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-rw-r--r--arch/powerpc/mm/mmu_context_nohash.c459
1 files changed, 0 insertions, 459 deletions
diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c
deleted file mode 100644
index af3d78e19302..000000000000
--- a/arch/powerpc/mm/mmu_context_nohash.c
+++ /dev/null
@@ -1,459 +0,0 @@
-/*
- * This file contains the routines for handling the MMU on those
- * PowerPC implementations where the MMU is not using the hash
- * table, such as 8xx, 4xx, BookE's etc...
- *
- * Copyright 2008 Ben Herrenschmidt <benh@kernel.crashing.org>
- * IBM Corp.
- *
- * Derived from previous arch/powerpc/mm/mmu_context.c
- * and arch/powerpc/include/asm/mmu_context.h
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- *
- * TODO:
- *
- * - The global context lock will not scale very well
- * - The maps should be dynamically allocated to allow for processors
- * that support more PID bits at runtime
- * - Implement flush_tlb_mm() by making the context stale and picking
- * a new one
- * - More aggressively clear stale map bits and maybe find some way to
- * also clear mm->cpu_vm_mask bits when processes are migrated
- */
-
-//#define DEBUG_MAP_CONSISTENCY
-//#define DEBUG_CLAMP_LAST_CONTEXT 31
-//#define DEBUG_HARDER
-
-/* We don't use DEBUG because it tends to be compiled in always nowadays
- * and this would generate way too much output
- */
-#ifdef DEBUG_HARDER
-#define pr_hard(args...) printk(KERN_DEBUG args)
-#define pr_hardcont(args...) printk(KERN_CONT args)
-#else
-#define pr_hard(args...) do { } while(0)
-#define pr_hardcont(args...) do { } while(0)
-#endif
-
-#include <linux/kernel.h>
-#include <linux/mm.h>
-#include <linux/init.h>
-#include <linux/spinlock.h>
-#include <linux/bootmem.h>
-#include <linux/notifier.h>
-#include <linux/cpu.h>
-#include <linux/slab.h>
-
-#include <asm/mmu_context.h>
-#include <asm/tlbflush.h>
-
-static unsigned int first_context, last_context;
-static unsigned int next_context, nr_free_contexts;
-static unsigned long *context_map;
-static unsigned long *stale_map[NR_CPUS];
-static struct mm_struct **context_mm;
-static DEFINE_RAW_SPINLOCK(context_lock);
-
-#define CTX_MAP_SIZE \
- (sizeof(unsigned long) * (last_context / BITS_PER_LONG + 1))
-
-
-/* Steal a context from a task that has one at the moment.
- *
- * This is used when we are running out of available PID numbers
- * on the processors.
- *
- * This isn't an LRU system, it just frees up each context in
- * turn (sort-of pseudo-random replacement :). This would be the
- * place to implement an LRU scheme if anyone was motivated to do it.
- * -- paulus
- *
- * For context stealing, we use a slightly different approach for
- * SMP and UP. Basically, the UP one is simpler and doesn't use
- * the stale map as we can just flush the local CPU
- * -- benh
- */
-#ifdef CONFIG_SMP
-static unsigned int steal_context_smp(unsigned int id)
-{
- struct mm_struct *mm;
- unsigned int cpu, max, i;
-
- max = last_context - first_context;
-
- /* Attempt to free next_context first and then loop until we manage */
- while (max--) {
- /* Pick up the victim mm */
- mm = context_mm[id];
-
- /* We have a candidate victim, check if it's active, on SMP
- * we cannot steal active contexts
- */
- if (mm->context.active) {
- id++;
- if (id > last_context)
- id = first_context;
- continue;
- }
- pr_hardcont(" | steal %d from 0x%p", id, mm);
-
- /* Mark this mm has having no context anymore */
- mm->context.id = MMU_NO_CONTEXT;
-
- /* Mark it stale on all CPUs that used this mm. For threaded
- * implementations, we set it on all threads on each core
- * represented in the mask. A future implementation will use
- * a core map instead but this will do for now.
