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/* SPDX-License-Identifier: GPL-2.0 */
/*
* KMSAN API for subsystems.
*
* Copyright (C) 2017-2022 Google LLC
* Author: Alexander Potapenko <glider@google.com>
*
*/
#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);
#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)
{
return true;
}
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)
{
return 0;
}
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)
{
return 0;
}
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)
{
}
#endif
#endif /* _LINUX_KMSAN_H */