1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/ioport.h>
 3#include <asm/e820/api.h>
 4
 5static void resource_clip(struct resource *res, resource_size_t start,
 6			  resource_size_t end)
 7{
 8	resource_size_t low = 0, high = 0;
 9
10	if (res->end < start || res->start > end)
11		return;		/* no conflict */
12
13	if (res->start < start)
14		low = start - res->start;
15
16	if (res->end > end)
17		high = res->end - end;
18
19	/* Keep the area above or below the conflict, whichever is larger */
20	if (low > high)
21		res->end = start - 1;
22	else
23		res->start = end + 1;
24}
25
26static void remove_e820_regions(struct resource *avail)
27{
28	int i;
29	struct e820_entry *entry;
30
31	for (i = 0; i < e820_table->nr_entries; i++) {
32		entry = &e820_table->entries[i];
33
34		resource_clip(avail, entry->addr,
35			      entry->addr + entry->size - 1);
36	}
37}
38
39void arch_remove_reservations(struct resource *avail)
40{
41	/*
42	 * Trim out BIOS area (high 2MB) and E820 regions. We do not remove
43	 * the low 1MB unconditionally, as this area is needed for some ISA
44	 * cards requiring a memory range, e.g. the i82365 PCMCIA controller.
45	 */
46	if (avail->flags & IORESOURCE_MEM) {
47		resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END);
48
49		remove_e820_regions(avail);
50	}
51}

 
 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	/*
41	 * Trim out BIOS area (high 2MB) and E820 regions. We do not remove
42	 * the low 1MB unconditionally, as this area is needed for some ISA
43	 * cards requiring a memory range, e.g. the i82365 PCMCIA controller.
44	 */
45	if (avail->flags & IORESOURCE_MEM) {
46		resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END);
47
48		remove_e820_regions(avail);
49	}
50}