1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/init.h>
4 #include <linux/errno.h>
5 #include <linux/mm.h>
6 #include <linux/mman.h>
7 #include <linux/slab.h>
8 #include <linux/vmalloc.h>
9 #include <linux/io_uring.h>
10 #include <linux/io_uring_types.h>
11 #include <asm/shmparam.h>
12
13 #include "memmap.h"
14 #include "kbuf.h"
15 #include "rsrc.h"
16 #include "zcrx.h"
17
io_mem_alloc_compound(struct page ** pages,int nr_pages,size_t size,gfp_t gfp)18 static void *io_mem_alloc_compound(struct page **pages, int nr_pages,
19 size_t size, gfp_t gfp)
20 {
21 struct page *page;
22 int i, order;
23
24 order = get_order(size);
25 if (order > MAX_PAGE_ORDER)
26 return ERR_PTR(-ENOMEM);
27 else if (order)
28 gfp |= __GFP_COMP;
29
30 page = alloc_pages(gfp, order);
31 if (!page)
32 return ERR_PTR(-ENOMEM);
33
34 for (i = 0; i < nr_pages; i++)
35 pages[i] = page + i;
36
37 return page_address(page);
38 }
39
io_pin_pages(unsigned long uaddr,unsigned long len,int * npages)40 struct page **io_pin_pages(unsigned long uaddr, unsigned long len, int *npages)
41 {
42 unsigned long start, end, nr_pages;
43 struct page **pages;
44 int ret;
45
46 if (check_add_overflow(uaddr, len, &end))
47 return ERR_PTR(-EOVERFLOW);
48 if (check_add_overflow(end, PAGE_SIZE - 1, &end))
49 return ERR_PTR(-EOVERFLOW);
50
51 end = end >> PAGE_SHIFT;
52 start = uaddr >> PAGE_SHIFT;
53 nr_pages = end - start;
54 if (WARN_ON_ONCE(!nr_pages))
55 return ERR_PTR(-EINVAL);
56 if (WARN_ON_ONCE(nr_pages > INT_MAX))
57 return ERR_PTR(-EOVERFLOW);
58
59 pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
60 if (!pages)
61 return ERR_PTR(-ENOMEM);
62
63 ret = pin_user_pages_fast(uaddr, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
64 pages);
65 /* success, mapped all pages */
66 if (ret == nr_pages) {
67 *npages = nr_pages;
68 return pages;
69 }
70
71 /* partial map, or didn't map anything */
72 if (ret >= 0) {
73 /* if we did partial map, release any pages we did get */
74 if (ret)
75 unpin_user_pages(pages, ret);
76 ret = -EFAULT;
77 }
78 kvfree(pages);
79 return ERR_PTR(ret);
80 }
81
82 enum {
83 /* memory was vmap'ed for the kernel, freeing the region vunmap's it */
84 IO_REGION_F_VMAP = 1,
85 /* memory is provided by user and pinned by the kernel */
86 IO_REGION_F_USER_PROVIDED = 2,
87 /* only the first page in the array is ref'ed */
88 IO_REGION_F_SINGLE_REF = 4,
89 };
90
io_free_region(struct io_ring_ctx * ctx,struct io_mapped_region * mr)91 void io_free_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr)
92 {
93 if (mr->pages) {
94 long nr_refs = mr->nr_pages;
95
96 if (mr->flags & IO_REGION_F_SINGLE_REF)
97 nr_refs = 1;
98
99 if (mr->flags & IO_REGION_F_USER_PROVIDED)
100 unpin_user_pages(mr->pages, nr_refs);
101 else
102 release_pages(mr->pages, nr_refs);
103
104 kvfree(mr->pages);
105 }
106 if ((mr->flags & IO_REGION_F_VMAP) && mr->ptr)
107 vunmap(mr->ptr);
108 if (mr->nr_pages && ctx->user)
109 __io_unaccount_mem(ctx->user, mr->nr_pages);
110
111 memset(mr, 0, sizeof(*mr));
112 }
113
io_region_init_ptr(struct io_mapped_region * mr)114 static int io_region_init_ptr(struct io_mapped_region *mr)
115 {
116 struct io_imu_folio_data ifd;
117 void *ptr;
118
119 if (io_check_coalesce_buffer(mr->pages, mr->nr_pages, &ifd)) {
