]>
git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - arch/mips/kernel/crash_dump.c
1 #include <linux/highmem.h>
2 #include <linux/bootmem.h>
3 #include <linux/crash_dump.h>
4 #include <linux/uaccess.h>
5 #include <linux/slab.h>
7 static void *kdump_buf_page
;
10 * copy_oldmem_page - copy one page from "oldmem"
11 * @pfn: page frame number to be copied
12 * @buf: target memory address for the copy; this can be in kernel address
13 * space or user address space (see @userbuf)
14 * @csize: number of bytes to copy
15 * @offset: offset in bytes into the page (based on pfn) to begin the copy
16 * @userbuf: if set, @buf is in user address space, use copy_to_user(),
17 * otherwise @buf is in kernel address space, use memcpy().
19 * Copy a page from "oldmem". For this page, there is no pte mapped
20 * in the current kernel.
22 * Calling copy_to_user() in atomic context is not desirable. Hence first
23 * copying the data to a pre-allocated kernel page and then copying to user
24 * space in non-atomic context.
26 ssize_t
copy_oldmem_page(unsigned long pfn
, char *buf
,
27 size_t csize
, unsigned long offset
, int userbuf
)
34 vaddr
= kmap_atomic_pfn(pfn
);
37 memcpy(buf
, (vaddr
+ offset
), csize
);
40 if (!kdump_buf_page
) {
41 pr_warn("Kdump: Kdump buffer page not allocated\n");
45 copy_page(kdump_buf_page
, vaddr
);
47 if (copy_to_user(buf
, (kdump_buf_page
+ offset
), csize
))
54 static int __init
kdump_buf_page_init(void)
58 kdump_buf_page
= kmalloc(PAGE_SIZE
, GFP_KERNEL
);
59 if (!kdump_buf_page
) {
60 pr_warn("Kdump: Failed to allocate kdump buffer page\n");
66 arch_initcall(kdump_buf_page_init
);