苏州整站优化,公司名称标志设计,绵竹移动网站建设,图虫网官网入口这是内核自带的文档#xff0c;讲解ARM芯片的内存是如何布局的#xff01;比较简单#xff0c;对于初学者可以看一下#xff01;但要想深入理解Linux内存管理#xff0c;建议还是找几本好书看看#xff0c;如深入理解Linux虚拟内存#xff0c;嵌入系统分析#xff0c;L…这是内核自带的文档讲解ARM芯片的内存是如何布局的比较简单对于初学者可以看一下但要想深入理解Linux内存管理建议还是找几本好书看看如深入理解Linux虚拟内存嵌入系统分析Linux内核分析及程序设计等 Kernel Memory Layout on ARM Linux Linux在ARM平台上的内存布局 Russell King rmkarm.linux.org.uk November 17, 2005 (2.6.15) This document describes the virtual memory layout which the Linux kernel uses for ARM processors. It indicates which regions are free for platforms to use, and which are used by generic code. 本文档描述了Linux内核在ARM处理器上的虚拟内存布局。说明了哪些区域是给ARM平台使用的哪些区域是通用代码使用的。 The ARM CPU is capable of addressing a maximum of 4GB virtual memory space, and this must be shared between user space processes, the kernel, and hardware devices. ARM系列的CPU最大有4GB的虚拟内存空间寻址能力但它必须用户空间内存以及硬件设备共享地址空间。 As the ARM architecture matures, it becomes necessary to reserve certain regions of VM space for use for new facilities; therefore this document may reserve more VM space over time. 在ARM架构成熟的同时它也开始需要在VM空间保留明确的区域让用户使用更简单因此随着时间的流逝本文档可能保留了更多的VM空间。 Start开始地址 End结束地址 Use使用说明--------------------------------------------------------------------------ffff8000 ffffffff copy_user_page / clear_user_page use. For SA11xx and Xscale, this is used to setup a minicache mapping. copy_user_page/clear_user_page使用对于SA11XX和Xscal它用于设置机器映射。 ffff1000 ffff7fff Reserved. Platforms must not use this address range. 保留ARM平台一定不使用这个区间。 ffff0000 ffff0fff CPU vector page. CPU向量表 The CPU vectors are mapped here if the CPU supports vector relocation (control register V bit.) 如果CPU支持向量重定向控制寄存器的V位则CPU向量被映射到这里。 ffc00000 fffeffff DMA memory mapping region. Memory returned by the dma_alloc_xxx functions will be dynamically mapped here. DMA内存映射区间。由dma_ammoc_xxx系列函数返回的内存会动态的映射到这里。 ff000000 ffbfffff Reserved for future expansion of DMA mapping region. 保留用于以后的DMA扩展映射区间。 VMALLOC_END feffffff Free for platform use, recommended. 建议平台保留。 VMALLOC_END must be aligned to a 2MB boundary. VMALLOC_END必须在2MB的边界上对齐。 VMALLOC_START VMALLOC_END-1 vmalloc() / ioremap() space. vmalloc Memory returned by vmalloc/ioremap will be dynamically placed in this region. VMALLOC_START may be based upon the value of the high_memory variable. vmalloc/ioremap 函数返回的内存会被动态的放到该区间。VMALLOC_START 可能的值可能会基于high_memory变量的值而有所不同。 PAGE_OFFSET high_memory-1 Kernel direct-mapped RAM region. 内核直接映射内存区间。 This maps the platforms RAM, and typically maps all platform RAM in a 1:1 relationship. 它映射平台的RAM通常所有的平台都使用11的映射关系。 TASK_SIZE PAGE_OFFSET-1 Kernel module space Kernel modules inserted via insmod are placed here using dynamic mappings. 内核模块空间内核模块通过insmod命令加载会动态的映射到这里。 00001000 TASK_SIZE-1 User space mappings 用户空间 Per-thread mappings are placed here via the mmap() system call.每个进程通过mmap系统调用的映射放到这里。 00000000 00000fff CPU vector page / null pointer trap CPU向量表NULL指针陷井 CPUs which do not support vector remapping place their vector page here. NULL pointer dereferences by both the kernel and user space are also caught via this mapping. 不支持向量重映射的CPU的向量表被映射到这里。用户空间和内核态的NULL指针引通过这个映射可以被捕获。 Please note that mappings which collide with the above areas may resultin a non-bootable kernel, or may cause the kernel to (eventually) panicat run time. 请注意一些与上面冲突的映射会导致内核无法启动或者可能在运行时会产生最终内核panic ! Since future CPUs may impact the kernel mapping layout, user programsmust not access any memory which is not mapped inside their 0x0001000to TASK_SIZE address range. If they wish to access these areas, theymust set up their own mappings using open() and mmap(). 不管CPU特性会是否与内核的映射布局冲突用户程序在内部没有映射0x0001000到TASK_SIZE之间的地址空间时必须不能访问这里面的内存。如果他们想这样做那么他们必须通过open和mmap来创建自己的映射。转载于:https://www.cnblogs.com/xmphoenix/p/3627024.html
