linux/arch/mips/kernel/crash_dump.c
Zhang Yanfei db9ab97d9d mips: remove savemaxmem parameter setup
saved_max_pfn is used to know the amount of memory that the previous
kernel used.  And for powerpc, we set saved_max_pfn by passing the kernel
commandline parameter "savemaxmem=".

The only user of saved_max_pfn in mips is read_oldmem interface.  Since we
have removed read_oldmem, so we don't need this parameter anymore.

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:08:03 -07:00

67 lines
1.7 KiB
C

#include <linux/highmem.h>
#include <linux/bootmem.h>
#include <linux/crash_dump.h>
#include <asm/uaccess.h>
#include <linux/slab.h>
static void *kdump_buf_page;
/**
* 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.
*
* 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;
vaddr = kmap_atomic_pfn(pfn);
if (!userbuf) {
memcpy(buf, (vaddr + offset), csize);
kunmap_atomic(vaddr);
} else {
if (!kdump_buf_page) {
pr_warning("Kdump: Kdump buffer page not allocated\n");
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;
}
static int __init kdump_buf_page_init(void)
{
int ret = 0;
kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!kdump_buf_page) {
pr_warning("Kdump: Failed to allocate kdump buffer page\n");
ret = -ENOMEM;
}
return ret;
}
arch_initcall(kdump_buf_page_init);