浅析armlinux-setup_arch()->paging_init()函数5
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建议首先参考《浅析armlinux2_4_19启动程序[head-armv.s文件]》[http://gliethttp.cublog.cn]
//---------------------------------------- //1.arch/arm/mm/Init.c->paging_init() void __init paging_init(struct meminfo *mi, struct machine_desc *mdesc) {void *zero_page; int node; //arch/arm/mm/Init.c->static struct meminfo meminfo __initdata = { 0, }; memcpy(&meminfo, mi, sizeof(meminfo));//将mi拷贝到全局量meminfo //请参考《浅析armlinux-setup_arch()->alloc_bootmem_low_pages()函数5-1》 zero_page = alloc_bootmem_low_pages(PAGE_SIZE);//zero_page指向清0后的虚拟地址 //页表初始化,请参考《浅析armlinux-setup_arch()->memtable_init()函数5-2》[http://gliethttp.cublog.cn] memtable_init(mi);//建立中断向量表虚拟地址0xFFFF0000和所有node内存区域虚拟地址到物理地址的映射 //++++++++++++++ //arch/arm/mach-at91rm9200/Core.c //位于.arch.info段 //MACHINE_START(AT91RM9200, "ATMEL AT91RM9200")//.nr = MACH_TYPE_##_type=MACH_TYPE_AT91RM9200=251 //与上面从u-boot传到r1中的一样[gliethttp] //MAINTAINER("SAN People / ATMEL") //BOOT_MEM(AT91_SDRAM_BASE, AT91C_BASE_SYS, AT91C_VA_BASE_SYS) //BOOT_PARAMS(AT91_SDRAM_BASE + 0x100)//tag list存放的物理地址0x20000100[gliethttp] //FIXUP(at91rm9200_fixup) //MAPIO(at91rm9200_map_io) //INITIRQ(at91rm9200_init_irq) //MACHINE_END[gliethttp] //-------------- if (mdesc->map_io) //请参见《浅析armlinux-paging_init()->at91rm9200_map_io()函数5-3》[http://gliethttp.cublog.cn] mdesc->map_io();//调用at91rm9200_map_io,映射at91rm9200处理器的所有控制寄存器 flush_cache_all(); flush_tlb_all();//以上两函数请见后 //初始化每个node内部的所有区域们 for (node = 0; node < numnodes; node++) { unsigned long zone_size[MAX_NR_ZONES]; unsigned long zhole_size[MAX_NR_ZONES]; struct bootmem_data *bdata; pg_data_t *pgdat; int i; //初始化zone区域们暂存变量 //#define MAX_NR_ZONES 3 //每个node最多可以划分成MAX_NR_ZONES个bank for (i = 0; i < MAX_NR_ZONES; i++) { zone_size[i] = 0; zhole_size[i] = 0; } pgdat = NODE_DATA(node);//&discontig_node_data[node] bdata = pgdat->bdata; //zone_size[0]存放当前node对应的空间大小 zone_size[0] = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT); if (!zone_size[0]) continue; zhole_size[0] = zone_size[0];//从zhole_size[0]扣除期间每个bank的大小,剩余的即为hole大小 for (i = 0; i < mi->nr_banks; i++) { if (mi->bank[i].node != node) continue; zhole_size[0] -= mi->bank[i].size >> PAGE_SHIFT; } arch_adjust_zones(node, zone_size, zhole_size);//我的armlinux是空定义 //请参见《浅析armlinux-paging_init()->free_area_init_core()函数5-4》[http://gliethttp.cublog.cn] //分配4k页面管理空间,并由指针mem_map指向之,同时对所有4k也管理单元mem_map_t进行初始化 free_area_init_node(node, pgdat, 0, zone_size,bdata->node_boot_start, zhole_size); } //arch/arm/lib/memzero.S->memzero() //对memzero的理解可参见《浅析armlinux-__arch_clear_user内存拷贝函数之3》[http://gliethttp.cublog.cn] memzero(zero_page, PAGE_SIZE); //include/asm-arm/arch-at91rm9200/memory.h //#define __virt_to_phys(vpage) ((vpage) - PAGE_OFFSET + PHYS_OFFSET) //include/asm-arm/Memory.h->virt_to_page() //#define __pa(x) __virt_to_phys((unsigned long)(x))//虚拟地址转换成线性对应的物理地址 ////转换成当前物理页帧号在mem_map中管理单元的虚拟地址值 //#define pfn_to_page(pfn) ((mem_map + (pfn)) - PHYS_PFN_OFFSET) //即:(mem_map+(pfn-PHYS_PFN_OFFSET)) //#define virt_to_page(kaddr) (pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)) empty_zero_page = virt_to_page(zero_page); //见后 flush_dcache_page(empty_zero_page); } //---------------------------------------- //2.include/asm-arm/proc-armv/Cache.h->flush_cache_all() #define flush_cache_all()\ do{\ cpu_cache_clean_invalidate_all();\ }while(0) //include/asm-arm/Cpu-single.h #define cpu_cache_clean_invalidate_all