- */
- for_each_cpu(cpu, mm_cpumask(mm)) {
- for (i = cpu_first_thread_sibling(cpu);
- i <= cpu_last_thread_sibling(cpu); i++) {
- if (stale_map[i])
- __set_bit(id, stale_map[i]);
- }
- cpu = i - 1;
- }
- return id;
- }
-
- /* This will happen if you have more CPUs than available contexts,
- * all we can do here is wait a bit and try again
- */
- raw_spin_unlock(&context_lock);
- cpu_relax();
- raw_spin_lock(&context_lock);
-
- /* This will cause the caller to try again */
- return MMU_NO_CONTEXT;
-}
-#endif /* CONFIG_SMP */
-
-/* Note that this will also be called on SMP if all other CPUs are
- * offlined, which means that it may be called for cpu != 0. For
- * this to work, we somewhat assume that CPUs that are onlined
- * come up with a fully clean TLB (or are cleaned when offlined)
- */
-static unsigned int steal_context_up(unsigned int id)
-{
- struct mm_struct *mm;
- int cpu = smp_processor_id();
-
- /* Pick up the victim mm */
- mm = context_mm[id];
-
- pr_hardcont(" | steal %d from 0x%p", id, mm);
-
- /* Flush the TLB for that context */
- local_flush_tlb_mm(mm);
-
- /* Mark this mm has having no context anymore */
- mm->context.id = MMU_NO_CONTEXT;
-
- /* XXX This clear should ultimately be part of local_flush_tlb_mm */
- __clear_bit(id, stale_map[cpu]);
-
- return id;
-}
-
-#ifdef DEBUG_MAP_CONSISTENCY
-static void context_check_map(void)
-{
- unsigned int id, nrf, nact;
-
- nrf = nact = 0;
- for (id = first_context; id <= last_context; id++) {
- int used = test_bit(id, context_map);
- if (!used)
- nrf++;
- if (used != (context_mm[id] != NULL))
- pr_err("MMU: Context %d is %s and MM is %p !\n",
- id, used ? "used" : "free", context_mm[id]);
- if (context_mm[id] != NULL)
- nact += context_mm[id]->context.active;
- }
- if (nrf != nr_free_contexts) {
- pr_err("MMU: Free context count out of sync ! (%d vs %d)\n",
- nr_free_contexts, nrf);
- nr_free_contexts = nrf;
- }
- if (nact > num_online_cpus())
- pr_err("MMU: More active contexts than CPUs ! (%d vs %d)\n",
- nact, num_online_cpus());
- if (first_context > 0 && !test_bit(0, context_map))
- pr_err("MMU: Context 0 has been freed !!!\n");
-}
-#else
-static void context_check_map(void) { }
-#endif
-
-void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
-{
- unsigned int i, id, cpu = smp_processor_id();
- unsigned long *map;
-
- /* No lockless fast path .. yet */
- raw_spin_lock(&context_lock);
-
- pr_hard("[%d] activating context for mm @%p, active=%d, id=%d",
- cpu, next, next->context.active, next->context.id);
-
-#ifdef CONFIG_SMP
- /* Mark us active and the previous one not anymore */
- next->context.active++;
- if (prev) {
- pr_hardcont(" (old=0x%p a=%d)", prev, prev->context.active);
- WARN_ON(prev->context.active < 1);
- prev->context.active--;
- }
-
- again:
-#endif /* CONFIG_SMP */
-
- /* If we already have a valid assigned context, skip all that */
- id = next->context.id;
- if (likely(id != MMU_NO_CONTEXT)) {
-#ifdef DEBUG_MAP_CONSISTENCY
- if (context_mm[id] != next)
- pr_err("MMU: mm 0x%p has id %d but context_mm[%d] says 0x%p\n",
- next, id, id, context_mm[id]);
-#endif
- goto ctxt_ok;
- }
-
- /* We really don't have a context, let's try to acquire one */
- id = next_context;
- if (id > last_context)
- id = first_context;
- map = context_map;
-
- /* No more free contexts, let's try to steal one */
