1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Access to PCI I/O memory from user space programs. 4 * 5 * Copyright IBM Corp. 2014 6 * Author(s): Alexey Ishchuk <aishchuk@linux.vnet.ibm.com> 7 */ 8 #include <linux/kernel.h> 9 #include <linux/syscalls.h> 10 #include <linux/init.h> 11 #include <linux/mm.h> 12 #include <linux/errno.h> 13 #include <linux/pci.h> 14 #include <asm/asm-extable.h> 15 #include <asm/pci_io.h> 16 #include <asm/pci_debug.h> 17 18 static inline void zpci_err_mmio(u8 cc, u8 status, u64 offset) 19 { 20 struct { 21 u64 offset; 22 u8 cc; 23 u8 status; 24 } data = {offset, cc, status}; 25 26 zpci_err_hex(&data, sizeof(data)); 27 } 28 29 static inline int __pcistb_mio_inuser( 30 void __iomem *ioaddr, const void __user *src, 31 u64 len, u8 *status) 32 { 33 int cc = -ENXIO; 34 35 asm volatile ( 36 " sacf 256\n" 37 "0: .insn rsy,0xeb00000000d4,%[len],%[ioaddr],%[src]\n" 38 "1: ipm %[cc]\n" 39 " srl %[cc],28\n" 40 "2: sacf 768\n" 41 EX_TABLE(0b, 2b) EX_TABLE(1b, 2b) 42 : [cc] "+d" (cc), [len] "+d" (len) 43 : [ioaddr] "a" (ioaddr), [src] "Q" (*((u8 __force *)src)) 44 : "cc", "memory"); 45 *status = len >> 24 & 0xff; 46 return cc; 47 } 48 49 static inline int __pcistg_mio_inuser( 50 void __iomem *ioaddr, const void __user *src, 51 u64 ulen, u8 *status) 52 { 53 union register_pair ioaddr_len = {.even = (u64 __force)ioaddr, .odd = ulen}; 54 int cc = -ENXIO; 55 u64 val = 0; 56 u64 cnt = ulen; 57 u8 tmp; 58 59 /* 60 * copy 0 < @len <= 8 bytes from @src into the right most bytes of 61 * a register, then store it to PCI at @ioaddr while in secondary 62 * address space. pcistg then uses the user mappings. 63 */ 64 asm volatile ( 65 " sacf 256\n" 66 "0: llgc %[tmp],0(%[src])\n" 67 " sllg %[val],%[val],8\n" 68 " aghi %[src],1\n" 69 " ogr %[val],%[tmp]\n" 70 " brctg %[cnt],0b\n" 71 "1: .insn rre,0xb9d40000,%[val],%[ioaddr_len]\n" 72 "2: ipm %[cc]\n" 73 " srl %[cc],28\n" 74 "3: sacf 768\n" 75 EX_TABLE(0b, 3b) EX_TABLE(1b, 3b) EX_TABLE(2b, 3b) 76 : 77 [src] "+a" (src), [cnt] "+d" (cnt), 78 [val] "+d" (val), [tmp] "=d" (tmp), 79 [cc] "+d" (cc), [ioaddr_len] "+&d" (ioaddr_len.pair) 80 :: "cc", "memory"); 81 *status = ioaddr_len.odd >> 24 & 0xff; 82 83 /* did we read everything from user memory? */ 84 if (!cc && cnt != 0) 85 cc = -EFAULT; 86 87 return cc; 88 } 89 90 static inline int __memcpy_toio_inuser(void __iomem *dst, 91 const void __user *src, size_t n) 92 { 93 int size, rc = 0; 94 u8 status = 0; 95 96 if (!src) 97 return -EINVAL; 98 99 while (n > 0) { 100 size = zpci_get_max_write_size((u64 __force) dst, 101 (u64 __force) src, n, 102 ZPCI_MAX_WRITE_SIZE); 103 if (size > 8) /* main path */ 104 rc = __pcistb_mio_inuser(dst, src, size, &status); 105 else 106 rc = __pcistg_mio_inuser(dst, src, size, &status); 107 if (rc) 108 break; 109 src += size; 110 dst += size; 111 n -= size; 112 } 113 if (rc) 114 zpci_err_mmio(rc, status, (__force u64) dst); 115 return rc; 116 } 117 118 SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr, 119 const void __user *, user_buffer, size_t, length) 120 { 121 u8 local_buf[64]; 122 void __iomem *io_addr; 123 void *buf; 124 struct vm_area_struct *vma; 125 pte_t *ptep; 126 spinlock_t *ptl; 127 long ret; 128 129 if (!zpci_is_enabled()) 130 return -ENODEV; 131 132 if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length) 133 return -EINVAL; 134 135 /* 136 * We only support write access to MIO capable devices if we are on 137 * a MIO enabled system. Otherwise we would have to check for every 138 * address if it is a special ZPCI_ADDR and would have to do 139 * a pfn lookup which we don't need for MIO capable devices. Currently 140 * ISM devices are the only devices without MIO support and there is no 141 * known need for accessing these from userspace. 142 */ 143 if (static_branch_likely(&have_mio)) { 144 ret = __memcpy_toio_inuser((void __iomem *) mmio_addr, 145 user_buffer, 146 length); 147 return ret; 148 } 149 150 if (length > 64) { 151 buf = kmalloc(length, GFP_KERNEL); 152 if (!buf) 153 return -ENOMEM; 154 } else 155 buf = local_buf; 156 157 ret = -EFAULT; 158 if (copy_from_user(buf, user_buffer, length)) 159 goto out_free; 160 161 mmap_read_lock(current->mm); 162 ret = -EINVAL; 163 vma = vma_lookup(current->mm, mmio_addr); 164 if (!vma) 165 goto out_unlock_mmap; 166 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 167 goto out_unlock_mmap; 168 ret = -EACCES; 169 if (!