Re: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads

Re: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads

[Nikolaus Voss]

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On Fri, 6 Sep 2019, Shevchenko, Andriy wrote:
> On Wed, Sep 04, 2019 at 09:20:03AM +0200, Nikolaus Voss wrote:
>> On Fri, 30 Aug 2019, Shevchenko, Andriy wrote:
>>> On Fri, Aug 16, 2019 at 01:57:26PM +0200, Nikolaus Voss wrote:
>>>> On Wed, 14 Aug 2019, Schmauss, Erik wrote:
>>>>>> -----Original Message-----
>>>>>> From: Shevchenko, Andriy
>>>>>> Sent: Wednesday, August 14, 2019 11:51 AM
>>>>>> To: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
>>>>>> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>;
>>>>>> Moore, Robert <robert.moore@intel.com>; Schmauss, Erik
>>>>>> <erik.schmauss@intel.com>; Jacek Anaszewski <jacek.anaszewski@gmail.com>;
>>>>>> Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; Thierry
>>>>>> Reding <thierry.reding@gmail.com>; linux-acpi@vger.kernel.org;
>>>>>> devel@acpica.org; linux-leds@vger.kernel.org; linux-pwm@vger.kernel.org
>>>>>> Subject: Re: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads
>>>>>>
>>>>>> On Wed, May 29, 2019 at 02:18:20PM +0200, Nikolaus Voss wrote:
>>>>>>> If an ACPI SSDT overlay is loaded after built-in tables have been
>>>>>>> loaded e.g. via configfs or efivar_ssdt_load() it is necessary to
>>>>>>> rewalk the namespace to resolve references. Without this, relative and
>>>>>>> absolute paths like ^PCI0.SBUS or \_SB.PCI0.SBUS are not resolved
>>>>>>> correctly.
>>>>>>>
>>>>>>> Make configfs load use the same method as efivar_ssdt_load().
>>>>>>
>>>>>> This patch brought a regression (bisect log below).
>>>>>> Now I'm unable to unload the table which was working before.
>>>>>>
>>>>>> Reverting (manual, due to ACPICA changes) helps.
>>>>>>
>>>>>> Please, consider to revert for this cycle, or fix. I will be glad to test any
>>>>>> proposed fix.
>>>>>
>>>>> We submitted a patch (d1fb5b2f623b1af5a0d2a83d205df1b61f430dc6)
>>>>> in response to this suggestion and I was not aware that this had been applied.
>>>>>
>>>>> Rafael, please revert at least the ACPICA portion of this patch.
>>>>
>>>> As I see it, my ACPICA change is not part of 5.3-rc1 any more. Reverting my
>>>> fix is part of the patch above (d1fb5b2f623b1af5a0d2a83d205df1b61f430dc6)
>>>> which is already applied.
>>>>
>>>> Nevertheless, what is new, is that acpi_ns_initialize_objects() is called in
>>>> acpi_load_table(). This is necessary to resolve the references in the newly
>>>> loaded table. Maybe this prevents the table from being unloaded?
>>>
>>> So, can we do something about it? It's a regression.
>>>
>>> Rafael, Nikolaus?
>>
>> can you describe how you unload the table (from userspace?). I cannot
>> reproduce this regression. I was not aware of any working interface for
>> unloading ACPI tables, I ended up in kexec'ing the kernel for my tests each
>> time I had to unload a table.
>
> Sure.
>
> I have connected an I²C device(s) to my board where I have compiled ACPI tables
> which describes them (more details if you want to know is on [1]).
>
> So, I create a folder in ConfigFS [1,2] and fill it up with SSDT (an *.aml file).
> After this, if I try to remove the folder in ConfigFS followed by table removal
> event, the actual nodes won't be removed, and this messes up with the internal
> representation of the ACPI device tree.
>
> [1]: https://www.kernel.org/doc/html/latest/admin-guide/acpi/ssdt-overlays.html
> [2]: https://htot.github.io/meta-intel-edison/1.3-ACPI-or-not.html#run-time-loading-through-configfs

Thanks, I have reproduced it and the culprit is my acpi_configfs patch 
that now uses acpi_load_table() to have the references resolved.

