forked from Minki/linux
16c57b3620
Create a new header that becomes a single location for defining PowerPC opcodes used by code that is either generationg instructions at runtime (fixups, debug, etc.), emulating instructions, or just compiling instructions old assemblers don't know about. We currently don't handle the floating point emulation or alignment decode as both are better handled by the specific decode support they already have. Added support for the new dcbzl, dcbal, msgsnd, tlbilx, & wait instructions since older assemblers don't know about them. Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
144 lines
3.8 KiB
C
144 lines
3.8 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 <linux/lmb.h>
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#include <asm/code-patching.h>
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#include <asm/kdump.h>
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#include <asm/prom.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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/* Stores the physical address of elf header of crash image. */
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unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
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#ifndef CONFIG_RELOCATABLE
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void __init reserve_kdump_trampoline(void)
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{
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lmb_reserve(0, KDUMP_RESERVE_LIMIT);
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}
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static void __init create_trampoline(unsigned long addr)
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{
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unsigned int *p = (unsigned int *)addr;
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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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patch_instruction(p, PPC_INST_NOP);
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patch_branch(++p, addr + PHYSICAL_START, 0);
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}
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void __init setup_kdump_trampoline(void)
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{
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unsigned long i;
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DBG(" -> setup_kdump_trampoline()\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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#ifdef CONFIG_PPC_PSERIES
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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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#endif /* CONFIG_PPC_PSERIES */
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DBG(" <- setup_kdump_trampoline()\n");
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}
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#endif /* CONFIG_RELOCATABLE */
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/*
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* Note: elfcorehdr_addr is not just limited to vmcore. It is also used by
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* is_kdump_kernel() to determine if we are booting after a panic. Hence
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* ifdef it under CONFIG_CRASH_DUMP and not CONFIG_PROC_VMCORE.
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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 1;
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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 1;
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}
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__setup("savemaxmem=", parse_savemaxmem);
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static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize,
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unsigned long offset, int userbuf)
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{
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if (userbuf) {
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if (copy_to_user((char __user *)buf, (vaddr + offset), csize))
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return -EFAULT;
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} else
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memcpy(buf, (vaddr + offset), csize);
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return csize;
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}
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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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csize = min(csize, PAGE_SIZE);
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if (pfn < max_pfn) {
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vaddr = __va(pfn << PAGE_SHIFT);
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csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
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} else {
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vaddr = __ioremap(pfn << PAGE_SHIFT, PAGE_SIZE, 0);
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csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
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iounmap(vaddr);
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}
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return csize;
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}
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