// SPDX-License-Identifier: GPL-2.0#include <linux/ioport.h>#include <linux/printk.h>#include <asm/e820/api.h>#include <asm/pci_x86.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 e820_entry *entry;	u64 e820_start, e820_end;	struct resource orig = *avail; 	if (!pci_use_e820)		return; 	for (i = 0; i < e820_table->nr_entries; i++) {		entry = &e820_table->entries[i];		e820_start = entry->addr;		e820_end = entry->addr + entry->size - 1; 		resource_clip(avail, e820_start, e820_end);		if (orig.start != avail->start || orig.end != avail->end) {			pr_info("resource: avoiding allocation from e820 entry [mem %#010Lx-%#010Lx]\n",				e820_start, e820_end);			if (avail->end > avail->start)				/*				 * Use %pa instead of %pR because "avail"				 * is typically IORESOURCE_UNSET, so %pR				 * shows the size instead of addresses.				 */				pr_info("resource: remaining [mem %pa-%pa] available\n",					&avail->start, &avail->end);			orig = *avail;		}	}} void arch_remove_reservations(struct resource *avail){	/*	 * Trim out BIOS area (high 2MB) and E820 regions. We do not remove	 * the low 1MB unconditionally, as this area is needed for some ISA	 * cards requiring a memory range.	 */	if (avail->flags & IORESOURCE_MEM) {		resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END); 		remove_e820_regions(avail);	}}