此函數在arch/arm/kernel/setup.c中定義
void __init setup_arch(char **cmdline_p)
{
struct tag *tags = (struct tag *)&init_tags;
struct machine_desc *mdesc;
char *from = default_command_line;
unwind_init();
setup_processor(); //進行處理器相關的一些設置
mdesc = setup_machine(machine_arch_type); //獲得開發板的
machine_desc結構
machine_name = mdesc->name;
if (mdesc->soft_reboot)
reboot_setup("s");
if (__atags_pointer)
tags = phys_to_virt(__atags_pointer);
else if (mdesc->boot_params) //定義了Bootloader傳入參數的地址
tags = phys_to_virt(mdesc->boot_params);
/*
* If we have the old style parameters, convert them to
* a tag list.
*/
if (tags->hdr.tag != ATAG_CORE)
convert_to_tag_list(tags);
if (tags->hdr.tag != ATAG_CORE)
tags = (struct tag *)&init_tags;
if (mdesc->fixup)
mdesc->fixup(mdesc, tags, &from, &meminfo);
if (tags->hdr.tag == ATAG_CORE) {
if (meminfo.nr_banks != 0) //如果已經在內核中定義了meminfo結構
squash_mem_tags(tags); 則忽略內存tag
save_atags(tags);
parse_tags(tags); //解釋每個tag
}
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;
memcpy(boot_command_line, from, COMMAND_LINE_SIZE);
boot_command_line[COMMAND_LINE_SIZE-1] = '\0';
parse_cmdline(cmdline_p, from); //對命令行進行一些先期的處理
paging_init(mdesc); //重新初始化頁表