120 if (ifd.nr_folios == 1 && !PageHighMem(mr->pages[0])) {
121 mr->ptr = page_address(mr->pages[0]);
122 return 0;
123 }
124 }
125 ptr = vmap(mr->pages, mr->nr_pages, VM_MAP, PAGE_KERNEL);
126 if (!ptr)
127 return -ENOMEM;
128
129 mr->ptr = ptr;
130 mr->flags |= IO_REGION_F_VMAP;
131 return 0;
132 }
133
io_region_pin_pages(struct io_ring_ctx * ctx,struct io_mapped_region * mr,struct io_uring_region_desc * reg)134 static int io_region_pin_pages(struct io_ring_ctx *ctx,
135 struct io_mapped_region *mr,
136 struct io_uring_region_desc *reg)
137 {
138 unsigned long size = mr->nr_pages << PAGE_SHIFT;
139 struct page **pages;
140 int nr_pages;
141
142 pages = io_pin_pages(reg->user_addr, size, &nr_pages);
143 if (IS_ERR(pages))
144 return PTR_ERR(pages);
145 if (WARN_ON_ONCE(nr_pages != mr->nr_pages))
146 return -EFAULT;
147
148 mr->pages = pages;
149 mr->flags |= IO_REGION_F_USER_PROVIDED;
150 return 0;
151 }
152
io_region_allocate_pages(struct io_ring_ctx * ctx,struct io_mapped_region * mr,struct io_uring_region_desc * reg,unsigned long mmap_offset)153 static int io_region_allocate_pages(struct io_ring_ctx *ctx,
154 struct io_mapped_region *mr,
155 struct io_uring_region_desc *reg,
156 unsigned long mmap_offset)
157 {
158 gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN;
159 unsigned long size = mr->nr_pages << PAGE_SHIFT;
160 unsigned long nr_allocated;
161 struct page **pages;
162 void *p;
163
164 pages = kvmalloc_array(mr->nr_pages, sizeof(*pages), gfp);
165 if (!pages)
166 return -ENOMEM;
167
168 p = io_mem_alloc_compound(pages, mr->nr_pages, size, gfp);
169 if (!IS_ERR(p)) {
170 mr->flags |= IO_REGION_F_SINGLE_REF;
171 goto done;
172 }
173
174 nr_allocated = alloc_pages_bulk_node(gfp, NUMA_NO_NODE,
175 mr->nr_pages, pages);
176 if (nr_allocated != mr->nr_pages) {
177 if (nr_allocated)
178 release_pages(pages, nr_allocated);
179 kvfree(pages);
180 return -ENOMEM;
181 }
182 done:
183 reg->mmap_offset = mmap_offset;
184 mr->pages = pages;
185 return 0;
186 }
187
io_create_region(struct io_ring_ctx * ctx,struct io_mapped_region * mr,struct io_uring_region_desc * reg,unsigned long mmap_offset)188 int io_create_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr,
189 struct io_uring_region_desc *reg,
190 unsigned long mmap_offset)
191 {
192 int nr_pages, ret;
193 u64 end;
194
195 if (WARN_ON_ONCE(mr->pages || mr->ptr || mr->nr_pages))
196 return -EFAULT;
197 if (memchr_inv(®->__resv, 0, sizeof(reg->__resv)))
198 return -EINVAL;
199 if (reg->flags & ~IORING_MEM_REGION_TYPE_USER)
200 return -EINVAL;
201 /* user_addr should be set IFF it's a user memory backed region */
202 if ((reg->flags & IORING_MEM_REGION_TYPE_USER) != !!reg->user_addr)
203 return -EFAULT;
204 if (!reg->size || reg->mmap_offset || reg->id)
205 return -EINVAL;
206 if ((reg->size >> PAGE_SHIFT) > INT_MAX)
207 return -E2BIG;
208 if ((reg->user_addr | reg->size) & ~PAGE_MASK)
209 return -EINVAL;
210 if (check_add_overflow(reg->user_addr, reg->size, &end))
211 return -EOVERFLOW;
212
213 nr_pages = reg->size >> PAGE_SHIFT;
214 if (ctx->user) {
215 ret = __io_account_mem(ctx->user, nr_pages);
216 if (ret)
217 return ret;
218 }
219 mr->nr_pages = nr_pages;
220
221 if (reg->flags & IORING_MEM_REGION_TYPE_USER)
222 ret = io_region_pin_pages(ctx, mr, reg);
