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
zpci_err_mmio(u8 cc,u8 status,u64 offset)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
__pcistb_mio_inuser(void __iomem * ioaddr,const void __user * src,u64 len,u8 * status)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
__pcistg_mio_inuser(void __iomem * ioaddr,const void __user * src,u64 ulen,u8 * status)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 "4: 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(4b, 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
__memcpy_toio_inuser(void __iomem * dst,const void __user * src,size_t n)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_io_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
SYSCALL_DEFINE3(s390_pci_mmio_write,unsigned long,mmio_addr,const void __user *,user_buffer,size_t,length)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, 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
__pcilg_mio_inuser(void __user * dst,const void __iomem * ioaddr,u64 ulen,u8 * status)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 "5: 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) EX_TABLE(5b, 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
__memcpy_fromio_inuser(void __user * dst,const void __iomem * src,unsigned long n)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_io_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
SYSCALL_DEFINE3(s390_pci_mmio_read,unsigned long,mmio_addr,void __user *,user_buffer,size_t,length)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, 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