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-rw-r--r--arch/arm/include/asm/mmu.h11
-rw-r--r--arch/arm/include/asm/mmu_context.h82
-rw-r--r--arch/arm/mm/context.c186
3 files changed, 93 insertions, 186 deletions
diff --git a/arch/arm/include/asm/mmu.h b/arch/arm/include/asm/mmu.h
index 14965658a923..5b53b53ab5cf 100644
--- a/arch/arm/include/asm/mmu.h
+++ b/arch/arm/include/asm/mmu.h
@@ -5,18 +5,15 @@
typedef struct {
#ifdef CONFIG_CPU_HAS_ASID
- unsigned int id;
- raw_spinlock_t id_lock;
+ u64 id;
#endif
unsigned int kvm_seq;
} mm_context_t;
#ifdef CONFIG_CPU_HAS_ASID
-#define ASID(mm) ((mm)->context.id & 255)
-
-/* init_mm.context.id_lock should be initialized. */
-#define INIT_MM_CONTEXT(name) \
- .context.id_lock = __RAW_SPIN_LOCK_UNLOCKED(name.context.id_lock),
+#define ASID_BITS 8
+#define ASID_MASK ((~0ULL) << ASID_BITS)
+#define ASID(mm) ((mm)->context.id & ~ASID_MASK)
#else
#define ASID(mm) (0)
#endif
diff --git a/arch/arm/include/asm/mmu_context.h b/arch/arm/include/asm/mmu_context.h
index 0306bc642c0d..a64f61cb23d1 100644
--- a/arch/arm/include/asm/mmu_context.h
+++ b/arch/arm/include/asm/mmu_context.h
@@ -24,84 +24,8 @@ void __check_kvm_seq(struct mm_struct *mm);
#ifdef CONFIG_CPU_HAS_ASID
-/*
- * 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)
-#define ASID_FIRST_VERSION (1 << 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);
-void cpu_set_reserved_ttbr0(void);
-
-static inline void switch_new_context(struct mm_struct *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)
-
-#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);
-}
+void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk);
+#define init_new_context(tsk,mm) ({ mm->context.id = 0; })
#else /* !CONFIG_CPU_HAS_ASID */
@@ -143,6 +67,7 @@ static inline void finish_arch_post_lock_switch(void)
#endif /* CONFIG_CPU_HAS_ASID */
#define destroy_context(mm) do { } while(0)
+#define activate_mm(prev,next) switch_mm(prev, next, NULL)
/*
* This is called when "tsk" is about to enter lazy TLB mode.
@@ -186,6 +111,5 @@ 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)
#endif
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 4e07eec1270d..3172781a8e2e 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -2,6 +2,9 @@
* linux/arch/arm/mm/context.c
*
* Copyright (C) 2002-2003 Deep Blue Solutions Ltd, all rights reserved.
+ * Copyright (C) 2012 ARM Limited
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
*
* 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
@@ -14,14 +17,35 @@
#include <linux/percpu.h>
#include <asm/mmu_context.h>
+#include <asm/smp_plat.h>
#include <asm/thread_notify.h>
#include <asm/tlbflush.h>
+/*
+ * 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_FIRST_VERSION (1ULL << ASID_BITS)
+
static DEFINE_RAW_SPINLOCK(cpu_asid_lock);
-unsigned int cpu_last_asid = ASID_FIRST_VERSION;
+static u64 cpu_last_asid = ASID_FIRST_VERSION;
+
+static DEFINE_PER_CPU(u64, active_asids);
+static DEFINE_PER_CPU(u64, reserved_asids);
+static cpumask_t tlb_flush_pending;
#ifdef CONFIG_ARM_LPAE
-void cpu_set_reserved_ttbr0(void)
+static void cpu_set_reserved_ttbr0(void)
{
unsigned long ttbl = __pa(swapper_pg_dir);
unsigned long ttbh = 0;
@@ -37,7 +61,7 @@ void cpu_set_reserved_ttbr0(void)
isb();
}
#else
-void cpu_set_reserved_ttbr0(void)
+static void cpu_set_reserved_ttbr0(void)
{
u32 ttb;
/* Copy TTBR1 into TTBR0 */
@@ -84,124 +108,86 @@ static int __init contextidr_notifier_init(void)
arch_initcall(contextidr_notifier_init);
#endif
-/*
- * We fork()ed a process, and we need a new context for the child
- * to run in.
