MN10300: Make the use of PIDR to mark TLB entries controllable

Make controllable the use of the PIDR register to mark TLB entries as belonging
to particular processes.

Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>

4 files changed, 84 insertions, 62 deletions

diff --git a/arch/mn10300/Kconfig b/arch/mn10300/Kconfig
index dd7b5700358b..7bd920b1c06f 100644
--- a/arch/mn10300/Kconfig
+++ b/arch/mn10300/Kconfig
@@ -142,6 +142,9 @@ config FPU
 
 source "arch/mn10300/mm/Kconfig.cache"
 
+config MN10300_TLB_USE_PIDR
+        def_bool y
+
 menu "Memory layout options"
 
 config KERNEL_RAM_BASE_ADDRESS
diff --git a/arch/mn10300/include/asm/mmu_context.h b/arch/mn10300/include/asm/mmu_context.h
index 24d63f0f7377..5fb3648968ae 100644
--- a/arch/mn10300/include/asm/mmu_context.h
+++ b/arch/mn10300/include/asm/mmu_context.h
@@ -27,28 +27,22 @@
 #include <asm/tlbflush.h>
 #include <asm-generic/mm_hooks.h>
 
+#define MMU_CONTEXT_TLBPID_NR           256
 #define MMU_CONTEXT_TLBPID_MASK         0x000000ffUL
 #define MMU_CONTEXT_VERSION_MASK        0xffffff00UL
 #define MMU_CONTEXT_FIRST_VERSION       0x00000100UL
 #define MMU_NO_CONTEXT                  0x00000000UL
-
-extern unsigned long mmu_context_cache[NR_CPUS];
-#define mm_context(mm)  (mm->context.tlbpid[smp_processor_id()])
+#define MMU_CONTEXT_TLBPID_LOCK_NR      0
 
 #define enter_lazy_tlb(mm, tsk) do {} while (0)
 
-#ifdef CONFIG_SMP
-#define cpu_ran_vm(cpu, mm) \
-        cpumask_set_cpu((cpu), mm_cpumask(mm))
-#define cpu_maybe_ran_vm(cpu, mm) \
-        cpumask_test_and_set_cpu((cpu), mm_cpumask(mm))
-#else
-#define cpu_ran_vm(cpu, mm)             do {} while (0)
-#define cpu_maybe_ran_vm(cpu, mm)       true
-#endif /* CONFIG_SMP */
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
+extern unsigned long mmu_context_cache[NR_CPUS];
+#define mm_context(mm)  (mm->context.tlbpid[smp_processor_id()])
 
-/*
- * allocate an MMU context
+/**
+ * allocate_mmu_context - Allocate storage for the arch-specific MMU data
+ * @mm: The userspace VM context being set up
  */
 static inline unsigned long allocate_mmu_context(struct mm_struct *mm)
 {
@@ -101,34 +95,41 @@ static inline int init_new_context(struct task_struct *tsk,
 }
 
 /*
- * destroy context related info for an mm_struct that is about to be put to
- * rest
- */
-#define destroy_context(mm)     do { } while (0)
-
-/*
  * after we have set current->mm to a new value, this activates the context for
  * the new mm so we see the new mappings.
  */
-static inline void activate_context(struct mm_struct *mm, int cpu)
+static inline void activate_context(struct mm_struct *mm)
 {
         PIDR = get_mmu_context(mm) & MMU_CONTEXT_TLBPID_MASK;
 }
+#else  /* CONFIG_MN10300_TLB_USE_PIDR */
 
-/*
- * change between virtual memory sets
+#define init_new_context(tsk, mm)       (0)
+#define activate_context(mm)            local_flush_tlb()
+
+#endif /* CONFIG_MN10300_TLB_USE_PIDR */
+
+/**
+ * destroy_context - Destroy mm context information
+ * @mm: The MM being destroyed.
+ *
+ * Destroy context related info for an mm_struct that is about to be put to
+ * rest
+ */
+#define destroy_context(mm)     do {} while (0)
+
+/**
+ * switch_mm - Change between userspace virtual memory contexts
+ * @prev: The outgoing MM context.
+ * @next: The incoming MM context.
+ * @tsk: The incoming task.
  */
 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
                              struct task_struct *tsk)
 {
-        int cpu = smp_processor_id();
-
         if (prev != next) {
-                cpu_ran_vm(cpu, next);
-                activate_context(next, cpu);
                 PTBR = (unsigned long) next->pgd;
-        } else if (!cpu_maybe_ran_vm(cpu, next)) {
-                activate_context(next, cpu);
+                activate_context(next);
         }
 }
 
diff --git a/arch/mn10300/include/asm/tlbflush.h b/arch/mn10300/include/asm/tlbflush.h
index 5d54bf57e6c3..c3c194d4031e 100644
--- a/arch/mn10300/include/asm/tlbflush.h
+++ b/arch/mn10300/include/asm/tlbflush.h
@@ -13,6 +13,12 @@
 
