patch-2.4.20 linux-2.4.20/arch/sparc/mm/highmem.c

• Lines: 85
• Date: Thu Nov 28 15:53:12 2002
• Orig file: linux-2.4.19/arch/sparc/mm/highmem.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/sparc/mm/highmem.c linux-2.4.20/arch/sparc/mm/highmem.c
@@ -0,0 +1,84 @@
+/*
+ *  highmem.c: virtual kernel memory mappings for high memory
+ *
+ *  Provides kernel-static versions of atomic kmap functions originally
+ *  found as inlines in include/asm-sparc/highmem.h.  These became
+ *  needed as kmap_atomic() and kunmap_atomic() started getting
+ *  called from within modules.
+ *  -- Tomas Szepe <szepe@pinerecords.com>, September 2002
+ */
+
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <asm/pgalloc.h>
+
+/*
+ * 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.
+ */
+void *kmap_atomic(struct page *page, enum km_type type)
+{
+	unsigned long idx;
+	unsigned long vaddr;
+
+	if (page < highmem_start_page)
+		return page_address(page);
+
+	idx = type + KM_TYPE_NR * smp_processor_id();
+	vaddr = fix_kmap_begin + idx * PAGE_SIZE;
+
+/* XXX Fix - Anton */
+#if 0
+	__flush_cache_one(vaddr);
+#else
+	flush_cache_all();
+#endif
+
+#if HIGHMEM_DEBUG
+	if (!pte_none(*(kmap_pte + idx)))
+		BUG();
+#endif
+	set_pte(kmap_pte + idx, mk_pte(page, kmap_prot));
+/* XXX Fix - Anton */
+#if 0
+	__flush_tlb_one(vaddr);
+#else
+	flush_tlb_all();
+#endif
+
+	return (void *) vaddr;
+}
+
+void kunmap_atomic(void *kvaddr, enum km_type type)
+{
+	unsigned long vaddr = (unsigned long) kvaddr;
+	unsigned long idx = type + KM_TYPE_NR * smp_processor_id();
+
+	if (vaddr < fix_kmap_begin) /* FIXME */
+		return;
+
+	if (vaddr != fix_kmap_begin + idx * PAGE_SIZE)
+		BUG();
+
+/* XXX Fix - Anton */
+#if 0
+	__flush_cache_one(vaddr);
+#else
+	flush_cache_all();
+#endif
+
+#ifdef HIGHMEM_DEBUG
+	/*
+	 *  Force other mappings to oops if they try to access
+	 *  this pte without first remapping it.
+	 */
+	pte_clear(kmap_pte + idx);
+/* XXX Fix - Anton */
+#if 0
+	__flush_tlb_one(vaddr);
+#else
+	flush_tlb_all();
+#endif
+#endif
+}