1 files changed, 92 insertions, 0 deletions
diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
new file mode 100644
index 000000000..075fe5131
--- /dev/null
+++ b/arch/x86/mm/highmem_32.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/highmem.h>
+#include <linux/export.h>
+#include <linux/swap.h> /* for totalram_pages */
+#include <linux/memblock.h>
+
+void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+{
+	unsigned long vaddr;
+	int idx, type;
+
+	type = kmap_atomic_idx_push();
+	idx = type + KM_TYPE_NR*smp_processor_id();
+	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+	BUG_ON(!pte_none(*(kmap_pte-idx)));
+	set_pte(kmap_pte-idx, mk_pte(page, prot));
+	arch_flush_lazy_mmu_mode();
+
+	return (void *)vaddr;
+}
+EXPORT_SYMBOL(kmap_atomic_high_prot);
+
+/*
+ * This is the same as kmap_atomic() but can map memory that doesn't
+ * have a struct page associated with it.
+ */
+void *kmap_atomic_pfn(unsigned long pfn)
+{
+	return kmap_atomic_prot_pfn(pfn, kmap_prot);
+}
+EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
+
+void kunmap_atomic_high(void *kvaddr)
+{
+	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+
+	if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
+	    vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
+		int idx, type;
+
+		type = kmap_atomic_idx();
+		idx = type + KM_TYPE_NR * smp_processor_id();
+
+#ifdef CONFIG_DEBUG_HIGHMEM
+		WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+#endif
+		/*
+		 * Force other mappings to Oops if they'll try to access this
+		 * pte without first remap it.  Keeping stale mappings around
+		 * is a bad idea also, in case the page changes cacheability
+		 * attributes or becomes a protected page in a hypervisor.
+		 */
+		kpte_clear_flush(kmap_pte-idx, vaddr);
+		kmap_atomic_idx_pop();
+		arch_flush_lazy_mmu_mode();
+	}
+#ifdef CONFIG_DEBUG_HIGHMEM
+	else {
+		BUG_ON(vaddr < PAGE_OFFSET);
+		BUG_ON(vaddr >= (unsigned long)high_memory);
+	}
+#endif
+}
+EXPORT_SYMBOL(kunmap_atomic_high);
+
+void __init set_highmem_pages_init(void)
+{
+	struct zone *zone;
+	int nid;
+
+	/*
+	 * Explicitly reset zone->managed_pages because set_highmem_pages_init()
+	 * is invoked before memblock_free_all()
+	 */
+	reset_all_zones_managed_pages();
+	for_each_zone(zone) {
+		unsigned long zone_start_pfn, zone_end_pfn;
+
+		if (!is_highmem(zone))
+			continue;
+
+		zone_start_pfn = zone->zone_start_pfn;
+		zone_end_pfn = zone_start_pfn + zone->spanned_pages;
+
+		nid = zone_to_nid(zone);
+		printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n",
+				zone->name, nid, zone_start_pfn, zone_end_pfn);
+
+		add_highpages_with_active_regions(nid, zone_start_pfn,
+				 zone_end_pfn);
+	}
+}