My proposal would be to have that function return the table index, which 
is needed to unload the table. I'll submit a patch, Andy, could you test 
it in your setup?

Erik/Robert, is it ok to change the acpi_load_table() ACPICA API 
function? It has only a few uses.

Niko

[PATCH] ACPICA: make acpi_load_table() return table index

[Nikolaus Voss]

For unloading an ACPI table, it is necessary to provide the
index of the table. The method intended for dynamically
loading or hotplug addition of tables, acpi_load_table(),
should provide this information via an optional pointer
to the loaded table index.

This patch fixes the table unload function of acpi_configfs.

Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table loads")
Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
---
 drivers/acpi/acpi_configfs.c   | 2 +-
 drivers/acpi/acpica/dbfileio.c | 2 +-
 drivers/acpi/acpica/tbxfload.c | 8 ++++++--
 drivers/firmware/efi/efi.c     | 2 +-
 include/acpi/acpixf.h          | 3 ++-
 5 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
index 57d9d574d4dde..77f81242a28e6 100644
--- a/drivers/acpi/acpi_configfs.c
+++ b/drivers/acpi/acpi_configfs.c
@@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
 	if (!table->header)
 		return -ENOMEM;
 
-	ret = acpi_load_table(table->header);
+	ret = acpi_load_table(table->header, &table->index);
 	if (ret) {
 		kfree(table->header);
 		table->header = NULL;
diff --git a/drivers/acpi/acpica/dbfileio.c b/drivers/acpi/acpica/dbfileio.c
index c6e25734dc5cd..e1b6e54a96ac1 100644
--- a/drivers/acpi/acpica/dbfileio.c
+++ b/drivers/acpi/acpica/dbfileio.c
@@ -93,7 +93,7 @@ acpi_status acpi_db_load_tables(struct acpi_new_table_desc *list_head)
 	while (table_list_head) {
 		table = table_list_head->table;
 
-		status = acpi_load_table(table);
+		status = acpi_load_table(table, NULL);
 		if (ACPI_FAILURE(status)) {
 			if (status == AE_ALREADY_EXISTS) {
 				acpi_os_printf
diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c
index 86f1693f6d29a..d08cd8ffcbdb6 100644
--- a/drivers/acpi/acpica/tbxfload.c
+++ b/drivers/acpi/acpica/tbxfload.c
@@ -268,7 +268,8 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
  *
  * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
  *                                    table to be loaded.
- *
+ *              table_idx           - Pointer to a u32 for storing the table
+ *                                    index, might be NULL
  * RETURN:      Status
  *
  * DESCRIPTION: Dynamically load an ACPI table from the caller's buffer. Must
@@ -278,7 +279,7 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
  *              to ensure that the table is not deleted or unmapped.
  *
  ******************************************************************************/
-acpi_status acpi_load_table(struct acpi_table_header *table)
+acpi_status acpi_load_table(struct acpi_table_header *table, u32 *table_idx)
 {
 	acpi_status status;
 	u32 table_index;
@@ -297,6 +298,9 @@ acpi_status acpi_load_table(struct acpi_table_header *table)
 	status = acpi_tb_install_and_load_table(ACPI_PTR_TO_PHYSADDR(table),
 						ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
 						FALSE, &table_index);
+	if (table_idx)
+		*table_idx = table_index;
+
 	if (ACPI_SUCCESS(status)) {
 
 		/* Complete the initialization/resolution of new objects */
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index ad3b1f4866b35..9773e4212baef 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -308,7 +308,7 @@ static __init int efivar_ssdt_load(void)
 			goto free_data;
 		}
 
-		ret = acpi_load_table(data);
+		ret = acpi_load_table(data, NULL);
 		if (ret) {
 			pr_err("failed to load table: %d\n", ret);
 			goto free_data;
diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
index 3845c8fcc94e5..c90bbdc4146a6 100644
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
 					       u8 physical))
 
