/* * 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/memblock.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; #ifndef CONFIG_RELOCATABLE void __init reserve_kdump_trampoline(void) { memblock_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_INST_NOP); 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"); } #endif /* CONFIG_RELOCATABLE */ /* * 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_t(size_t, csize, PAGE_SIZE); if ((min_low_pfn < pfn) && (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; }