- if (nr_free_contexts == 0) {
-#ifdef CONFIG_SMP
- if (num_online_cpus() > 1) {
- id = steal_context_smp(id);
- if (id == MMU_NO_CONTEXT)
- goto again;
- goto stolen;
- }
-#endif /* CONFIG_SMP */
- id = steal_context_up(id);
- goto stolen;
- }
- nr_free_contexts--;
-
- /* We know there's at least one free context, try to find it */
- while (__test_and_set_bit(id, map)) {
- id = find_next_zero_bit(map, last_context+1, id);
- if (id > last_context)
- id = first_context;
- }
- stolen:
- next_context = id + 1;
- context_mm[id] = next;
- next->context.id = id;
- pr_hardcont(" | new id=%d,nrf=%d", id, nr_free_contexts);
-
- context_check_map();
- ctxt_ok:
-
- /* If that context got marked stale on this CPU, then flush the
- * local TLB for it and unmark it before we use it
- */
- if (test_bit(id, stale_map[cpu])) {
- pr_hardcont(" | stale flush %d [%d..%d]",
- id, cpu_first_thread_sibling(cpu),
- cpu_last_thread_sibling(cpu));
-
- local_flush_tlb_mm(next);
-
- /* XXX This clear should ultimately be part of local_flush_tlb_mm */
- for (i = cpu_first_thread_sibling(cpu);
- i <= cpu_last_thread_sibling(cpu); i++) {
- if (stale_map[i])
- __clear_bit(id, stale_map[i]);
- }
- }
-
- /* Flick the MMU and release lock */
- pr_hardcont(" -> %d\n", id);
- set_context(id, next->pgd);
- raw_spin_unlock(&context_lock);
-}
-
-/*
- * Set up the context for a new address space.
- */
-int init_new_context(struct task_struct *t, struct mm_struct *mm)
-{
- pr_hard("initing context for mm @%p\n", mm);
-
- mm->context.id = MMU_NO_CONTEXT;
- mm->context.active = 0;
-
-#ifdef CONFIG_PPC_MM_SLICES
- if (slice_mm_new_context(mm))
- slice_set_user_psize(mm, mmu_virtual_psize);
-#endif
-
- return 0;
-}
-
-/*
- * We're finished using the context for an address space.
- */
-void destroy_context(struct mm_struct *mm)
-{
- unsigned long flags;
- unsigned int id;
-
- if (mm->context.id == MMU_NO_CONTEXT)
- return;
-
- WARN_ON(mm->context.active != 0);
-
- raw_spin_lock_irqsave(&context_lock, flags);
- id = mm->context.id;
- if (id != MMU_NO_CONTEXT) {
- __clear_bit(id, context_map);
- mm->context.id = MMU_NO_CONTEXT;
-#ifdef DEBUG_MAP_CONSISTENCY
- mm->context.active = 0;
-#endif
- context_mm[id] = NULL;
- nr_free_contexts++;
- }
- raw_spin_unlock_irqrestore(&context_lock, flags);
-}
-
-#ifdef CONFIG_SMP
-
-static int mmu_context_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
-{
- unsigned int cpu = (unsigned int)(long)hcpu;
-
- /* We don't touch CPU 0 map, it's allocated at aboot and kept
- * around forever
- */
- if (cpu == boot_cpuid)
- return NOTIFY_OK;
-
- switch (action) {
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- pr_devel("MMU: Allocating stale context map for CPU %d\n", cpu);
- stale_map[cpu] = kzalloc(CTX_MAP_SIZE, GFP_KERNEL);
- break;
-#ifdef CONFIG_HOTPLUG_CPU
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- pr_devel("MMU: Freeing stale context map for CPU %d\n", cpu);
- kfree(stale_map[cpu]);
- stale_map[cpu] = NULL;
-
- /* We also clear the cpu_vm_mask bits of CPUs going away */
- clear_tasks_mm_cpumask(cpu);
- break;
-#endif /* CONFIG_HOTPLUG_CPU */
- }
- return NOTIFY_OK;
-}
-
-static struct notifier_block mmu_context_cpu_nb = {
- .notifier_call = mmu_context_cpu_notify,
-};
-
-#endif /* CONFIG_SMP */
-
-/*
- * Initialize the context management stuff.
