/* SPDX-License-Identifier: GPL-2.0 */ /* * KMSAN API for subsystems. * * Copyright (C) 2017-2022 Google LLC * Author: Alexander Potapenko <[email protected]> * */ #ifndef _LINUX_KMSAN_H #define _LINUX_KMSAN_H #include <linux/dma-direction.h> #include <linux/gfp.h> #include <linux/kmsan-checks.h> #include <linux/types.h> struct page; struct kmem_cache; struct task_struct; struct scatterlist; struct urb; #ifdef CONFIG_KMSAN /** * kmsan_task_create() - Initialize KMSAN state for the task. * @task: task to initialize. */ void kmsan_task_create(struct task_struct *task); /** * kmsan_task_exit() - Notify KMSAN that a task has exited. * @task: task about to finish. */ void kmsan_task_exit(struct task_struct *task); /** * kmsan_init_shadow() - Initialize KMSAN shadow at boot time. * * Allocate and initialize KMSAN metadata for early allocations. */ void __init kmsan_init_shadow(void); /** * kmsan_init_runtime() - Initialize KMSAN state and enable KMSAN. */ void __init kmsan_init_runtime(void); /** * kmsan_memblock_free_pages() - handle freeing of memblock pages. * @page: struct page to free. * @order: order of @page. * * Freed pages are either returned to buddy allocator or held back to be used * as metadata pages. */ bool __init __must_check kmsan_memblock_free_pages(struct page *page, unsigned int order); /** * kmsan_alloc_page() - Notify KMSAN about an alloc_pages() call. * @page: struct page pointer returned by alloc_pages(). * @order: order of allocated struct page. * @flags: GFP flags used by alloc_pages() * * KMSAN marks 1<<@order pages starting at @page as uninitialized, unless * @flags contain __GFP_ZERO. */ void kmsan_alloc_page(struct page *page, unsigned int order, gfp_t flags); /** * kmsan_free_page() - Notify KMSAN about a free_pages() call. * @page: struct page pointer passed to free_pages(). * @order: order of deallocated struct page. * * KMSAN marks freed memory as uninitialized. */ void kmsan_free_page(struct page *page, unsigned int order); /** * kmsan_copy_page_meta() - Copy KMSAN metadata between two pages. * @dst: destination page. * @src: source page. * * KMSAN copies the contents of metadata pages for @src into the metadata pages * for @dst. If @dst has no associated metadata pages, nothing happens. * If @src has no associated metadata pages, @dst metadata pages are unpoisoned. */ void kmsan_copy_page_meta(struct page *dst, struct page *src); /** * kmsan_slab_alloc() - Notify KMSAN about a slab allocation. * @s: slab cache the object belongs to. * @object: object pointer. * @flags: GFP flags passed to the allocator. * * Depending on cache flags and GFP flags, KMSAN sets up the metadata of the * newly created object, marking it as initialized or uninitialized. */ void kmsan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags); /** * kmsan_slab_free() - Notify KMSAN about a slab deallocation. * @s: slab cache the object belongs to. * @object: object pointer. * * KMSAN marks the freed object as uninitialized. */ void kmsan_slab_free(struct kmem_cache *s, void *object); /** * kmsan_kmalloc_large() - Notify KMSAN about a large slab allocation. * @ptr: object pointer. * @size: object size. * @flags: GFP flags passed to the allocator. * * Similar to kmsan_slab_alloc(), but for large allocations. */ void kmsan_kmalloc_large(const void *ptr, size_t size, gfp_t flags); /** * kmsan_kfree_large() - Notify KMSAN about a large slab deallocation. * @ptr: object pointer. * * Similar to kmsan_slab_free(), but for large allocations. */ void kmsan_kfree_large(const void *ptr); /** * kmsan_map_kernel_range_noflush() - Notify KMSAN about a vmap. * @start: start of vmapped range. * @end: end of vmapped range. * @prot: page protection flags used for vmap. * @pages: array of pages. * @page_shift: page_shift passed to vmap_range_noflush(). * * KMSAN maps shadow and origin pages of @pages into contiguous ranges in * vmalloc metadata address range. Returns 0 on success, callers must check * for non-zero return value. */ int __must_check kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, pgprot_t prot, struct page **pages, unsigned int page_shift); /** * kmsan_vunmap_kernel_range_noflush() - Notify KMSAN about a vunmap. * @start: start of vunmapped range. * @end: end of vunmapped range. * * KMSAN unmaps the contiguous metadata ranges created by * kmsan_map_kernel_range_noflush(). */ void kmsan_vunmap_range_noflush(unsigned long start, unsigned long end); /** * kmsan_ioremap_page_range() - Notify KMSAN about a ioremap_page_range() call. * @addr: range start. * @end: range end. * @phys_addr: physical range start. * @prot: page protection flags used for ioremap_page_range(). * @page_shift: page_shift argument passed to vmap_range_noflush(). * * KMSAN creates new metadata pages for the physical pages mapped into the * virtual memory. Returns 0 on success, callers must check for non-zero return * value. */ int __must_check kmsan_ioremap_page_range(unsigned long addr, unsigned long end, phys_addr_t phys_addr, pgprot_t prot, unsigned int page_shift); /** * kmsan_iounmap_page_range() - Notify KMSAN about a iounmap_page_range() call. * @start: range start. * @end: range end. * * KMSAN unmaps the metadata pages for the given range and, unlike for * vunmap_page_range(), also deallocates them. */ void kmsan_iounmap_page_range(unsigned long start, unsigned long end); /** * kmsan_handle_dma() - Handle