patch-2.1.44 linux/include/asm-mips/mmu_context.h

• Lines: 66
• Date: Thu Jun 26 12:33:40 1997
• Orig file: v2.1.43/linux/include/asm-mips/mmu_context.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.43/linux/include/asm-mips/mmu_context.h linux/include/asm-mips/mmu_context.h
@@ -0,0 +1,65 @@
+/*
+ * Switch a MMU context.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1996 by Ralf Baechle
+ */
+#ifndef __ASM_MIPS_MMU_CONTEXT_H
+#define __ASM_MIPS_MMU_CONTEXT_H
+
+#define MAX_ASID 255
+
+extern unsigned long asid_cache;
+
+#define ASID_VERSION_SHIFT 16
+#define ASID_VERSION_MASK  ((~0UL) << ASID_VERSION_SHIFT)
+#define ASID_FIRST_VERSION (1UL << ASID_VERSION_SHIFT)
+
+extern inline void get_new_mmu_context(struct mm_struct *mm, unsigned long asid)
+{
+	/* check if it's legal.. */
+	if ((asid & ~ASID_VERSION_MASK) > MAX_ASID) {
+		/* start a new version, invalidate all old asid's */
+		flush_tlb_all();
+		asid = (asid & ASID_VERSION_MASK) + ASID_FIRST_VERSION;
+		if (!asid)
+			asid = ASID_FIRST_VERSION;
+	}
+	asid_cache = asid + 1;
+	mm->context = asid;			 /* full version + asid */
+}
+
+extern inline void get_mmu_context(struct task_struct *p)
+{
+	struct mm_struct *mm = p->mm;
+
+	if (mm) {
+		unsigned long asid = asid_cache;
+		/* Check if our ASID is of an older version and thus invalid */
+		if ((mm->context ^ asid) & ASID_VERSION_MASK)
+			get_new_mmu_context(mm, asid);
+	}
+}
+
+/*
+ * Initialize the context related info for a new mm_struct
+ * instance.
+ */
+extern inline void init_new_context(struct mm_struct *mm)
+{
+	mm->context = 0;
+}
+
+/*
+ * Destroy context related info for an mm_struct that is about
+ * to be put to rest.
+ */
+extern inline void destroy_context(struct mm_struct *mm)
+{
+	mm->context = 0;
+}
+
+#endif /* __ASM_MIPS_MMU_CONTEXT_H */