v4.19.13 snapshot.
diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
new file mode 100644
index 0000000..d02f818
--- /dev/null
+++ b/arch/arm/mm/highmem.c
@@ -0,0 +1,149 @@
+/*
+ * arch/arm/mm/highmem.c -- ARM highmem support
+ *
+ * Author: Nicolas Pitre
+ * Created: september 8, 2008
+ * Copyright: Marvell Semiconductors Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/highmem.h>
+#include <linux/interrupt.h>
+#include <asm/fixmap.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include "mm.h"
+
+static inline void set_fixmap_pte(int idx, pte_t pte)
+{
+ unsigned long vaddr = __fix_to_virt(idx);
+ pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
+
+ set_pte_ext(ptep, pte, 0);
+ local_flush_tlb_kernel_page(vaddr);
+}
+
+static inline pte_t get_fixmap_pte(unsigned long vaddr)
+{
+ pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
+
+ return *ptep;
+}
+
+void *kmap(struct page *page)
+{
+ might_sleep();
+ if (!PageHighMem(page))
+ return page_address(page);
+ return kmap_high(page);
+}
+EXPORT_SYMBOL(kmap);
+
+void kunmap(struct page *page)
+{
+ BUG_ON(in_interrupt());
+ if (!PageHighMem(page))
+ return;
+ kunmap_high(page);
+}
+EXPORT_SYMBOL(kunmap);
+
+void *kmap_atomic(struct page *page)
+{
+ unsigned int idx;
+ unsigned long vaddr;
+ void *kmap;
+ int type;
+
+ preempt_disable();
+ pagefault_disable();
+ if (!PageHighMem(page))
+ return page_address(page);
+
+#ifdef CONFIG_DEBUG_HIGHMEM
+ /*
+ * There is no cache coherency issue when non VIVT, so force the
+ * dedicated kmap usage for better debugging purposes in that case.
+ */
+ if (!cache_is_vivt())
+ kmap = NULL;
+ else
+#endif
+ kmap = kmap_high_get(page);
+ if (kmap)
+ return kmap;
+
+ type = kmap_atomic_idx_push();
+
+ idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+ vaddr = __fix_to_virt(idx);
+#ifdef CONFIG_DEBUG_HIGHMEM
+ /*
+ * With debugging enabled, kunmap_atomic forces that entry to 0.
+ * Make sure it was indeed properly unmapped.
+ */
+ BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
+#endif
+ /*
+ * When debugging is off, kunmap_atomic leaves the previous mapping
+ * in place, so the contained TLB flush ensures the TLB is updated
+ * with the new mapping.
+ */
+ set_fixmap_pte(idx, mk_pte(page, kmap_prot));
+
+ return (void *)vaddr;
+}
+EXPORT_SYMBOL(kmap_atomic);
+
+void __kunmap_atomic(void *kvaddr)
+{
+ unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+ int idx, type;
+
+ if (kvaddr >= (void *)FIXADDR_START) {
+ type = kmap_atomic_idx();
+ idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+
+ if (cache_is_vivt())
+ __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
+#ifdef CONFIG_DEBUG_HIGHMEM
+ BUG_ON(vaddr != __fix_to_virt(idx));
+ set_fixmap_pte(idx, __pte(0));
+#else
+ (void) idx; /* to kill a warning */
+#endif
+ kmap_atomic_idx_pop();
+ } else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
+ /* this address was obtained through kmap_high_get() */
+ kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
+ }
+ pagefault_enable();
+ preempt_enable();
+}
+EXPORT_SYMBOL(__kunmap_atomic);
+
+void *kmap_atomic_pfn(unsigned long pfn)
+{
+ unsigned long vaddr;
+ int idx, type;
+ struct page *page = pfn_to_page(pfn);
+
+ preempt_disable();
+ pagefault_disable();
+ if (!PageHighMem(page))
+ return page_address(page);
+
+ type = kmap_atomic_idx_push();
+ idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+ vaddr = __fix_to_virt(idx);
+#ifdef CONFIG_DEBUG_HIGHMEM
+ BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
+#endif
+ set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
+
+ return (void *)vaddr;
+}