[Intel-xe] [PATCH 1/2] Revert "drm: Add a gpu page-table walker helper"
Rodrigo Vivi
rodrigo.vivi at intel.com
Mon May 1 19:03:13 UTC 2023
This reverts commit 500e50fde9938fdc16c05caf5468db9ab2e69156.
---
drivers/gpu/drm/Makefile | 1 -
drivers/gpu/drm/drm_pt_walk.c | 159 ---------------------------------
include/drm/drm_pt_walk.h | 161 ----------------------------------
3 files changed, 321 deletions(-)
delete mode 100644 drivers/gpu/drm/drm_pt_walk.c
delete mode 100644 include/drm/drm_pt_walk.h
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 66dd2c48944a..795abcc0ca7e 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -39,7 +39,6 @@ drm-y := \
drm_prime.o \
drm_print.o \
drm_property.o \
- drm_pt_walk.o \
drm_syncobj.o \
drm_sysfs.o \
drm_trace_points.o \
diff --git a/drivers/gpu/drm/drm_pt_walk.c b/drivers/gpu/drm/drm_pt_walk.c
deleted file mode 100644
index 1a0b147a3acc..000000000000
--- a/drivers/gpu/drm/drm_pt_walk.c
+++ /dev/null
@@ -1,159 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright © 2022 Intel Corporation
- */
-#include <drm/drm_pt_walk.h>
-
-/**
- * DOC: GPU page-table tree walking.
- * The utilities in this file are similar to the CPU page-table walk
- * utilities in mm/pagewalk.c. The main difference is that we distinguish
- * the various levels of a page-table tree with an unsigned integer rather
- * than by name. 0 is the lowest level, and page-tables with level 0 can
- * not be directories pointing to lower levels, whereas all other levels
- * can. The user of the utilities determines the highest level.
- *
- * Nomenclature:
- * Each struct drm_pt, regardless of level is referred to as a page table, and
- * multiple page tables typically form a page table tree with page tables at
- * intermediate levels being page directories pointing at page tables at lower
- * levels. A shared page table for a given address range is a page-table which
- * is neither fully within nor fully outside the address range and that can
- * thus be shared by two or more address ranges.
- */
-static u64 drm_pt_addr_end(u64 addr, u64 end, unsigned int level,
- const struct drm_pt_walk *walk)
-{
- u64 size = 1ull << walk->shifts[level];
- u64 tmp = round_up(addr + 1, size);
-
- return min_t(u64, tmp, end);
-}
-
-static bool drm_pt_next(pgoff_t *offset, u64 *addr, u64 next, u64 end,
- unsigned int level, const struct drm_pt_walk *walk)
-{
- pgoff_t step = 1;
-
- /* Shared pt walk skips to the last pagetable */
- if (unlikely(walk->shared_pt_mode)) {
- unsigned int shift = walk->shifts[level];
- u64 skip_to = round_down(end, 1ull << shift);
-
- if (skip_to > next) {
- step += (skip_to - next) >> shift;
- next = skip_to;
- }
- }
-
- *addr = next;
- *offset += step;
-
- return next != end;
-}
-
-/**
- * drm_pt_walk_range() - Walk a range of a gpu page table tree with callbacks
- * for each page-table entry in all levels.
- * @parent: The root page table for walk start.
- * @level: The root page table level.
- * @addr: Virtual address start.
- * @end: Virtual address end + 1.
- * @walk: Walk info.
- *
- * Similar to the CPU page-table walker, this is a helper to walk
- * a gpu page table and call a provided callback function for each entry.
- *
- * Return: 0 on success, negative error code on error. The error is
- * propagated from the callback and on error the walk is terminated.
