On 2017-06-09 20:36, Jan Kiszka wrote:
> Call directly into acpica to load a table to obtain its index on return.
> We choose the direct call of acpica internal functions to avoid having
> to modify its API which is used outside of Linux as well.
>
> Use that index to unload the table again when the corresponding
> directory in configfs gets removed. This allows to change SSDTs without
> rebooting the system. It also allows to destroy devices again that a
> dynamically loaded SSDT created.
>
> This is widely similar to the DT overlay behavior.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> ---
>
> Change in v3:
> - fix breakage if acpi_configfs is modular
>
> drivers/acpi/acpi_configfs.c | 20 +++++++++++++++++++-
> drivers/acpi/acpica/tbdata.c | 4 ++++
> 2 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
> index 146a77fb762d..853bc7fc673f 100644
> --- a/drivers/acpi/acpi_configfs.c
> +++ b/drivers/acpi/acpi_configfs.c
> @@ -15,11 +15,15 @@
> #include <linux/configfs.h>
> #include <linux/acpi.h>
>
> +#include "acpica/accommon.h"
> +#include "acpica/actables.h"
> +
> static struct config_group *acpi_table_group;
>
> struct acpi_table {
> struct config_item cfg;
> struct acpi_table_header *header;
> + u32 index;
> };
>
> static ssize_t acpi_table_aml_write(struct config_item *cfg,
> @@ -52,7 +56,11 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
> if (!table->header)
> return -ENOMEM;
>
> - ret = acpi_load_table(table->header);
> + ACPI_INFO(("Host-directed Dynamic ACPI Table Load:"));
> + ret = acpi_tb_install_and_load_table(
> + ACPI_PTR_TO_PHYSADDR(table->header),
> + ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL, FALSE,
> + &table->index);
> if (ret) {
> kfree(table->header);
> table->header = NULL;
> @@ -215,8 +223,18 @@ static struct config_item *acpi_table_make_item(struct config_group *group,
> return &table->cfg;
> }
>
> +static void acpi_table_drop_item(struct config_group *group,
> + struct config_item *cfg)
> +{
> + struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);
> +
> + ACPI_INFO(("Host-directed Dynamic ACPI Table Unload"));
> + acpi_tb_unload_table(table->index);
> +}
> +
> struct configfs_group_operations acpi_table_group_ops = {
> .make_item = acpi_table_make_item,
> + .drop_item = acpi_table_drop_item,
> };
>
> static struct config_item_type acpi_tables_type = {
> diff --git a/drivers/acpi/acpica/tbdata.c b/drivers/acpi/acpica/tbdata.c
> index 27c5c27d4818..c9d6fa6d7cc6 100644
> --- a/drivers/acpi/acpica/tbdata.c
> +++ b/drivers/acpi/acpica/tbdata.c
> @@ -867,6 +867,8 @@ acpi_tb_install_and_load_table(acpi_physical_address address,
> return_ACPI_STATUS(status);
> }
>
> +ACPI_EXPORT_SYMBOL(acpi_tb_install_and_load_table)
> +
> /*******************************************************************************
> *
> * FUNCTION: acpi_tb_unload_table
> @@ -914,3 +916,5 @@ acpi_status acpi_tb_unload_table(u32 table_index)
> acpi_tb_set_table_loaded_flag(table_index, FALSE);
> return_ACPI_STATUS(status);
> }
> +
> +ACPI_EXPORT_SYMBOL(acpi_tb_unload_table)
>
Ping for this patch.
Jan
--
Siemens AG, Corporate Technology, CT RDA ITP SES-DE
Corporate Competence Center Embedded Linux
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