patch-2.4.0-test9 linux/include/asm-ppc/highmem.h

• Lines: 122
• Date: Sun Sep 17 09:48:08 2000
• Orig file: v2.4.0-test8/linux/include/asm-ppc/highmem.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.0-test8/linux/include/asm-ppc/highmem.h linux/include/asm-ppc/highmem.h
@@ -0,0 +1,121 @@
+/*
+ * highmem.h: virtual kernel memory mappings for high memory
+ *
+ * PowerPC version, stolen from the i386 version.
+ *
+ * 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
+
+#ifdef __KERNEL__
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <asm/kmap_types.h>
+#include <asm/pgtable.h>
+
+/* undef for production */
+#define HIGHMEM_DEBUG 1
+
+extern pte_t *kmap_pte;
+extern pgprot_t kmap_prot;
+extern pte_t *pkmap_page_table;
+
+extern void kmap_init(void) __init;
+
+/*
+ * Right now we initialize only a single pte table. It can be extended
+ * easily, subsequent pte tables have to be allocated in one physical
+ * chunk of RAM.
+ */
+#define PKMAP_BASE (0xfe000000UL)
+#define LAST_PKMAP 1024
+#define LAST_PKMAP_MASK (LAST_PKMAP-1)
+#define PKMAP_NR(virt)  ((virt-PKMAP_BASE) >> PAGE_SHIFT)
+#define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
+
+#define KMAP_FIX_BEGIN	(0xfe400000UL)
+
+extern unsigned long kmap_high(struct page *page);
+extern void kunmap_high(struct page *page);
+
+extern inline unsigned long kmap(struct page *page)
+{
+	if (in_interrupt())
+		BUG();
+	if (page < highmem_start_page)
+		return (unsigned long) page_address(page);
+	return kmap_high(page);
+}
+
+extern inline void kunmap(struct page *page)
+{
+	if (in_interrupt())
+		BUG();
+	if (page < highmem_start_page)
+		return;
+	kunmap_high(page);
+}
+
+/*
+ * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
+ * gives a more generic (and caching) interface. But kmap_atomic can
+ * be used in IRQ contexts, so in some (very limited) cases we need
+ * it.
+ */
+extern inline unsigned long kmap_atomic(struct page *page, enum km_type type)
+{
+	unsigned int idx;
+	unsigned long vaddr;
+
+	if (page < highmem_start_page)
+		return (unsigned long) page_address(page);
+
+	idx = type + KM_TYPE_NR*smp_processor_id();
+	vaddr = KMAP_FIX_BEGIN + idx * PAGE_SIZE;
+#if HIGHMEM_DEBUG
+	if (!pte_none(*(kmap_pte+idx)))
+		BUG();
+#endif
+	set_pte(kmap_pte+idx, mk_pte(page, kmap_prot));
+	flush_hash_page(0, vaddr);
+
+	return vaddr;
+}
+
+extern inline void kunmap_atomic(unsigned long vaddr, enum km_type type)
+{
+#if HIGHMEM_DEBUG
+	unsigned int idx = type + KM_TYPE_NR*smp_processor_id();
+
+	if (vaddr < KMAP_FIX_BEGIN) // FIXME
+		return;
+
+	if (vaddr != KMAP_FIX_BEGIN + idx * PAGE_SIZE)
+		BUG();
+
+	/*
+	 * force other mappings to Oops if they'll try to access
+	 * this pte without first remap it
+	 */
+	pte_clear(kmap_pte+idx);
+	flush_hash_page(0, vaddr);
+#endif
+}
+
+#endif /* __KERNEL__ */
+
+#endif /* _ASM_HIGHMEM_H */