1 /* 2 * Routines for doing kexec-based kdump. 3 * 4 * Copyright (C) 2005, IBM Corp. 5 * 6 * Created by: Michael Ellerman 7 * 8 * This source code is licensed under the GNU General Public License, 9 * Version 2. See the file COPYING for more details. 10 */ 11 12 #undef DEBUG 13 14 #include <linux/crash_dump.h> 15 #include <linux/bootmem.h> 16 #include <linux/io.h> 17 #include <linux/memblock.h> 18 #include <asm/code-patching.h> 19 #include <asm/kdump.h> 20 #include <asm/prom.h> 21 #include <asm/firmware.h> 22 #include <asm/uaccess.h> 23 #include <asm/rtas.h> 24 25 #ifdef DEBUG 26 #include <asm/udbg.h> 27 #define DBG(fmt...) udbg_printf(fmt) 28 #else 29 #define DBG(fmt...) 30 #endif 31 32 #ifndef CONFIG_NONSTATIC_KERNEL 33 void __init reserve_kdump_trampoline(void) 34 { 35 memblock_reserve(0, KDUMP_RESERVE_LIMIT); 36 } 37 38 static void __init create_trampoline(unsigned long addr) 39 { 40 unsigned int *p = (unsigned int *)addr; 41 42 /* The maximum range of a single instruction branch, is the current 43 * instruction's address + (32 MB - 4) bytes. For the trampoline we 44 * need to branch to current address + 32 MB. So we insert a nop at 45 * the trampoline address, then the next instruction (+ 4 bytes) 46 * does a branch to (32 MB - 4). The net effect is that when we 47 * branch to "addr" we jump to ("addr" + 32 MB). Although it requires 48 * two instructions it doesn't require any registers. 49 */ 50 patch_instruction(p, PPC_INST_NOP); 51 patch_branch(++p, addr + PHYSICAL_START, 0); 52 } 53 54 void __init setup_kdump_trampoline(void) 55 { 56 unsigned long i; 57 58 DBG(" -> setup_kdump_trampoline()\n"); 59 60 for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) { 61 create_trampoline(i); 62 } 63 64 #ifdef CONFIG_PPC_PSERIES 65 create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START); 66 create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START); 67 #endif /* CONFIG_PPC_PSERIES */ 68 69 DBG(" <- setup_kdump_trampoline()\n"); 70 } 71 #endif /* CONFIG_NONSTATIC_KERNEL */ 72 73 static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize, 74 unsigned long offset, int userbuf) 75 { 76 if (userbuf) { 77 if (copy_to_user((char __user *)buf, (vaddr + offset), csize)) 78 return -EFAULT; 79 } else 80 memcpy(buf, (vaddr + offset), csize); 81 82 return csize; 83 } 84 85 /** 86 * copy_oldmem_page - copy one page from "oldmem" 87 * @pfn: page frame number to be copied 88 * @buf: target memory address for the copy; this can be in kernel address 89 * space or user address space (see @userbuf) 90 * @csize: number of bytes to copy 91 * @offset: offset in bytes into the page (based on pfn) to begin the copy 92 * @userbuf: if set, @buf is in user address space, use copy_to_user(), 93 * otherwise @buf is in kernel address space, use memcpy(). 94 * 95 * Copy a page from "oldmem". For this page, there is no pte mapped 96 * in the current kernel. We stitch up a pte, similar to kmap_atomic. 97 */ 98 ssize_t copy_oldmem_page(unsigned long pfn, char *buf, 99 size_t csize, unsigned long offset, int userbuf) 100 { 101 void *vaddr; 102 phys_addr_t paddr; 103 104 if (!csize) 105 return 0; 106 107 csize = min_t(size_t, csize, PAGE_SIZE); 108 paddr = pfn << PAGE_SHIFT; 109 110 if (memblock_is_region_memory(paddr, csize)) { 111 vaddr = __va(paddr); 112 csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); 113 } else { 114 vaddr = __ioremap(paddr, PAGE_SIZE, 0); 115 csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); 116 iounmap(vaddr); 117 } 118 119 return csize; 120 } 121 122 #ifdef CONFIG_PPC_RTAS 123 /* 124 * The crashkernel region will almost always overlap the RTAS region, so 125 * we have to be careful when shrinking the crashkernel region. 126 */ 127 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 128 { 129 unsigned long addr; 130 const __be32 *basep, *sizep; 131 unsigned int rtas_start = 0, rtas_end = 0; 132 133 basep = of_get_property(rtas.dev, "linux,rtas-base", NULL); 134 sizep = of_get_property(rtas.dev, "rtas-size", NULL); 135 136 if (basep && sizep) { 137 rtas_start = be32_to_cpup(basep); 138 rtas_end = rtas_start + be32_to_cpup(sizep); 139 } 140 141 for (addr = begin; addr < end; addr += PAGE_SIZE) { 142 /* Does this page overlap with the RTAS region? */ 143 if (addr <= rtas_end && ((addr + PAGE_SIZE) > rtas_start)) 144 continue; 145 146 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 147 } 148 } 149 #endif 150