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authorMichal Simek <monstr@monstr.eu>2009-05-26 16:30:14 +0200
committerMichal Simek <monstr@monstr.eu>2009-05-26 16:45:15 +0200
commitfc34d1eb1ca09d3450508e2cf9cf511364c2c460 (patch)
tree96c7b5ccd8ec0c4a541596ee8963a9ab9fab5903 /arch/microblaze/mm
parent5de96121009f4de43ffeb7160109e23132278c07 (diff)
downloadlinux-fc34d1eb1ca09d3450508e2cf9cf511364c2c460.tar.bz2
microblaze_mmu_v2: Context handling - mmu_context.c/h
Signed-off-by: Michal Simek <monstr@monstr.eu>
Diffstat (limited to 'arch/microblaze/mm')
-rw-r--r--arch/microblaze/mm/mmu_context.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/arch/microblaze/mm/mmu_context.c b/arch/microblaze/mm/mmu_context.c
new file mode 100644
index 000000000000..26ff82f4fa8f
--- /dev/null
+++ b/arch/microblaze/mm/mmu_context.c
@@ -0,0 +1,70 @@
+/*
+ * This file contains the routines for handling the MMU.
+ *
+ * Copyright (C) 2007 Xilinx, Inc. All rights reserved.
+ *
+ * Derived from arch/ppc/mm/4xx_mmu.c:
+ * -- paulus
+ *
+ * Derived from arch/ppc/mm/init.c:
+ * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
+ * and Cort Dougan (PReP) (cort@cs.nmt.edu)
+ * Copyright (C) 1996 Paul Mackerras
+ * Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
+ *
+ * Derived from "arch/i386/mm/init.c"
+ * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/init.h>
+
+#include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
+
+mm_context_t next_mmu_context;
+unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
+atomic_t nr_free_contexts;
+struct mm_struct *context_mm[LAST_CONTEXT+1];
+
+/*
+ * Initialize the context management stuff.
+ */
+void __init mmu_context_init(void)
+{
+ /*
+ * The use of context zero is reserved for the kernel.
+ * This code assumes FIRST_CONTEXT < 32.
+ */
+ context_map[0] = (1 << FIRST_CONTEXT) - 1;
+ next_mmu_context = FIRST_CONTEXT;
+ atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1);
+}
+
+/*
+ * Steal a context from a task that has one at the moment.
+ *
+ * This isn't an LRU system, it just frees up each context in
+ * turn (sort-of pseudo-random replacement :). This would be the
+ * place to implement an LRU scheme if anyone were motivated to do it.
+ */
+void steal_context(void)
+{
+ struct mm_struct *mm;
+
+ /* free up context `next_mmu_context' */
+ /* if we shouldn't free context 0, don't... */
+ if (next_mmu_context < FIRST_CONTEXT)
+ next_mmu_context = FIRST_CONTEXT;
+ mm = context_mm[next_mmu_context];
+ flush_tlb_mm(mm);
+ destroy_context(mm);
+}