cpu_fn(CPU_NAME,_cache_clean_invalidate_all) 转换后 #define cpu_cache_clean_invalidate_all cpu_arm920_cache_clean_invalidate_all //arch/arm/mm/proc-arm920.S->cpu_arm920_cache_clean_invalidate_all() .align 5 ENTRY(cpu_arm920_cache_clean_invalidate_all) mov r2, #1 cpu_arm920_cache_clean_invalidate_all_r2: mov ip, #0 #ifdef CONFIG_CPU_DCACHE_WRITETHROUGH//无定义 mcr p15, 0, ip, c7, c6, 0 #else /* * 'Clean & Invalidate whole DCache' * Re-written to use Index Ops. * Uses registers r1, r3 and ip */ mov r1, #7 << 5 @ 8 segments//8个缓冲块 1: orr r3, r1, #63 << 26 @ 64 entries//64根缓存线 2: mcr p15, 0, r3, c7, c14, 2 @ clean & invalidate D index subs r3, r3, #1 << 26 bcs 2b @ entries 63 to 0 subs r1, r1, #1 << 5 bcs 1b @ segments 7 to 0//每个缓冲块均对应64根缓存线 #endif teq r2, #0 mcrne p15, 0, ip, c7, c5, 0 @ invalidate I cache mcr p15, 0, ip, c7, c10, 4 @ drain WB mov pc, lr //---------------------------------------- //3.include/asm-arm/proc-armv/Cache.h->flush_tlb_all() #define flush_tlb_all()\ do {\ cpu_tlb_invalidate_all();\ } while (0) //include/asm-arm/Cpu-single.h #define cpu_tlb_invalidate_all cpu_fn(CPU_NAME,_tlb_invalidate_all) 转换后 #define cpu_tlb_invalidate_all cpu_arm920_tlb_invalidate_all //arch/arm/mm/proc-arm920.S->cpu_arm920_tlb_invalidate_all() .align 5 ENTRY(cpu_arm920_tlb_invalidate_all) mov r0, #0 mcr p15, 0, r0, c7, c10, 4 @ drain WB//耗写缓冲器 mcr p15, 0, r0, c8, c7, 0 @ invalidate I & D TLBs//使指令和数据TLB无效 mov pc, lr //4.include/asm-arm/proc-amrv/Cache.h->flush_dcache_page() #define mapping_mapped(map) ((map)->i_mmap || (map)->i_mmap_shared) static inline void flush_dcache_page(struct page *page) { if (page->mapping && !mapping_mapped(page->mapping)) //该page已经使用 set_bit(PG_dcache_dirty, &page->flags); else { //该page还没有使用 //计算page对应管理的空间虚拟地址 unsigned long virt = (unsigned long)page_address(page); cpu_cache_clean_invalidate_range(virt, virt + PAGE_SIZE, 0); } } //include/linux/Mm.h->page_address #define page_address(page)\ //该宏很方便的将page所属的node空间对应的zone_mem_map和zone_start_paddr //进行综合运算,计算出page页对应的虚拟地址值 __va( (((page) - page_zone(page)->zone_mem_map) << PAGE_SHIFT)\ + page_zone(page)->zone_start_paddr) static inline zone_t *page_zone(struct page *page) { return zone_table[page->flags >> ZONE_SHIFT]; } //cpu_cache_clean_invalidate_range //include/asm-arm/Cpu-singnal.h->cpu_cache_clean_invalidate_range() #define cpu_cache_clean_invalidate_range cpu_fn(CPU_NAME,_cache_clean_invalidate_range) 翻译后 #define cpu_cache_clean_invalidate_range cpu_arm920_cache_clean_invalidate_range //arch/arm/mm/proc-arm920.S->cpu_arm920_cache_clean_invalidate_range /* * the cache line size of the I and D cache */ #define MAX_AREA_SIZE 16384 #define DCACHELINESIZE 32 #define ICACHELINESIZE 32 .align 5 ENTRY(cpu_arm920_cache_clean_invalidate_range) bic r0, r0, #DCACHELINESIZE - 1 @ && added by PGM bic r1, r1, #DCACHELINESIZE - 1 @ && added by DHM sub r3, r1, r0 cmp r3, #MAX_AREA_SIZE bgt cpu_arm920_cache_clean_invalidate_all_r2 1: teq r2, #0 #ifdef CONFIG_CPU_DCACHE_WRITETHROUGH//无定义 mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry add r0, r0, #DCACHELINESIZE mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry add r0, r0, #DCACHELINESIZE #else mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry add r0, r0, #DCACHELINESIZE mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry add r0, r0, #DCACHELINESIZE #endif cmp r0, r1 blt 1b mcr p15, 0, r1, c7, c10, 4 @ drain WB mov pc, lr
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