linux/tools/perf/util/cpumap.h
Ian Rogers b2f10cd4e8 perf cpumap: Fix alignment for masks in event encoding
A mask encoding of a cpu map is laid out as:

  u16 nr
  u16 long_size
  unsigned long mask[];

However, the mask may be 8-byte aligned meaning there is a 4-byte pad
after long_size. This means 32-bit and 64-bit builds see the mask as
being at different offsets. On top of this the structure is in the byte
data[] encoded as:

  u16 type
  char data[]

This means the mask's struct isn't the required 4 or 8 byte aligned, but
is offset by 2. Consequently the long reads and writes are causing
undefined behavior as the alignment is broken.

Fix the mask struct by creating explicit 32 and 64-bit variants, use a
union to avoid data[] and casts; the struct must be packed so the
layout matches the existing perf.data layout. Taking an address of a
member of a packed struct breaks alignment so pass the packed
perf_record_cpu_map_data to functions, so they can access variables with
the right alignment.

As the 64-bit version has 4 bytes of padding, optimizing writing to only
write the 32-bit version.

Committer notes:

Disable warnings about 'packed' that break the build in some arches like
riscv64, but just around that specific struct.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Colin Ian King <colin.king@intel.com>
Cc: Dave Marchevsky <davemarchevsky@fb.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Kees Kook <keescook@chromium.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20220614143353.1559597-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-08-19 15:30:28 -03:00

138 lines
4.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __PERF_CPUMAP_H
#define __PERF_CPUMAP_H
#include <stdbool.h>
#include <stdio.h>
#include <internal/cpumap.h>
#include <perf/cpumap.h>
/** Identify where counts are aggregated, -1 implies not to aggregate. */
struct aggr_cpu_id {
/** A value in the range 0 to number of threads. */
int thread;
/** The numa node X as read from /sys/devices/system/node/nodeX. */
int node;
/**
* The socket number as read from
* /sys/devices/system/cpu/cpuX/topology/physical_package_id.
*/
int socket;
/** The die id as read from /sys/devices/system/cpu/cpuX/topology/die_id. */
int die;
/** The core id as read from /sys/devices/system/cpu/cpuX/topology/core_id. */
int core;
/** CPU aggregation, note there is one CPU for each SMT thread. */
struct perf_cpu cpu;
};
/** A collection of aggr_cpu_id values, the "built" version is sorted and uniqued. */
struct cpu_aggr_map {
refcount_t refcnt;
/** Number of valid entries. */
int nr;
/** The entries. */
struct aggr_cpu_id map[];
};
struct perf_record_cpu_map_data;
bool perf_record_cpu_map_data__test_bit(int i, const struct perf_record_cpu_map_data *data);
struct perf_cpu_map *perf_cpu_map__empty_new(int nr);
struct perf_cpu_map *cpu_map__new_data(const struct perf_record_cpu_map_data *data);
size_t cpu_map__snprint(struct perf_cpu_map *map, char *buf, size_t size);
size_t cpu_map__snprint_mask(struct perf_cpu_map *map, char *buf, size_t size);
size_t cpu_map__fprintf(struct perf_cpu_map *map, FILE *fp);
const struct perf_cpu_map *cpu_map__online(void); /* thread unsafe */
int cpu__setup_cpunode_map(void);
int cpu__max_node(void);
struct perf_cpu cpu__max_cpu(void);
struct perf_cpu cpu__max_present_cpu(void);
/**
* cpu_map__is_dummy - Events associated with a pid, rather than a CPU, use a single dummy map with an entry of -1.
*/
static inline bool cpu_map__is_dummy(struct perf_cpu_map *cpus)
{
return perf_cpu_map__nr(cpus) == 1 && perf_cpu_map__cpu(cpus, 0).cpu == -1;
}
/**
* cpu__get_node - Returns the numa node X as read from
* /sys/devices/system/node/nodeX for the given CPU.
*/
int cpu__get_node(struct perf_cpu cpu);
/**
* cpu__get_socket_id - Returns the socket number as read from
* /sys/devices/system/cpu/cpuX/topology/physical_package_id for the given CPU.
*/
int cpu__get_socket_id(struct perf_cpu cpu);
/**
* cpu__get_die_id - Returns the die id as read from
* /sys/devices/system/cpu/cpuX/topology/die_id for the given CPU.
*/
int cpu__get_die_id(struct perf_cpu cpu);
/**
* cpu__get_core_id - Returns the core id as read from
* /sys/devices/system/cpu/cpuX/topology/core_id for the given CPU.
*/
int cpu__get_core_id(struct perf_cpu cpu);
/**
* cpu_aggr_map__empty_new - Create a cpu_aggr_map of size nr with every entry
* being empty.
*/
struct cpu_aggr_map *cpu_aggr_map__empty_new(int nr);
typedef struct aggr_cpu_id (*aggr_cpu_id_get_t)(struct perf_cpu cpu, void *data);
/**
* cpu_aggr_map__new - Create a cpu_aggr_map with an aggr_cpu_id for each cpu in
* cpus. The aggr_cpu_id is created with 'get_id' that may have a data value
* passed to it. The cpu_aggr_map is sorted with duplicate values removed.
*/
struct cpu_aggr_map *cpu_aggr_map__new(const struct perf_cpu_map *cpus,
aggr_cpu_id_get_t get_id,
void *data);
bool aggr_cpu_id__equal(const struct aggr_cpu_id *a, const struct aggr_cpu_id *b);
bool aggr_cpu_id__is_empty(const struct aggr_cpu_id *a);
struct aggr_cpu_id aggr_cpu_id__empty(void);
/**
* aggr_cpu_id__socket - Create an aggr_cpu_id with the socket populated with
* the socket for cpu. The function signature is compatible with
* aggr_cpu_id_get_t.
*/
struct aggr_cpu_id aggr_cpu_id__socket(struct perf_cpu cpu, void *data);
/**
* aggr_cpu_id__die - Create an aggr_cpu_id with the die and socket populated
* with the die and socket for cpu. The function signature is compatible with
* aggr_cpu_id_get_t.
*/
struct aggr_cpu_id aggr_cpu_id__die(struct perf_cpu cpu, void *data);
/**
* aggr_cpu_id__core - Create an aggr_cpu_id with the core, die and socket
* populated with the core, die and socket for cpu. The function signature is
* compatible with aggr_cpu_id_get_t.
*/
struct aggr_cpu_id aggr_cpu_id__core(struct perf_cpu cpu, void *data);
/**
* aggr_cpu_id__core - Create an aggr_cpu_id with the cpu, core, die and socket
* populated with the cpu, core, die and socket for cpu. The function signature
* is compatible with aggr_cpu_id_get_t.
*/
struct aggr_cpu_id aggr_cpu_id__cpu(struct perf_cpu cpu, void *data);
/**
* aggr_cpu_id__node - Create an aggr_cpu_id with the numa node populated for
* cpu. The function signature is compatible with aggr_cpu_id_get_t.
*/
struct aggr_cpu_id aggr_cpu_id__node(struct perf_cpu cpu, void *data);
#endif /* __PERF_CPUMAP_H */