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Diffstat (limited to 'arch/powerpc/mm/mmu_context_nohash.c')
-rw-r--r--arch/powerpc/mm/mmu_context_nohash.c152
1 files changed, 102 insertions, 50 deletions
diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c
index 030d0005b4d..928ebe79668 100644
--- a/arch/powerpc/mm/mmu_context_nohash.c
+++ b/arch/powerpc/mm/mmu_context_nohash.c
@@ -25,10 +25,20 @@
* also clear mm->cpu_vm_mask bits when processes are migrated
*/
-#undef DEBUG
-#define DEBUG_STEAL_ONLY
-#undef DEBUG_MAP_CONSISTENCY
-/*#define DEBUG_CLAMP_LAST_CONTEXT 15 */
+//#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>
@@ -37,6 +47,7 @@
#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>
@@ -46,7 +57,7 @@ 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 spinlock_t context_lock = SPIN_LOCK_UNLOCKED;
+static DEFINE_RAW_SPINLOCK(context_lock);
#define CTX_MAP_SIZE \
(sizeof(unsigned long) * (last_context / BITS_PER_LONG + 1))
@@ -71,9 +82,8 @@ static spinlock_t context_lock = SPIN_LOCK_UNLOCKED;
static unsigned int steal_context_smp(unsigned int id)
{
struct mm_struct *mm;
- unsigned int cpu, max;
+ unsigned int cpu, max, i;
- again:
max = last_context - first_context;
/* Attempt to free next_context first and then loop until we manage */
@@ -90,25 +100,36 @@ static unsigned int steal_context_smp(unsigned int id)
id = first_context;
continue;
}
- pr_debug("[%d] steal context %d from mm @%p\n",
- smp_processor_id(), id, mm);
+ 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_each_cpu(cpu, mm_cpumask(mm))
- __set_bit(id, stale_map[cpu]);
+ /* 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
*/
- spin_unlock(&context_lock);
+ raw_spin_unlock(&context_lock);
cpu_relax();
- spin_lock(&context_lock);
- goto again;
+ raw_spin_lock(&context_lock);
+
+ /* This will cause the caller to try again */
+ return MMU_NO_CONTEXT;
}
#endif /* CONFIG_SMP */
@@ -125,7 +146,7 @@ static unsigned int steal_context_up(unsigned int id)
/* Pick up the victim mm */
mm = context_mm[id];
- pr_debug("[%d] steal context %d from mm @%p\n", cpu, id, mm);
+ pr_hardcont(" | steal %d from 0x%p", id, mm);
/* Flush the TLB for that context */
local_flush_tlb_mm(mm);
@@ -172,34 +193,37 @@ static void context_check_map(void) { }
void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
{
- unsigned int id, cpu = smp_processor_id();
+ unsigned int i, id, cpu = smp_processor_id();
unsigned long *map;
/* No lockless fast path .. yet */
- spin_lock(&context_lock);
+ raw_spin_lock(&context_lock);
-#ifndef DEBUG_STEAL_ONLY
- pr_debug("[%d] activating context for mm @%p, active=%d, id=%d\n",
- cpu, next, next->context.active, next->context.id);
-#endif
+ 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) {
-#ifndef DEBUG_STEAL_ONLY
- pr_debug(" old context %p active was: %d\n",
- prev, prev->context.active);
-#endif
+ 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))
+ 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;
@@ -212,6 +236,8 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
#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 */
@@ -230,11 +256,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
next_context = id + 1;
context_mm[id] = next;
next->context.id = id;
-
-#ifndef DEBUG_STEAL_ONLY
- pr_debug("[%d] picked up new id %d, nrf is now %d\n",
- cpu, id, nr_free_contexts);
-#endif
+ pr_hardcont(" | new id=%d,nrf=%d", id, nr_free_contexts);
context_check_map();
ctxt_ok:
@@ -243,17 +265,24 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
* local TLB for it and unmark it before we use it
*/
if (test_bit(id, stale_map[cpu])) {
- pr_debug("[%d] flushing stale context %d for mm @%p !\n",
- cpu, id, next);
+ 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 */
- __clear_bit(id, stale_map[cpu]);
+ 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);
- spin_unlock(&context_lock);
+ raw_spin_unlock(&context_lock);
}
/*
@@ -261,9 +290,16 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
*/
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;
}
@@ -272,6 +308,7 @@ int init_new_context(struct task_struct *t, struct mm_struct *mm)
*/
void destroy_context(struct mm_struct *mm)
{
+ unsigned long flags;
unsigned int id;
if (mm->context.id == MMU_NO_CONTEXT)
@@ -279,52 +316,57 @@ void destroy_context(struct mm_struct *mm)
WARN_ON(mm->context.active != 0);
- spin_lock(&context_lock);
+ 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;
- context_mm[id] = NULL;
#endif
+ context_mm[id] = NULL;
nr_free_contexts++;
}
- spin_unlock(&context_lock);
+ raw_spin_unlock_irqrestore(&context_lock, flags);
}
#ifdef CONFIG_SMP
-static int __cpuinit mmu_context_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
+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 == 0)
+ if (cpu == boot_cpuid)
return NOTIFY_OK;
switch (action) {
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- pr_debug("MMU: Allocating stale context map for CPU %d\n", cpu);
+ 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_debug("MMU: Freeing stale context map for CPU %d\n", cpu);
+ pr_devel("MMU: Freeing stale context map for CPU %d\n", cpu);
kfree(stale_map[cpu]);
stale_map[cpu] = NULL;
- break;
-#endif
+
+ /* 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 __cpuinitdata mmu_context_cpu_nb = {
+static struct notifier_block mmu_context_cpu_nb = {
.notifier_call = mmu_context_cpu_notify,
};
@@ -356,10 +398,18 @@ void __init mmu_context_init(void)
* 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 {
first_context = 1;
last_context = 255;
@@ -373,9 +423,11 @@ void __init mmu_context_init(void)
*/
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);
-#ifdef CONFIG_SMP
register_cpu_notifier(&mmu_context_cpu_nb);
#endif
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-12-06 03:42:19 +0000