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![Michel Lespinasse](/assets/img/avatar_default.png)
Add RB_DECLARE_CALLBACKS_MAX, which generates augmented rbtree callbacks for the case where the augmented value is a scalar whose definition follows a max(f(node)) pattern. This actually covers all present uses of RB_DECLARE_CALLBACKS, and saves some (source) code duplication in the various RBCOMPUTE function definitions. [walken@google.com: fix mm/vmalloc.c] Link: http://lkml.kernel.org/r/CANN689FXgK13wDYNh1zKxdipeTuALG4eKvKpsdZqKFJ-rvtGiQ@mail.gmail.com [walken@google.com: re-add check to check_augmented()] Link: http://lkml.kernel.org/r/20190727022027.GA86863@google.com Link: http://lkml.kernel.org/r/20190703040156.56953-3-walken@google.com Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
268 lines
6.5 KiB
C
268 lines
6.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Handle caching attributes in page tables (PAT)
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*
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* Authors: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
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* Suresh B Siddha <suresh.b.siddha@intel.com>
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*
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* Interval tree (augmented rbtree) used to store the PAT memory type
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* reservations.
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*/
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#include <linux/seq_file.h>
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#include <linux/debugfs.h>
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#include <linux/kernel.h>
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#include <linux/rbtree_augmented.h>
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#include <linux/sched.h>
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#include <linux/gfp.h>
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#include <asm/pgtable.h>
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#include <asm/pat.h>
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#include "pat_internal.h"
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/*
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* The memtype tree keeps track of memory type for specific
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* physical memory areas. Without proper tracking, conflicting memory
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* types in different mappings can cause CPU cache corruption.
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*
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* The tree is an interval tree (augmented rbtree) with tree ordered
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* on starting address. Tree can contain multiple entries for
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* different regions which overlap. All the aliases have the same
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* cache attributes of course.
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*
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* memtype_lock protects the rbtree.
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*/
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static struct rb_root memtype_rbroot = RB_ROOT;
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static int is_node_overlap(struct memtype *node, u64 start, u64 end)
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{
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if (node->start >= end || node->end <= start)
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return 0;
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return 1;
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}
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static u64 get_subtree_max_end(struct rb_node *node)
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{
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u64 ret = 0;
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if (node) {
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struct memtype *data = rb_entry(node, struct memtype, rb);
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ret = data->subtree_max_end;
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}
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return ret;
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}
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#define NODE_END(node) ((node)->end)
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RB_DECLARE_CALLBACKS_MAX(static, memtype_rb_augment_cb,
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struct memtype, rb, u64, subtree_max_end, NODE_END)
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/* Find the first (lowest start addr) overlapping range from rb tree */
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static struct memtype *memtype_rb_lowest_match(struct rb_root *root,
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u64 start, u64 end)
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{
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struct rb_node *node = root->rb_node;
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struct memtype *last_lower = NULL;
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while (node) {
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struct memtype *data = rb_entry(node, struct memtype, rb);
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if (get_subtree_max_end(node->rb_left) > start) {
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/* Lowest overlap if any must be on left side */
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node = node->rb_left;
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} else if (is_node_overlap(data, start, end)) {
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last_lower = data;
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break;
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} else if (start >= data->start) {
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/* Lowest overlap if any must be on right side */
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node = node->rb_right;
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} else {
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break;
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}
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}
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return last_lower; /* Returns NULL if there is no overlap */
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}
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enum {
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MEMTYPE_EXACT_MATCH = 0,
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MEMTYPE_END_MATCH = 1
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};
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static struct memtype *memtype_rb_match(struct rb_root *root,
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u64 start, u64 end, int match_type)
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{
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struct memtype *match;
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match = memtype_rb_lowest_match(root, start, end);
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while (match != NULL && match->start < end) {
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struct rb_node *node;
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if ((match_type == MEMTYPE_EXACT_MATCH) &&
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(match->start == start) && (match->end == end))
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return match;
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if ((match_type == MEMTYPE_END_MATCH) &&
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(match->start < start) && (match->end == end))
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return match;
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node = rb_next(&match->rb);
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if (node)
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match = rb_entry(node, struct memtype, rb);
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else
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match = NULL;
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}
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return NULL; /* Returns NULL if there is no match */
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}
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static int memtype_rb_check_conflict(struct rb_root *root,
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u64 start, u64 end,
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enum page_cache_mode reqtype,
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enum page_cache_mode *newtype)
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{
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struct rb_node *node;
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struct memtype *match;
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enum page_cache_mode found_type = reqtype;
