arch/s390/pci/pci_mmio.c

   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/pci_io.h>
  15 #include <asm/pci_debug.h>
  16
  17 static inline void zpci_err_mmio(u8 cc, u8 status, u64 offset)
  18 {
  19         struct {
  20                 u64 offset;
  21                 u8 cc;
  22                 u8 status;
  23         } data = {offset, cc, status};
  24
  25         zpci_err_hex(&data, sizeof(data));
  26 }
  27
  28 static inline int __pcistb_mio_inuser(
  29                 void __iomem *ioaddr, const void __user *src,
  30                 u64 len, u8 *status)
  31 {
  32         int cc = -ENXIO;
  33
  34         asm volatile (
  35                 "       sacf 256\n"
  36                 "0:     .insn   rsy,0xeb00000000d4,%[len],%[ioaddr],%[src]\n"
  37                 "1:     ipm     %[cc]\n"
  38                 "       srl     %[cc],28\n"
  39                 "2:     sacf 768\n"
  40                 EX_TABLE(0b, 2b) EX_TABLE(1b, 2b)
  41                 : [cc] "+d" (cc), [len] "+d" (len)
  42                 : [ioaddr] "a" (ioaddr), [src] "Q" (*((u8 __force *)src))
  43                 : "cc", "memory");
  44         *status = len >> 24 & 0xff;
  45         return cc;
  46 }
  47
  48 static inline int __pcistg_mio_inuser(
  49                 void __iomem *ioaddr, const void __user *src,
  50                 u64 ulen, u8 *status)
  51 {
  52         register u64 addr asm("2") = (u64 __force) ioaddr;
  53         register u64 len asm("3") = 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]\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                 [len] "+d" (len), [cc] "+d" (cc),
  80                 [ioaddr] "+a" (addr)
  81                 :: "cc", "memory");
  82         *status = len >> 24 & 0xff;
  83
  84         /* did we read everything from user memory? */
  85         if (!cc && cnt != 0)
  86                 cc = -EFAULT;
  87
  88         return cc;
  89 }
  90
  91 static inline int __memcpy_toio_inuser(void __iomem *dst,
  92                                    const void __user *src, size_t n)
  93 {
  94         int size, rc = 0;
  95         u8 status = 0;
  96         mm_segment_t old_fs;
  97
  98         if (!src)
  99                 return -EINVAL;
 100
 101         old_fs = enable_sacf_uaccess();
 102         while (n > 0) {
 103                 size = zpci_get_max_write_size((u64 __force) dst,
 104                                                (u64 __force) src, n,
 105                                                ZPCI_MAX_WRITE_SIZE);
 106                 if (size > 8) /* main path */
 107                         rc = __pcistb_mio_inuser(dst, src, size, &status);
 108                 else
 109                         rc = __pcistg_mio_inuser(dst, src, size, &status);
 110                 if (rc)
 111                         break;
 112                 src += size;
 113                 dst += size;
 114                 n -= size;
 115         }
 116         disable_sacf_uaccess(old_fs);
 117         if (rc)
 118                 zpci_err_mmio(rc, status, (__force u64) dst);
 119         return rc;
 120 }
 121
 122 static long get_pfn(unsigned long user_addr, unsigned long access,
 123                     unsigned long *pfn)
 124 {
 125         struct vm_area_struct *vma;
 126         long ret;
 127
 128         mmap_read_lock(current->mm);
 129         ret = -EINVAL;
 130         vma = find_vma(current->mm, user_addr);
 131         if (!vma)
 132                 goto out;
 133         ret = -EACCES;
 134         if (!(vma->vm_flags & access))
 135                 goto out;
 136         ret = follow_pfn(vma, user_addr, pfn);
 137 out:
 138         mmap_read_unlock(current->mm);
 139         return ret;
 140 }
 141
 142 SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 143                 const void __user *, user_buffer, size_t, length)
 144 {
 145         u8 local_buf[64];
 146         void __iomem *io_addr;
 147         void *buf;
 148         unsigned long pfn;
 149         long ret;
 150
 151         if (!zpci_is_enabled())
 152                 return -ENODEV;
 153
 154         if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
 155                 return -EINVAL;
 156
 157         /*
 158          * Only support read access to MIO capable devices on a MIO enabled
 159          * system. Otherwise we would have to check for every address if it is
 160          * a special ZPCI_ADDR and we would have to do a get_pfn() which we
 161          * don't need for MIO capable devices.