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
-			    acpi_load_table(struct acpi_table_header *table))
+			    acpi_load_table(struct acpi_table_header *table,
+					    u32 *table_idx))
 
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			    acpi_unload_parent_table(acpi_handle object))
-- 
2.17.1

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Moore, Robert]

Nikolaus,
The ability to unload an ACPI table (especially AML tables such as SSDTs) is in the process of being deprecated in ACPICA -- since it is also deprecated in the current ACPI specification. This is being done because of the difficulty of deleting the namespace entries for the table.  FYI, Windows does not properly support this function either.

Bob


-----Original Message-----
From: Nikolaus Voss [mailto:nikolaus.voss@loewensteinmedical.de] 
Sent: Thursday, September 12, 2019 1:08 AM
To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Moore, Robert <robert.moore@intel.com>
Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; nv@vosn.de; Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
Subject: [PATCH] ACPICA: make acpi_load_table() return table index

For unloading an ACPI table, it is necessary to provide the index of the table. The method intended for dynamically loading or hotplug addition of tables, acpi_load_table(), should provide this information via an optional pointer to the loaded table index.

This patch fixes the table unload function of acpi_configfs.

Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table loads")
Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
---
 drivers/acpi/acpi_configfs.c   | 2 +-
 drivers/acpi/acpica/dbfileio.c | 2 +-
 drivers/acpi/acpica/tbxfload.c | 8 ++++++--
 drivers/firmware/efi/efi.c     | 2 +-
 include/acpi/acpixf.h          | 3 ++-
 5 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c index 57d9d574d4dde..77f81242a28e6 100644
--- a/drivers/acpi/acpi_configfs.c
+++ b/drivers/acpi/acpi_configfs.c
@@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
 	if (!table->header)
 		return -ENOMEM;
 
-	ret = acpi_load_table(table->header);
+	ret = acpi_load_table(table->header, &table->index);
 	if (ret) {
 		kfree(table->header);
 		table->header = NULL;
diff --git a/drivers/acpi/acpica/dbfileio.c b/drivers/acpi/acpica/dbfileio.c index c6e25734dc5cd..e1b6e54a96ac1 100644
--- a/drivers/acpi/acpica/dbfileio.c
+++ b/drivers/acpi/acpica/dbfileio.c
@@ -93,7 +93,7 @@ acpi_status acpi_db_load_tables(struct acpi_new_table_desc *list_head)
 	while (table_list_head) {
 		table = table_list_head->table;
 
-		status = acpi_load_table(table);
+		status = acpi_load_table(table, NULL);
 		if (ACPI_FAILURE(status)) {
 			if (status == AE_ALREADY_EXISTS) {
 				acpi_os_printf
diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c index 86f1693f6d29a..d08cd8ffcbdb6 100644
--- a/drivers/acpi/acpica/tbxfload.c
+++ b/drivers/acpi/acpica/tbxfload.c
@@ -268,7 +268,8 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
  *
  * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
  *                                    table to be loaded.
- *
+ *              table_idx           - Pointer to a u32 for storing the table
+ *                                    index, might be NULL
  * RETURN:      Status
  *
  * DESCRIPTION: Dynamically load an ACPI table from the caller's buffer. Must @@ -278,7 +279,7 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
  *              to ensure that the table is not deleted or unmapped.
  *
  ******************************************************************************/
-acpi_status acpi_load_table(struct acpi_table_header *table)
+acpi_status acpi_load_table(struct acpi_table_header *table, u32 
+*table_idx)
 {
 	acpi_status status;
 	u32 table_index;
@@ -297,6 +298,9 @@ acpi_status acpi_load_table(struct acpi_table_header *table)
 	status = acpi_tb_install_and_load_table(ACPI_PTR_TO_PHYSADDR(table),
 						ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
 						FALSE, &table_index);
+	if (table_idx)
+		*table_idx = table_index;
+
 	if (ACPI_SUCCESS(status)) {
 
