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authorPatrick McHardy <kaber@trash.net>2012-08-08 21:03:47 +0200
committerPatrick McHardy <kaber@trash.net>2012-08-08 21:03:47 +0200
commitd53b4ed072d9779cdf53582c46436dec06d0961f (patch)
treeac95ecab33e31cd79aae69c475e8348adac51230 /arch/arm/include/asm/mmu_context.h
parent5d4dff7f1011a81a693a9c7b1f6a0b9c842eb60c (diff)
parent28a33cbc24e4256c143dce96c7d93bf423229f92 (diff)
Merge tag 'v3.5' of 192.168.0.154:/repos/git/linux-2.6
Conflicts: drivers/Kconfig Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'arch/arm/include/asm/mmu_context.h')
-rw-r--r--arch/arm/include/asm/mmu_context.h133
1 files changed, 80 insertions, 53 deletions
diff --git a/arch/arm/include/asm/mmu_context.h b/arch/arm/include/asm/mmu_context.h
index 71605d9f8e4..0306bc642c0 100644
--- a/arch/arm/include/asm/mmu_context.h
+++ b/arch/arm/include/asm/mmu_context.h
@@ -18,6 +18,7 @@
#include <asm/cacheflush.h>
#include <asm/cachetype.h>
#include <asm/proc-fns.h>
+#include <asm-generic/mm_hooks.h>
void __check_kvm_seq(struct mm_struct *mm);
@@ -42,45 +43,104 @@ void __check_kvm_seq(struct mm_struct *mm);
#define ASID_FIRST_VERSION (1 << ASID_BITS)
extern unsigned int cpu_last_asid;
-#ifdef CONFIG_SMP
-DECLARE_PER_CPU(struct mm_struct *, current_mm);
-#endif
void __init_new_context(struct task_struct *tsk, struct mm_struct *mm);
void __new_context(struct mm_struct *mm);
+void cpu_set_reserved_ttbr0(void);
-static inline void check_context(struct mm_struct *mm)
+static inline void switch_new_context(struct mm_struct *mm)
{
- /*
- * This code is executed with interrupts enabled. Therefore,
- * mm->context.id cannot be updated to the latest ASID version
- * on a different CPU (and condition below not triggered)
- * without first getting an IPI to reset the context. The
- * alternative is to take a read_lock on mm->context.id_lock
- * (after changing its type to rwlock_t).
- */
- if (unlikely((mm->context.id ^ cpu_last_asid) >> ASID_BITS))
- __new_context(mm);
+ unsigned long flags;
+ __new_context(mm);
+
+ local_irq_save(flags);
+ cpu_switch_mm(mm->pgd, mm);
+ local_irq_restore(flags);
+}
+
+static inline void check_and_switch_context(struct mm_struct *mm,
+ struct task_struct *tsk)
+{
if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
__check_kvm_seq(mm);
+
+ /*
+ * Required during context switch to avoid speculative page table
+ * walking with the wrong TTBR.
+ */
+ cpu_set_reserved_ttbr0();
+
+ if (!((mm->context.id ^ cpu_last_asid) >> ASID_BITS))
+ /*
+ * The ASID is from the current generation, just switch to the
+ * new pgd. This condition is only true for calls from
+ * context_switch() and interrupts are already disabled.
+ */
+ cpu_switch_mm(mm->pgd, mm);
+ else if (irqs_disabled())
+ /*
+ * Defer the new ASID allocation until after the context
+ * switch critical region since __new_context() cannot be
+ * called with interrupts disabled (it sends IPIs).
+ */
+ set_ti_thread_flag(task_thread_info(tsk), TIF_SWITCH_MM);
+ else
+ /*
+ * That is a direct call to switch_mm() or activate_mm() with
+ * interrupts enabled and a new context.
+ */
+ switch_new_context(mm);
}
#define init_new_context(tsk,mm) (__init_new_context(tsk,mm),0)
-#else
-
-static inline void check_context(struct mm_struct *mm)
+#define finish_arch_post_lock_switch \
+ finish_arch_post_lock_switch
+static inline void finish_arch_post_lock_switch(void)
{
+ if (test_and_clear_thread_flag(TIF_SWITCH_MM))
+ switch_new_context(current->mm);
+}
+
+#else /* !CONFIG_CPU_HAS_ASID */
+
#ifdef CONFIG_MMU
+
+static inline void check_and_switch_context(struct mm_struct *mm,
+ struct task_struct *tsk)
+{
if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
__check_kvm_seq(mm);
-#endif
+
+ if (irqs_disabled())
+ /*
+ * cpu_switch_mm() needs to flush the VIVT caches. To avoid
+ * high interrupt latencies, defer the call and continue
+ * running with the old mm. Since we only support UP systems
+ * on non-ASID CPUs, the old mm will remain valid until the
+ * finish_arch_post_lock_switch() call.
+ */
+ set_ti_thread_flag(task_thread_info(tsk), TIF_SWITCH_MM);
+ else
+ cpu_switch_mm(mm->pgd, mm);
+}
+
+#define finish_arch_post_lock_switch \
+ finish_arch_post_lock_switch
+static inline void finish_arch_post_lock_switch(void)
+{
+ if (test_and_clear_thread_flag(TIF_SWITCH_MM)) {
+ struct mm_struct *mm = current->mm;
+ cpu_switch_mm(mm->pgd, mm);
+ }
}
+#endif /* CONFIG_MMU */
+
#define init_new_context(tsk,mm) 0
-#endif
+#endif /* CONFIG_CPU_HAS_ASID */
#define destroy_context(mm) do { } while(0)
@@ -118,12 +178,7 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next,
__flush_icache_all();
#endif
if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
-#ifdef CONFIG_SMP
- struct mm_struct **crt_mm = &per_cpu(current_mm, cpu);
- *crt_mm = next;
-#endif
- check_context(next);
- cpu_switch_mm(next->pgd, next);
+ check_and_switch_context(next, tsk);
if (cache_is_vivt())
cpumask_clear_cpu(cpu, mm_cpumask(prev));
}
@@ -133,32 +188,4 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next,
#define deactivate_mm(tsk,mm) do { } while (0)
#define activate_mm(prev,next) switch_mm(prev, next, NULL)
-/*
- * We are inserting a "fake" vma for the user-accessible vector page so
- * gdb and friends can get to it through ptrace and /proc/<pid>/mem.
- * But we also want to remove it before the generic code gets to see it
- * during process exit or the unmapping of it would cause total havoc.
- * (the macro is used as remove_vma() is static to mm/mmap.c)
- */
-#define arch_exit_mmap(mm) \
-do { \
- struct vm_area_struct *high_vma = find_vma(mm, 0xffff0000); \
- if (high_vma) { \
- BUG_ON(high_vma->vm_next); /* it should be last */ \
- if (high_vma->vm_prev) \
- high_vma->vm_prev->vm_next = NULL; \
- else \
- mm->mmap = NULL; \
- rb_erase(&high_vma->vm_rb, &mm->mm_rb); \
- mm->mmap_cache = NULL; \
- mm->map_count--; \
- remove_vma(high_vma); \
- } \
-} while (0)
-
-static inline void arch_dup_mmap(struct mm_struct *oldmm,
- struct mm_struct *mm)
-{
-}
-
#endif