) + PAGE_SIZE-1;
 prof_buffer = (unsigned int *) alloc_bootmem(size);
 }
 /*   slab   */
 kmem_cache_init();
 sti();
 calibrate_delay();
#ifdef CONFIG_BLK_DEV_INITRD
 if (initrd_start && !initrd_below_start_ok &&
 initrd_start < min_low_pfn << PAGE_SHIFT) {
 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 "disabling it.
",initrd_start,min_low_pfn << PAGE_SHIFT);
 initrd_start = 0;
 }
#endif
 /*             */
 mem_init(); 
 /*         slab   */
 kmem_cache_sizes_init();
#ifdef CONFIG_3215_CONSOLE
 con3215_activate();
#endif
#ifdef CONFIG_PROC_FS
 /*  proc       */
 proc_root_init();
#endif
 mempages = num_physpages;
 /*        */
 fork_init(mempages);
 /*       slab        */
 proc_caches_init();
 vfs_caches_init(mempages);
 /*   buffer    */
 buffer_init(mempages);
 /*          */
 page_cache_init(mempages);
 kiobuf_setup();
 /*  signal slab    */
 signals_init();
 bdev_init();
 /*        inode  */
 inode_init(mempages);
#if defined(CONFIG_SYSVIPC)
 /*   sysv    ，  ，    */
 ipc_init();
#endif
#if defined(CONFIG_QUOTA)
 dquot_init_hash();
#endif
 check_bugs();
 printk("POSIX conformance testing by UNIFIX
");
 
 /* 
 * We count on the initial thread going ok 
 * Like idlers init is an unlocked kernel thread, which will
 * make syscalls (and thus be locked).
 */
 /*   SMP,   APIC    */
 smp_init();
 /*  init  */
 kernel_thread(init, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGNAL);
 unlock_kernel();
 current->need_resched = 1;
 /*  idle  ，    */
 cpu_idle();
} 
void __init setup_arch(char **cmdline_p)
{
 unsigned long bootmap_size;
 unsigned long start_pfn, max_pfn, max_low_pfn;
 int i;
 
#ifdef CONFIG_VISWS
 visws_get_board_type_and_rev();
#endif
 /* rootfs   kdev     ，            */
 ROOT_DEV = to_kdev_t(ORIG_ROOT_DEV);
 drive_info = DRIVE_INFO;
 screen_info = SCREEN_INFO;
 apm_info.bios = APM_BIOS_INFO;
 /*               */
 if( SYS_DESC_TABLE.length != 0 ) {
 MCA_bus = SYS_DESC_TABLE.table[3] &0x2;
 machine_id = SYS_DESC_TABLE.table[0];
 machine_submodel_id = SYS_DESC_TABLE.table[1];
 BIOS_revision = SYS_DESC_TABLE.table[2];
 }
 aux_device_present = AUX_DEVICE_INFO;
 
#ifdef CONFIG_BLK_DEV_RAM
 /*  RAMDISK   */
 rd_image_start = RAMDISK_FLAGS & RAMDISK_IMAGE_START_MASK;
 rd_prompt = ((RAMDISK_FLAGS & RAMDISK_PROMPT_FLAG) != 0);
 rd_doload = ((RAMDISK_FLAGS & RAMDISK_LOAD_FLAG) != 0);
#endif
 setup_memory_region();
 
 if (!MOUNT_ROOT_RDONLY)
 root_mountflags &= ~MS_RDONLY;
 /* init_mm     ，            ,    */
 init_mm.start_code = (unsigned long) &_text;
 init_mm.end_code = (unsigned long) &_etext;
 init_mm.end_data = (unsigned long) &_edata;
 init_mm.brk = (unsigned long) &_end;
 
 /*                ，             */
 code_resource.start = virt_to_bus(&_text);
 code_resource.end = virt_to_bus(&_etext)-1;
 data_resource.start = virt_to_bus(&_etext);
 data_resource.end = virt_to_bus(&_edata)-1;
 
