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/abs_lowcore.h> 17 #include <asm/os_info.h> 18 #include <asm/physmem_info.h> 19 #include <asm/maccess.h> 20 #include <asm/asm-offsets.h> 21 22 /* 23 * OS info structure has to be page aligned 24 */ 25 static struct os_info os_info __page_aligned_data; 26 27 /* 28 * Compute checksum over OS info structure 29 */ 30 u32 os_info_csum(struct os_info *os_info) 31 { 32 int size = sizeof(*os_info) - offsetof(struct os_info, version_major); 33 return (__force u32)cksm(&os_info->version_major, size, 0); 34 } 35 36 /* 37 * Add crashkernel info to OS info and update checksum 38 */ 39 void os_info_crashkernel_add(unsigned long base, unsigned long size) 40 { 41 os_info.crashkernel_addr = (u64)(unsigned long)base; 42 os_info.crashkernel_size = (u64)(unsigned long)size; 43 os_info.csum = os_info_csum(&os_info); 44 } 45 46 /* 47 * Add OS info data entry and update checksum 48 */ 49 void os_info_entry_add_data(int nr, void *ptr, u64 size) 50 { 51 os_info.entry[nr].addr = __pa(ptr); 52 os_info.entry[nr].size = size; 53 os_info.entry[nr].csum = (__force u32)cksm(ptr, size, 0); 54 os_info.csum = os_info_csum(&os_info); 55 } 56 57 /* 58 * Add OS info value entry and update checksum 59 */ 60 void os_info_entry_add_val(int nr, u64 value) 61 { 62 os_info.entry[nr].val = value; 63 os_info.entry[nr].size = 0; 64 os_info.entry[nr].csum = 0; 65 os_info.csum = os_info_csum(&os_info); 66 } 67 68 /* 69 * Initialize OS info structure and set lowcore pointer 70 */ 71 void __init os_info_init(void) 72 { 73 struct lowcore *abs_lc; 74 75 os_info.version_major = OS_INFO_VERSION_MAJOR; 76 os_info.version_minor = OS_INFO_VERSION_MINOR; 77 os_info.magic = OS_INFO_MAGIC; 78 os_info_entry_add_val(OS_INFO_IDENTITY_BASE, __identity_base); 79 os_info_entry_add_val(OS_INFO_KASLR_OFFSET, kaslr_offset()); 80 os_info_entry_add_val(OS_INFO_KASLR_OFF_PHYS, __kaslr_offset_phys); 81 os_info_entry_add_val(OS_INFO_VMEMMAP, (unsigned long)vmemmap); 82 os_info_entry_add_val(OS_INFO_AMODE31_START, AMODE31_START); 83 os_info_entry_add_val(OS_INFO_AMODE31_END, AMODE31_END); 84 os_info_entry_add_val(OS_INFO_IMAGE_START, (unsigned long)_stext); 85 os_info_entry_add_val(OS_INFO_IMAGE_END, (unsigned long)_end); 86 os_info_entry_add_val(OS_INFO_IMAGE_PHYS, __pa_symbol(_stext)); 87 os_info.csum = os_info_csum(&os_info); 88 abs_lc = get_abs_lowcore(); 89 abs_lc->os_info = __pa(&os_info); 90 put_abs_lowcore(abs_lc); 91 } 92 93 #ifdef CONFIG_CRASH_DUMP 94 95 static struct os_info *os_info_old; 96 97 /* 98 * Allocate and copy OS info entry from oldmem 99 */ 100 static void os_info_old_alloc(int nr, int align) 101 { 102 unsigned long addr, size = 0; 103 char *buf, *buf_align, *msg; 104 u32 csum; 105 106 addr = os_info_old->entry[nr].addr; 107 if (!addr) { 108 msg = "not available"; 109 goto fail; 110 } 111 size = os_info_old->entry[nr].size; 112 buf = kmalloc(size + align - 1, GFP_KERNEL); 113 if (!buf) { 114 msg = "alloc failed"; 115 goto fail; 116 } 117 buf_align = PTR_ALIGN(buf, align); 118 if (copy_oldmem_kernel(buf_align, addr, size)) { 119 msg = "copy failed"; 120 goto fail_free; 121 } 122 csum = (__force u32)cksm(buf_align, size, 0); 123 if (csum != os_info_old->entry[nr].csum) { 124 msg = "checksum failed"; 125 goto fail_free; 126 } 127 os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align; 128 msg = "copied"; 129 goto out; 130 fail_free: 131 kfree(buf); 132 fail: 133 os_info_old->entry[nr].addr = 0; 134 out: 135 pr_info("entry %i: %s (addr=0x%lx size=%lu)\n", 136 nr, msg, addr, size); 137 } 138 139 /* 140 * Initialize os info and os info entries from oldmem 141 */ 142 static void os_info_old_init(void) 143 { 144 static int os_info_init; 145 unsigned long addr; 146 147 if (os_info_init) 148 return; 149 if (!oldmem_data.start) 150 goto fail; 151 if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr))) 152 goto fail; 153 if (addr == 0 || addr % PAGE_SIZE) 154 goto fail; 155 os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL); 156 if (!os_info_old) 157 goto fail; 158 if (copy_oldmem_kernel(os_info_old, addr, sizeof(*os_info_old))) 159 goto fail_free; 160 if (os_info_old->magic != OS_INFO_MAGIC) 161 goto fail_free; 162 if (os_info_old->csum != os_info_csum(os_info_old)) 163 goto fail_free; 164 if (os_info_old->version_major > OS_INFO_VERSION_MAJOR) 165 goto fail_free; 166 os_info_old_alloc(OS_INFO_VMCOREINFO, 1); 167 os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1); 168 pr_info("crashkernel: addr=0x%lx size=%lu\n", 169 (unsigned long) os_info_old->crashkernel_addr, 170 (unsigned long) os_info_old->crashkernel_size); 171 os_info_init = 1; 172 return; 173 fail_free: 174 kfree(os_info_old); 175 fail: 176 os_info_init = 1; 177 os_info_old = NULL; 178 } 179 180 /* 181 * Return pointer to os infor entry and its size 182 */ 183 void *os_info_old_entry(int nr, unsigned long *size) 184 { 185 os_info_old_init(); 186 187 if (!os_info_old) 188 return NULL; 189 if (!os_info_old->entry[nr].addr) 190 return NULL; 191 *size = (unsigned long) os_info_old->entry[nr].size; 192 return (void *)(unsigned long)os_info_old->entry[nr].addr; 193 } 194 #endif 195