patch-2.3.16 linux/include/asm-sh/mmu_context.h

• Lines: 140
• Date: Mon Aug 30 18:12:59 1999
• Orig file: v2.3.15/linux/include/asm-sh/mmu_context.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.15/linux/include/asm-sh/mmu_context.h linux/include/asm-sh/mmu_context.h
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 1999 Niibe Yutaka
+ *
+ * ASID handling idea taken from MIPS implementation.
+ */
+#ifndef __ASM_SH_MMU_CONTEXT_H
+#define __ASM_SH_MMU_CONTEXT_H
+
+/* The MMU "context" consists of two things:
+     (a) TLB cache version (or round, cycle whatever expression you like)
+     (b) ASID (Address Space IDentifier)
+ */
+
+/*
+ * Cache of MMU context last used.
+ */
+extern unsigned long mmu_context_cache;
+
+#define MMU_CONTEXT_ASID_MASK 0xff
+#define MMU_CONTEXT_VERSION_MASK 0xffffff00
+#define MMU_CONTEXT_FIRST_VERSION 0x100
+#define NO_CONTEXT 0
+
+extern __inline__ void
+get_new_mmu_context(struct mm_struct *mm)
+{
+	unsigned long mc = ++mmu_context_cache;
+
+	if (!(mc & MMU_CONTEXT_ASID_MASK)) {
+		/* We exhaust ASID of this version.
+		   Flush all TLB and start new cycle. */
+		flush_tlb_all();
+		/* Fix version if needed.
+		   Note that we avoid version #0 to distingush NO_CONTEXT. */
+		if (!mc) 
+			mmu_context_cache = mc = MMU_CONTEXT_FIRST_VERSION;
+	}
+	mm->context = mc;
+}
+
+/*P
+ * Get MMU context if needed.
+ */
+extern __inline__ void
+get_mmu_context(struct mm_struct *mm)
+{
+	if (mm) {
+		unsigned long mc = mmu_context_cache;
+		/* Check if we have old version of context.
+		   If it's old, we need to get new context with new version. */
+		if ((mm->context ^ mc) & MMU_CONTEXT_VERSION_MASK)
+			get_new_mmu_context(mm);
+	}
+}
+
+/*P
+ * Initialize the context related info for a new mm_struct
+ * instance.
+ */
+extern __inline__ void init_new_context(struct task_struct *tsk,
+					struct mm_struct *mm)
+{
+	mm->context = NO_CONTEXT;
+}
+
+/*P
+ * Destroy context related info for an mm_struct that is about
+ * to be put to rest.
+ */
+extern __inline__ void destroy_context(struct mm_struct *mm)
+{
+	mm->context = NO_CONTEXT;
+}
+
+/* Other MMU related constants. */
+
+#define MMU_PTEH	0xFFFFFFF0	/* Page table entry register HIGH */
+#define MMU_PTEL	0xFFFFFFF4	/* Page table entry register LOW */
+#define MMUCR		0xFFFFFFE0	/* MMU Control Register */
+
+#define MMU_TLB_ADDRESS_ARRAY 0xF2000000
+#define MMU_PAGE_ASSOC_BIT 0x80
+
+#define MMU_NTLB_ENTRIES       128	/* for 7708 */
+
+#define MMU_CONTROL_INIT 0x007	/* SV=0, TF=1, IX=1, AT=1 */
+
+#include <asm/uaccess.h> /* to get the definition of  __m */
+
+extern __inline__ void set_asid (unsigned long asid)
+{
+	__asm__ __volatile__ ("mov.l	%0,%1"
+			      : /* no output */
+			      : "r" (asid), "m" (__m(MMU_PTEH)));
+}
+
+extern __inline__ unsigned long get_asid (void)
+{
+	unsigned long asid;
+
+	__asm__ __volatile__ ("mov.l %1,%0"
+			      : "=r" (asid)
+			      : "m" (__m(MMU_PTEH)));
+	asid &= MMU_CONTEXT_ASID_MASK;
+	return asid;
+}
+
+/*P
+ * After we have set current->mm to a new value, this activates
+ * the context for the new mm so we see the new mappings.
+ */
+extern __inline__ void activate_context(struct mm_struct *mm)
+{
+	get_mmu_context(mm);
+	set_asid(mm->context & MMU_CONTEXT_ASID_MASK);
+}
+
+/* MMU_TTB can be used for optimizing the fault handling.
+   (Currently not used) */
+#define MMU_TTB   0xFFFFFFF8	/* Translation table base register */
+extern __inline__ void switch_mm(struct mm_struct *prev,
+				 struct mm_struct *next,
+				 struct task_struct *tsk, unsigned int cpu)
+{
+	if (prev != next) {
+		unsigned long __pgdir = __pa(next->pgd);
+
+		__asm__ __volatile__("mov.l	%0,%1": \
+				     :"r" (__pgdir), "m" (__m(MMU_TTB)));
+		activate_context(next);
+		clear_bit(cpu, &prev->cpu_vm_mask);
+	}
+	set_bit(cpu, &next->cpu_vm_mask);
+}
+
+#define activate_mm(prev, next) \
+	switch_mm((prev),(next),NULL,smp_processor_id())
+
+#endif /* __ASM_SH_MMU_CONTEXT_H */