 		/* Complete the initialization/resolution of new objects */ diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index ad3b1f4866b35..9773e4212baef 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -308,7 +308,7 @@ static __init int efivar_ssdt_load(void)
 			goto free_data;
 		}
 
-		ret = acpi_load_table(data);
+		ret = acpi_load_table(data, NULL);
 		if (ret) {
 			pr_err("failed to load table: %d\n", ret);
 			goto free_data;
diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h index 3845c8fcc94e5..c90bbdc4146a6 100644
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
 					       u8 physical))
 
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
-			    acpi_load_table(struct acpi_table_header *table))
+			    acpi_load_table(struct acpi_table_header *table,
+					    u32 *table_idx))
 
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			    acpi_unload_parent_table(acpi_handle object))
--
2.17.1

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Ferry Toth]

Op 12-09-19 om 16:19 schreef Moore, Robert:
> Nikolaus,
> The ability to unload an ACPI table (especially AML tables such as SSDTs) is in the process of being deprecated in ACPICA -- since it is also deprecated in the current ACPI specification. This is being done because of the difficulty of deleting the namespace entries for the table.  FYI, Windows does not properly support this function either.

I really hope this is not the case. On x86 loading/unloading SSDTs has 
proven to be a powerful way to handle reconfigurable hardware without 
rebooting and without requiring dedicated platform drivers. Same for 
user plugable hardware on i2c/spi busses.

This has worked before and will violate the "don't break user space" rule.

I don't see why Windows is an example to follow. On Windows platform 
drivers don't get compiled into the kernel and don't need to be upstreamed.

> Bob
> 
> 
> -----Original Message-----
> From: Nikolaus Voss [mailto:nikolaus.voss@loewensteinmedical.de]
> Sent: Thursday, September 12, 2019 1:08 AM
> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Moore, Robert <robert.moore@intel.com>
> Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; nv@vosn.de; Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> Subject: [PATCH] ACPICA: make acpi_load_table() return table index
> 
> For unloading an ACPI table, it is necessary to provide the index of the table. The method intended for dynamically loading or hotplug addition of tables, acpi_load_table(), should provide this information via an optional pointer to the loaded table index.
> 
> This patch fixes the table unload function of acpi_configfs.
> 
> Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table loads")
> Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> ---
>   drivers/acpi/acpi_configfs.c   | 2 +-
>   drivers/acpi/acpica/dbfileio.c | 2 +-
>   drivers/acpi/acpica/tbxfload.c | 8 ++++++--
>   drivers/firmware/efi/efi.c     | 2 +-
>   include/acpi/acpixf.h          | 3 ++-
>   5 files changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c index 57d9d574d4dde..77f81242a28e6 100644
> --- a/drivers/acpi/acpi_configfs.c
> +++ b/drivers/acpi/acpi_configfs.c
> @@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
>   	if (!table->header)
>   		return -ENOMEM;
>   
> -	ret = acpi_load_table(table->header);
> +	ret = acpi_load_table(table->header, &table->index);
>   	if (ret) {
>   		kfree(table->header);
>   		table->header = NULL;
> diff --git a/drivers/acpi/acpica/dbfileio.c b/drivers/acpi/acpica/dbfileio.c index c6e25734dc5cd..e1b6e54a96ac1 100644
> --- a/drivers/acpi/acpica/dbfileio.c
> +++ b/drivers/acpi/acpica/dbfileio.c
> @@ -93,7 +93,7 @@ acpi_status acpi_db_load_tables(struct acpi_new_table_desc *list_head)
>   	while (table_list_head) {
>   		table = table_list_head->table;
>   
> -		status = acpi_load_table(table);
> +		status = acpi_load_table(table, NULL);
>   		if (ACPI_FAILURE(status)) {
>   			if (status == AE_ALREADY_EXISTS) {
>   				acpi_os_printf
> diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c index 86f1693f6d29a..d08cd8ffcbdb6 100644
> --- a/drivers/acpi/acpica/tbxfload.c
> +++ b/drivers/acpi/acpica/tbxfload.c
> @@ -268,7 +268,8 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
>    *
>    * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
>    *                                    table to be loaded.
> - *
> + *              table_idx           - Pointer to a u32 for storing the table
> + *                                    index, might be NULL
>    * RETURN:      Status
>    *
>    * DESCRIPTION: Dynamically load an ACPI table from the caller's buffer. Must @@ -278,7 +279,7 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
>    *              to ensure that the table is not deleted or unmapped.
>    *
>    ******************************************************************************/
> -acpi_status acpi_load_table(struct acpi_table_header *table)
> +acpi_status acpi_load_table(struct acpi_table_header *table, u32
> +*table_idx)
>   {
>   	acpi_status status;
>   	u32 table_index;
> @@ -297,6 +298,9 @@ acpi_status acpi_load_table(struct acpi_table_header *table)
>   	status = acpi_tb_install_and_load_table(ACPI_PTR_TO_PHYSADDR(table),
>   						ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
>   						FALSE, &table_index);
> +	if (table_idx)
> +		*table_idx = table_index;
> +
>   	if (ACPI_SUCCESS(status)) {
>   
>   		/* Complete the initialization/resolution of new objects */ diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index ad3b1f4866b35..9773e4212baef 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -308,7 +308,7 @@ static __init int efivar_ssdt_load(void)
>   			goto free_data;
>   		}
>   
> -		ret = acpi_load_table(data);
> +		ret = acpi_load_table(data, NULL);
>   		if (ret) {
>   			pr_err("failed to load table: %d\n", ret);
>   			goto free_data;
> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h index 3845c8fcc94e5..c90bbdc4146a6 100644
> --- a/include/acpi/acpixf.h
> +++ b/include/acpi/acpixf.h
> @@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
>   					       u8 physical))
>   
>   ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> -			    acpi_load_table(struct acpi_table_header *table))
> +			    acpi_load_table(struct acpi_table_header *table,
> +					    u32 *table_idx))
>   
>   ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>   			    acpi_unload_parent_table(acpi_handle object))
> --
> 2.17.1
> 
> 