 /*       "mem="  */
 parse_mem_cmdline(cmdline_p);
 
#define PFN_UP(x) (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)
#define PFN_DOWN(x) ((x) >> PAGE_SHIFT)
#define PFN_PHYS(x) ((x) << PAGE_SHIFT)
 
/*
 * 128MB for vmalloc and initrd
 */
#define VMALLOC_RESERVE (unsigned long)(128 << 20)
#define MAXMEM (unsigned long)(-PAGE_OFFSET-VMALLOC_RESERVE)
#define MAXMEM_PFN PFN_DOWN(MAXMEM)
#define MAX_NONPAE_PFN (1 << 20)
 /*
 * partially used pages are not usable - thus
 * we are rounding upwards:
 */
 /*        */ 
 start_pfn = PFN_UP(__pa(&_end));
 
 /*
 * Find the highest page frame number we have available
 */
 /* E820         */
 max_pfn = 0;
 for (i = 0; i < e820.nr_map; i++) {
 unsigned long start, end;
 /* RAM? */
 if (e820.map[i].type != E820_RAM)
 continue;
 start = PFN_UP(e820.map[i].addr);
 end = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
 if (start >= end)
 continue;
 if (end > max_pfn)
 max_pfn = end;
 }
 
 /*
 * Determine low and high memory ranges:
 */
 /*           , 896M       */ 
 max_low_pfn = max_pfn;
 if (max_low_pfn > MAXMEM_PFN) {
 max_low_pfn = MAXMEM_PFN;
#ifndef CONFIG_HIGHMEM
 /* Maximum memory usable is what is directly addressable */
 printk(KERN_WARNING "Warning only %ldMB will be used.
",
 MAXMEM>>20);
 if (max_pfn > MAX_NONPAE_PFN)
 printk(KERN_WARNING "Use a PAE enabled kernel.
");
 else
 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.
");
#else /* !CONFIG_HIGHMEM */
#ifndef CONFIG_X86_PAE
 if (max_pfn > MAX_NONPAE_PFN) {
 max_pfn = MAX_NONPAE_PFN;
 printk(KERN_WARNING "Warning only 4GB will be used.
");
 printk(KERN_WARNING "Use a PAE enabled kernel.
");
 }
#endif /* !CONFIG_X86_PAE */
#endif /* !CONFIG_HIGHMEM */
 }
 /*              */
#ifdef CONFIG_HIGHMEM
 highstart_pfn = highend_pfn = max_pfn;
 if (max_pfn > MAXMEM_PFN) {
 highstart_pfn = MAXMEM_PFN;
 printk(KERN_NOTICE "%ldMB HIGHMEM available.
",
 pages_to_mb(highend_pfn - highstart_pfn));
 }
#endif
 /*
 * Initialize the boot-time allocator (with low memory only):
 */
 /*   896M   boot  */ 
 bootmap_size = init_bootmem(start_pfn, max_low_pfn);
 