 #include <asm/processor.h>
 
+struct tlb_state {
+        struct mm_struct        *active_mm;
+        int                     state;
+};
+DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate);
+
 /**
  * local_flush_tlb - Flush the current MM's entries from the local CPU's TLBs
  */
@@ -31,20 +37,51 @@ static inline void local_flush_tlb(void)
 /**
  * local_flush_tlb_all - Flush all entries from the local CPU's TLBs
  */
-#define local_flush_tlb_all()           local_flush_tlb()
+static inline void local_flush_tlb_all(void)
+{
+        local_flush_tlb();
+}
 
 /**
  * local_flush_tlb_one - Flush one entry from the local CPU's TLBs
  */
-#define local_flush_tlb_one(addr)       local_flush_tlb()
+static inline void local_flush_tlb_one(unsigned long addr)
+{
+        local_flush_tlb();
+}
 
 /**
  * local_flush_tlb_page - Flush a page's entry from the local CPU's TLBs
  * @mm: The MM to flush for
  * @addr: The address of the target page in RAM (not its page struct)
  */
-extern void local_flush_tlb_page(struct mm_struct *mm, unsigned long addr);
+static inline
+void local_flush_tlb_page(struct mm_struct *mm, unsigned long addr)
+{
+        unsigned long pteu, flags, cnx;
+
+        addr &= PAGE_MASK;
 
+        local_irq_save(flags);
+
+        cnx = 1;
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
+        cnx = mm->context.tlbpid[smp_processor_id()];
+#endif
+        if (cnx) {
+                pteu = addr;
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
+                pteu |= cnx & xPTEU_PID;
+#endif
+                IPTEU = pteu;
+                DPTEU = pteu;
+                if (IPTEL & xPTEL_V)
+                        IPTEL = 0;
+                if (DPTEL & xPTEL_V)
+                        DPTEL = 0;
+        }
+        local_irq_restore(flags);
+}
 
 /*
  * TLB flushing:
diff --git a/arch/mn10300/mm/mmu-context.c b/arch/mn10300/mm/mmu-context.c
index 3d83966e30e1..a4f7d3dcc6e6 100644
--- a/arch/mn10300/mm/mmu-context.c
+++ b/arch/mn10300/mm/mmu-context.c
@@ -13,40 +13,15 @@
 #include <asm/mmu_context.h>
 #include <asm/tlbflush.h>
 
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
 /*
  * list of the MMU contexts last allocated on each CPU
  */
 unsigned long mmu_context_cache[NR_CPUS] = {
-        [0 ... NR_CPUS - 1] = MMU_CONTEXT_FIRST_VERSION * 2 - 1,
+        [0 ... NR_CPUS - 1] =
+        MMU_CONTEXT_FIRST_VERSION * 2 - (1 - MMU_CONTEXT_TLBPID_LOCK_NR),
 };
-
-/*
- * flush the specified TLB entry
- */
-void local_flush_tlb_page(struct mm_struct *mm, unsigned long addr)
-{
-        unsigned long pteu, cnx, flags;
-
-        addr &= PAGE_MASK;
-
-        /* make sure the context doesn't migrate and defend against
-         * interference from vmalloc'd regions */
-        local_irq_save(flags);
-
-        cnx = mm_context(mm);
-
-        if (cnx != MMU_NO_CONTEXT) {
-                pteu = addr | (cnx & 0x000000ffUL);
-                IPTEU = pteu;
-                DPTEU = pteu;
-                if (IPTEL & xPTEL_V)
-                        IPTEL = 0;
-                if (DPTEL & xPTEL_V)
-                        DPTEL = 0;
-        }
-
-        local_irq_restore(flags);
-}
+#endif /* CONFIG_MN10300_TLB_USE_PIDR */
 
 /*
  * preemptively set a TLB entry
@@ -63,10 +38,16 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, pte_t *pte
          * interference from vmalloc'd regions */
         local_irq_save(flags);
 
+        cnx = ~MMU_NO_CONTEXT;
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
         cnx = mm_context(vma->vm_mm);
+#endif
 
         if (cnx != MMU_NO_CONTEXT) {
-                pteu = addr | (cnx & 0x000000ffUL);
+                pteu = addr;
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
+                pteu |= cnx & MMU_CONTEXT_TLBPID_MASK;
+#endif
                 if (!(pte_val(pte) & _PAGE_NX)) {
                         IPTEU = pteu;
                         if (IPTEL & xPTEL_V)