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