powerpc: Merge enough to start building in arch/powerpc.

This creates the directory structure under arch/powerpc and a bunch
of Kconfig files.  It does a first-cut merge of arch/powerpc/mm,
arch/powerpc/lib and arch/powerpc/platforms/powermac.  This is enough
to build a 32-bit powermac kernel with ARCH=powerpc.

For now we are getting some unmerged files from arch/ppc/kernel and
arch/ppc/syslib, or arch/ppc64/kernel.  This makes some minor changes
to files in those directories and files outside arch/powerpc.

The boot directory is still not merged.  That's going to be interesting.

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 63 insertions, 0 deletions

diff --git a/arch/powerpc/mm/mmu_context64.c b/arch/powerpc/mm/mmu_context64.c
new file mode 100644
index 00000000000..714a84dd8d5
--- /dev/null
+++ b/arch/powerpc/mm/mmu_context64.c
@@ -0,0 +1,63 @@
+/*
+ *  MMU context allocation for 64-bit kernels.
+ *
+ *  Copyright (C) 2004 Anton Blanchard, IBM Corp. <anton@samba.org>
+ *
+ *  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/config.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/spinlock.h>
+#include <linux/idr.h>
+
+#include <asm/mmu_context.h>
+
+static DEFINE_SPINLOCK(mmu_context_lock);
+static DEFINE_IDR(mmu_context_idr);
+
+int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+	int index;
+	int err;
+
+again:
+	if (!idr_pre_get(&mmu_context_idr, GFP_KERNEL))
+		return -ENOMEM;
+
+	spin_lock(&mmu_context_lock);
+	err = idr_get_new_above(&mmu_context_idr, NULL, 1, &index);
+	spin_unlock(&mmu_context_lock);
+
+	if (err == -EAGAIN)
+		goto again;
+	else if (err)
+		return err;
+
+	if (index > MAX_CONTEXT) {
+		idr_remove(&mmu_context_idr, index);
+		return -ENOMEM;
+	}
+
+	mm->context.id = index;
+
+	return 0;
+}
+
+void destroy_context(struct mm_struct *mm)
+{
+	spin_lock(&mmu_context_lock);
+	idr_remove(&mmu_context_idr, mm->context.id);
+	spin_unlock(&mmu_context_lock);
+
+	mm->context.id = NO_CONTEXT;
+}