pci-iommu_table.c

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#include <linux/dma-mapping.h>
#include <asm/iommu_table.h>
#include <linux/string.h>
#include <linux/kallsyms.h>


#define DEBUG 1

static struct iommu_table_entry * __init
find_dependents_of(struct iommu_table_entry *start,
           struct iommu_table_entry *finish,
           struct iommu_table_entry *q)
{
    struct iommu_table_entry *p;

    if (!q)
        return NULL;

    for (p = start; p < finish; p++)
        if (p->detect == q->depend)
            return p;

    return NULL;
}


void __init sort_iommu_table(struct iommu_table_entry *start,
                 struct iommu_table_entry *finish) {

    struct iommu_table_entry *p, *q, tmp;

    for (p = start; p < finish; p++) {
again:
        q = find_dependents_of(start, finish, p);
        /* We are bit sneaky here. We use the memory address to figure
         * out if the node we depend on is past our point, if so, swap.
         */
        if (q > p) {
            tmp = *p;
            memmove(p, q, sizeof(*p));
            *q = tmp;
            goto again;
        }
    }

}

#ifdef DEBUG
void __init check_iommu_entries(struct iommu_table_entry *start,
                struct iommu_table_entry *finish)
{
    struct iommu_table_entry *p, *q, *x;

    /* Simple cyclic dependency checker. */
    for (p = start; p < finish; p++) {
        q = find_dependents_of(start, finish, p);
        x = find_dependents_of(start, finish, q);
        if (p == x) {
            printk(KERN_ERR "CYCLIC DEPENDENCY FOUND! %pS depends on %pS and vice-versa. BREAKING IT.\n",
                   p->detect, q->detect);
            /* Heavy handed way..*/
            x->depend = 0;
        }
    }

    for (p = start; p < finish; p++) {
        q = find_dependents_of(p, finish, p);
        if (q && q > p) {
            printk(KERN_ERR "EXECUTION ORDER INVALID! %pS should be called before %pS!\n",
                   p->detect, q->detect);
        }
    }
}
#else
inline void check_iommu_entries(struct iommu_table_entry *start,
                       struct iommu_table_entry *finish)
{
}
#endif