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match = memtype_rb_lowest_match(&memtype_rbroot, start, end);
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if (match == NULL)
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goto success;
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if (match->type != found_type && newtype == NULL)
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goto failure;
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dprintk("Overlap at 0x%Lx-0x%Lx\n", match->start, match->end);
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found_type = match->type;
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node = rb_next(&match->rb);
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while (node) {
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match = rb_entry(node, struct memtype, rb);
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if (match->start >= end) /* Checked all possible matches */
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goto success;
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if (is_node_overlap(match, start, end) &&
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match->type != found_type) {
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goto failure;
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}
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node = rb_next(&match->rb);
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}
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success:
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if (newtype)
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*newtype = found_type;
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return 0;
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failure:
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pr_info("x86/PAT: %s:%d conflicting memory types %Lx-%Lx %s<->%s\n",
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current->comm, current->pid, start, end,
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cattr_name(found_type), cattr_name(match->type));
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return -EBUSY;
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}
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static void memtype_rb_insert(struct rb_root *root, struct memtype *newdata)
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{
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struct rb_node **node = &(root->rb_node);
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struct rb_node *parent = NULL;
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while (*node) {
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struct memtype *data = rb_entry(*node, struct memtype, rb);
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parent = *node;
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if (data->subtree_max_end < newdata->end)
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data->subtree_max_end = newdata->end;
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if (newdata->start <= data->start)
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node = &((*node)->rb_left);
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else if (newdata->start > data->start)
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node = &((*node)->rb_right);
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}
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newdata->subtree_max_end = newdata->end;
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rb_link_node(&newdata->rb, parent, node);
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rb_insert_augmented(&newdata->rb, root, &memtype_rb_augment_cb);
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}
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int rbt_memtype_check_insert(struct memtype *new,
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enum page_cache_mode *ret_type)
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{
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int err = 0;
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err = memtype_rb_check_conflict(&memtype_rbroot, new->start, new->end,
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new->type, ret_type);
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if (!err) {
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if (ret_type)
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new->type = *ret_type;
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new->subtree_max_end = new->end;
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memtype_rb_insert(&memtype_rbroot, new);
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}
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return err;
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}
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struct memtype *rbt_memtype_erase(u64 start, u64 end)
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{
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struct memtype *data;
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/*
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* Since the memtype_rbroot tree allows overlapping ranges,
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* rbt_memtype_erase() checks with EXACT_MATCH first, i.e. free
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* a whole node for the munmap case. If no such entry is found,
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* it then checks with END_MATCH, i.e. shrink the size of a node
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* from the end for the mremap case.
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*/
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data = memtype_rb_match(&memtype_rbroot, start, end,
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MEMTYPE_EXACT_MATCH);
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if (!data) {
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data = memtype_rb_match(&memtype_rbroot, start, end,
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MEMTYPE_END_MATCH);
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if (!data)
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return ERR_PTR(-EINVAL);
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}
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if (data->start == start) {
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/* munmap: erase this node */
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rb_erase_augmented(&data->rb, &memtype_rbroot,
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&memtype_rb_augment_cb);
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} else {
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/* mremap: update the end value of this node */
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rb_erase_augmented(&data->rb, &memtype_rbroot,
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&memtype_rb_augment_cb);
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data->end = start;
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data->subtree_max_end = data->end;
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memtype_rb_insert(&memtype_rbroot, data);
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return NULL;
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}
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return data;
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}
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struct memtype *rbt_memtype_lookup(u64 addr)
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{
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return memtype_rb_lowest_match(&memtype_rbroot, addr, addr + PAGE_SIZE);
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}
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#if defined(CONFIG_DEBUG_FS)
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int rbt_memtype_copy_nth_element(struct memtype *out, loff_t pos)
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{
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struct rb_node *node;
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int i = 1;
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node = rb_first(&memtype_rbroot);
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while (node && pos != i) {
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node = rb_next(node);
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i++;
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}
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if (node) { /* pos == i */
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struct memtype *this = rb_entry(node, struct memtype, rb);
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*out = *this;
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return 0;
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} else {
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return 1;
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}
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}
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#endif
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