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Schmauss, Erik]

> -----Original Message-----
> From: Ferry Toth <ftoth@telfort.nl>
> Sent: Thursday, September 12, 2019 12:37 PM
> To: Moore, Robert <robert.moore@intel.com>; Nikolaus Voss
> <nikolaus.voss@loewensteinmedical.de>; Shevchenko, Andriy
> <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>;
> Rafael J. Wysocki <rjw@rjwysocki.net>
> Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-
> kernel@vger.kernel.org; nv@vosn.de
> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
> 
> Op 12-09-19 om 16:19 schreef Moore, Robert:
> > Nikolaus,
> > The ability to unload an ACPI table (especially AML tables such as SSDTs) is in
> the process of being deprecated in ACPICA -- since it is also deprecated in the
> current ACPI specification. This is being done because of the difficulty of
> deleting the namespace entries for the table.  FYI, Windows does not properly
> support this function either.
> 
> I really hope this is not the case. On x86 loading/unloading SSDTs has proven to
> be a powerful way to handle reconfigurable hardware without rebooting and
> without requiring dedicated platform drivers. Same for user plugable hardware
> on i2c/spi busses.
> 
> This has worked before and will violate the "don't break user space" rule.

If the table index wasn't being used, how did this work before?
Which commit broke this?

Bob and I are trying to understand if this is a regression or a new feature request...

