1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Privileged ADI driver for sparc64 4 * 5 * Author: Tom Hromatka <tom.hromatka@oracle.com> 6 */ 7 #include <linux/kernel.h> 8 #include <linux/miscdevice.h> 9 #include <linux/module.h> 10 #include <linux/proc_fs.h> 11 #include <linux/slab.h> 12 #include <linux/uaccess.h> 13 #include <asm/asi.h> 14 15 #define MAX_BUF_SZ PAGE_SIZE 16 17 static int adi_open(struct inode *inode, struct file *file) 18 { 19 file->f_mode |= FMODE_UNSIGNED_OFFSET; 20 return 0; 21 } 22 23 static int read_mcd_tag(unsigned long addr) 24 { 25 long err; 26 int ver; 27 28 __asm__ __volatile__( 29 "1: ldxa [%[addr]] %[asi], %[ver]\n" 30 " mov 0, %[err]\n" 31 "2:\n" 32 " .section .fixup,#alloc,#execinstr\n" 33 " .align 4\n" 34 "3: sethi %%hi(2b), %%g1\n" 35 " jmpl %%g1 + %%lo(2b), %%g0\n" 36 " mov %[invalid], %[err]\n" 37 " .previous\n" 38 " .section __ex_table, \"a\"\n" 39 " .align 4\n" 40 " .word 1b, 3b\n" 41 " .previous\n" 42 : [ver] "=r" (ver), [err] "=r" (err) 43 : [addr] "r" (addr), [invalid] "i" (EFAULT), 44 [asi] "i" (ASI_MCD_REAL) 45 : "memory", "g1" 46 ); 47 48 if (err) 49 return -EFAULT; 50 else 51 return ver; 52 } 53 54 static ssize_t adi_read(struct file *file, char __user *buf, 55 size_t count, loff_t *offp) 56 { 57 size_t ver_buf_sz, bytes_read = 0; 58 int ver_buf_idx = 0; 59 loff_t offset; 60 u8 *ver_buf; 61 ssize_t ret; 62 63 ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ); 64 ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL); 65 if (!ver_buf) 66 return -ENOMEM; 67 68 offset = (*offp) * adi_blksize(); 69 70 while (bytes_read < count) { 71 ret = read_mcd_tag(offset); 72 if (ret < 0) 73 goto out; 74 75 ver_buf[ver_buf_idx] = (u8)ret; 76 ver_buf_idx++; 77 offset += adi_blksize(); 78 79 if (ver_buf_idx >= ver_buf_sz) { 80 if (copy_to_user(buf + bytes_read, ver_buf, 81 ver_buf_sz)) { 82 ret = -EFAULT; 83 goto out; 84 } 85 86 bytes_read += ver_buf_sz; 87 ver_buf_idx = 0; 88 89 ver_buf_sz = min(count - bytes_read, 90 (size_t)MAX_BUF_SZ); 91 } 92 } 93 94 (*offp) += bytes_read; 95 ret = bytes_read; 96 out: 97 kfree(ver_buf); 98 return ret; 99 } 100 101 static int set_mcd_tag(unsigned long addr, u8 ver) 102 { 103 long err; 104 105 __asm__ __volatile__( 106 "1: stxa %[ver], [%[addr]] %[asi]\n" 107 " mov 0, %[err]\n" 108 "2:\n" 109 " .section .fixup,#alloc,#execinstr\n" 110 " .align 4\n" 111 "3: sethi %%hi(2b), %%g1\n" 112 " jmpl %%g1 + %%lo(2b), %%g0\n" 113 " mov %[invalid], %[err]\n" 114 " .previous\n" 115 " .section __ex_table, \"a\"\n" 116 " .align 4\n" 117 " .word 1b, 3b\n" 118 " .previous\n" 119 : [err] "=r" (err) 120 : [ver] "r" (ver), [addr] "r" (addr), 121 [invalid] "i" (EFAULT), [asi] "i" (ASI_MCD_REAL) 122 : "memory", "g1" 123 ); 124 125 if (err) 126 return -EFAULT; 127 else 128 return ver; 129 } 130 131 static ssize_t adi_write(struct file *file, const char __user *buf, 132 size_t count, loff_t *offp) 133 { 134 size_t ver_buf_sz, bytes_written = 0; 135 loff_t offset; 136 u8 *ver_buf; 137 ssize_t ret; 138 int i; 139 140 if (count <= 0) 141 return -EINVAL; 142 143 ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ); 144 ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL); 145 if (!ver_buf) 146 return -ENOMEM; 147 148 offset = (*offp) * adi_blksize(); 149 150 do { 151 if (copy_from_user(ver_buf, &buf[bytes_written], 152 ver_buf_sz)) { 153 ret = -EFAULT; 154 goto out; 155 } 156 157 for (i = 0; i < ver_buf_sz; i++) { 158 ret = set_mcd_tag(offset, ver_buf[i]); 159 if (ret < 0) 160 goto out; 161 162 offset += adi_blksize(); 163 } 164 165 bytes_written += ver_buf_sz; 166 ver_buf_sz = min(count - bytes_written, (size_t)MAX_BUF_SZ); 167 } while (bytes_written < count); 168 169 (*offp) += bytes_written; 170 ret = bytes_written; 171 out: 172 __asm__ __volatile__("membar #Sync"); 173 kfree(ver_buf); 174 return ret; 175 } 176 177 static loff_t adi_llseek(struct file *file, loff_t offset, int whence) 178 { 179 loff_t ret = -EINVAL; 180 181 switch (whence) { 182 case SEEK_END: 183 case SEEK_DATA: 184 case SEEK_HOLE: 185 /* unsupported */ 186 return -EINVAL; 187 case SEEK_CUR: 188 if (offset == 0) 189 return file->f_pos; 190 191 offset += file->f_pos; 192 break; 193 case SEEK_SET: 194 break; 195 } 196 197 if (offset != file->f_pos) { 198 file->f_pos = offset; 199 file->f_version = 0; 200 ret = offset; 201 } 202 203 return ret; 204 } 205 206 static const struct file_operations adi_fops = { 207 .owner = THIS_MODULE, 208 .llseek = adi_llseek, 209 .open = adi_open, 210 .read = adi_read, 211 .write = adi_write, 212 }; 213 214 static struct miscdevice adi_miscdev = { 215 .minor = MISC_DYNAMIC_MINOR, 216 .name = KBUILD_MODNAME, 217 .fops = &adi_fops, 218 }; 219 220 static int __init adi_init(void) 221 { 222 if (!adi_capable()) 223 return -EPERM; 224 225 return misc_register(&adi_miscdev); 226 } 227 228 static void __exit adi_exit(void) 229 { 230 misc_deregister(&adi_miscdev); 231 } 232 233 module_init(adi_init); 234 module_exit(adi_exit); 235 236 MODULE_AUTHOR("Tom Hromatka <tom.hromatka@oracle.com>"); 237 MODULE_DESCRIPTION("Privileged interface to ADI"); 238 MODULE_VERSION("1.0"); 239 MODULE_LICENSE("GPL v2"); 240