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Message-Id: <03c175e506e88e57f48f01de9120768e1b942c6e.1521641042.git.christophe.leroy@c-s.fr>
Date: Wed, 21 Mar 2018 15:07:47 +0100 (CET)
From: Christophe Leroy <christophe.leroy@....fr>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
Scott Wood <oss@...error.net>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH 1/4] 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@....fr>
---
arch/powerpc/mm/mmu_context_nohash.c | 37 ++++++++++++++++++------------------
1 file changed, 18 insertions(+), 19 deletions(-)
diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c
index be8f5c9d4d08..5051c9363f8c 100644
--- 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;
}
--
2.13.3
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