1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * OS info memory interface 4 * 5 * Copyright IBM Corp. 2012 6 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com> 7 */ 8 9 #define KMSG_COMPONENT "os_info" 10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 11 12 #include <linux/crash_dump.h> 13 #include <linux/kernel.h> 14 #include <linux/slab.h> 15 #include <asm/checksum.h> 16 #include <asm/lowcore.h> 17 #include <asm/os_info.h> 18 #include <asm/asm-offsets.h> 19 20 /* 21 * OS info structure has to be page aligned 22 */ 23 static struct os_info os_info __page_aligned_data; 24 25 /* 26 * Compute checksum over OS info structure 27 */ 28 u32 os_info_csum(struct os_info *os_info) 29 { 30 int size = sizeof(*os_info) - offsetof(struct os_info, version_major); 31 return (__force u32)csum_partial(&os_info->version_major, size, 0); 32 } 33 34 /* 35 * Add crashkernel info to OS info and update checksum 36 */ 37 void os_info_crashkernel_add(unsigned long base, unsigned long size) 38 { 39 os_info.crashkernel_addr = (u64)(unsigned long)base; 40 os_info.crashkernel_size = (u64)(unsigned long)size; 41 os_info.csum = os_info_csum(&os_info); 42 } 43 44 /* 45 * Add OS info entry and update checksum 46 */ 47 void os_info_entry_add(int nr, void *ptr, u64 size) 48 { 49 os_info.entry[nr].addr = __pa(ptr); 50 os_info.entry[nr].size = size; 51 os_info.entry[nr].csum = (__force u32)csum_partial(ptr, size, 0); 52 os_info.csum = os_info_csum(&os_info); 53 } 54 55 /* 56 * Initialize OS info structure and set lowcore pointer 57 */ 58 void __init os_info_init(void) 59 { 60 void *ptr = &os_info; 61 62 os_info.version_major = OS_INFO_VERSION_MAJOR; 63 os_info.version_minor = OS_INFO_VERSION_MINOR; 64 os_info.magic = OS_INFO_MAGIC; 65 os_info.csum = os_info_csum(&os_info); 66 put_abs_lowcore(os_info, __pa(ptr)); 67 } 68 69 #ifdef CONFIG_CRASH_DUMP 70 71 static struct os_info *os_info_old; 72 73 /* 74 * Allocate and copy OS info entry from oldmem 75 */ 76 static void os_info_old_alloc(int nr, int align) 77 { 78 unsigned long addr, size = 0; 79 char *buf, *buf_align, *msg; 80 u32 csum; 81 82 addr = os_info_old->entry[nr].addr; 83 if (!addr) { 84 msg = "not available"; 85 goto fail; 86 } 87 size = os_info_old->entry[nr].size; 88 buf = kmalloc(size + align - 1, GFP_KERNEL); 89 if (!buf) { 90 msg = "alloc failed"; 91 goto fail; 92 } 93 buf_align = PTR_ALIGN(buf, align); 94 if (copy_oldmem_kernel(buf_align, addr, size)) { 95 msg = "copy failed"; 96 goto fail_free; 97 } 98 csum = (__force u32)csum_partial(buf_align, size, 0); 99 if (csum != os_info_old->entry[nr].csum) { 100 msg = "checksum failed"; 101 goto fail_free; 102 } 103 os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align; 104 msg = "copied"; 105 goto out; 106 fail_free: 107 kfree(buf); 108 fail: 109 os_info_old->entry[nr].addr = 0; 110 out: 111 pr_info("entry %i: %s (addr=0x%lx size=%lu)\n", 112 nr, msg, addr, size); 113 } 114 115 /* 116 * Initialize os info and os info entries from oldmem 117 */ 118 static void os_info_old_init(void) 119 { 120 static int os_info_init; 121 unsigned long addr; 122 123 if (os_info_init) 124 return; 125 if (!oldmem_data.start) 126 goto fail; 127 if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr))) 128 goto fail; 129 if (addr == 0 || addr % PAGE_SIZE) 130 goto fail; 131 os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL); 132 if (!os_info_old) 133 goto fail; 134 if (copy_oldmem_kernel(os_info_old, addr, sizeof(*os_info_old))) 135 goto fail_free; 136 if (os_info_old->magic != OS_INFO_MAGIC) 137 goto fail_free; 138 if (os_info_old->csum != os_info_csum(os_info_old)) 139 goto fail_free; 140 if (os_info_old->version_major > OS_INFO_VERSION_MAJOR) 141 goto fail_free; 142 os_info_old_alloc(OS_INFO_VMCOREINFO, 1); 143 os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1); 144 pr_info("crashkernel: addr=0x%lx size=%lu\n", 145 (unsigned long) os_info_old->crashkernel_addr, 146 (unsigned long) os_info_old->crashkernel_size); 147 os_info_init = 1; 148 return; 149 fail_free: 150 kfree(os_info_old); 151 fail: 152 os_info_init = 1; 153 os_info_old = NULL; 154 } 155 156 /* 157 * Return pointer to os infor entry and its size 158 */ 159 void *os_info_old_entry(int nr, unsigned long *size) 160 { 161 os_info_old_init(); 162 163 if (!os_info_old) 164 return NULL; 165 if (!os_info_old->entry[nr].addr) 166 return NULL; 167 *size = (unsigned long) os_info_old->entry[nr].size; 168 return (void *)(unsigned long)os_info_old->entry[nr].addr; 169 } 170 #endif 171