- */
-int drm_pt_walk_range(struct drm_pt *parent, unsigned int level,
- u64 addr, u64 end, struct drm_pt_walk *walk)
-{
- pgoff_t offset = drm_pt_offset(addr, level, walk);
- struct drm_pt **entries = parent->dir ? parent->dir->entries : NULL;
- const struct drm_pt_walk_ops *ops = walk->ops;
- enum page_walk_action action;
- struct drm_pt *child;
- int err = 0;
- u64 next;
-
- do {
- next = drm_pt_addr_end(addr, end, level, walk);
- if (walk->shared_pt_mode && drm_pt_covers(addr, next, level,
- walk))
- continue;
-again:
- action = ACTION_SUBTREE;
- child = entries ? entries[offset] : NULL;
- err = ops->pt_entry(parent, offset, level, addr, next,
- &child, &action, walk);
- if (err)
- break;
-
- /* Probably not needed yet for gpu pagetable walk. */
- if (unlikely(action == ACTION_AGAIN))
- goto again;
-
- if (likely(!level || !child || action == ACTION_CONTINUE))
- continue;
-
- err = drm_pt_walk_range(child, level - 1, addr, next, walk);
-
- if (!err && ops->pt_post_descend)
- err = ops->pt_post_descend(parent, offset, level, addr,
- next, &child, &action, walk);
- if (err)
- break;
-
- } while (drm_pt_next(&offset, &addr, next, end, level, walk));
-
- return err;
-}
-EXPORT_SYMBOL(drm_pt_walk_range);
-
-/**
- * drm_pt_walk_shared() - Walk shared page tables of a page-table tree.
- * @parent: Root page table directory.
- * @level: Level of the root.
- * @addr: Start address.
- * @end: Last address + 1.
- * @walk: Walk info.
- *
- * This function is similar to drm_pt_walk_range() but it skips page tables
- * that are private to the range. Since the root (or @parent) page table is
- * typically also a shared page table this function is different in that it
- * calls the pt_entry callback and the post_descend callback also for the
- * root. The root can be detected in the callbacks by checking whether
- * parent == *child.
- * Walking only the shared page tables is common for unbind-type operations
- * where the page-table entries for an address range are cleared or detached
- * from the main page-table tree.
- *
- * Return: 0 on success, negative error code on error: If a callback
- * returns an error, the walk will be terminated and the error returned by
- * this function.
- */
-int drm_pt_walk_shared(struct drm_pt *parent, unsigned int level,
- u64 addr, u64 end, struct drm_pt_walk *walk)
-{
- const struct drm_pt_walk_ops *ops = walk->ops;
- enum page_walk_action action = ACTION_SUBTREE;
- struct drm_pt *child = parent;
- int err;
-
- walk->shared_pt_mode = true;
- err = walk->ops->pt_entry(parent, 0, level + 1, addr, end,
- &child, &action, walk);
-
- if (err || action != ACTION_SUBTREE)
- return err;
-
- err = drm_pt_walk_range(parent, level, addr, end, walk);
- if (!err && ops->pt_post_descend) {
- err = ops->pt_post_descend(parent, 0, level + 1, addr, end,
- &child, &action, walk);
- }
- return err;
-}
-EXPORT_SYMBOL(drm_pt_walk_shared);
diff --git a/include/drm/drm_pt_walk.h b/include/drm/drm_pt_walk.h
deleted file mode 100644
index 64e7a418217c..000000000000
--- a/include/drm/drm_pt_walk.h
+++ /dev/null
@@ -1,161 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Copyright © 2022 Intel Corporation
- */
-#ifndef __DRM_PT_WALK__
-#define __DRM_PT_WALK__
-
-#include <linux/pagewalk.h>
-#include <linux/types.h>
-
-struct drm_pt_dir;
-
-/**
- * struct drm_pt - base class for driver pagetable subclassing.
- * @dir: Pointer to an array of children if any.
- *
- * Drivers could subclass this, and if it's a page-directory, typically
- * embed the drm_pt_dir::entries array in the same allocation.
- */
-struct drm_pt {
- struct drm_pt_dir *dir;
-};
-
-/**
- * struct drm_pt_dir - page directory structure
- * @entries: Array holding page directory children.
- *
- * It is the responsibility of the user to ensure @entries is
- * correctly sized.
- */
-struct drm_pt_dir {
- struct drm_pt *entries[0];
-};
-
-/**
- * struct drm_pt_walk - Embeddable struct for walk parameters
- */
-struct drm_pt_walk {
- /** @ops: The walk ops used for the pagewalk */
- const struct drm_pt_walk_ops *ops;
- /**
- * @shifts: Array of page-table entry shifts used for the
- * different levels, starting out with the leaf level 0
- * page-shift as the first entry. It's legal for this pointer to be
- * changed during the walk.
