Re: [PATCH v6 1/5] powercap/drivers/dtpm: Convert the init table section to a simple array

[Ulf Hansson]

On Wed, 19 Jan 2022 at 09:57, Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> wrote:
>
> The init table section is freed after the system booted. However the
> next changes will make per module the DTPM description, so the table
> won't be accessible when the module is loaded.
>
> In order to fix that, we should move the table to the data section
> where there are very few entries and that makes strange to add it
> there.
>
> The main goal of the table was to keep self-encapsulated code and we
> can keep it almost as it by using an array instead.
>
> Suggested-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>

Thanks for updating!

Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>

Kind regards
Uffe

> ---
>  drivers/powercap/dtpm.c           |  2 ++
>  drivers/powercap/dtpm_cpu.c       |  5 ++++-
>  drivers/powercap/dtpm_subsys.h    | 18 ++++++++++++++++++
>  include/asm-generic/vmlinux.lds.h | 11 -----------
>  include/linux/dtpm.h              | 24 +++---------------------
>  5 files changed, 27 insertions(+), 33 deletions(-)
>  create mode 100644 drivers/powercap/dtpm_subsys.h
>
> diff --git a/drivers/powercap/dtpm.c b/drivers/powercap/dtpm.c
> index 8cb45f2d3d78..0e5c93443c70 100644
> --- a/drivers/powercap/dtpm.c
> +++ b/drivers/powercap/dtpm.c
> @@ -24,6 +24,8 @@
>  #include <linux/slab.h>
>  #include <linux/mutex.h>
>
> +#include "dtpm_subsys.h"
> +
>  #define DTPM_POWER_LIMIT_FLAG 0
>
>  static const char *constraint_name[] = {
> diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c
> index b740866b228d..5763e0ce2af5 100644
> --- a/drivers/powercap/dtpm_cpu.c
> +++ b/drivers/powercap/dtpm_cpu.c
> @@ -269,4 +269,7 @@ static int __init dtpm_cpu_init(void)
>         return 0;
>  }
>
> -DTPM_DECLARE(dtpm_cpu, dtpm_cpu_init);
> +struct dtpm_subsys_ops dtpm_cpu_ops = {
> +       .name = KBUILD_MODNAME,
> +       .init = dtpm_cpu_init,
> +};
> diff --git a/drivers/powercap/dtpm_subsys.h b/drivers/powercap/dtpm_subsys.h
> new file mode 100644
> index 000000000000..2a3a2055f60e
> --- /dev/null
> +++ b/drivers/powercap/dtpm_subsys.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2022 Linaro Ltd
> + *
> + * Author: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> + */
> +#ifndef ___DTPM_SUBSYS_H__
> +#define ___DTPM_SUBSYS_H__
> +
> +extern struct dtpm_subsys_ops dtpm_cpu_ops;
> +
> +struct dtpm_subsys_ops *dtpm_subsys[] = {
> +#ifdef CONFIG_DTPM_CPU
> +       &dtpm_cpu_ops,
> +#endif
> +};
> +
> +#endif
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index 42f3866bca69..2a10db2f0bc5 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -321,16 +321,6 @@
>  #define THERMAL_TABLE(name)
>  #endif
>
> -#ifdef CONFIG_DTPM
> -#define DTPM_TABLE()                                                   \
> -       . = ALIGN(8);                                                   \
> -       __dtpm_table = .;                                               \
> -       KEEP(*(__dtpm_table))                                           \
> -       __dtpm_table_end = .;
> -#else
> -#define DTPM_TABLE()
> -#endif
> -
>  #define KERNEL_DTB()                                                   \
>         STRUCT_ALIGN();                                                 \
>         __dtb_start = .;                                                \
> @@ -723,7 +713,6 @@
>         ACPI_PROBE_TABLE(irqchip)                                       \
>         ACPI_PROBE_TABLE(timer)                                         \
>         THERMAL_TABLE(governor)                                         \
> -       DTPM_TABLE()                                                    \
>         EARLYCON_TABLE()                                                \
>         LSM_TABLE()                                                     \
>         EARLY_LSM_TABLE()                                               \
> diff --git a/include/linux/dtpm.h b/include/linux/dtpm.h
> index d37e5d06a357..506048158a50 100644
> --- a/include/linux/dtpm.h
> +++ b/include/linux/dtpm.h
> @@ -32,29 +32,11 @@ struct dtpm_ops {
>         void (*release)(struct dtpm *);
>  };
>
> -typedef int (*dtpm_init_t)(void);
> -
> -struct dtpm_descr {
> -       dtpm_init_t init;
> +struct dtpm_subsys_ops {
> +       const char *name;
> +       int (*init)(void);
>  };
>
> -/* Init section thermal table */
> -extern struct dtpm_descr __dtpm_table[];
> -extern struct dtpm_descr __dtpm_table_end[];
> -
> -#define DTPM_TABLE_ENTRY(name, __init)                         \
> -       static struct dtpm_descr __dtpm_table_entry_##name      \
> -       __used __section("__dtpm_table") = {                    \
> -               .init = __init,                                 \
> -       }
> -
> -#define DTPM_DECLARE(name, init)       DTPM_TABLE_ENTRY(name, init)
> -
> -#define for_each_dtpm_table(__dtpm)    \
> -       for (__dtpm = __dtpm_table;     \
> -            __dtpm < __dtpm_table_end; \
> -            __dtpm++)
> -
>  static inline struct dtpm *to_dtpm(struct powercap_zone *zone)
>  {
>         return container_of(zone, struct dtpm, zone);
> --
> 2.25.1
>