- */
-void __init mmu_context_init(void)
-{
- /* Mark init_mm as being active on all possible CPUs since
- * we'll get called with prev == init_mm the first time
- * we schedule on a given CPU
- */
- init_mm.context.active = NR_CPUS;
-
- /*
- * The MPC8xx has only 16 contexts. We rotate through them on each
- * task switch. A better way would be to keep track of tasks that
- * own contexts, and implement an LRU usage. That way very active
- * tasks don't always have to pay the TLB reload overhead. The
- * kernel pages are mapped shared, so the kernel can run on behalf
- * of any task that makes a kernel entry. Shared does not mean they
- * are not protected, just that the ASID comparison is not performed.
- * -- Dan
- *
- * The IBM4xx has 256 contexts, so we can just rotate through these
- * as a way of "switching" contexts. If the TID of the TLB is zero,
- * the PID/TID comparison is disabled, so we can use a TID of zero
- * to represent all kernel pages as shared among all contexts.
- * -- Dan
- *
- * The IBM 47x core supports 16-bit PIDs, thus 65535 contexts. We
- * should normally never have to steal though the facility is
- * present if needed.
- * -- BenH
- */
- if (mmu_has_feature(MMU_FTR_TYPE_8xx)) {
- first_context = 0;
- last_context = 15;
- } else if (mmu_has_feature(MMU_FTR_TYPE_47x)) {
- first_context = 1;
- last_context = 65535;
- } else
-#ifdef CONFIG_PPC_BOOK3E_MMU
- if (mmu_has_feature(MMU_FTR_TYPE_3E)) {
- u32 mmucfg = mfspr(SPRN_MMUCFG);
- u32 pid_bits = (mmucfg & MMUCFG_PIDSIZE_MASK)
- >> MMUCFG_PIDSIZE_SHIFT;
- first_context = 1;
- last_context = (1UL << (pid_bits + 1)) - 1;
- } else
-#endif
- {
- first_context = 1;
- last_context = 255;
- }
-
-#ifdef DEBUG_CLAMP_LAST_CONTEXT
- last_context = DEBUG_CLAMP_LAST_CONTEXT;
-#endif
- /*
- * Allocate the maps used by context management
- */
- context_map = alloc_bootmem(CTX_MAP_SIZE);
- context_mm = alloc_bootmem(sizeof(void *) * (last_context + 1));
-#ifndef CONFIG_SMP
- stale_map[0] = alloc_bootmem(CTX_MAP_SIZE);
-#else
- stale_map[boot_cpuid] = alloc_bootmem(CTX_MAP_SIZE);
-
- register_cpu_notifier(&mmu_context_cpu_nb);
-#endif
-
- printk(KERN_INFO
- "MMU: Allocated %zu bytes of context maps for %d contexts\n",
- 2 * CTX_MAP_SIZE + (sizeof(void *) * (last_context + 1)),
- last_context - first_context + 1);
-
- /*
- * Some processors have too few contexts to reserve one for
- * init_mm, and require using context 0 for a normal task.
- * Other processors reserve the use of context zero for the kernel.
- * This code assumes first_context < 32.
- */
- context_map[0] = (1 << first_context) - 1;
- next_context = first_context;
- nr_free_contexts = last_context - first_context + 1;
-}
-
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