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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * KMSAN API for subsystems.
4 *
5 * Copyright (C) 2017-2022 Google LLC
6 * Author: Alexander Potapenko <glider@google.com>
7 *
8 */
9#ifndef _LINUX_KMSAN_H
10#define _LINUX_KMSAN_H
11
12#include <linux/dma-direction.h>
13#include <linux/gfp.h>
14#include <linux/kmsan-checks.h>
15#include <linux/types.h>
16
17struct page;
18struct kmem_cache;
19struct task_struct;
20struct scatterlist;
21struct urb;
22
23#ifdef CONFIG_KMSAN
24
25/**
26 * kmsan_task_create() - Initialize KMSAN state for the task.
27 * @task: task to initialize.
28 */
29void kmsan_task_create(struct task_struct *task);
30
31/**
32 * kmsan_task_exit() - Notify KMSAN that a task has exited.
33 * @task: task about to finish.
34 */
35void kmsan_task_exit(struct task_struct *task);
36
37/**
38 * kmsan_init_shadow() - Initialize KMSAN shadow at boot time.
39 *
40 * Allocate and initialize KMSAN metadata for early allocations.
41 */
42void __init kmsan_init_shadow(void);
43
44/**
45 * kmsan_init_runtime() - Initialize KMSAN state and enable KMSAN.
46 */
47void __init kmsan_init_runtime(void);
48
49/**
50 * kmsan_memblock_free_pages() - handle freeing of memblock pages.
51 * @page: struct page to free.
52 * @order: order of @page.
53 *
54 * Freed pages are either returned to buddy allocator or held back to be used
55 * as metadata pages.
56 */
57bool __init kmsan_memblock_free_pages(struct page *page, unsigned int order);
58
59/**
60 * kmsan_alloc_page() - Notify KMSAN about an alloc_pages() call.
61 * @page: struct page pointer returned by alloc_pages().
62 * @order: order of allocated struct page.
63 * @flags: GFP flags used by alloc_pages()
64 *
65 * KMSAN marks 1<<@order pages starting at @page as uninitialized, unless
66 * @flags contain __GFP_ZERO.
67 */
68void kmsan_alloc_page(struct page *page, unsigned int order, gfp_t flags);
69
70/**
71 * kmsan_free_page() - Notify KMSAN about a free_pages() call.
72 * @page: struct page pointer passed to free_pages().
73 * @order: order of deallocated struct page.
74 *
75 * KMSAN marks freed memory as uninitialized.
76 */
77void kmsan_free_page(struct page *page, unsigned int order);
78
79/**
80 * kmsan_copy_page_meta() - Copy KMSAN metadata between two pages.
81 * @dst: destination page.
82 * @src: source page.
83 *
84 * KMSAN copies the contents of metadata pages for @src into the metadata pages
85 * for @dst. If @dst has no associated metadata pages, nothing happens.
86 * If @src has no associated metadata pages, @dst metadata pages are unpoisoned.
87 */
88void kmsan_copy_page_meta(struct page *dst, struct page *src);
89
90/**
91 * kmsan_slab_alloc() - Notify KMSAN about a slab allocation.
92 * @s: slab cache the object belongs to.
93 * @object: object pointer.
94 * @flags: GFP flags passed to the allocator.
95 *
96 * Depending on cache flags and GFP flags, KMSAN sets up the metadata of the
97 * newly created object, marking it as initialized or uninitialized.
98 */
99void kmsan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags);
100
101/**
102 * kmsan_slab_free() - Notify KMSAN about a slab deallocation.
103 * @s: slab cache the object belongs to.
104 * @object: object pointer.
105 *
106 * KMSAN marks the freed object as uninitialized.
107 */
108void kmsan_slab_free(struct kmem_cache *s, void *object);
109
110/**
111 * kmsan_kmalloc_large() - Notify KMSAN about a large slab allocation.
112 * @ptr: object pointer.
113 * @size: object size.
114 * @flags: GFP flags passed to the allocator.
115 *
116 * Similar to kmsan_slab_alloc(), but for large allocations.
117 */
118void kmsan_kmalloc_large(const void *ptr, size_t size, gfp_t flags);
119
120/**
121 * kmsan_kfree_large() - Notify KMSAN about a large slab deallocation.
122 * @ptr: object pointer.
123 *
124 * Similar to kmsan_slab_free(), but for large allocations.
125 */
126void kmsan_kfree_large(const void *ptr);
127
128/**
129 * kmsan_map_kernel_range_noflush() - Notify KMSAN about a vmap.
130 * @start: start of vmapped range.
131 * @end: end of vmapped range.
132 * @prot: page protection flags used for vmap.
133 * @pages: array of pages.
134 * @page_shift: page_shift passed to vmap_range_noflush().
135 *
136 * KMSAN maps shadow and origin pages of @pages into contiguous ranges in
137 * vmalloc metadata address range.
138 */
139void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end,
140 pgprot_t prot, struct page **pages,
141 unsigned int page_shift);
142
143/**
144 * kmsan_vunmap_kernel_range_noflush() - Notify KMSAN about a vunmap.
145 * @start: start of vunmapped range.
146 * @end: end of vunmapped range.
147 *
148 * KMSAN unmaps the contiguous metadata ranges created by
149 * kmsan_map_kernel_range_noflush().
150 */
151void kmsan_vunmap_range_noflush(unsigned long start, unsigned long end);
152
153/**
154 * kmsan_ioremap_page_range() - Notify KMSAN about a ioremap_page_range() call.
155 * @addr: range start.
