cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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hmm.h (4023B)

      1/* SPDX-License-Identifier: GPL-2.0-or-later */
      2/*
      3 * Copyright 2013 Red Hat Inc.
      4 *
      5 * Authors: Jérôme Glisse <jglisse@redhat.com>
      6 *
      7 * See Documentation/vm/hmm.rst for reasons and overview of what HMM is.
      8 */
      9#ifndef LINUX_HMM_H
     10#define LINUX_HMM_H
     11
     12#include <linux/mm.h>
     13
     14struct mmu_interval_notifier;
     15
     16/*
     17 * On output:
     18 * 0             - The page is faultable and a future call with 
     19 *                 HMM_PFN_REQ_FAULT could succeed.
     20 * HMM_PFN_VALID - the pfn field points to a valid PFN. This PFN is at
     21 *                 least readable. If dev_private_owner is !NULL then this could
     22 *                 point at a DEVICE_PRIVATE page.
     23 * HMM_PFN_WRITE - if the page memory can be written to (requires HMM_PFN_VALID)
     24 * HMM_PFN_ERROR - accessing the pfn is impossible and the device should
     25 *                 fail. ie poisoned memory, special pages, no vma, etc
     26 *
     27 * On input:
     28 * 0                 - Return the current state of the page, do not fault it.
     29 * HMM_PFN_REQ_FAULT - The output must have HMM_PFN_VALID or hmm_range_fault()
     30 *                     will fail
     31 * HMM_PFN_REQ_WRITE - The output must have HMM_PFN_WRITE or hmm_range_fault()
     32 *                     will fail. Must be combined with HMM_PFN_REQ_FAULT.
     33 */
     34enum hmm_pfn_flags {
     35	/* Output fields and flags */
     36	HMM_PFN_VALID = 1UL << (BITS_PER_LONG - 1),
     37	HMM_PFN_WRITE = 1UL << (BITS_PER_LONG - 2),
     38	HMM_PFN_ERROR = 1UL << (BITS_PER_LONG - 3),
     39	HMM_PFN_ORDER_SHIFT = (BITS_PER_LONG - 8),
     40
     41	/* Input flags */
     42	HMM_PFN_REQ_FAULT = HMM_PFN_VALID,
     43	HMM_PFN_REQ_WRITE = HMM_PFN_WRITE,
     44
     45	HMM_PFN_FLAGS = 0xFFUL << HMM_PFN_ORDER_SHIFT,
     46};
     47
     48/*
     49 * hmm_pfn_to_page() - return struct page pointed to by a device entry
     50 *
     51 * This must be called under the caller 'user_lock' after a successful
     52 * mmu_interval_read_begin(). The caller must have tested for HMM_PFN_VALID
     53 * already.
     54 */
     55static inline struct page *hmm_pfn_to_page(unsigned long hmm_pfn)
     56{
     57	return pfn_to_page(hmm_pfn & ~HMM_PFN_FLAGS);
     58}
     59
     60/*
     61 * hmm_pfn_to_map_order() - return the CPU mapping size order
     62 *
     63 * This is optionally useful to optimize processing of the pfn result
     64 * array. It indicates that the page starts at the order aligned VA and is
     65 * 1<<order bytes long.  Every pfn within an high order page will have the
     66 * same pfn flags, both access protections and the map_order.  The caller must
     67 * be careful with edge cases as the start and end VA of the given page may
     68 * extend past the range used with hmm_range_fault().
     69 *
     70 * This must be called under the caller 'user_lock' after a successful
     71 * mmu_interval_read_begin(). The caller must have tested for HMM_PFN_VALID
     72 * already.
     73 */
     74static inline unsigned int hmm_pfn_to_map_order(unsigned long hmm_pfn)
     75{
     76	return (hmm_pfn >> HMM_PFN_ORDER_SHIFT) & 0x1F;
     77}
     78
     79/*
     80 * struct hmm_range - track invalidation lock on virtual address range
     81 *
     82 * @notifier: a mmu_interval_notifier that includes the start/end
     83 * @notifier_seq: result of mmu_interval_read_begin()
     84 * @start: range virtual start address (inclusive)
     85 * @end: range virtual end address (exclusive)
     86 * @hmm_pfns: array of pfns (big enough for the range)
     87 * @default_flags: default flags for the range (write, read, ... see hmm doc)
     88 * @pfn_flags_mask: allows to mask pfn flags so that only default_flags matter
     89 * @dev_private_owner: owner of device private pages
     90 */
     91struct hmm_range {
     92	struct mmu_interval_notifier *notifier;
     93	unsigned long		notifier_seq;
     94	unsigned long		start;
     95	unsigned long		end;
     96	unsigned long		*hmm_pfns;
     97	unsigned long		default_flags;
     98	unsigned long		pfn_flags_mask;
     99	void			*dev_private_owner;
    100};
    101
    102/*
    103 * Please see Documentation/vm/hmm.rst for how to use the range API.
    104 */
    105int hmm_range_fault(struct hmm_range *range);
    106
    107/*
    108 * HMM_RANGE_DEFAULT_TIMEOUT - default timeout (ms) when waiting for a range
    109 *
    110 * When waiting for mmu notifiers we need some kind of time out otherwise we
    111 * could potentially wait for ever, 1000ms ie 1s sounds like a long time to
    112 * wait already.
    113 */
    114#define HMM_RANGE_DEFAULT_TIMEOUT 1000
    115
    116#endif /* LINUX_HMM_H */