223 else
224 ret = io_region_allocate_pages(ctx, mr, reg, mmap_offset);
225 if (ret)
226 goto out_free;
227
228 ret = io_region_init_ptr(mr);
229 if (ret)
230 goto out_free;
231 return 0;
232 out_free:
233 io_free_region(ctx, mr);
234 return ret;
235 }
236
io_create_region_mmap_safe(struct io_ring_ctx * ctx,struct io_mapped_region * mr,struct io_uring_region_desc * reg,unsigned long mmap_offset)237 int io_create_region_mmap_safe(struct io_ring_ctx *ctx, struct io_mapped_region *mr,
238 struct io_uring_region_desc *reg,
239 unsigned long mmap_offset)
240 {
241 struct io_mapped_region tmp_mr;
242 int ret;
243
244 memcpy(&tmp_mr, mr, sizeof(tmp_mr));
245 ret = io_create_region(ctx, &tmp_mr, reg, mmap_offset);
246 if (ret)
247 return ret;
248
249 /*
250 * Once published mmap can find it without holding only the ->mmap_lock
251 * and not ->uring_lock.
252 */
253 guard(mutex)(&ctx->mmap_lock);
254 memcpy(mr, &tmp_mr, sizeof(tmp_mr));
255 return 0;
256 }
257
io_mmap_get_region(struct io_ring_ctx * ctx,loff_t pgoff)258 static struct io_mapped_region *io_mmap_get_region(struct io_ring_ctx *ctx,
259 loff_t pgoff)
260 {
261 loff_t offset = pgoff << PAGE_SHIFT;
262 unsigned int id;
263
264
265 switch (offset & IORING_OFF_MMAP_MASK) {
266 case IORING_OFF_SQ_RING:
267 case IORING_OFF_CQ_RING:
268 return &ctx->ring_region;
269 case IORING_OFF_SQES:
270 return &ctx->sq_region;
271 case IORING_OFF_PBUF_RING:
272 id = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
273 return io_pbuf_get_region(ctx, id);
274 case IORING_MAP_OFF_PARAM_REGION:
275 return &ctx->param_region;
276 case IORING_MAP_OFF_ZCRX_REGION:
277 id = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_ZCRX_SHIFT;
278 return io_zcrx_get_region(ctx, id);
279 }
280 return NULL;
281 }
282
io_region_validate_mmap(struct io_ring_ctx * ctx,struct io_mapped_region * mr)283 static void *io_region_validate_mmap(struct io_ring_ctx *ctx,
284 struct io_mapped_region *mr)
285 {
286 lockdep_assert_held(&ctx->mmap_lock);
287
288 if (!io_region_is_set(mr))
289 return ERR_PTR(-EINVAL);
290 if (mr->flags & IO_REGION_F_USER_PROVIDED)
291 return ERR_PTR(-EINVAL);
292
293 return io_region_get_ptr(mr);
294 }
295
io_uring_validate_mmap_request(struct file * file,loff_t pgoff,size_t sz)296 static void *io_uring_validate_mmap_request(struct file *file, loff_t pgoff,
297 size_t sz)
298 {
299 struct io_ring_ctx *ctx = file->private_data;
300 struct io_mapped_region *region;
301
302 region = io_mmap_get_region(ctx, pgoff);
303 if (!region)
304 return ERR_PTR(-EINVAL);
305 return io_region_validate_mmap(ctx, region);
306 }
307
308 #ifdef CONFIG_MMU
309
io_region_mmap(struct io_ring_ctx * ctx,struct io_mapped_region * mr,struct vm_area_struct * vma,unsigned max_pages)310 static int io_region_mmap(struct io_ring_ctx *ctx,
311 struct io_mapped_region *mr,
312 struct vm_area_struct *vma,
313 unsigned max_pages)
314 {
315 unsigned long nr_pages = min(mr->nr_pages, max_pages);
316
317 vm_flags_set(vma, VM_DONTEXPAND);
318 return vm_insert_pages(vma, vma->vm_start, mr->pages, &nr_pages);
319 }
320
io_uring_mmap(struct file * file,struct vm_area_struct * vma)321 __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
322 {
323 struct io_ring_ctx *ctx = file->private_data;
