powerpc/mm: Rework context management for CPUs with no hash table
This reworks the context management code used by 4xx,8xx and
freescale BookE. It adds support for SMP by implementing a
concept of stale context map to lazily flush the TLB on
processors where a context may have been invalidated. This
also contains the ground work for generalizing such lazy TLB
flushing by just picking up a new PID and marking the old one
stale. This will be implemented later.
This is a first implementation that uses a global spinlock.
Ideally, we should try to get at least the fast path (context ID
already assigned) lockless or limited to a per context lock,
but for now this will do.
I tried to keep the UP case reasonably simple to avoid adding
too much overhead to 8xx which does a lot of context stealing
since it effectively has only 16 PIDs available.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/include/asm/mmu-40x.h b/arch/powerpc/include/asm/mmu-40x.h
index 3d10867..776f415a 100644
--- a/arch/powerpc/include/asm/mmu-40x.h
+++ b/arch/powerpc/include/asm/mmu-40x.h
@@ -54,8 +54,9 @@
#ifndef __ASSEMBLY__
typedef struct {
- unsigned long id;
- unsigned long vdso_base;
+ unsigned int id;
+ unsigned int active;
+ unsigned long vdso_base;
} mm_context_t;
#endif /* !__ASSEMBLY__ */
diff --git a/arch/powerpc/include/asm/mmu-44x.h b/arch/powerpc/include/asm/mmu-44x.h
index a825524..b21af32 100644
--- a/arch/powerpc/include/asm/mmu-44x.h
+++ b/arch/powerpc/include/asm/mmu-44x.h
@@ -56,8 +56,9 @@
extern unsigned int tlb_44x_hwater;
typedef struct {
- unsigned long id;
- unsigned long vdso_base;
+ unsigned int id;
+ unsigned int active;
+ unsigned long vdso_base;
} mm_context_t;
#endif /* !__ASSEMBLY__ */
diff --git a/arch/powerpc/include/asm/mmu-8xx.h b/arch/powerpc/include/asm/mmu-8xx.h
index 9db877e..07865a3 100644
--- a/arch/powerpc/include/asm/mmu-8xx.h
+++ b/arch/powerpc/include/asm/mmu-8xx.h
@@ -137,7 +137,8 @@
#ifndef __ASSEMBLY__
typedef struct {
- unsigned long id;
+ unsigned int id;
+ unsigned int active;
unsigned long vdso_base;
} mm_context_t;
#endif /* !__ASSEMBLY__ */
diff --git a/arch/powerpc/include/asm/mmu-fsl-booke.h b/arch/powerpc/include/asm/mmu-fsl-booke.h
index 5588a41..3f941c0 100644
--- a/arch/powerpc/include/asm/mmu-fsl-booke.h
+++ b/arch/powerpc/include/asm/mmu-fsl-booke.h
@@ -76,8 +76,9 @@
#ifndef __ASSEMBLY__
typedef struct {
- unsigned long id;
- unsigned long vdso_base;
+ unsigned int id;
+ unsigned int active;
+ unsigned long vdso_base;
} mm_context_t;
#endif /* !__ASSEMBLY__ */
diff --git a/arch/powerpc/include/asm/tlbflush.h b/arch/powerpc/include/asm/tlbflush.h
index 333c24b..9ed363d 100644
--- a/arch/powerpc/include/asm/tlbflush.h
+++ b/arch/powerpc/include/asm/tlbflush.h
@@ -29,6 +29,8 @@
#include <linux/mm.h>
+#define MMU_NO_CONTEXT ((unsigned int)-1)
+
extern void _tlbie(unsigned long address, unsigned int pid);
extern void _tlbil_all(void);
extern void _tlbil_pid(unsigned int pid);