- */
- const u64 *shifts;
- /** @max_level: Highest populated level in @sizes */
- unsigned int max_level;
- /**
- * @shared_pt_mode: Whether to skip all entries that are private
- * to the address range and called only for entries that are
- * shared with other address ranges. Such entries are referred to
- * as shared pagetables.
- */
- bool shared_pt_mode;
-};
-
-/**
- * typedef drm_pt_entry_fn - gpu page-table-walk callback-function
- * @parent: The parent page.table.
- * @offset: The offset (number of entries) into the page table.
- * @level: The level of @parent.
- * @addr: The virtual address.
- * @next: The virtual address for the next call, or end address.
- * @child: Pointer to pointer to child page-table at this @offset. The
- * function may modify the value pointed to if, for example, allocating a
- * child page table.
- * @action: The walk action to take upon return. See <linux/pagewalk.h>.
- * @walk: The walk parameters.
- */
-typedef int (*drm_pt_entry_fn)(struct drm_pt *parent, pgoff_t offset,
- unsigned int level, u64 addr, u64 next,
- struct drm_pt **child,
- enum page_walk_action *action,
- struct drm_pt_walk *walk);
-
-/**
- * struct drm_pt_walk_ops - Walk callbacks.
- */
-struct drm_pt_walk_ops {
- /**
- * @pt_entry: Callback to be called for each page table entry prior
- * to descending to the next level. The returned value of the action
- * function parameter is honored.
- */
- drm_pt_entry_fn pt_entry;
- /**
- * @pt_post_descend: Callback to be called for each page table entry
- * after return from descending to the next level. The returned value
- * of the action function parameter is ignored.
- */
- drm_pt_entry_fn pt_post_descend;
-};
-
-int drm_pt_walk_range(struct drm_pt *parent, unsigned int level,
- u64 addr, u64 end, struct drm_pt_walk *walk);
-
-int drm_pt_walk_shared(struct drm_pt *parent, unsigned int level,
- u64 addr, u64 end, struct drm_pt_walk *walk);
-
-/**
- * drm_pt_covers - Whether the address range covers an entire entry in @level
- * @addr: Start of the range.
- * @end: End of range + 1.
- * @level: Page table level.
- * @walk: Page table walk info.
- *
- * This function is a helper to aid in determining whether a leaf page table
- * entry can be inserted at this @level.
- *
- * Return: Whether the range provided covers exactly an entry at this level.
- */
-static inline bool drm_pt_covers(u64 addr, u64 end, unsigned int level,
- const struct drm_pt_walk *walk)
-{
- u64 pt_size = 1ull << walk->shifts[level];
-
- return end - addr == pt_size && IS_ALIGNED(addr, pt_size);
-}
-
-/**
- * drm_pt_num_entries: Number of page-table entries of a given range at this
- * level
- * @addr: Start address.
- * @end: End address.
- * @level: Page table level.
- * @walk: Walk info.
- *
- * Return: The number of page table entries at this level between @start and
- * @end.
- */
-static inline pgoff_t
-drm_pt_num_entries(u64 addr, u64 end, unsigned int level,
- const struct drm_pt_walk *walk)
-{
- u64 pt_size = 1ull << walk->shifts[level];
-
- return (round_up(end, pt_size) - round_down(addr, pt_size)) >>
- walk->shifts[level];
-}
-
-/**
- * drm_pt_offset: Offset of the page-table entry for a given address.
- * @addr: The address.
- * @level: Page table level.
- * @walk: Walk info.
- *
- * Return: The page table entry offset for the given address in a
- * page table with size indicated by @level.
- */
-static inline pgoff_t
-drm_pt_offset(u64 addr, unsigned int level, const struct drm_pt_walk *walk)
-{
- if (level < walk->max_level)
- addr &= ((1ull << walk->shifts[level + 1]) - 1);
-
- return addr >> walk->shifts[level];
-}
-
-#endif
--
2.39.2
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