4 files changed, 131 insertions, 1 deletions

diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
index 480f78a3611a..185e7dc7dcf2 100644
--- a/arch/arm/mm/Makefile
+++ b/arch/arm/mm/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_MODULES)		+= proc-syms.o
 
 obj-$(CONFIG_ALIGNMENT_TRAP)    += alignment.o
 obj-$(CONFIG_DISCONTIGMEM)      += discontig.o
+obj-$(CONFIG_HIGHMEM)           += highmem.o
 
 obj-$(CONFIG_CPU_ABRT_NOMMU)    += abort-nommu.o
 obj-$(CONFIG_CPU_ABRT_EV4)      += abort-ev4.o
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 0fa9bf388f0b..4e283481cee1 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -192,7 +192,7 @@ void flush_dcache_page(struct page *page)
         struct address_space *mapping = page_mapping(page);
 
 #ifndef CONFIG_SMP
-        if (mapping && !mapping_mapped(mapping))
+        if (!PageHighMem(page) && mapping && !mapping_mapped(mapping))
                 set_bit(PG_dcache_dirty, &page->flags);
         else
 #endif
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);
+}
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index d4d082c5c2d4..4810a4c9ffce 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -21,6 +21,7 @@
 #include <asm/setup.h>
 #include <asm/sizes.h>
 #include <asm/tlb.h>
+#include <asm/highmem.h>
 
 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>
@@ -895,6 +896,17 @@ static void __init devicemaps_init(struct machine_desc *mdesc)
         flush_cache_all();
 }
 
+static void __init kmap_init(void)
+{
+#ifdef CONFIG_HIGHMEM
+        pmd_t *pmd = pmd_off_k(PKMAP_BASE);
+        pte_t *pte = alloc_bootmem_low_pages(2 * PTRS_PER_PTE * sizeof(pte_t));
+        BUG_ON(!pmd_none(*pmd) || !pte);
+        __pmd_populate(pmd, __pa(pte) | _PAGE_KERNEL_TABLE);
+        pkmap_page_table = pte + PTRS_PER_PTE;
+#endif
+}
+
 /*
  * paging_init() sets up the page tables, initialises the zone memory
  * maps, and sets up the zero page, bad page and bad page tables.
@@ -908,6 +920,7 @@ void __init paging_init(struct machine_desc *mdesc)
         prepare_page_table();
         bootmem_init();
         devicemaps_init(mdesc);
+        kmap_init();
 
         top_pmd = pmd_off_k(0xffff0000);