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/arch/x86/kernel/resource.c

https://bitbucket.org/ndreys/linux-sunxi
C | 48 lines | 36 code | 10 blank | 2 comment | 8 complexity | 38edda3e008a6d4555bac5092ab619c7 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
 1#include <linux/ioport.h>
 2#include <asm/e820.h>
 3
 4static void resource_clip(struct resource *res, resource_size_t start,
 5			  resource_size_t end)
 6{
 7	resource_size_t low = 0, high = 0;
 8
 9	if (res->end < start || res->start > end)
10		return;		/* no conflict */
11
12	if (res->start < start)
13		low = start - res->start;
14
15	if (res->end > end)
16		high = res->end - end;
17
18	/* Keep the area above or below the conflict, whichever is larger */
19	if (low > high)
20		res->end = start - 1;
21	else
22		res->start = end + 1;
23}
24
25static void remove_e820_regions(struct resource *avail)
26{
27	int i;
28	struct e820entry *entry;
29
30	for (i = 0; i < e820.nr_map; i++) {
31		entry = &e820.map[i];
32
33		resource_clip(avail, entry->addr,
34			      entry->addr + entry->size - 1);
35	}
36}
37
38void arch_remove_reservations(struct resource *avail)
39{
40	/* Trim out BIOS areas (low 1MB and high 2MB) and E820 regions */
41	if (avail->flags & IORESOURCE_MEM) {
42		if (avail->start < BIOS_END)
43			avail->start = BIOS_END;
44		resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END);
45
46		remove_e820_regions(avail);
47	}
48}