Thanks,
Erik
> 
> I don't see why Windows is an example to follow. On Windows platform drivers
> don't get compiled into the kernel and don't need to be upstreamed.
> 
> > Bob
> >
> >
> > -----Original Message-----
> > From: Nikolaus Voss [mailto:nikolaus.voss@loewensteinmedical.de]
> > Sent: Thursday, September 12, 2019 1:08 AM
> > To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik
> > <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>;
> > Moore, Robert <robert.moore@intel.com>
> > Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
> > <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
> > <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org;
> > linux-kernel@vger.kernel.org; nv@vosn.de; Nikolaus Voss
> > <nikolaus.voss@loewensteinmedical.de>
> > Subject: [PATCH] ACPICA: make acpi_load_table() return table index
> >
> > For unloading an ACPI table, it is necessary to provide the index of the table.
> The method intended for dynamically loading or hotplug addition of tables,
> acpi_load_table(), should provide this information via an optional pointer to
> the loaded table index.
> >
> > This patch fixes the table unload function of acpi_configfs.
> >
> > Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on
> > host-directed table loads")
> > Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> > ---
> >   drivers/acpi/acpi_configfs.c   | 2 +-
> >   drivers/acpi/acpica/dbfileio.c | 2 +-
> >   drivers/acpi/acpica/tbxfload.c | 8 ++++++--
> >   drivers/firmware/efi/efi.c     | 2 +-
> >   include/acpi/acpixf.h          | 3 ++-
> >   5 files changed, 11 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/acpi/acpi_configfs.c
> > b/drivers/acpi/acpi_configfs.c index 57d9d574d4dde..77f81242a28e6
> > 100644
> > --- a/drivers/acpi/acpi_configfs.c
> > +++ b/drivers/acpi/acpi_configfs.c
> > @@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item
> *cfg,
> >   	if (!table->header)
> >   		return -ENOMEM;
> >
> > -	ret = acpi_load_table(table->header);
> > +	ret = acpi_load_table(table->header, &table->index);
> >   	if (ret) {
> >   		kfree(table->header);
> >   		table->header = NULL;
> > diff --git a/drivers/acpi/acpica/dbfileio.c
> > b/drivers/acpi/acpica/dbfileio.c index c6e25734dc5cd..e1b6e54a96ac1
> > 100644
> > --- a/drivers/acpi/acpica/dbfileio.c
> > +++ b/drivers/acpi/acpica/dbfileio.c
> > @@ -93,7 +93,7 @@ acpi_status acpi_db_load_tables(struct
> acpi_new_table_desc *list_head)
> >   	while (table_list_head) {
> >   		table = table_list_head->table;
> >
> > -		status = acpi_load_table(table);
> > +		status = acpi_load_table(table, NULL);
> >   		if (ACPI_FAILURE(status)) {
> >   			if (status == AE_ALREADY_EXISTS) {
> >   				acpi_os_printf
> > diff --git a/drivers/acpi/acpica/tbxfload.c
> > b/drivers/acpi/acpica/tbxfload.c index 86f1693f6d29a..d08cd8ffcbdb6
> > 100644
> > --- a/drivers/acpi/acpica/tbxfload.c
> > +++ b/drivers/acpi/acpica/tbxfload.c
> > @@ -268,7 +268,8 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
> >    *
> >    * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
> >    *                                    table to be loaded.
> > - *
> > + *              table_idx           - Pointer to a u32 for storing the table
> > + *                                    index, might be NULL
> >    * RETURN:      Status
> >    *
> >    * DESCRIPTION: Dynamically load an ACPI table from the caller's buffer.
> Must @@ -278,7 +279,7 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
> >    *              to ensure that the table is not deleted or unmapped.
> >    *
> >
> >
> *******************************************************************
> ***
> > ********/ -acpi_status acpi_load_table(struct acpi_table_header
> > *table)
> > +acpi_status acpi_load_table(struct acpi_table_header *table, u32
> > +*table_idx)
> >   {
> >   	acpi_status status;
> >   	u32 table_index;
> > @@ -297,6 +298,9 @@ acpi_status acpi_load_table(struct acpi_table_header
> *table)
> >   	status =
> acpi_tb_install_and_load_table(ACPI_PTR_TO_PHYSADDR(table),
> >
> 	ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
> >   						FALSE, &table_index);
> > +	if (table_idx)
> > +		*table_idx = table_index;
> > +
> >   	if (ACPI_SUCCESS(status)) {
> >
> >   		/* Complete the initialization/resolution of new objects */ diff
> > --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index
> > ad3b1f4866b35..9773e4212baef 100644
> > --- a/drivers/firmware/efi/efi.c
> > +++ b/drivers/firmware/efi/efi.c
> > @@ -308,7 +308,7 @@ static __init int efivar_ssdt_load(void)
> >   			goto free_data;
> >   		}
> >
> > -		ret = acpi_load_table(data);
> > +		ret = acpi_load_table(data, NULL);
> >   		if (ret) {
> >   			pr_err("failed to load table: %d\n", ret);
> >   			goto free_data;
> > diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h index
> > 3845c8fcc94e5..c90bbdc4146a6 100644
> > --- a/include/acpi/acpixf.h
> > +++ b/include/acpi/acpixf.h
> > @@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> ACPI_INIT_FUNCTION
> >   					       u8 physical))
> >
> >   ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> > -			    acpi_load_table(struct acpi_table_header *table))
> > +			    acpi_load_table(struct acpi_table_header *table,
> > +					    u32 *table_idx))
> >
> >   ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> >   			    acpi_unload_parent_table(acpi_handle object))
> > --
> > 2.17.1
> >
> >

