[PATCH 05/27] PPC: Split context init/destroy functions

[Alexander Graf]

We need to reserve a context from KVM to make sure we have our own
segment space. While we did that split for Book3S_64 already, 32 bit
is still outstanding.

So let's split it now.

Signed-off-by: Alexander Graf <ag...@suse.de>
CC: Benjamin Herrenschmidt <b...@kernel.crashing.org>
---
 arch/powerpc/include/asm/mmu_context.h |    2 ++
 arch/powerpc/mm/mmu_context_hash32.c   |   29 ++++++++++++++++++++++-------
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/include/asm/mmu_context.h 
b/arch/powerpc/include/asm/mmu_context.h
index 26383e0..81fb412 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -27,6 +27,8 @@ extern int __init_new_context(void);
 extern void __destroy_context(int context_id);
 static inline void mmu_context_init(void) { }
 #else
+extern unsigned long __init_new_context(void);
+extern void __destroy_context(unsigned long context_id);
 extern void mmu_context_init(void);
 #endif
 
diff --git a/arch/powerpc/mm/mmu_context_hash32.c 
b/arch/powerpc/mm/mmu_context_hash32.c
index 0dfba2b..d0ee554 100644
--- a/arch/powerpc/mm/mmu_context_hash32.c
+++ b/arch/powerpc/mm/mmu_context_hash32.c
@@ -60,11 +60,7 @@
 static unsigned long next_mmu_context;
 static unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
 
-
-/*
- * Set up the context for a new address space.
- */
-int init_new_context(struct task_struct *t, struct mm_struct *mm)
+unsigned long __init_new_context(void)
 {
        unsigned long ctx = next_mmu_context;
 
@@ -74,19 +70,38 @@ int init_new_context(struct task_struct *t, struct 
mm_struct *mm)
                        ctx = 0;
        }
        next_mmu_context = (ctx + 1) & LAST_CONTEXT;
-       mm->context.id = ctx;
+
+       return ctx;
+}
+EXPORT_SYMBOL_GPL(__init_new_context);
+
+/*
+ * Set up the context for a new address space.
+ */
+int init_new_context(struct task_struct *t, struct mm_struct *mm)
+{
+       mm->context.id = __init_new_context();
 
        return 0;
 }
 
 /*
+ * Free a context ID. Make sure to call this with preempt disabled!
+ */
+void __destroy_context(unsigned long ctx)
+{
+       clear_bit(ctx, context_map);
+}
+EXPORT_SYMBOL_GPL(__destroy_context);
+
+/*
  * We're finished using the context for an address space.
  */
 void destroy_context(struct mm_struct *mm)
 {
        preempt_disable();
        if (mm->context.id != NO_CONTEXT) {
-               clear_bit(mm->context.id, context_map);
+               __destroy_context(mm->context.id);
                mm->context.id = NO_CONTEXT;
        }
        preempt_enable();
-- 
1.6.0.2

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