 /*
 * Register fully available low RAM pages with the bootmem allocator.
 */
 /* 896M           */ 
 for (i = 0; i < e820.nr_map; i++) {
 unsigned long curr_pfn, last_pfn, size;
 /*
 * Reserve usable low memory
 */
 if (e820.map[i].type != E820_RAM)
 continue;
 /*
 * We are rounding up the start address of usable memory:
 */
 curr_pfn = PFN_UP(e820.map[i].addr);
 if (curr_pfn >= max_low_pfn)
 continue;
 /*
 * ... and at the end of the usable range downwards:
 */
 last_pfn = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
 if (last_pfn > max_low_pfn)
 last_pfn = max_low_pfn;
 /*
 * .. finally, did all the rounding and playing
 * around just make the area go away?
 */
 if (last_pfn <= curr_pfn)
 continue;
 size = last_pfn - curr_pfn;
 free_bootmem(PFN_PHYS(curr_pfn), PFN_PHYS(size));
 }
 /*
 * Reserve the bootmem bitmap itself as well. We do this in two
 * steps (first step was init_bootmem()) because this catches
 * the (very unlikely) case of us accidentally initializing the
 * bootmem allocator with an invalid RAM area.
 */
 /*  bootmem     */ 
 reserve_bootmem(HIGH_MEMORY, (PFN_PHYS(start_pfn) +
 bootmap_size + PAGE_SIZE-1) - (HIGH_MEMORY));
 /*
 * reserve physical page 0 - it's a special BIOS page on many boxes,
 * enabling clean reboots, SMP operation, laptop functions.
 */
 /*        */ 
 reserve_bootmem(0, PAGE_SIZE);
#ifdef CONFIG_SMP
 /*
 * But first pinch a few for the stack/trampoline stuff
 * FIXME: Don't need the extra page at 4K, but need to fix
 * trampoline before removing it. (see the GDT stuff)
 */
 reserve_bootmem(PAGE_SIZE, PAGE_SIZE);
 smp_alloc_memory(); /* AP processor realmode stacks in low memory*/
#endif
#ifdef CONFIG_X86_IO_APIC
 /*
 * Find and reserve possible boot-time SMP configuration:
 */
 find_smp_config();
#endif
 /*       */
 paging_init();
#ifdef CONFIG_X86_IO_APIC
 /*
 * get boot-time SMP configuration:
 */
 if (smp_found_config)
 get_smp_config();
#endif
#ifdef CONFIG_X86_LOCAL_APIC
 init_apic_mappings();
#endif
#ifdef CONFIG_BLK_DEV_INITRD
 /* RAMDISK       */
 if (LOADER_TYPE && INITRD_START) {
 if (INITRD_START + INITRD_SIZE <= (max_low_pfn << PAGE_SHIFT)) {
 reserve_bootmem(INITRD_START, INITRD_SIZE);
 initrd_start =
 INITRD_START ? INITRD_START + PAGE_OFFSET : 0;
 initrd_end = initrd_start+INITRD_SIZE;
 }
 else {
 printk("initrd extends beyond end of memory "
 "(0x%08lx > 0x%08lx)
disabling initrd
",
 INITRD_START + INITRD_SIZE,
 max_low_pfn << PAGE_SHIFT);
 initrd_start = 0;
 }
 }
#endif
 
 /*
 * Request address space for all standard RAM and ROM resources
 * and also for regions reported as reserved by the e820.
 */
 /* ROM       */ 
 probe_roms();
 /* RAM          */
 for (i = 0; i < e820.nr_map; i++) {
 struct resource *res;
 if (e820.map[i].addr + e820.map[i].size > 0x100000000ULL)
 continue;
 res = alloc_bootmem_low(sizeof(struct resource));
 switch (e820.map[i].type) {
 case E820_RAM: res->name = "System RAM"; break;
 case E820_ACPI: res->name = "ACPI Tables"; break;
 case E820_NVS: res->name = "ACPI Non-volatile Storage"; break;
 default: res->name = "reserved";
 }
 res->start = e820.map[i].addr;
 res->end = res->start + e820.map[i].size - 1;
 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 request_resource(&iomem_resource, res);
 if (e820.map[i].type == E820_RAM) {
 /*
 * We dont't know which RAM region contains kernel data,
 * so we try it repeatedly and let the resource manager
 * test it.
 */
 request_resource(res, &code_resource);
 request_resource(res, &data_resource);
 }
 }
 request_resource(&iomem_resource, &vram_resource);
 /* request I/O space for devices used on all i[345]86 PCs */
 for (i = 0; i < STANDARD_IO_RESOURCES; i++)
 request_resource(&ioport_resource, standard_io_resources+i);
 
#ifdef CONFIG_VT
#if defined(CONFIG_VGA_CONSOLE)
 conswitchp = &vga_con;
#elif defined(CONFIG_DUMMY_CONSOLE)
 conswitchp = &dummy_con;
#endif
#endif
}