powerpc/mm: constify FIRST_CONTEXT in mmu_context_nohash

First context is now 1 for all supported platforms, so it
can be made a constant.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c
index be8f5c9d4d088fad3539b1ffeb9ea3fed3dc4ff7..5051c9363f8cb41b2d2651c5704df6576171dec9 100644 (file)
--- a/arch/powerpc/mm/mmu_context_nohash.c
+++ b/arch/powerpc/mm/mmu_context_nohash.c
@@ -54,7 +54,9 @@
 
 #include "mmu_decl.h"
 
-static unsigned int first_context, last_context;
+#define FIRST_CONTEXT 1
+
+static unsigned int last_context;
 static unsigned int next_context, nr_free_contexts;
 static unsigned long *context_map;
 static unsigned long *stale_map[NR_CPUS];
@@ -87,7 +89,7 @@ static unsigned int steal_context_smp(unsigned int id)
        struct mm_struct *mm;
        unsigned int cpu, max, i;
 
-       max = last_context - first_context;
+       max = last_context - FIRST_CONTEXT;
 
        /* Attempt to free next_context first and then loop until we manage */
        while (max--) {
@@ -100,7 +102,7 @@ static unsigned int steal_context_smp(unsigned int id)
                if (mm->context.active) {
                        id++;
                        if (id > last_context)
-                               id = first_context;
+                               id = FIRST_CONTEXT;
                        continue;
                }
                pr_hardcont(" | steal %d from 0x%p", id, mm);
@@ -142,7 +144,7 @@ static unsigned int steal_all_contexts(void)
        int cpu = smp_processor_id();
        unsigned int id;
 
-       for (id = first_context; id <= last_context; id++) {
+       for (id = FIRST_CONTEXT; id <= last_context; id++) {
                /* Pick up the victim mm */
                mm = context_mm[id];
 
@@ -150,7 +152,7 @@ static unsigned int steal_all_contexts(void)
 
                /* Mark this mm as having no context anymore */
                mm->context.id = MMU_NO_CONTEXT;
-               if (id != first_context) {
+               if (id != FIRST_CONTEXT) {
                        context_mm[id] = NULL;
                        __clear_bit(id, context_map);
 #ifdef DEBUG_MAP_CONSISTENCY
@@ -163,9 +165,9 @@ static unsigned int steal_all_contexts(void)
        /* Flush the TLB for all contexts (not to be used on SMP) */
        _tlbil_all();
 
-       nr_free_contexts = last_context - first_context;
+       nr_free_contexts = last_context - FIRST_CONTEXT;
 
-       return first_context;
+       return FIRST_CONTEXT;
 }
 
 /* Note that this will also be called on SMP if all other CPUs are
@@ -201,7 +203,7 @@ 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++;
@@ -219,7 +221,7 @@ 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))
+       if (FIRST_CONTEXT > 0 && !test_bit(0, context_map))
                pr_err("MMU: Context 0 has been freed !!!\n");
 }
 #else
@@ -264,7 +266,7 @@ 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;
+               id = FIRST_CONTEXT;
        map = context_map;
 
        /* No more free contexts, let's try to steal one */
@@ -289,7 +291,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
        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 = FIRST_CONTEXT;
        }
  stolen:
        next_context = id + 1;
@@ -439,15 +441,12 @@ void __init mmu_context_init(void)
         *      -- BenH
         */
        if (mmu_has_feature(MMU_FTR_TYPE_8xx)) {
-               first_context = 1;
                last_context = 16;
                no_selective_tlbil = true;
        } else if (mmu_has_feature(MMU_FTR_TYPE_47x)) {
-               first_context = 1;
                last_context = 65535;
                no_selective_tlbil = false;
        } else {
-               first_context = 1;
                last_context = 255;
                no_selective_tlbil = false;
        }
@@ -473,16 +472,16 @@ void __init mmu_context_init(void)
        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);
+              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;
 }