---

yaml
---
r: 123118
b: refs/heads/master
c: 7752035
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 760ec0e02d8a13d0ed60d99f47879d4aa8ef1910
+refs/heads/master: 77520351805cc19ba37394ae33f862ef6d3c2a23

trunk/arch/powerpc/kernel/setup_32.c

@@ -38,6 +38,7 @@
 #include <asm/time.h>
 #include <asm/serial.h>
 #include <asm/udbg.h>
+#include <asm/mmu_context.h>
 
 #include "setup.h"
 
@@ -330,4 +331,8 @@ void __init setup_arch(char **cmdline_p)
 	if ( ppc_md.progress ) ppc_md.progress("arch: exit", 0x3eab);
 
 	paging_init();
+
+	/* Initialize the MMU context management stuff */
+	mmu_context_init();
+
 }

trunk/arch/powerpc/mm/init_32.c

@@ -35,7 +35,6 @@
 #include <asm/pgalloc.h>
 #include <asm/prom.h>
 #include <asm/io.h>
-#include <asm/mmu_context.h>
 #include <asm/pgtable.h>
 #include <asm/mmu.h>
 #include <asm/smp.h>
@@ -180,9 +179,6 @@ void __init MMU_init(void)
 	if (ppc_md.progress)
 		ppc_md.progress("MMU:setio", 0x302);
 
-	/* Initialize the context management stuff */
-	mmu_context_init();
-
 	if (ppc_md.progress)
 		ppc_md.progress("MMU:exit", 0x211);
 

trunk/arch/powerpc/mm/mmu_context_nohash.c

@@ -28,54 +28,30 @@
 #undef DEBUG
 #define DEBUG_STEAL_ONLY
 #undef DEBUG_MAP_CONSISTENCY
+/*#define DEBUG_CLAMP_LAST_CONTEXT   15 */
 
 #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 <asm/mmu_context.h>
 #include <asm/tlbflush.h>
-#include <linux/spinlock.h>
-
-/*
- *   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
- */
-
-#ifdef CONFIG_8xx
-#define LAST_CONTEXT    	15
-#define FIRST_CONTEXT    	0
-
-#elif defined(CONFIG_4xx)
-#define LAST_CONTEXT    	255
-#define FIRST_CONTEXT    	1
-
-#elif defined(CONFIG_E200) || defined(CONFIG_E500)
-#define LAST_CONTEXT    	255
-#define FIRST_CONTEXT    	1
-
-#else
-#error Unsupported processor type
-#endif
 
+static unsigned int first_context, last_context;
 static unsigned int next_context, nr_free_contexts;
-static unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
-static unsigned long stale_map[NR_CPUS][LAST_CONTEXT / BITS_PER_LONG + 1];
-static struct mm_struct *context_mm[LAST_CONTEXT+1];
+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;
 
+#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
@@ -98,7 +74,7 @@ static unsigned int steal_context_smp(unsigned int id)
 	unsigned int cpu, max;
 
  again:
-	max = LAST_CONTEXT - FIRST_CONTEXT;
+	max = last_context - first_context;
 
 	/* Attempt to free next_context first and then loop until we manage */
 	while (max--) {
@@ -110,8 +86,8 @@ static unsigned int steal_context_smp(unsigned int id)
 		 */
 		if (mm->context.active) {
 			id++;
-			if (id > LAST_CONTEXT)
-				id = FIRST_CONTEXT;
+			if (id > last_context)
+				id = first_context;
 			continue;
 		}
 		pr_debug("[%d] steal context %d from mm @%p\n",
@@ -169,7 +145,7 @@ static void context_check_map(void)
 	unsigned int id, nrf, nact;
 
 	nrf = nact = 0;
-	for (id = FIRST_CONTEXT; id <= LAST_CONTEXT; id++) {
+	for (id = first_context; id <= last_context; id++) {
 		int used = test_bit(id, context_map);
 		if (!used)
 			nrf++;
@@ -187,6 +163,8 @@ static void context_check_map(void)
 	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) { }
@@ -209,6 +187,10 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
 	/* 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
 		WARN_ON(prev->context.active < 1);
 		prev->context.active--;
 	}
@@ -221,8 +203,8 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
 
 	/* We really don't have a context, let's try to acquire one */
 	id = next_context;
-	if (id > LAST_CONTEXT)
-		id = FIRST_CONTEXT;
+	if (id > last_context)
+		id = first_context;
 	map = context_map;
 
 	/* No more free contexts, let's try to steal one */
@@ -240,9 +222,9 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
 
 	/* 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;
+		id = find_next_zero_bit(map, last_context+1, id);
+		if (id > last_context)
+			id = first_context;
 	}
  stolen:
 	next_context = id + 1;
@@ -311,6 +293,42 @@ void destroy_context(struct mm_struct *mm)
 	spin_unlock(&context_lock);
 }
 
+#ifdef CONFIG_SMP
+
+static int __cpuinit 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)
+		return NOTIFY_OK;
+
+	switch (action) {
+	case CPU_ONLINE:
+	case CPU_ONLINE_FROZEN:
+		pr_debug("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_DEAD:
+	case CPU_DEAD_FROZEN:
+		pr_debug("MMU: Freeing stale context map for CPU %d\n", cpu);
+		kfree(stale_map[cpu]);
+		stale_map[cpu] = NULL;
+		break;
+#endif
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata mmu_context_cpu_nb = {
+	.notifier_call	= mmu_context_cpu_notify,
+};
+
+#endif /* CONFIG_SMP */
 
 /*
  * Initialize the context management stuff.
@@ -323,14 +341,57 @@ void __init mmu_context_init(void)
 	 */
 	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
+	 */
+	if (mmu_has_feature(MMU_FTR_TYPE_8xx)) {
+		first_context = 0;
+		last_context = 15;
+	} else {
+		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));
+	stale_map[0] = alloc_bootmem(CTX_MAP_SIZE);
+
+#ifdef CONFIG_SMP
+	register_cpu_notifier(&mmu_context_cpu_nb);
+#endif
+
+	printk(KERN_INFO
+	       "MMU: Allocated %d 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.
+	 * 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;
+	context_map[0] = (1 << first_context) - 1;
+	next_context = first_context;
+	nr_free_contexts = last_context - first_context + 1;
 }