Re: [PATCH v3] acpi: configfs: Unload SSDT on configfs entry removal

From: Jan Kiszka
Date: Tue Jul 04 2017 - 08:08:52 EST


On 2017-07-04 14:05, Rafael J. Wysocki wrote:
> On Tue, Jul 4, 2017 at 8:14 AM, Jan Kiszka <jan.kiszka@xxxxxxxxxxx> wrote:
>> 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.
>
> Pushed to Linus and is waiting for merging (along with the other ACPI
> changes for 4.13).
>

Ah, perfect - seems I didn't receive any notification.

Thanks,
Jan

--
Siemens AG, Corporate Technology, CT RDA ITP SES-DE
Corporate Competence Center Embedded Linux