// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2022, Linaro Limited, All rights reserved.
* Author: Mike Leach <[email protected]>
*/
#include <linux/coresight.h>
#include <linux/coresight-pmu.h>
#include <linux/cpumask.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include "coresight-trace-id.h"
/* Default trace ID map. Used in sysfs mode and for system sources */
static DEFINE_PER_CPU(atomic_t, id_map_default_cpu_ids) = ATOMIC_INIT(0);
static struct coresight_trace_id_map id_map_default = {
.cpu_map = &id_map_default_cpu_ids,
.lock = __SPIN_LOCK_UNLOCKED(id_map_default.lock)
};
/* #define TRACE_ID_DEBUG 1 */
#if defined(TRACE_ID_DEBUG) || defined(CONFIG_COMPILE_TEST)
static void coresight_trace_id_dump_table(struct coresight_trace_id_map *id_map,
const char *func_name)
{
pr_debug("%s id_map::\n", func_name);
pr_debug("Used = %*pb\n", CORESIGHT_TRACE_IDS_MAX, id_map->used_ids);
}
#define DUMP_ID_MAP(map) coresight_trace_id_dump_table(map, __func__)
#define DUMP_ID_CPU(cpu, id) pr_debug("%s called; cpu=%d, id=%d\n", __func__, cpu, id)
#define DUMP_ID(id) pr_debug("%s called; id=%d\n", __func__, id)
#define PERF_SESSION(n) pr_debug("%s perf count %d\n", __func__, n)
#else
#define DUMP_ID_MAP(map)
#define DUMP_ID(id)
#define DUMP_ID_CPU(cpu, id)
#define PERF_SESSION(n)
#endif
/* unlocked read of current trace ID value for given CPU */
static int _coresight_trace_id_read_cpu_id(int cpu, struct coresight_trace_id_map *id_map)
{
return atomic_read(per_cpu_ptr(id_map->cpu_map, cpu));
}
/* look for next available odd ID, return 0 if none found */
static int coresight_trace_id_find_odd_id(struct coresight_trace_id_map *id_map)
{
int found_id = 0, bit = 1, next_id;
while ((bit < CORESIGHT_TRACE_ID_RES_TOP) && !found_id) {
/*
* bitmap length of CORESIGHT_TRACE_ID_RES_TOP,
* search from offset `bit`.
*/
next_id = find_next_zero_bit(id_map->used_ids,
CORESIGHT_TRACE_ID_RES_TOP, bit);
if ((next_id < CORESIGHT_TRACE_ID_RES_TOP) && (next_id & 0x1))
found_id = next_id;
else
bit = next_id + 1;
}
return found_id;
}
/*
* Allocate new ID and set in use
*
* if @preferred_id is a valid id then try to use that value if available.
* if @preferred_id is not valid and @prefer_odd_id is true, try for odd id.
*
* Otherwise allocate next available ID.
*/
static int coresight_trace_id_alloc_new_id(struct coresight_trace_id_map *id_map,
int preferred_id, bool prefer_odd_id)
{
int id = 0;
/* for backwards compatibility, cpu IDs may use preferred value */
if (IS_VALID_CS_TRACE_ID(preferred_id) &&
!test_bit(preferred_id, id_map->used_ids)) {
id = preferred_id;
goto trace_id_allocated;
} else if (prefer_odd_id) {
/* may use odd ids to avoid preferred legacy cpu IDs */
id = coresight_trace_id_find_odd_id(id_map);
if (id)
goto trace_id_allocated;
}
/*
* skip reserved bit 0, look at bitmap length of
* CORESIGHT_TRACE_ID_RES_TOP from offset of bit 1.
*/
id = find_next_zero_bit(id_map->used_ids, CORESIGHT_TRACE_ID_RES_TOP, 1);
if (id >= CORESIGHT_TRACE_ID_RES_TOP)
return -EINVAL;
/* mark as used */
trace_id_allocated:
set_bit(id, id_map->used_ids);
return id;
}
static void coresight_trace_id_free(int id, struct coresight_trace_id_map *id_map)
{
if (WARN(!IS_VALID_CS_TRACE_ID(id), "Invalid Trace ID %d\n", id))
return;
if (WARN(!test_bit(id, id_map->used_ids), "Freeing unused ID %d\n", id))
return;
clear_bit(id, id_map->used_ids);
}
/*
* Release all IDs and clear CPU associations.
*/
static void coresight_trace_id_release_all(struct coresight_trace_id_map *id_map)
{
unsigned long flags;
int cpu;
spin_lock_irqsave(&id_map->lock, flags);
bitmap_zero(id_map->used_ids, CORESIGHT_TRACE_IDS_MAX);
for_each_possible_cpu(cpu)
atomic_set(per_cpu_ptr(id_map->cpu_map, cpu), 0);
spin_unlock_irqrestore(&id_map->lock, flags);
DUMP_ID_MAP(id_map);
}
static int _coresight_trace_id_get_cpu_id(int cpu, struct coresight_trace_id_map *id_map)
{
unsigned long flags;
int id;
spin_lock_irqsave(&id_map->lock, flags);
/* check for existing allocation for this CPU */
id = _coresight_trace_id_read_cpu_id(cpu, id_map);
if (id)
goto get_cpu_id_out_unlock;
/*
* Find a new ID.