(vma->vm_flags & VM_WRITE)) 170 goto out_unlock_mmap; 171 172 ret = follow_pte(vma->vm_mm, mmio_addr, &ptep, &ptl); 173 if (ret) 174 goto out_unlock_mmap; 175 176 io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) | 177 (mmio_addr & ~PAGE_MASK)); 178 179 if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) 180 goto out_unlock_pt; 181 182 ret = zpci_memcpy_toio(io_addr, buf, length); 183 out_unlock_pt: 184 pte_unmap_unlock(ptep, ptl); 185 out_unlock_mmap: 186 mmap_read_unlock(current->mm); 187 out_free: 188 if (buf != local_buf) 189 kfree(buf); 190 return ret; 191 } 192 193 static inline int __pcilg_mio_inuser( 194 void __user *dst, const void __iomem *ioaddr, 195 u64 ulen, u8 *status) 196 { 197 union register_pair ioaddr_len = {.even = (u64 __force)ioaddr, .odd = ulen}; 198 u64 cnt = ulen; 199 int shift = ulen * 8; 200 int cc = -ENXIO; 201 u64 val, tmp; 202 203 /* 204 * read 0 < @len <= 8 bytes from the PCI memory mapped at @ioaddr (in 205 * user space) into a register using pcilg then store these bytes at 206 * user address @dst 207 */ 208 asm volatile ( 209 " sacf 256\n" 210 "0: .insn rre,0xb9d60000,%[val],%[ioaddr_len]\n" 211 "1: ipm %[cc]\n" 212 " srl %[cc],28\n" 213 " ltr %[cc],%[cc]\n" 214 " jne 4f\n" 215 "2: ahi %[shift],-8\n" 216 " srlg %[tmp],%[val],0(%[shift])\n" 217 "3: stc %[tmp],0(%[dst])\n" 218 " aghi %[dst],1\n" 219 " brctg %[cnt],2b\n" 220 "4: sacf 768\n" 221 EX_TABLE(0b, 4b) EX_TABLE(1b, 4b) EX_TABLE(3b, 4b) 222 : 223 [ioaddr_len] "+&d" (ioaddr_len.pair), 224 [cc] "+d" (cc), [val] "=d" (val), 225 [dst] "+a" (dst), [cnt] "+d" (cnt), [tmp] "=d" (tmp), 226 [shift] "+d" (shift) 227 :: "cc", "memory"); 228 229 /* did we write everything to the user space buffer? */ 230 if (!cc && cnt != 0) 231 cc = -EFAULT; 232 233 *status = ioaddr_len.odd >> 24 & 0xff; 234 return cc; 235 } 236 237 static inline int __memcpy_fromio_inuser(void __user *dst, 238 const void __iomem *src, 239 unsigned long n) 240 { 241 int size, rc = 0; 242 u8 status; 243 244 while (n > 0) { 245 size = zpci_get_max_write_size((u64 __force) src, 246 (u64 __force) dst, n, 247 ZPCI_MAX_READ_SIZE); 248 rc = __pcilg_mio_inuser(dst, src, size, &status); 249 if (rc) 250 break; 251 src += size; 252 dst += size; 253 n -= size; 254 } 255 if (rc) 256 zpci_err_mmio(rc, status, (__force u64) dst); 257 return rc; 258 } 259 260 SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr, 261 void __user *, user_buffer, size_t, length) 262 { 263 u8 local_buf[64]; 264 void __iomem *io_addr; 265 void *buf; 266 struct vm_area_struct *vma; 267 pte_t *ptep; 268 spinlock_t *ptl; 269 long ret; 270 271 if (!zpci_is_enabled()) 272 return -ENODEV; 273 274 if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length) 275 return -EINVAL; 276 277 /* 278 * We only support read access to MIO capable devices if we are on 279 * a MIO enabled system. Otherwise we would have to check for every 280 * address if it is a special ZPCI_ADDR and would have to do 281 * a pfn lookup which we don't need for MIO capable devices. Currently 282 * ISM devices are the only devices without MIO support and there is no 283 * known need for accessing these from userspace. 284 */ 285 if (static_branch_likely(&have_mio)) { 286 ret = __memcpy_fromio_inuser( 287 user_buffer, (const void __iomem *)mmio_addr, 288 length); 289 return ret; 290 } 291 292 if (length > 64) { 293 buf = kmalloc(length, GFP_KERNEL); 294 if (!buf) 295 return -ENOMEM; 296 } else { 297 buf = local_buf; 298 } 299 300 mmap_read_lock(current->mm); 301 ret = -EINVAL; 302 vma = vma_lookup(current->mm, mmio_addr); 303 if (!vma) 304 goto out_unlock_mmap; 305 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) 306 goto out_unlock_mmap; 307 ret = -EACCES; 308 if (!(vma->vm_flags & VM_WRITE)) 309 goto out_unlock_mmap; 310 311 ret = follow_pte(vma->vm_mm, mmio_addr, &ptep, &ptl); 312 if (ret) 313 goto out_unlock_mmap; 314 315 io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) | 316 (mmio_addr & ~PAGE_MASK)); 317 318 if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) { 319 ret = -EFAULT; 320 goto out_unlock_pt; 321 } 322 ret = zpci_memcpy_fromio(buf, io_addr, length); 323 324 out_unlock_pt: 325 pte_unmap_unlock(ptep, ptl); 326 out_unlock_mmap: 327 mmap_read_unlock(current->mm); 328 329 if (!ret && copy_to_user(user_buffer, buf, length)) 330 ret = -EFAULT; 331 332 if (buf != local_buf) 333 kfree(buf); 334 return ret; 335 } 336