a DMA data transfer. * @page: first page of the buffer. * @offset: offset of the buffer within the first page. * @size: buffer size. * @dir: one of possible dma_data_direction values. * * Depending on @direction, KMSAN: * * checks the buffer, if it is copied to device; * * initializes the buffer, if it is copied from device; * * does both, if this is a DMA_BIDIRECTIONAL transfer. */ void kmsan_handle_dma(struct page *page, size_t offset, size_t size, enum dma_data_direction dir); /** * kmsan_handle_dma_sg() - Handle a DMA transfer using scatterlist. * @sg: scatterlist holding DMA buffers. * @nents: number of scatterlist entries. * @dir: one of possible dma_data_direction values. * * Depending on @direction, KMSAN: * * checks the buffers in the scatterlist, if they are copied to device; * * initializes the buffers, if they are copied from device; * * does both, if this is a DMA_BIDIRECTIONAL transfer. */ void kmsan_handle_dma_sg(struct scatterlist *sg, int nents, enum dma_data_direction dir); /** * kmsan_handle_urb() - Handle a USB data transfer. * @urb: struct urb pointer. * @is_out: data transfer direction (true means output to hardware). * * If @is_out is true, KMSAN checks the transfer buffer of @urb. Otherwise, * KMSAN initializes the transfer buffer. */ void kmsan_handle_urb(const struct urb *urb, bool is_out); /** * kmsan_unpoison_entry_regs() - Handle pt_regs in low-level entry code. * @regs: struct pt_regs pointer received from assembly code. * * KMSAN unpoisons the contents of the passed pt_regs, preventing potential * false positive reports. Unlike kmsan_unpoison_memory(), * kmsan_unpoison_entry_regs() can be called from the regions where * kmsan_in_runtime() returns true, which is the case in early entry code. */ void kmsan_unpoison_entry_regs(const struct pt_regs *regs); /** * kmsan_get_metadata() - Return a pointer to KMSAN shadow or origins. * @addr: kernel address. * @is_origin: whether to return origins or shadow. * * Return NULL if metadata cannot be found. */ void *kmsan_get_metadata(void *addr, bool is_origin); /** * kmsan_enable_current(): Enable KMSAN for the current task. * * Each kmsan_enable_current() current call must be preceded by a * kmsan_disable_current() call. These call pairs may be nested. */ void kmsan_enable_current(void); /** * kmsan_disable_current(): Disable KMSAN for the current task. * * Each kmsan_disable_current() current call must be followed by a * kmsan_enable_current() call. These call pairs may be nested. */ void kmsan_disable_current(void); /** * memset_no_sanitize_memory(): Fill memory without KMSAN instrumentation. * @s: address of kernel memory to fill. * @c: constant byte to fill the memory with. * @n: number of bytes to fill. * * This is like memset(), but without KMSAN instrumentation. */ static inline void *memset_no_sanitize_memory(void *s, int c, size_t n) { return __memset(s, c, n); } extern bool kmsan_enabled; extern int panic_on_kmsan; /* * KMSAN performs a lot of consistency checks that are currently enabled by * default. BUG_ON is normally discouraged in the kernel, unless used for * debugging, but KMSAN itself is a debugging tool, so it makes little sense to * recover if something goes wrong. */ #define KMSAN_WARN_ON … #else static inline void kmsan_init_shadow(void) { … } static inline void kmsan_init_runtime(void) { … } static inline bool __must_check kmsan_memblock_free_pages(struct page *page, unsigned int order) { … } static inline void kmsan_task_create(struct task_struct *task) { … } static inline void kmsan_task_exit(struct task_struct *task) { … } static inline void kmsan_alloc_page(struct page *page, unsigned int order, gfp_t flags) { … } static inline void kmsan_free_page(struct page *page, unsigned int order) { … } static inline void kmsan_copy_page_meta(struct page *dst, struct page *src) { … } static inline void kmsan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags) { … } static inline void kmsan_slab_free(struct kmem_cache *s, void *object) { … } static inline void kmsan_kmalloc_large(const void *ptr, size_t size, gfp_t flags) { … } static inline void kmsan_kfree_large(const void *ptr) { … } static inline int __must_check kmsan_vmap_pages_range_noflush( unsigned long start, unsigned long end, pgprot_t prot, struct page **pages, unsigned int page_shift) { … } static inline void kmsan_vunmap_range_noflush(unsigned long start, unsigned long end) { … } static inline int __must_check kmsan_ioremap_page_range(unsigned long start, unsigned long end, phys_addr_t phys_addr, pgprot_t prot, unsigned int page_shift) { … } static inline void kmsan_iounmap_page_range(unsigned long start, unsigned long end) { … } static inline void kmsan_handle_dma(struct page *page, size_t offset, size_t size, enum dma_data_direction dir) { … } static inline void kmsan_handle_dma_sg(struct scatterlist *sg, int nents, enum dma_data_direction dir) { … } static inline void kmsan_handle_urb(const struct urb *urb, bool is_out) { … } static inline void kmsan_unpoison_entry_regs(const struct pt_regs *regs) { … } static inline void kmsan_enable_current(void) { … } static inline void kmsan_disable_current(void) { … } static inline void *memset_no_sanitize_memory(void *s, int c, size_t n) { … } #define KMSAN_WARN_ON … #endif #endif /* _LINUX_KMSAN_H */
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