81 lines
1.8 KiB
C
81 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/dma-mapping.h>
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#include <asm/iommu_table.h>
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#include <linux/string.h>
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#include <linux/kallsyms.h>
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#define DEBUG 1
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static struct iommu_table_entry * __init
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find_dependents_of(struct iommu_table_entry *start,
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struct iommu_table_entry *finish,
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struct iommu_table_entry *q)
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{
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struct iommu_table_entry *p;
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if (!q)
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return NULL;
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for (p = start; p < finish; p++)
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if (p->detect == q->depend)
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return p;
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return NULL;
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}
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void __init sort_iommu_table(struct iommu_table_entry *start,
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struct iommu_table_entry *finish) {
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struct iommu_table_entry *p, *q, tmp;
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for (p = start; p < finish; p++) {
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again:
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q = find_dependents_of(start, finish, p);
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/* We are bit sneaky here. We use the memory address to figure
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* out if the node we depend on is past our point, if so, swap.
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*/
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if (q > p) {
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tmp = *p;
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memmove(p, q, sizeof(*p));
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*q = tmp;
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goto again;
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}
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}
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}
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#ifdef DEBUG
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void __init check_iommu_entries(struct iommu_table_entry *start,
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struct iommu_table_entry *finish)
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{
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struct iommu_table_entry *p, *q, *x;
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/* Simple cyclic dependency checker. */
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for (p = start; p < finish; p++) {
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q = find_dependents_of(start, finish, p);
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x = find_dependents_of(start, finish, q);
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if (p == x) {
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printk(KERN_ERR "CYCLIC DEPENDENCY FOUND! %pS depends on %pS and vice-versa. BREAKING IT.\n",
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p->detect, q->detect);
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/* Heavy handed way..*/
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x->depend = 0;
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}
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}
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for (p = start; p < finish; p++) {
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q = find_dependents_of(p, finish, p);
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if (q && q > p) {
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printk(KERN_ERR "EXECUTION ORDER INVALID! %pS should be called before %pS!\n",
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p->detect, q->detect);
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}
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}
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}
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#else
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void __init check_iommu_entries(struct iommu_table_entry *start,
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struct iommu_table_entry *finish)
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{
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}
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#endif
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