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 #include <asm/sections.h> 22 #include <asm/ipl.h> 23 24 /* 25 * OS info structure has to be page aligned 26 */ 27 static struct os_info os_info __page_aligned_data; 28 29 /* 30 * Compute checksum over OS info structure 31 */ 32 u32 os_info_csum(struct os_info *os_info) 33 { 34 int size = sizeof(*os_info) - offsetof(struct os_info, version_major); 35 return (__force u32)cksm(&os_info->version_major, size, 0); 36 } 37 38 /* 39 * Add crashkernel info to OS info and update checksum 40 */ 41 void os_info_crashkernel_add(unsigned long base, unsigned long size) 42 { 43 os_info.crashkernel_addr = (u64)(unsigned long)base; 44 os_info.crashkernel_size = (u64)(unsigned long)size; 45 os_info.csum = os_info_csum(&os_info); 46 } 47 48 /* 49 * Add OS info data entry and update checksum 50 */ 51 void os_info_entry_add_data(int nr, void *ptr, u64 size) 52 { 53 os_info.entry[nr].addr = __pa(ptr); 54 os_info.entry[nr].size = size; 55 os_info.entry[nr].csum = (__force u32)cksm(ptr, size, 0); 56 os_info.csum = os_info_csum(&os_info); 57 } 58 59 /* 60 * Add OS info value entry and update checksum 61 */ 62 void os_info_entry_add_val(int nr, u64 value) 63 { 64 os_info.entry[nr].val = value; 65 os_info.entry[nr].size = 0; 66 os_info.entry[nr].csum = 0; 67 os_info.csum = os_info_csum(&os_info); 68 } 69 70 /* 71 * Initialize OS info structure and set lowcore pointer 72 */ 73 void __init os_info_init(void) 74 { 75 struct lowcore *abs_lc; 76 77 BUILD_BUG_ON(sizeof(struct os_info) != PAGE_SIZE); 78 os_info.version_major = OS_INFO_VERSION_MAJOR; 79 os_info.version_minor = OS_INFO_VERSION_MINOR; 80 os_info.magic = OS_INFO_MAGIC; 81 os_info_entry_add_val(OS_INFO_IDENTITY_BASE, __identity_base); 82 os_info_entry_add_val(OS_INFO_KASLR_OFFSET, kaslr_offset()); 83 os_info_entry_add_val(OS_INFO_KASLR_OFF_PHYS, __kaslr_offset_phys); 84 os_info_entry_add_val(OS_INFO_VMEMMAP, (unsigned long)vmemmap); 85 os_info_entry_add_val(OS_INFO_AMODE31_START, AMODE31_START); 86 os_info_entry_add_val(OS_INFO_AMODE31_END, AMODE31_END); 87 os_info_entry_add_val(OS_INFO_IMAGE_START, (unsigned long)_stext); 88 os_info_entry_add_val(OS_INFO_IMAGE_END, (unsigned long)_end); 89 os_info_entry_add_val(OS_INFO_IMAGE_PHYS, __pa_symbol(_stext)); 90 os_info.csum = os_info_csum(&os_info); 91 abs_lc = get_abs_lowcore(); 92 abs_lc->os_info = __pa(&os_info); 93 put_abs_lowcore(abs_lc); 94 } 95 96 #ifdef CONFIG_CRASH_DUMP 97 98 static struct os_info *os_info_old; 99 100 /* 101 * Allocate and copy OS info entry from oldmem 102 */ 103 static void os_info_old_alloc(int nr, int align) 104 { 105 unsigned long addr, size = 0; 106 char *buf, *buf_align, *msg; 107 u32 csum; 108 109 addr = os_info_old->entry[nr].addr; 110 if (!addr) { 111 msg = "not available"; 112 goto fail; 113 } 114 size = os_info_old->entry[nr].size; 115 buf = kmalloc(size + align - 1, GFP_KERNEL); 116 if (!buf) { 117 msg = "alloc failed"; 118 goto fail; 119 } 120 buf_align = PTR_ALIGN(buf, align); 121 if (copy_oldmem_kernel(buf_align, addr, size)) { 122 msg = "copy failed"; 123 goto fail_free; 124 } 125 csum = (__force u32)cksm(buf_align, size, 0); 126 if (csum != os_info_old->entry[nr].csum) { 127 msg = "checksum failed"; 128 goto fail_free; 129 } 130 os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align; 131 msg = "copied"; 132 goto out; 133 fail_free: 134 kfree(buf); 135 fail: 136 os_info_old->entry[nr].addr = 0; 137 out: 138 pr_info("entry %i: %s (addr=0x%lx size=%lu)\n", 139 nr, msg, addr, size); 140 } 141 142 /* 143 * Initialize os info and os info entries from oldmem 144 */ 145 static void os_info_old_init(void) 146 { 147 static int os_info_init; 148 unsigned long addr; 149 150 if (os_info_init) 151 return; 152 if (!oldmem_data.start && !is_ipl_type_dump()) 153 goto fail; 154 if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr))) 155 goto fail; 156 if (addr == 0 || addr % PAGE_SIZE) 157 goto fail; 158 os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL); 159 if (!os_info_old) 160 goto fail; 161 if (copy_oldmem_kernel(os_info_old, addr, sizeof(*os_info_old))) 162 goto fail_free; 163 if (os_info_old->magic != OS_INFO_MAGIC) 164 goto fail_free; 165 if (os_info_old->csum != os_info_csum(os_info_old)) 166 goto fail_free; 167 if (os_info_old->version_major > OS_INFO_VERSION_MAJOR) 168 goto fail_free; 169 os_info_old_alloc(OS_INFO_VMCOREINFO, 1); 170 os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1); 171 pr_info("crashkernel: addr=0x%lx size=%lu\n", 172 (unsigned long) os_info_old->crashkernel_addr, 173 (unsigned long) os_info_old->crashkernel_size); 174 os_info_init = 1; 175 return; 176 fail_free: 177 kfree(os_info_old); 178 fail: 179 os_info_init = 1; 180 os_info_old = NULL; 181 } 182 183 /* 184 * Return pointer to os info entry and its size 185 */ 186 void *os_info_old_entry(int nr, unsigned long *size) 187 { 188 os_info_old_init(); 189 190 if (!os_info_old) 191 return NULL; 192 if (!os_info_old->entry[nr].addr) 193 return NULL; 194 *size = (unsigned long) os_info_old->entry[nr].size; 195 return (void *)(unsigned long)os_info_old->entry[nr].addr; 196 } 197 #endif 198