*
* Use legacy values where possible in the dynamic trace ID allocator to
* allow older tools to continue working if they are not upgraded at the
* same time as the kernel drivers.
*
* If the generated legacy ID is invalid, or not available then the next
* available dynamic ID will be used.
*/
id = coresight_trace_id_alloc_new_id(id_map,
CORESIGHT_LEGACY_CPU_TRACE_ID(cpu),
false);
if (!IS_VALID_CS_TRACE_ID(id))
goto get_cpu_id_out_unlock;
/* allocate the new id to the cpu */
atomic_set(per_cpu_ptr(id_map->cpu_map, cpu), id);
get_cpu_id_out_unlock:
spin_unlock_irqrestore(&id_map->lock, flags);
DUMP_ID_CPU(cpu, id);
DUMP_ID_MAP(id_map);
return id;
}
static void _coresight_trace_id_put_cpu_id(int cpu, struct coresight_trace_id_map *id_map)
{
unsigned long flags;
int id;
/* check for existing allocation for this CPU */
id = _coresight_trace_id_read_cpu_id(cpu, id_map);
if (!id)
return;
spin_lock_irqsave(&id_map->lock, flags);
coresight_trace_id_free(id, id_map);
atomic_set(per_cpu_ptr(id_map->cpu_map, cpu), 0);
spin_unlock_irqrestore(&id_map->lock, flags);
DUMP_ID_CPU(cpu, id);
DUMP_ID_MAP(id_map);
}
static int coresight_trace_id_map_get_system_id(struct coresight_trace_id_map *id_map)
{
unsigned long flags;
int id;
spin_lock_irqsave(&id_map->lock, flags);
/* prefer odd IDs for system components to avoid legacy CPU IDS */
id = coresight_trace_id_alloc_new_id(id_map, 0, true);
spin_unlock_irqrestore(&id_map->lock, flags);
DUMP_ID(id);
DUMP_ID_MAP(id_map);
return id;
}
static void coresight_trace_id_map_put_system_id(struct coresight_trace_id_map *id_map, int id)
{
unsigned long flags;
spin_lock_irqsave(&id_map->lock, flags);
coresight_trace_id_free(id, id_map);
spin_unlock_irqrestore(&id_map->lock, flags);
DUMP_ID(id);
DUMP_ID_MAP(id_map);
}
/* API functions */
int coresight_trace_id_get_cpu_id(int cpu)
{
return _coresight_trace_id_get_cpu_id(cpu, &id_map_default);
}
EXPORT_SYMBOL_GPL(coresight_trace_id_get_cpu_id);
int coresight_trace_id_get_cpu_id_map(int cpu, struct coresight_trace_id_map *id_map)
{
return _coresight_trace_id_get_cpu_id(cpu, id_map);
}
EXPORT_SYMBOL_GPL(coresight_trace_id_get_cpu_id_map);
void coresight_trace_id_put_cpu_id(int cpu)
{
_coresight_trace_id_put_cpu_id(cpu, &id_map_default);
}
EXPORT_SYMBOL_GPL(coresight_trace_id_put_cpu_id);
void coresight_trace_id_put_cpu_id_map(int cpu, struct coresight_trace_id_map *id_map)
{
_coresight_trace_id_put_cpu_id(cpu, id_map);
}
EXPORT_SYMBOL_GPL(coresight_trace_id_put_cpu_id_map);
int coresight_trace_id_read_cpu_id(int cpu)
{
return _coresight_trace_id_read_cpu_id(cpu, &id_map_default);
}
EXPORT_SYMBOL_GPL(coresight_trace_id_read_cpu_id);
int coresight_trace_id_read_cpu_id_map(int cpu, struct coresight_trace_id_map *id_map)
{
return _coresight_trace_id_read_cpu_id(cpu, id_map);
}
EXPORT_SYMBOL_GPL(coresight_trace_id_read_cpu_id_map);
int coresight_trace_id_get_system_id(void)
{
return coresight_trace_id_map_get_system_id(&id_map_default);
}
EXPORT_SYMBOL_GPL(coresight_trace_id_get_system_id);
void coresight_trace_id_put_system_id(int id)
{
coresight_trace_id_map_put_system_id(&id_map_default, id);
}
EXPORT_SYMBOL_GPL(coresight_trace_id_put_system_id);
void coresight_trace_id_perf_start(struct coresight_trace_id_map *id_map)
{
atomic_inc(&id_map->perf_cs_etm_session_active);
PERF_SESSION(atomic_read(&id_map->perf_cs_etm_session_active));
}
EXPORT_SYMBOL_GPL(coresight_trace_id_perf_start);
void coresight_trace_id_perf_stop(struct coresight_trace_id_map *id_map)
{
if (!atomic_dec_return(&id_map->perf_cs_etm_session_active))
coresight_trace_id_release_all(id_map);
PERF_SESSION(atomic_read(&id_map->perf_cs_etm_session_active));
}
EXPORT_SYMBOL_GPL(coresight_trace_id_perf_stop);
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