Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) #include <linux/highmem.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) #include <linux/memblock.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) #include <linux/crash_dump.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) static void *kdump_buf_page;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11)  * copy_oldmem_page - copy one page from "oldmem"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)  * @pfn: page frame number to be copied
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13)  * @buf: target memory address for the copy; this can be in kernel address
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)  *	space or user address space (see @userbuf)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)  * @csize: number of bytes to copy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16)  * @offset: offset in bytes into the page (based on pfn) to begin the copy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)  * @userbuf: if set, @buf is in user address space, use copy_to_user(),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)  *	otherwise @buf is in kernel address space, use memcpy().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)  * Copy a page from "oldmem". For this page, there is no pte mapped
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)  * in the current kernel.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)  * Calling copy_to_user() in atomic context is not desirable. Hence first
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)  * copying the data to a pre-allocated kernel page and then copying to user
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)  * space in non-atomic context.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 			 size_t csize, unsigned long offset, int userbuf)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 	void  *vaddr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 	if (!csize)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 	vaddr = kmap_atomic_pfn(pfn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 	if (!userbuf) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 		memcpy(buf, (vaddr + offset), csize);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 		kunmap_atomic(vaddr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 		if (!kdump_buf_page) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 			pr_warn("Kdump: Kdump buffer page not allocated\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 			return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 		copy_page(kdump_buf_page, vaddr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) 		kunmap_atomic(vaddr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) 		if (copy_to_user(buf, (kdump_buf_page + offset), csize))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 			return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 	return csize;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) static int __init kdump_buf_page_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) 	int ret = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) 	kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) 	if (!kdump_buf_page) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) 		pr_warn("Kdump: Failed to allocate kdump buffer page\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) 		ret = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) arch_initcall(kdump_buf_page_init);