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/*
* Routines for doing kexec-based kdump.
*
* Copyright (C) 2005, IBM Corp.
*
* Created by: Michael Ellerman
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#undef DEBUG
#include <linux/crash_dump.h>
#include <linux/bootmem.h>
#include <linux/lmb.h>
#include <asm/code-patching.h>
#include <asm/kdump.h>
#include <asm/prom.h>
#include <asm/firmware.h>
#include <asm/uaccess.h>
#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif
/* Stores the physical address of elf header of crash image. */
unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
void __init reserve_kdump_trampoline(void)
{
lmb_reserve(0, KDUMP_RESERVE_LIMIT);
}
static void __init create_trampoline(unsigned long addr)
{
unsigned int *p = (unsigned int *)addr;
/* The maximum range of a single instruction branch, is the current
* instruction's address + (32 MB - 4) bytes. For the trampoline we
* need to branch to current address + 32 MB. So we insert a nop at
* the trampoline address, then the next instruction (+ 4 bytes)
* does a branch to (32 MB - 4). The net effect is that when we
* branch to "addr" we jump to ("addr" + 32 MB). Although it requires
* two instructions it doesn't require any registers.
*/
patch_instruction(p, PPC_NOP_INSTR);
patch_branch(++p, addr + PHYSICAL_START, 0);
}
void __init setup_kdump_trampoline(void)
{
unsigned long i;
DBG(" -> setup_kdump_trampoline()\n");
for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) {
create_trampoline(i);
}
#ifdef CONFIG_PPC_PSERIES
create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START);
create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START);
#endif /* CONFIG_PPC_PSERIES */
DBG(" <- setup_kdump_trampoline()\n");
}
/*
* Note: elfcorehdr_addr is not just limited to vmcore. It is also used by
* is_kdump_kernel() to determine if we are booting after a panic. Hence
* ifdef it under CONFIG_CRASH_DUMP and not CONFIG_PROC_VMCORE.
*/
static int __init parse_elfcorehdr(char *p)
{
if (p)
elfcorehdr_addr = memparse(p, &p);
return 1;
}
__setup("elfcorehdr=", parse_elfcorehdr);
static int __init parse_savemaxmem(char *p)
{
if (p)
saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1;
return 1;
}
__setup("savemaxmem=", parse_savemaxmem);
static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize,
unsigned long offset, int userbuf)
{
if (userbuf) {
if (copy_to_user((char __user *)buf, (vaddr + offset), csize))
return -EFAULT;
} else
memcpy(buf, (vaddr + offset), csize);
return csize;
}
/**
* 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.
*/
ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
size_t csize, unsigned long offset, int userbuf)
{
void *vaddr;
if (!csize)
return 0;
csize = min(csize, PAGE_SIZE);
if (pfn < max_pfn) {
vaddr = __va(pfn << PAGE_SHIFT);
csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
} else {
vaddr = __ioremap(pfn << PAGE_SHIFT, PAGE_SIZE, 0);
csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
iounmap(vaddr);
}
return csize;
}
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