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浅析armlinux-setup_arch()->paging_init()函数5
文章来源:http://gliethttp.cublog.cn
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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