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 unsigned long flags; 63 64 os_info.version_major = OS_INFO_VERSION_MAJOR; 65 os_info.version_minor = OS_INFO_VERSION_MINOR; 66 os_info.magic = OS_INFO_MAGIC; 67 os_info.csum = os_info_csum(&os_info); 68 abs_lc = get_abs_lowcore(&flags); 69 abs_lc->os_info = __pa(&os_info); 70 put_abs_lowcore(abs_lc, flags); 71 } 72 73 #ifdef CONFIG_CRASH_DUMP 74 75 static struct os_info *os_info_old; 76 77 /* 78 * Allocate and copy OS info entry from oldmem 79 */ 80 static void os_info_old_alloc(int nr, int align) 81 { 82 unsigned long addr, size = 0; 83 char *buf, *buf_align, *msg; 84 u32 csum; 85 86 addr = os_info_old->entry[nr].addr; 87 if (!addr) { 88 msg = "not available"; 89 goto fail; 90 } 91 size = os_info_old->entry[nr].size; 92 buf = kmalloc(size + align - 1, GFP_KERNEL); 93 if (!buf) { 94 msg = "alloc failed"; 95 goto fail; 96 } 97 buf_align = PTR_ALIGN(buf, align); 98 if (copy_oldmem_kernel(buf_align, addr, size)) { 99 msg = "copy failed"; 100 goto fail_free; 101 } 102 csum = (__force u32)csum_partial(buf_align, size, 0); 103 if (csum != os_info_old->entry[nr].csum) { 104 msg = "checksum failed"; 105 goto fail_free; 106 } 107 os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align; 108 msg = "copied"; 109 goto out; 110 fail_free: 111 kfree(buf); 112 fail: 113 os_info_old->entry[nr].addr = 0; 114 out: 115 pr_info("entry %i: %s (addr=0x%lx size=%lu)\n", 116 nr, msg, addr, size); 117 } 118 119 /* 120 * Initialize os info and os info entries from oldmem 121 */ 122 static void os_info_old_init(void) 123 { 124 static int os_info_init; 125 unsigned long addr; 126 127 if (os_info_init) 128 return; 129 if (!oldmem_data.start) 130 goto fail; 131 if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr))) 132 goto fail; 133 if (addr == 0 || addr % PAGE_SIZE) 134 goto fail; 135 os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL); 136 if (!os_info_old) 137 goto fail; 138 if (copy_oldmem_kernel(os_info_old, addr, sizeof(*os_info_old))) 139 goto fail_free; 140 if (os_info_old->magic != OS_INFO_MAGIC) 141 goto fail_free; 142 if (os_info_old->csum != os_info_csum(os_info_old)) 143 goto fail_free; 144 if (os_info_old->version_major > OS_INFO_VERSION_MAJOR) 145 goto fail_free; 146 os_info_old_alloc(OS_INFO_VMCOREINFO, 1); 147 os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1); 148 pr_info("crashkernel: addr=0x%lx size=%lu\n", 149 (unsigned long) os_info_old->crashkernel_addr, 150 (unsigned long) os_info_old->crashkernel_size); 151 os_info_init = 1; 152 return; 153 fail_free: 154 kfree(os_info_old); 155 fail: 156 os_info_init = 1; 157 os_info_old = NULL; 158 } 159 160 /* 161 * Return pointer to os infor entry and its size 162 */ 163 void *os_info_old_entry(int nr, unsigned long *size) 164 { 165 os_info_old_init(); 166 167 if (!os_info_old) 168 return NULL; 169 if (!os_info_old->entry[nr].addr) 170 return NULL; 171 *size = (unsigned long) os_info_old->entry[nr].size; 172 return (void *)(unsigned long)os_info_old->entry[nr].addr; 173 } 174 #endif 175