1 files changed, 154 insertions, 0 deletions

diff --git a/kernel/arch/x86/mm/highmem_32.c b/kernel/arch/x86/mm/highmem_32.c
new file mode 100644
index 000000000..0d1cbcf47
--- /dev/null
+++ b/kernel/arch/x86/mm/highmem_32.c
@@ -0,0 +1,154 @@
+#include <linux/highmem.h>
+#include <linux/module.h>
+#include <linux/swap.h> /* for totalram_pages */
+#include <linux/bootmem.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)
+{
+	if (in_interrupt())
+		BUG();
+	if (!PageHighMem(page))
+		return;
+	kunmap_high(page);
+}
+EXPORT_SYMBOL(kunmap);
+
+/*
+ * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
+ * no global lock is needed and because the kmap code must perform a global TLB
+ * invalidation when the kmap pool wraps.
+ *
+ * However when holding an atomic kmap it is not legal to sleep, so atomic
+ * kmaps are appropriate for short, tight code paths only.
+ */
+void *kmap_atomic_prot(struct page *page, pgprot_t prot)
+{
+	pte_t pte = mk_pte(page, prot);
+	unsigned long vaddr;
+	int idx, type;
+
+	preempt_disable_nort();
+	pagefault_disable();
+
+	if (!PageHighMem(page))
+		return page_address(page);
+
+	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)));
+#ifdef CONFIG_PREEMPT_RT_FULL
+	current->kmap_pte[type] = pte;
+#endif
+	set_pte(kmap_pte-idx, pte);
+	arch_flush_lazy_mmu_mode();
+
+	return (void *)vaddr;
+}
+EXPORT_SYMBOL(kmap_atomic_prot);
+
+void *kmap_atomic(struct page *page)
+{
+	return kmap_atomic_prot(page, kmap_prot);
+}
+EXPORT_SYMBOL(kmap_atomic);
+
+/*
+ * 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(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.
+		 */
+#ifdef CONFIG_PREEMPT_RT_FULL
+		current->kmap_pte[type] = __pte(0);
+#endif
+		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
+
+	pagefault_enable();
+	preempt_enable_nort();
+}
+EXPORT_SYMBOL(__kunmap_atomic);
+
+struct page *kmap_atomic_to_page(void *ptr)
+{
+	unsigned long idx, vaddr = (unsigned long)ptr;
+	pte_t *pte;
+
+	if (vaddr < FIXADDR_START)
+		return virt_to_page(ptr);
+
+	idx = virt_to_fix(vaddr);
+	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
+	return pte_page(*pte);
+}
+EXPORT_SYMBOL(kmap_atomic_to_page);
+
+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 free_all_bootmem()
+	 */
+	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);
+	}
+}