1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/ioport.h>
 3#include <linux/printk.h>
 4#include <asm/e820/api.h>
 5#include <asm/pci_x86.h>
 6
 7static void resource_clip(struct resource *res, resource_size_t start,
 8			  resource_size_t end)
 9{
10	resource_size_t low = 0, high = 0;
11
12	if (res->end < start || res->start > end)
13		return;		/* no conflict */
14
15	if (res->start < start)
16		low = start - res->start;
17
18	if (res->end > end)
19		high = res->end - end;
20
21	/* Keep the area above or below the conflict, whichever is larger */
22	if (low > high)
23		res->end = start - 1;
24	else
25		res->start = end + 1;
26}
27
28static void remove_e820_regions(struct resource *avail)
29{
30	int i;
31	struct e820_entry *entry;
32	u64 e820_start, e820_end;
33	struct resource orig = *avail;
34
35	if (!pci_use_e820)
36		return;
37
38	for (i = 0; i < e820_table->nr_entries; i++) {
39		entry = &e820_table->entries[i];
40		e820_start = entry->addr;
41		e820_end = entry->addr + entry->size - 1;
42
43		resource_clip(avail, e820_start, e820_end);
44		if (orig.start != avail->start || orig.end != avail->end) {
45			pr_info("resource: avoiding allocation from e820 entry [mem %#010Lx-%#010Lx]\n",
46				e820_start, e820_end);
47			if (avail->end > avail->start)
48				/*
49				 * Use %pa instead of %pR because "avail"
50				 * is typically IORESOURCE_UNSET, so %pR
51				 * shows the size instead of addresses.
52				 */
53				pr_info("resource: remaining [mem %pa-%pa] available\n",
54					&avail->start, &avail->end);
55			orig = *avail;
56		}
57	}
58}
59
60void arch_remove_reservations(struct resource *avail)
61{
62	/*
63	 * Trim out BIOS area (high 2MB) and E820 regions. We do not remove
64	 * the low 1MB unconditionally, as this area is needed for some ISA
65	 * cards requiring a memory range, e.g. the i82365 PCMCIA controller.
66	 */
67	if (avail->flags & IORESOURCE_MEM) {
 
 
68		resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END);
69
70		remove_e820_regions(avail);
71	}
72}

 
 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}