summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/mm/mmu_context_nohash.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/mm/mmu_context_nohash.c')
-rw-r--r--arch/powerpc/mm/mmu_context_nohash.c135
1 files changed, 68 insertions, 67 deletions
diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c
index be8f5c9d4d088..4d80239ef83c3 100644
--- a/arch/powerpc/mm/mmu_context_nohash.c
+++ b/arch/powerpc/mm/mmu_context_nohash.c
@@ -54,16 +54,44 @@
#include "mmu_decl.h"
-static unsigned int first_context, last_context;
+/*
+ * 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
+ */
+#define FIRST_CONTEXT 1
+#ifdef DEBUG_CLAMP_LAST_CONTEXT
+#define LAST_CONTEXT DEBUG_CLAMP_LAST_CONTEXT
+#elif defined(CONFIG_PPC_8xx)
+#define LAST_CONTEXT 16
+#elif defined(CONFIG_PPC_47x)
+#define LAST_CONTEXT 65535
+#else
+#define LAST_CONTEXT 255
+#endif
+
static unsigned int next_context, nr_free_contexts;
static unsigned long *context_map;
+#ifdef CONFIG_SMP
static unsigned long *stale_map[NR_CPUS];
+#endif
static struct mm_struct **context_mm;
static DEFINE_RAW_SPINLOCK(context_lock);
-static bool no_selective_tlbil;
#define CTX_MAP_SIZE \
- (sizeof(unsigned long) * (last_context / BITS_PER_LONG + 1))
+ (sizeof(unsigned long) * (LAST_CONTEXT / BITS_PER_LONG + 1))
/* Steal a context from a task that has one at the moment.
@@ -87,7 +115,7 @@ 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--) {
@@ -99,8 +127,8 @@ 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_hardcont(" | steal %d from 0x%p", id, mm);
@@ -139,10 +167,12 @@ static unsigned int steal_context_smp(unsigned int id)
static unsigned int steal_all_contexts(void)
{
struct mm_struct *mm;
+#ifdef CONFIG_SMP
int cpu = smp_processor_id();
+#endif
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];
@@ -150,22 +180,24 @@ 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
mm->context.active = 0;
#endif
}
+#ifdef CONFIG_SMP
__clear_bit(id, stale_map[cpu]);
+#endif
}
/* 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
@@ -176,7 +208,9 @@ static unsigned int steal_all_contexts(void)
static unsigned int steal_context_up(unsigned int id)
{
struct mm_struct *mm;
+#ifdef CONFIG_SMP
int cpu = smp_processor_id();
+#endif
/* Pick up the victim mm */
mm = context_mm[id];
@@ -190,7 +224,9 @@ static unsigned int steal_context_up(unsigned int id)
mm->context.id = MMU_NO_CONTEXT;
/* XXX This clear should ultimately be part of local_flush_tlb_mm */
+#ifdef CONFIG_SMP
__clear_bit(id, stale_map[cpu]);
+#endif
return id;
}
@@ -201,7 +237,7 @@ 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 +255,7 @@ 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
@@ -229,7 +265,10 @@ static void context_check_map(void) { }
void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
{
- unsigned int i, id, cpu = smp_processor_id();
+ unsigned int id;
+#ifdef CONFIG_SMP
+ unsigned int i, cpu = smp_processor_id();
+#endif
unsigned long *map;
/* No lockless fast path .. yet */
@@ -263,8 +302,8 @@ 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 */
@@ -277,7 +316,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
goto stolen;
}
#endif /* CONFIG_SMP */
- if (no_selective_tlbil)
+ if (IS_ENABLED(CONFIG_PPC_8xx))
id = steal_all_contexts();
else
id = steal_context_up(id);
@@ -287,9 +326,9 @@ 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;
@@ -303,6 +342,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
/* If that context got marked stale on this CPU, then flush the
* local TLB for it and unmark it before we use it
*/
+#ifdef CONFIG_SMP
if (test_bit(id, stale_map[cpu])) {
pr_hardcont(" | stale flush %d [%d..%d]",
id, cpu_first_thread_sibling(cpu),
@@ -317,6 +357,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
__clear_bit(id, stale_map[i]);
}
}
+#endif
/* Flick the MMU and release lock */
pr_hardcont(" -> %d\n", id);
@@ -418,51 +459,11 @@ 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
- *
- * 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 = 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;
- }
-
-#ifdef DEBUG_CLAMP_LAST_CONTEXT
- last_context = DEBUG_CLAMP_LAST_CONTEXT;
-#endif
- /*
* Allocate the maps used by context management
*/
context_map = memblock_virt_alloc(CTX_MAP_SIZE, 0);
- context_mm = memblock_virt_alloc(sizeof(void *) * (last_context + 1), 0);
-#ifndef CONFIG_SMP
- stale_map[0] = memblock_virt_alloc(CTX_MAP_SIZE, 0);
-#else
+ context_mm = memblock_virt_alloc(sizeof(void *) * (LAST_CONTEXT + 1), 0);
+#ifdef CONFIG_SMP
stale_map[boot_cpuid] = memblock_virt_alloc(CTX_MAP_SIZE, 0);
cpuhp_setup_state_nocalls(CPUHP_POWERPC_MMU_CTX_PREPARE,
@@ -472,17 +473,17 @@ 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);
+ 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;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-26 15:56:37 +0000