如何在 Linux 中解码/proc/pid/pagemap 条目? [英] How to decode /proc/pid/pagemap entries in Linux?
问题描述
我正在尝试破解如何使用/proc/pid/pagemap 来获取给定页面集的物理地址.假设从/proc/pid/maps 中，我得到了对应于堆的虚拟地址 afa2d000-afa42000.我的问题是如何使用此信息遍历页面映射文件并找到与地址 afa2d000-afa42000 对应的物理页框.
I am trying to decipher how to use /proc/pid/pagemap to get the physical address of a given set of pages. Suppose from the /proc/pid/maps, I get the virtual address afa2d000-afa42000 which corresponds to the heap. My question is how do I use this info to traverse the pagemap file and find the physical page frames correspond to the address afa2d000-afa42000.
/proc/pid/pagemap 条目是二进制格式.有什么工具可以帮助解析这个文件吗?
The /proc/pid/pagemap entry is in binary format. Is there any tools to help parsing of this file?
推荐答案
试试这个http://www.eqware.net/Articles/CapturingProcessMemoryUsageUnderLinux/它可以为您解析页面映射，例如，如果虚拟地址您感兴趣的是堆 0x055468 := 0004c000-0005a000 rw-p 00000000 00:00 0 [堆]: 86000000000FD6D6: 0600000000000000
: 0600000000000000
: 86000000000FE921
: 86000000000FE922
: 0600000000000000
: 86000000000FD5AD
: 86000000000FD6D4
: 86000000000FD5F8
: 86000000000FD5FA =>9
Try this
http://www.eqware.net/Articles/CapturingProcessMemoryUsageUnderLinux/
It can parse the pagemap for you, for example, if the virtual address
you are interested is in the heap which is 0x055468 :
= 0004c000-0005a000 rw-p 00000000 00:00 0 [heap]
: 86000000000FD6D6
: 0600000000000000
: 0600000000000000
: 86000000000FE921
: 86000000000FE922
: 0600000000000000
: 86000000000FD5AD
: 86000000000FD6D4
: 86000000000FD5F8
: 86000000000FD5FA =>9th
假设页面大小为 4KB，并且(0x055468 - 0x4c000) mod 4K = 9,所以你页面的页框号是第9个页框==>:86000000000FD5FA所以物理 pfn 是 0xFD5FA000(取最后 55 位和页面大小的倍数)加上偏移量:(0x055468 - 0x4c000 - 9*4K)= 0x468==> 物理地址为 0xFD5FA000 + 0x468 = 0xFD5FA468
Suppose the page size as 4KB, and (0x055468 - 0x4c000) mod 4K = 9, So the page frame number of your page is the 9th page frames ==> : 86000000000FD5FA So the physical pfn is 0xFD5FA000 (take the last 55 bits and times page size) plus the offset: ( 0x055468 - 0x4c000 - 9*4K) = 0x468 ==> the physical addr is 0xFD5FA000 + 0x468 = 0xFD5FA468
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