> Subject: [PATCH v10 06/10] lib/pmu: do not try enabling perf counter access on
> arm64
>
> /proc/sys/kernel/perf_user_access attribute allow user process to access perf
> counters. Though in order to change it binary requires elevated capabilities
> or
> must be run as root. If that's not the case counter access remains disabled.
> Hence
> to avoid confusion log message that that warns user about that.
>
> Signed-off-by: Tomasz Duszynski <tduszyn...@marvell.com>
Acked-by: Wathsala Vithanage <wathsala.vithan...@arm.com>
> ---
> lib/pmu/pmu.c | 4 ----
> lib/pmu/pmu_arm64.c | 39 +++++++--------------------------------
> lib/pmu/pmu_private.h | 8 ++++++++
> 3 files changed, 15 insertions(+), 36 deletions(-)
>
> diff --git a/lib/pmu/pmu.c b/lib/pmu/pmu.c index 8cf2e89c69..97bab80368
> 100644
> --- a/lib/pmu/pmu.c
> +++ b/lib/pmu/pmu.c
> @@ -25,10 +25,6 @@
> #define FIELD_PREP(m, v) (((uint64_t)(v) << (rte_ffs64(m) - 1)) & (m))
>
> RTE_LOG_REGISTER_DEFAULT(rte_pmu_logtype, INFO) -#define
> RTE_LOGTYPE_PMU rte_pmu_logtype
> -
> -#define PMU_LOG(level, ...) \
> - RTE_LOG_LINE(level, PMU, ## __VA_ARGS__)
>
> /* A structure describing an event */
> struct rte_pmu_event {
> diff --git a/lib/pmu/pmu_arm64.c b/lib/pmu/pmu_arm64.c index
> 3f4f5fa297..2c40b5f702 100644
> --- a/lib/pmu/pmu_arm64.c
> +++ b/lib/pmu/pmu_arm64.c
> @@ -14,8 +14,6 @@
>
> #define PERF_USER_ACCESS_PATH "/proc/sys/kernel/perf_user_access"
>
> -static int restore_uaccess;
> -
> static int
> read_attr_int(const char *path, int *val) { @@ -39,49 +37,26 @@
> read_attr_int(const char *path, int *val)
> return 0;
> }
>
> -static int
> -write_attr_int(const char *path, int val) -{
> - char buf[BUFSIZ];
> - int num, ret, fd;
> -
> - fd = open(path, O_WRONLY);
> - if (fd == -1)
> - return -errno;
> -
> - num = snprintf(buf, sizeof(buf), "%d", val);
> - ret = write(fd, buf, num);
> - if (ret == -1) {
> - close(fd);
> -
> - return -errno;
> - }
> -
> - close(fd);
> -
> - return 0;
> -}
> -
> static int
> pmu_arm64_init(void)
> {
> - int ret;
> + int uaccess, ret;
>
> - ret = read_attr_int(PERF_USER_ACCESS_PATH, &restore_uaccess);
> + ret = read_attr_int(PERF_USER_ACCESS_PATH, &uaccess);
> if (ret)
> return ret;
>
> - /* user access already enabled */
> - if (restore_uaccess == 1)
> - return 0;
> + if (uaccess != 1)
> + PMU_LOG(WARNING, "access to perf counters disabled, "
> + "run 'echo 1 > %s' to enable",
> + PERF_USER_ACCESS_PATH);
>
> - return write_attr_int(PERF_USER_ACCESS_PATH, 1);
> + return ret;
> }
>
> static void
> pmu_arm64_fini(void)
> {
> - write_attr_int(PERF_USER_ACCESS_PATH, restore_uaccess);
> }
>
> static void
> diff --git a/lib/pmu/pmu_private.h b/lib/pmu/pmu_private.h index
> d74f7f4092..82118df8b3 100644
> --- a/lib/pmu/pmu_private.h
> +++ b/lib/pmu/pmu_private.h
> @@ -5,6 +5,14 @@
> #ifndef PMU_PRIVATE_H
> #define PMU_PRIVATE_H
>
> +#include <rte_log.h>
> +
> +extern int rte_pmu_logtype;
> +#define RTE_LOGTYPE_PMU rte_pmu_logtype
> +
> +#define PMU_LOG(level, ...) \
> + RTE_LOG_LINE(level, PMU, ## __VA_ARGS__)
> +
> /**
> * Structure describing architecture specific PMU operations.
> */
> --
> 2.34.1
