mirror of https://gitee.com/openkylin/linux.git
110 lines
2.8 KiB
C
110 lines
2.8 KiB
C
/*
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* Routines for doing kexec-based kdump.
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*
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* Copyright (C) 2005, IBM Corp.
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*
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* Created by: Michael Ellerman
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#undef DEBUG
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#include <linux/crash_dump.h>
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#include <linux/bootmem.h>
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#include <asm/kdump.h>
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#include <asm/lmb.h>
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#include <asm/firmware.h>
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#include <asm/uaccess.h>
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#ifdef DEBUG
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#include <asm/udbg.h>
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#define DBG(fmt...) udbg_printf(fmt)
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#else
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#define DBG(fmt...)
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#endif
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static void __init create_trampoline(unsigned long addr)
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{
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/* The maximum range of a single instruction branch, is the current
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* instruction's address + (32 MB - 4) bytes. For the trampoline we
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* need to branch to current address + 32 MB. So we insert a nop at
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* the trampoline address, then the next instruction (+ 4 bytes)
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* does a branch to (32 MB - 4). The net effect is that when we
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* branch to "addr" we jump to ("addr" + 32 MB). Although it requires
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* two instructions it doesn't require any registers.
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*/
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create_instruction(addr, 0x60000000); /* nop */
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create_branch(addr + 4, addr + PHYSICAL_START, 0);
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}
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void __init kdump_setup(void)
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{
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unsigned long i;
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DBG(" -> kdump_setup()\n");
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for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) {
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create_trampoline(i);
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}
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create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START);
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create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START);
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DBG(" <- kdump_setup()\n");
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}
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static int __init parse_elfcorehdr(char *p)
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{
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if (p)
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elfcorehdr_addr = memparse(p, &p);
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return 0;
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}
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__setup("elfcorehdr=", parse_elfcorehdr);
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static int __init parse_savemaxmem(char *p)
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{
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if (p)
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saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1;
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return 0;
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}
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__setup("savemaxmem=", parse_savemaxmem);
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/*
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* copy_oldmem_page - copy one page from "oldmem"
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* @pfn: page frame number to be copied
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* @buf: target memory address for the copy; this can be in kernel address
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* space or user address space (see @userbuf)
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* @csize: number of bytes to copy
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* @offset: offset in bytes into the page (based on pfn) to begin the copy
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* @userbuf: if set, @buf is in user address space, use copy_to_user(),
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* otherwise @buf is in kernel address space, use memcpy().
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*
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* Copy a page from "oldmem". For this page, there is no pte mapped
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* in the current kernel. We stitch up a pte, similar to kmap_atomic.
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*/
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ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
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size_t csize, unsigned long offset, int userbuf)
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{
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void *vaddr;
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if (!csize)
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return 0;
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vaddr = __ioremap(pfn << PAGE_SHIFT, PAGE_SIZE, 0);
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if (userbuf) {
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if (copy_to_user((char __user *)buf, (vaddr + offset), csize)) {
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iounmap(vaddr);
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return -EFAULT;
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}
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} else
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memcpy(buf, (vaddr + offset), csize);
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iounmap(vaddr);
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return csize;
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}
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