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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * Copyright © 2022 Intel Corporation4 */5#ifndef __XE_PT_WALK__6#define __XE_PT_WALK__7 8#include <linux/pagewalk.h>9#include <linux/types.h>10 11/**12 * struct xe_ptw - base class for driver pagetable subclassing.13 * @children: Pointer to an array of children if any.14 *15 * Drivers could subclass this, and if it's a page-directory, typically16 * embed an array of xe_ptw pointers.17 */18struct xe_ptw {19 struct xe_ptw **children;20};21 22/**23 * struct xe_pt_walk - Embeddable struct for walk parameters24 */25struct xe_pt_walk {26 /** @ops: The walk ops used for the pagewalk */27 const struct xe_pt_walk_ops *ops;28 /**29 * @shifts: Array of page-table entry shifts used for the30 * different levels, starting out with the leaf level 031 * page-shift as the first entry. It's legal for this pointer to be32 * changed during the walk.33 */34 const u64 *shifts;35 /** @max_level: Highest populated level in @sizes */36 unsigned int max_level;37 /**38 * @shared_pt_mode: Whether to skip all entries that are private39 * to the address range and called only for entries that are40 * shared with other address ranges. Such entries are referred to41 * as shared pagetables.42 */43 bool shared_pt_mode;44};45 46/**47 * typedef xe_pt_entry_fn - gpu page-table-walk callback-function48 * @parent: The parent page.table.49 * @offset: The offset (number of entries) into the page table.50 * @level: The level of @parent.51 * @addr: The virtual address.52 * @next: The virtual address for the next call, or end address.53 * @child: Pointer to pointer to child page-table at this @offset. The54 * function may modify the value pointed to if, for example, allocating a55 * child page table.56 * @action: The walk action to take upon return. See <linux/pagewalk.h>.57 * @walk: The walk parameters.58 */59typedef int (*xe_pt_entry_fn)(struct xe_ptw *parent, pgoff_t offset,60 unsigned int level, u64 addr, u64 next,61 struct xe_ptw **child,62 enum page_walk_action *action,63 struct xe_pt_walk *walk);64 65/**66 * struct xe_pt_walk_ops - Walk callbacks.67 */68struct xe_pt_walk_ops {69 /**70 * @pt_entry: Callback to be called for each page table entry prior71 * to descending to the next level. The returned value of the action72 * function parameter is honored.73 */74 xe_pt_entry_fn pt_entry;75 /**76 * @pt_post_descend: Callback to be called for each page table entry77 * after return from descending to the next level. The returned value78 * of the action function parameter is ignored.79 */80 xe_pt_entry_fn pt_post_descend;81};82 83int xe_pt_walk_range(struct xe_ptw *parent, unsigned int level,84 u64 addr, u64 end, struct xe_pt_walk *walk);85 86int xe_pt_walk_shared(struct xe_ptw *parent, unsigned int level,87 u64 addr, u64 end, struct xe_pt_walk *walk);88 89/**90 * xe_pt_covers - Whether the address range covers an entire entry in @level91 * @addr: Start of the range.92 * @end: End of range + 1.93 * @level: Page table level.94 * @walk: Page table walk info.95 *96 * This function is a helper to aid in determining whether a leaf page table97 * entry can be inserted at this @level.98 *99 * Return: Whether the range provided covers exactly an entry at this level.100 */101static inline bool xe_pt_covers(u64 addr, u64 end, unsigned int level,102 const struct xe_pt_walk *walk)103{104 u64 pt_size = 1ull << walk->shifts[level];105 106 return end - addr == pt_size && IS_ALIGNED(addr, pt_size);107}108 109/**110 * xe_pt_num_entries: Number of page-table entries of a given range at this111 * level112 * @addr: Start address.113 * @end: End address.114 * @level: Page table level.115 * @walk: Walk info.116 *117 * Return: The number of page table entries at this level between @start and118 * @end.119 */120static inline pgoff_t121xe_pt_num_entries(u64 addr, u64 end, unsigned int level,122 const struct xe_pt_walk *walk)123{124 u64 pt_size = 1ull << walk->shifts[level];125 126 return (round_up(end, pt_size) - round_down(addr, pt_size)) >>127 walk->shifts[level];128}129 130/**131 * xe_pt_offset: Offset of the page-table entry for a given address.132 * @addr: The address.133 * @level: Page table level.134 * @walk: Walk info.135 *136 * Return: The page table entry offset for the given address in a137 * page table with size indicated by @level.138 */139static inline pgoff_t140xe_pt_offset(u64 addr, unsigned int level, const struct xe_pt_walk *walk)141{142 if (level < walk->max_level)143 addr &= ((1ull << walk->shifts[level + 1]) - 1);144 145 return addr >> walk->shifts[level];146}147 148#endif149