patch-2.3.23 linux/include/asm-i386/highmem.h

• Lines: 86
• Date: Fri Oct 22 12:46:21 1999
• Orig file: v2.3.22/linux/include/asm-i386/highmem.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.22/linux/include/asm-i386/highmem.h linux/include/asm-i386/highmem.h
@@ -0,0 +1,85 @@
+/*
+ * highmem.h: virtual kernel memory mappings for high memory
+ *
+ * Used in CONFIG_HIGHMEM systems for memory pages which
+ * are not addressable by direct kernel virtual adresses.
+ *
+ * Copyright (C) 1999 Gerhard Wichert, Siemens AG
+ *		      Gerhard.Wichert@pdb.siemens.de
+ *
+ *
+ * Redesigned the x86 32-bit VM architecture to deal with 
+ * up to 16 Terrabyte physical memory. With current x86 CPUs
+ * we now support up to 64 Gigabytes physical RAM.
+ *
+ * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
+ */
+
+#ifndef _ASM_HIGHMEM_H
+#define _ASM_HIGHMEM_H
+
+#include <linux/init.h>
+
+/* undef for production */
+#define HIGHMEM_DEBUG 1
+
+/* declarations for highmem.c */
+extern unsigned long highstart_pfn, highend_pfn;
+
+extern pte_t *kmap_pte;
+extern pgprot_t kmap_prot;
+
+extern void kmap_init(void) __init;
+
+/* kmap helper functions necessary to access the highmem pages in kernel */
+#include <asm/pgtable.h>
+#include <asm/kmap_types.h>
+
+extern inline unsigned long kmap(struct page *page, enum km_type type)
+{
+	if (page < highmem_start_page)
+		return page_address(page);
+	{
+		enum fixed_addresses idx = type+KM_TYPE_NR*smp_processor_id();
+		unsigned long vaddr = __fix_to_virt(FIX_KMAP_BEGIN+idx);
+
+#if HIGHMEM_DEBUG
+		if (!pte_none(*(kmap_pte-idx)))
+		{
+			__label__ here;
+		here:
+			printk(KERN_ERR "not null pte on CPU %d from %p\n",
+			       smp_processor_id(), &&here);
+		}
+#endif
+		set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
+		__flush_tlb_one(vaddr);
+
+		return vaddr;
+	}
+}
+
+extern inline void kunmap(unsigned long vaddr, enum km_type type)
+{
+#if HIGHMEM_DEBUG
+	enum fixed_addresses idx = type+KM_TYPE_NR*smp_processor_id();
+	if ((vaddr & PAGE_MASK) == __fix_to_virt(FIX_KMAP_BEGIN+idx))
+	{
+		/* force other mappings to Oops if they'll try to access
+		   this pte without first remap it */
+		pte_clear(kmap_pte-idx);
+		__flush_tlb_one(vaddr);
+	}
+#endif
+}
+
+extern inline void kmap_check(void)
+{
+#if HIGHMEM_DEBUG
+	int idx_base = KM_TYPE_NR*smp_processor_id(), i;
+	for (i = idx_base; i < idx_base+KM_TYPE_NR; i++)
+		if (!pte_none(*(kmap_pte-i)))
+			BUG();
+#endif
+}
+#endif /* _ASM_HIGHMEM_H */