156 * @end: range end.
157 * @phys_addr: physical range start.
158 * @prot: page protection flags used for ioremap_page_range().
159 * @page_shift: page_shift argument passed to vmap_range_noflush().
160 *
161 * KMSAN creates new metadata pages for the physical pages mapped into the
162 * virtual memory.
163 */
164void kmsan_ioremap_page_range(unsigned long addr, unsigned long end,
165 phys_addr_t phys_addr, pgprot_t prot,
166 unsigned int page_shift);
167
168/**
169 * kmsan_iounmap_page_range() - Notify KMSAN about a iounmap_page_range() call.
170 * @start: range start.
171 * @end: range end.
172 *
173 * KMSAN unmaps the metadata pages for the given range and, unlike for
174 * vunmap_page_range(), also deallocates them.
175 */
176void kmsan_iounmap_page_range(unsigned long start, unsigned long end);
177
178/**
179 * kmsan_handle_dma() - Handle a DMA data transfer.
180 * @page: first page of the buffer.
181 * @offset: offset of the buffer within the first page.
182 * @size: buffer size.
183 * @dir: one of possible dma_data_direction values.
184 *
185 * Depending on @direction, KMSAN:
186 * * checks the buffer, if it is copied to device;
187 * * initializes the buffer, if it is copied from device;
188 * * does both, if this is a DMA_BIDIRECTIONAL transfer.
189 */
190void kmsan_handle_dma(struct page *page, size_t offset, size_t size,
191 enum dma_data_direction dir);
192
193/**
194 * kmsan_handle_dma_sg() - Handle a DMA transfer using scatterlist.
195 * @sg: scatterlist holding DMA buffers.
196 * @nents: number of scatterlist entries.
197 * @dir: one of possible dma_data_direction values.
198 *
199 * Depending on @direction, KMSAN:
200 * * checks the buffers in the scatterlist, if they are copied to device;
201 * * initializes the buffers, if they are copied from device;
202 * * does both, if this is a DMA_BIDIRECTIONAL transfer.
203 */
204void kmsan_handle_dma_sg(struct scatterlist *sg, int nents,
205 enum dma_data_direction dir);
206
207/**
208 * kmsan_handle_urb() - Handle a USB data transfer.
209 * @urb: struct urb pointer.
210 * @is_out: data transfer direction (true means output to hardware).
211 *
212 * If @is_out is true, KMSAN checks the transfer buffer of @urb. Otherwise,
213 * KMSAN initializes the transfer buffer.
214 */
215void kmsan_handle_urb(const struct urb *urb, bool is_out);
216
217/**
218 * kmsan_unpoison_entry_regs() - Handle pt_regs in low-level entry code.
219 * @regs: struct pt_regs pointer received from assembly code.
220 *
221 * KMSAN unpoisons the contents of the passed pt_regs, preventing potential
222 * false positive reports. Unlike kmsan_unpoison_memory(),
223 * kmsan_unpoison_entry_regs() can be called from the regions where
224 * kmsan_in_runtime() returns true, which is the case in early entry code.
225 */
226void kmsan_unpoison_entry_regs(const struct pt_regs *regs);
227
228#else
229
230static inline void kmsan_init_shadow(void)
231{
232}
233
234static inline void kmsan_init_runtime(void)
235{
236}
237
238static inline bool kmsan_memblock_free_pages(struct page *page,
239 unsigned int order)
240{
241 return true;
242}
243
244static inline void kmsan_task_create(struct task_struct *task)
245{
246}
247
248static inline void kmsan_task_exit(struct task_struct *task)
249{
250}
251
252static inline int kmsan_alloc_page(struct page *page, unsigned int order,
253 gfp_t flags)
254{
255 return 0;
256}
257
258static inline void kmsan_free_page(struct page *page, unsigned int order)
259{
260}
261
262static inline void kmsan_copy_page_meta(struct page *dst, struct page *src)
263{
264}
265
266static inline void kmsan_slab_alloc(struct kmem_cache *s, void *object,
267 gfp_t flags)
268{
269}
270
271static inline void kmsan_slab_free(struct kmem_cache *s, void *object)
272{
273}
274
275static inline void kmsan_kmalloc_large(const void *ptr, size_t size,
276 gfp_t flags)
277{
278}
279
280static inline void kmsan_kfree_large(const void *ptr)
281{
282}
283
284static inline void kmsan_vmap_pages_range_noflush(unsigned long start,
285 unsigned long end,
286 pgprot_t prot,
287 struct page **pages,
288 unsigned int page_shift)
289{
290}
291
292static inline void kmsan_vunmap_range_noflush(unsigned long start,
293 unsigned long end)
294{
295}
296
297static inline void kmsan_ioremap_page_range(unsigned long start,
298 unsigned long end,
299 phys_addr_t phys_addr,
300 pgprot_t prot,
301 unsigned int page_shift)
302{
303}
304
305static inline void kmsan_iounmap_page_range(unsigned long start,
306 unsigned long end)
307{
308}
309
310static inline void kmsan_handle_dma(struct page *page, size_t offset,
311 size_t size, enum dma_data_direction dir)
312{
313}
314
315static inline void kmsan_handle_dma_sg(struct scatterlist *sg, int nents,
316 enum dma_data_direction dir)
317{
318}
319
320static inline void kmsan_handle_urb(const struct urb *urb, bool is_out)
321{
322}
323
324static inline void kmsan_unpoison_entry_regs(const struct pt_regs *regs)
325{
326}
327
328#endif
329
330#endif /* _LINUX_KMSAN_H */