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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-arm/mmu_context.h
downloadlwn-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
lwn-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'include/asm-arm/mmu_context.h')
-rw-r--r--include/asm-arm/mmu_context.h96
1 files changed, 96 insertions, 0 deletions
diff --git a/include/asm-arm/mmu_context.h b/include/asm-arm/mmu_context.h
new file mode 100644
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+++ b/include/asm-arm/mmu_context.h
@@ -0,0 +1,96 @@
+/*
+ * linux/include/asm-arm/mmu_context.h
+ *
+ * Copyright (C) 1996 Russell King.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Changelog:
+ * 27-06-1996 RMK Created
+ */
+#ifndef __ASM_ARM_MMU_CONTEXT_H
+#define __ASM_ARM_MMU_CONTEXT_H
+
+#include <asm/proc-fns.h>
+
+#if __LINUX_ARM_ARCH__ >= 6
+
+/*
+ * On ARMv6, we have the following structure in the Context ID:
+ *
+ * 31 7 0
+ * +-------------------------+-----------+
+ * | process ID | ASID |
+ * +-------------------------+-----------+
+ * | context ID |
+ * +-------------------------------------+
+ *
+ * The ASID is used to tag entries in the CPU caches and TLBs.
+ * The context ID is used by debuggers and trace logic, and
+ * should be unique within all running processes.
+ */
+#define ASID_BITS 8
+#define ASID_MASK ((~0) << ASID_BITS)
+
+extern unsigned int cpu_last_asid;
+
+void __init_new_context(struct task_struct *tsk, struct mm_struct *mm);
+void __new_context(struct mm_struct *mm);
+
+static inline void check_context(struct mm_struct *mm)
+{
+ if (unlikely((mm->context.id ^ cpu_last_asid) >> ASID_BITS))
+ __new_context(mm);
+}
+
+#define init_new_context(tsk,mm) (__init_new_context(tsk,mm),0)
+
+#else
+
+#define check_context(mm) do { } while (0)
+#define init_new_context(tsk,mm) 0
+
+#endif
+
+#define destroy_context(mm) do { } while(0)
+
+/*
+ * This is called when "tsk" is about to enter lazy TLB mode.
+ *
+ * mm: describes the currently active mm context
+ * tsk: task which is entering lazy tlb
+ * cpu: cpu number which is entering lazy tlb
+ *
+ * tsk->mm will be NULL
+ */
+static inline void
+enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
+{
+}
+
+/*
+ * This is the actual mm switch as far as the scheduler
+ * is concerned. No registers are touched. We avoid
+ * calling the CPU specific function when the mm hasn't
+ * actually changed.
+ */
+static inline void
+switch_mm(struct mm_struct *prev, struct mm_struct *next,
+ struct task_struct *tsk)
+{
+ unsigned int cpu = smp_processor_id();
+
+ if (prev != next) {
+ cpu_set(cpu, next->cpu_vm_mask);
+ check_context(next);
+ cpu_switch_mm(next->pgd, next);
+ cpu_clear(cpu, prev->cpu_vm_mask);
+ }
+}
+
+#define deactivate_mm(tsk,mm) do { } while (0)
+#define activate_mm(prev,next) switch_mm(prev, next, NULL)
+
+#endif