From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001
From: root <root@artemis.panaceas.org>
Date: Fri, 25 Dec 2015 04:40:36 +0000
Subject: initial_commit

---
 arch/arm/mm/highmem.c | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 arch/arm/mm/highmem.c

(limited to 'arch/arm/mm/highmem.c')

diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
new file mode 100644
index 00000000..807c0573
--- /dev/null
+++ b/arch/arm/mm/highmem.c
@@ -0,0 +1,142 @@
+/*
+ * 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"
+
+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;
+
+	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 = type + KM_TYPE_NR * smp_processor_id();
+	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + 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(*(TOP_PTE(vaddr))));
+#endif
+	set_pte_ext(TOP_PTE(vaddr), mk_pte(page, kmap_prot), 0);
+	/*
+	 * When debugging is off, kunmap_atomic leaves the previous mapping
+	 * in place, so this TLB flush ensures the TLB is updated with the
+	 * new mapping.
+	 */
+	local_flush_tlb_kernel_page(vaddr);
+
+	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 = 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(FIX_KMAP_BEGIN + idx));
+		set_pte_ext(TOP_PTE(vaddr), __pte(0), 0);
+		local_flush_tlb_kernel_page(vaddr);
+#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();
+}
+EXPORT_SYMBOL(__kunmap_atomic);
+
+void *kmap_atomic_pfn(unsigned long pfn)
+{
+	unsigned long vaddr;
+	int idx, type;
+
+	pagefault_disable();
+
+	type = kmap_atomic_idx_push();
+	idx = type + KM_TYPE_NR * smp_processor_id();
+	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+#ifdef CONFIG_DEBUG_HIGHMEM
+	BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
+#endif
+	set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0);
+	local_flush_tlb_kernel_page(vaddr);
+
+	return (void *)vaddr;
+}
+
+struct page *kmap_atomic_to_page(const void *ptr)
+{
+	unsigned long vaddr = (unsigned long)ptr;
+	pte_t *pte;
+
+	if (vaddr < FIXADDR_START)
+		return virt_to_page(ptr);
+
+	pte = TOP_PTE(vaddr);
+	return pte_page(*pte);
+}
-- 
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