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// 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}