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-rw-r--r--arch/arm/mm/highmem.c116
1 files changed, 116 insertions, 0 deletions
diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
new file mode 100644
index 000000000000..a34954d9df7d
--- /dev/null
+++ b/arch/arm/mm/highmem.c
@@ -0,0 +1,116 @@
+/*
+ * 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, enum km_type type)
+{
+ unsigned int idx;
+ unsigned long vaddr;
+
+ pagefault_disable();
+ if (!PageHighMem(page))
+ return page_address(page);
+
+ 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, enum km_type type)
+{
+ unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+ unsigned int idx = type + KM_TYPE_NR * smp_processor_id();
+
+ if (kvaddr >= (void *)FIXADDR_START) {
+ __cpuc_flush_dcache_page((void *)vaddr);
+#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
+ }
+ pagefault_enable();
+}
+EXPORT_SYMBOL(kunmap_atomic);
+
+void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
+{
+ unsigned int idx;
+ unsigned long vaddr;
+
+ pagefault_disable();
+
+ 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);
+}