函数源码 |
Source File:arch\x86\kernel\crash_dump_32.c |
Create Date:2022-07-27 09:37:12 |
首页 | Copyright©Brick |
33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 | /** * copy_oldmem_page - copy one page from "oldmem" * @pfn: page frame number to be copied * @buf: target memory address for the copy; this can be in kernel address * space or user address space (see @userbuf) * @csize: number of bytes to copy * @offset: offset in bytes into the page (based on pfn) to begin the copy * @userbuf: if set, @buf is in user address space, use copy_to_user(), * otherwise @buf is in kernel address space, use memcpy(). * * Copy a page from "oldmem". For this page, there is no pte mapped * in the current kernel. We stitch up a pte, similar to kmap_atomic. * * Calling copy_to_user() in atomic context is not desirable. Hence first * copying the data to a pre-allocated kernel page and then copying to user * space in non-atomic context. */ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, unsigned long offset, int userbuf) { void *vaddr; if (!csize) return 0; if (!is_crashed_pfn_valid(pfn)) return -EFAULT; vaddr = kmap_atomic_pfn(pfn); if (!userbuf) { memcpy (buf, (vaddr + offset), csize); kunmap_atomic(vaddr); } else { if (!kdump_buf_page) { printk(KERN_WARNING "Kdump: Kdump buffer page not" " allocated\n" ); kunmap_atomic(vaddr); return -EFAULT; } copy_page(kdump_buf_page, vaddr); kunmap_atomic(vaddr); if (copy_to_user(buf, (kdump_buf_page + offset), csize)) return -EFAULT; } return csize; } |