- */
-void __init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+static void flush_context(unsigned int cpu)
{
- mm->context.id = 0;
- raw_spin_lock_init(&mm->context.id_lock);
-}
+ int i;
-static void flush_context(void)
-{
- cpu_set_reserved_ttbr0();
- local_flush_tlb_all();
- if (icache_is_vivt_asid_tagged()) {
+ /* Update the list of reserved ASIDs. */
+ per_cpu(active_asids, cpu) = 0;
+ for_each_possible_cpu(i)
+ per_cpu(reserved_asids, i) = per_cpu(active_asids, i);
+
+ /* Queue a TLB invalidate and flush the I-cache if necessary. */
+ if (!tlb_ops_need_broadcast())
+ cpumask_set_cpu(cpu, &tlb_flush_pending);
+ else
+ cpumask_setall(&tlb_flush_pending);
+
+ if (icache_is_vivt_asid_tagged())
__flush_icache_all();
- dsb();
- }
}
-#ifdef CONFIG_SMP
+static int is_reserved_asid(u64 asid, u64 mask)
+{
+ int cpu;
+ for_each_possible_cpu(cpu)
+ if ((per_cpu(reserved_asids, cpu) & mask) == (asid & mask))
+ return 1;
+ return 0;
+}
-static void set_mm_context(struct mm_struct *mm, unsigned int asid)
+static void new_context(struct mm_struct *mm, unsigned int cpu)
{
- unsigned long flags;
+ u64 asid = mm->context.id;
- /*
- * Locking needed for multi-threaded applications where the
- * same mm->context.id could be set from different CPUs during
- * the broadcast. This function is also called via IPI so the
- * mm->context.id_lock has to be IRQ-safe.
- */
- raw_spin_lock_irqsave(&mm->context.id_lock, flags);
- if (likely((mm->context.id ^ cpu_last_asid) >> ASID_BITS)) {
+ if (asid != 0 && is_reserved_asid(asid, ULLONG_MAX)) {
/*
- * Old version of ASID found. Set the new one and
- * reset mm_cpumask(mm).
+ * Our current ASID was active during a rollover, we can
+ * continue to use it and this was just a false alarm.
*/
- mm->context.id = asid;
+ asid = (cpu_last_asid & ASID_MASK) | (asid & ~ASID_MASK);
+ } else {
+ /*
+ * Allocate a free ASID. If we can't find one, take a
+ * note of the currently active ASIDs and mark the TLBs
+ * as requiring flushes.
+ */
+ do {
+ asid = ++cpu_last_asid;
+ if ((asid & ~ASID_MASK) == 0)
+ flush_context(cpu);
+ } while (is_reserved_asid(asid, ~ASID_MASK));
cpumask_clear(mm_cpumask(mm));
}
- raw_spin_unlock_irqrestore(&mm->context.id_lock, flags);
- /*
- * Set the mm_cpumask(mm) bit for the current CPU.
- */
- cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
+ mm->context.id = asid;
}
-/*
- * Reset the ASID on the current CPU. This function call is broadcast
- * from the CPU handling the ASID rollover and holding cpu_asid_lock.
- */
-static void reset_context(void *info)
+void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk)
{
- unsigned int asid;
+ unsigned long flags;
unsigned int cpu = smp_processor_id();
- struct mm_struct *mm = current->active_mm;
-
- smp_rmb();
- asid = cpu_last_asid + cpu + 1;
-
- flush_context();
- set_mm_context(mm, asid);
-
- /* set the new ASID */
- cpu_switch_mm(mm->pgd, mm);
-}
-
-#else
-static inline void set_mm_context(struct mm_struct *mm, unsigned int asid)
-{
- mm->context.id = asid;
- cpumask_copy(mm_cpumask(mm), cpumask_of(smp_processor_id()));
-}
+ if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
+ __check_kvm_seq(mm);
-#endif
-
-void __new_context(struct mm_struct *mm)
-{
- unsigned int asid;
-
- raw_spin_lock(&cpu_asid_lock);
-#ifdef CONFIG_SMP
/*
- * Check the ASID again, in case the change was broadcast from
- * another CPU before we acquired the lock.
+ * Required during context switch to avoid speculative page table
+ * walking with the wrong TTBR.
*/
- if (unlikely(((mm->context.id ^ cpu_last_asid) >> ASID_BITS) == 0)) {
- cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
- raw_spin_unlock(&cpu_asid_lock);
- return;
- }
-#endif
- /*
- * At this point, it is guaranteed that the current mm (with
- * an old ASID) isn't active on any other CPU since the ASIDs
- * are changed simultaneously via IPI.
- */
- asid = ++cpu_last_asid;
- if (asid == 0)
- asid = cpu_last_asid = ASID_FIRST_VERSION;
+ cpu_set_reserved_ttbr0();
- /*
- * If we've used up all our ASIDs, we need
- * to start a new version and flush the TLB.
- */
- if (unlikely((asid & ~ASID_MASK) == 0)) {
- asid = cpu_last_asid + smp_processor_id() + 1;
- flush_context();
-#ifdef CONFIG_SMP
- smp_wmb();
- smp_call_function(reset_context, NULL, 1);
-#endif
- cpu_last_asid += NR_CPUS;
- }
+ raw_spin_lock_irqsave(&cpu_asid_lock, flags);
+ /* Check that our ASID belongs to the current generation. */
+ if ((mm->context.id ^ cpu_last_asid) >> ASID_BITS)
+ new_context(mm, cpu);
- set_mm_context(mm, asid);
- raw_spin_unlock(&cpu_asid_lock);
+ *this_cpu_ptr(&active_asids) = mm->context.id;
+ cpumask_set_cpu(cpu, mm_cpumask(mm));
+
+ if (cpumask_test_and_clear_cpu(cpu, &tlb_flush_pending))
+ local_flush_tlb_all();
+ raw_spin_unlock_irqrestore(&cpu_asid_lock, flags);
+
+ cpu_switch_mm(mm->pgd, mm);
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-23 15:59:54 +0300