 162          */
 163         if (static_branch_likely(&have_mio)) {
 164                 ret = __memcpy_toio_inuser((void  __iomem *) mmio_addr,
 165                                         user_buffer,
 166                                         length);
 167                 return ret;
 168         }
 169
 170         if (length > 64) {
 171                 buf = kmalloc(length, GFP_KERNEL);
 172                 if (!buf)
 173                         return -ENOMEM;
 174         } else
 175                 buf = local_buf;
 176
 177         ret = get_pfn(mmio_addr, VM_WRITE, &pfn);
 178         if (ret)
 179                 goto out;
 180         io_addr = (void __iomem *)((pfn << PAGE_SHIFT) |
 181                         (mmio_addr & ~PAGE_MASK));
 182
 183         ret = -EFAULT;
 184         if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
 185                 goto out;
 186
 187         if (copy_from_user(buf, user_buffer, length))
 188                 goto out;
 189
 190         ret = zpci_memcpy_toio(io_addr, buf, length);
 191 out:
 192         if (buf != local_buf)
 193                 kfree(buf);
 194         return ret;
 195 }
 196
 197 static inline int __pcilg_mio_inuser(
 198                 void __user *dst, const void __iomem *ioaddr,
 199                 u64 ulen, u8 *status)
 200 {
 201         register u64 addr asm("2") = (u64 __force) ioaddr;
 202         register u64 len asm("3") = ulen;
 203         u64 cnt = ulen;
 204         int shift = ulen * 8;
 205         int cc = -ENXIO;
 206         u64 val, tmp;
 207
 208         /*
 209          * read 0 < @len <= 8 bytes from the PCI memory mapped at @ioaddr (in
 210          * user space) into a register using pcilg then store these bytes at
 211          * user address @dst
 212          */
 213         asm volatile (
 214                 "       sacf    256\n"
 215                 "0:     .insn   rre,0xb9d60000,%[val],%[ioaddr]\n"
 216                 "1:     ipm     %[cc]\n"
 217                 "       srl     %[cc],28\n"
 218                 "       ltr     %[cc],%[cc]\n"
 219                 "       jne     4f\n"
 220                 "2:     ahi     %[shift],-8\n"
 221                 "       srlg    %[tmp],%[val],0(%[shift])\n"
 222                 "3:     stc     %[tmp],0(%[dst])\n"
 223                 "       aghi    %[dst],1\n"
 224                 "       brctg   %[cnt],2b\n"
 225                 "4:     sacf    768\n"
 226                 EX_TABLE(0b, 4b) EX_TABLE(1b, 4b) EX_TABLE(3b, 4b)
 227                 :
 228                 [cc] "+d" (cc), [val] "=d" (val), [len] "+d" (len),
 229                 [dst] "+a" (dst), [cnt] "+d" (cnt), [tmp] "=d" (tmp),
 230                 [shift] "+d" (shift)
 231                 :
 232                 [ioaddr] "a" (addr)
 233                 : "cc", "memory");
 234
 235         /* did we write everything to the user space buffer? */
 236         if (!cc && cnt != 0)
 237                 cc = -EFAULT;
 238
 239         *status = len >> 24 & 0xff;
 240         return cc;
 241 }
 242
 243 static inline int __memcpy_fromio_inuser(void __user *dst,
 244                                      const void __iomem *src,
 245                                      unsigned long n)
 246 {
 247         int size, rc = 0;
 248         u8 status;
 249         mm_segment_t old_fs;
 250
 251         old_fs = enable_sacf_uaccess();
 252         while (n > 0) {
 253                 size = zpci_get_max_write_size((u64 __force) src,
 254                                                (u64 __force) dst, n,
 255                                                ZPCI_MAX_READ_SIZE);
 256                 rc = __pcilg_mio_inuser(dst, src, size, &status);
 257                 if (rc)
 258                         break;
 259                 src += size;
 260                 dst += size;
 261                 n -= size;
 262         }
 263         disable_sacf_uaccess(old_fs);
 264         if (rc)
 265                 zpci_err_mmio(rc, status, (__force u64) dst);
 266         return rc;
 267 }
 268
 269 SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 270                 void __user *, user_buffer, size_t, length)
 271 {
 272         u8 local_buf[64];
 273         void __iomem *io_addr;
 274         void *buf;
 275         unsigned long pfn;
 276         long ret;
 277
 278         if (!zpci_is_enabled())
 279                 return -ENODEV;
 280
 281         if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
 282                 return -EINVAL;
 283
 284         /*
 285          * Only support write access to MIO capable devices on a MIO enabled
 286          * system. Otherwise we would have to check for every address if it is
 287          * a special ZPCI_ADDR and we would have to do a get_pfn() which we
 288          * don't need for MIO capable devices.
 289          */
 290         if (static_branch_likely(&have_mio)) {
 291                 ret = __memcpy_fromio_inuser(
 292                                 user_buffer, (const void __iomem *)mmio_addr,
 293                                 length);
 294                 return ret;
 295         }
 296
 297         if (length > 64) {
 298                 buf = kmalloc(length, GFP_KERNEL);
 299                 if (!buf)
 300                         return -ENOMEM;
 301         } else {
 302                 buf = local_buf;
 303         }
 304
 305         ret = get_pfn(mmio_addr, VM_READ, &pfn);
 306         if (ret)
 307                 goto out;
 308         io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
 309
 310         if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) {
 311                 ret = -EFAULT;
 312                 goto out;
 313         }
 314         ret = zpci_memcpy_fromio(buf, io_addr, length);
 315         if (ret)
 316                 goto out;
 317         if (copy_to_user(user_buffer, buf, length))
 318                 ret = -EFAULT;
 319
 320 out:
 321         if (buf != local_buf)
 322                 kfree(buf);
 323         return ret;
 324 }