resource.c

Go to the documentation of this file.

#include <linux/ioport.h>
#include <asm/e820.h>

static void resource_clip(struct resource *res, resource_size_t start,
              resource_size_t end)
{
    resource_size_t low = 0, high = 0;

    if (res->end < start || res->start > end)
        return;     /* no conflict */

    if (res->start < start)
        low = start - res->start;

    if (res->end > end)
        high = res->end - end;

    /* Keep the area above or below the conflict, whichever is larger */
    if (low > high)
        res->end = start - 1;
    else
        res->start = end + 1;
}

static void remove_e820_regions(struct resource *avail)
{
    int i;
    struct e820entry *entry;

    for (i = 0; i < e820.nr_map; i++) {
        entry = &e820.map[i];

        resource_clip(avail, entry->addr,
                  entry->addr + entry->size - 1);
    }
}

void arch_remove_reservations(struct resource *avail)
{
    /* Trim out BIOS areas (low 1MB and high 2MB) and E820 regions */
    if (avail->flags & IORESOURCE_MEM) {
        if (avail->start < BIOS_END)
            avail->start = BIOS_END;
        resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END);

        remove_e820_regions(avail);
    }
}