324 size_t sz = vma->vm_end - vma->vm_start;
325 long offset = vma->vm_pgoff << PAGE_SHIFT;
326 unsigned int page_limit = UINT_MAX;
327 struct io_mapped_region *region;
328 void *ptr;
329
330 guard(mutex)(&ctx->mmap_lock);
331
332 ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
333 if (IS_ERR(ptr))
334 return PTR_ERR(ptr);
335
336 switch (offset & IORING_OFF_MMAP_MASK) {
337 case IORING_OFF_SQ_RING:
338 case IORING_OFF_CQ_RING:
339 page_limit = (sz + PAGE_SIZE - 1) >> PAGE_SHIFT;
340 break;
341 }
342
343 region = io_mmap_get_region(ctx, vma->vm_pgoff);
344 return io_region_mmap(ctx, region, vma, page_limit);
345 }
346
io_uring_get_unmapped_area(struct file * filp,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)347 unsigned long io_uring_get_unmapped_area(struct file *filp, unsigned long addr,
348 unsigned long len, unsigned long pgoff,
349 unsigned long flags)
350 {
351 struct io_ring_ctx *ctx = filp->private_data;
352 void *ptr;
353
354 /*
355 * Do not allow to map to user-provided address to avoid breaking the
356 * aliasing rules. Userspace is not able to guess the offset address of
357 * kernel kmalloc()ed memory area.
358 */
359 if (addr)
360 return -EINVAL;
361
362 guard(mutex)(&ctx->mmap_lock);
363
364 ptr = io_uring_validate_mmap_request(filp, pgoff, len);
365 if (IS_ERR(ptr))
366 return -ENOMEM;
367
368 /*
369 * Some architectures have strong cache aliasing requirements.
370 * For such architectures we need a coherent mapping which aliases
371 * kernel memory *and* userspace memory. To achieve that:
372 * - use a NULL file pointer to reference physical memory, and
373 * - use the kernel virtual address of the shared io_uring context
374 * (instead of the userspace-provided address, which has to be 0UL
375 * anyway).
376 * - use the same pgoff which the get_unmapped_area() uses to
377 * calculate the page colouring.
378 * For architectures without such aliasing requirements, the
379 * architecture will return any suitable mapping because addr is 0.
380 */
381 filp = NULL;
382 flags |= MAP_SHARED;
383 pgoff = 0; /* has been translated to ptr above */
384 #ifdef SHM_COLOUR
385 addr = (uintptr_t) ptr;
386 pgoff = addr >> PAGE_SHIFT;
387 #else
388 addr = 0UL;
389 #endif
390 return mm_get_unmapped_area(current->mm, filp, addr, len, pgoff, flags);
391 }
392
393 #else /* !CONFIG_MMU */
394
io_uring_mmap(struct file * file,struct vm_area_struct * vma)395 int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
396 {
397 return is_nommu_shared_mapping(vma->vm_flags) ? 0 : -EINVAL;
398 }
399
io_uring_nommu_mmap_capabilities(struct file * file)400 unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
401 {
402 return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
403 }
404
io_uring_get_unmapped_area(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)405 unsigned long io_uring_get_unmapped_area(struct file *file, unsigned long addr,
406 unsigned long len, unsigned long pgoff,
407 unsigned long flags)
408 {
409 struct io_ring_ctx *ctx = file->private_data;
410 void *ptr;
411
412 guard(mutex)(&ctx->mmap_lock);
413
414 ptr = io_uring_validate_mmap_request(file, pgoff, len);
415 if (IS_ERR(ptr))
416 return PTR_ERR(ptr);
417
418 return (unsigned long) ptr;
419 }
420
421 #endif /* !CONFIG_MMU */
422