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Shevchenko, Andriy]

On Wed, Sep 25, 2019 at 09:13:34PM +0300, Schmauss, Erik wrote:
> > -----Original Message-----
> > From: Ferry Toth <ftoth@telfort.nl>
> > Sent: Thursday, September 12, 2019 12:37 PM
> > To: Moore, Robert <robert.moore@intel.com>; Nikolaus Voss
> > <nikolaus.voss@loewensteinmedical.de>; Shevchenko, Andriy
> > <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>;
> > Rafael J. Wysocki <rjw@rjwysocki.net>
> > Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
> > <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
> > <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-
> > kernel@vger.kernel.org; nv@vosn.de
> > Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
> > 
> > Op 12-09-19 om 16:19 schreef Moore, Robert:
> > > Nikolaus,
> > > The ability to unload an ACPI table (especially AML tables such as SSDTs) is in
> > the process of being deprecated in ACPICA -- since it is also deprecated in the
> > current ACPI specification. This is being done because of the difficulty of
> > deleting the namespace entries for the table.  FYI, Windows does not properly
> > support this function either.
> > 
> > I really hope this is not the case. On x86 loading/unloading SSDTs has proven to
> > be a powerful way to handle reconfigurable hardware without rebooting and
> > without requiring dedicated platform drivers. Same for user plugable hardware
> > on i2c/spi busses.
> > 
> > This has worked before and will violate the "don't break user space" rule.
> 
> If the table index wasn't being used, how did this work before?
> Which commit broke this?
> 
> Bob and I are trying to understand if this is a regression or a new feature request...

It is a regression as I explained in my bisecting message.

Before it uses acpi_tb_* API directly.
I thought Bob already got the idea.

-- 
With Best Regards,
Andy Shevchenko

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Nikolaus Voss]

Bob,

On Thu, 12 Sep 2019, Moore, Robert wrote:
> The ability to unload an ACPI table (especially AML tables such as 
> SSDTs) is in the process of being deprecated in ACPICA -- since it is 
> also deprecated in the current ACPI specification. This is being done 
> because of the difficulty of deleting the namespace entries for the 
> table.  FYI, Windows does not properly support this function either.

ok, I see it can be a problem to unload an AML table with all it's 
consequences e.g. with respect to driver unregistering in setups with 
complex dependencies. It will only work properly under certain conditions 
- nevertheless acpi_tb_unload_table() is still exported in ACPICA and we 
should get this working as it worked before.

The API change I request is not directly related to table unloading, it's 
just that the index of the loaded table is returned for future reference:

[...]

>> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h index 3845c8fcc94e5..c90bbdc4146a6 100644
>> --- a/include/acpi/acpixf.h
>> +++ b/include/acpi/acpixf.h
>> @@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
>> 					       u8 physical))
>>
>> ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>> -			    acpi_load_table(struct acpi_table_header *table))
>> +			    acpi_load_table(struct acpi_table_header *table,
>> +					    u32 *table_idx))
>>
>> ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>> 			    acpi_unload_parent_table(acpi_handle object))
>> --
>> 2.17.1
>>

This allows for a simple fix of the regression and doesn't imply future 
support for table unloading. Would this be acceptable?

Niko

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Moore, Robert]

-----Original Message-----
From: Nikolaus Voss [mailto:nv@vosn.de] 
Sent: Friday, September 13, 2019 12:44 AM
To: Moore, Robert <robert.moore@intel.com>
Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth <ftoth@telfort.nl>; nikolaus.voss@loewensteinmedical.de
Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index

Bob,

On Thu, 12 Sep 2019, Moore, Robert wrote:
> The ability to unload an ACPI table (especially AML tables such as
> SSDTs) is in the process of being deprecated in ACPICA -- since it is 
> also deprecated in the current ACPI specification. This is being done 
> because of the difficulty of deleting the namespace entries for the 
> table.  FYI, Windows does not properly support this function either.

ok, I see it can be a problem to unload an AML table with all it's consequences e.g. with respect to driver unregistering in setups with complex dependencies. It will only work properly under certain conditions
- nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.

AcpiTbUnloadTable is not exported, it is an internal interface only -- as recognized by the "AcpiTb". I'm not sure that I want to change the interface to AcpiLoadTable just for something that is being deprecated. Already, we throw an ACPI_EXCEPTION if the Unload operator is encountered in the AML byte stream. The same thing with AcpiUnloadParentTable - it is being deprecated.


    ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
        "AML Unload operator is not supported"));


The API change I request is not directly related to table unloading, it's just that the index of the loaded table is returned for future reference:

[...]

>> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h index 
>> 3845c8fcc94e5..c90bbdc4146a6 100644
>> --- a/include/acpi/acpixf.h
>> +++ b/include/acpi/acpixf.h
>> @@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
>> 					       u8 physical))
>>
>> ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>> -			    acpi_load_table(struct acpi_table_header *table))
>> +			    acpi_load_table(struct acpi_table_header *table,
>> +					    u32 *table_idx))
>>
>> ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>> 			    acpi_unload_parent_table(acpi_handle object))
>> --
>> 2.17.1
>>

This allows for a simple fix of the regression and doesn't imply future support for table unloading. Would this be acceptable?

Niko

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Shevchenko, Andriy]

On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
> -----Original Message-----
> From: Nikolaus Voss [mailto:nv@vosn.de] 
> Sent: Friday, September 13, 2019 12:44 AM
> To: Moore, Robert <robert.moore@intel.com>
> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth <ftoth@telfort.nl>; nikolaus.voss@loewensteinmedical.de
> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
> 
> Bob,
> 
> On Thu, 12 Sep 2019, Moore, Robert wrote:
> > The ability to unload an ACPI table (especially AML tables such as
> > SSDTs) is in the process of being deprecated in ACPICA -- since it is 
> > also deprecated in the current ACPI specification. This is being done 
> > because of the difficulty of deleting the namespace entries for the 
> > table.  FYI, Windows does not properly support this function either.
> 
> ok, I see it can be a problem to unload an AML table with all it's consequences e.g. with respect to driver unregistering in setups with complex dependencies. It will only work properly under certain conditions
> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
> 
> AcpiTbUnloadTable is not exported, it is an internal interface only -- as
> recognized by the "AcpiTb".

In Linux it became a part of ABI when the

commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
Author: Jan Kiszka <jan.kiszka@siemens.com>
Date:   Fri Jun 9 20:36:31 2017 +0200

    ACPI: configfs: Unload SSDT on configfs entry removal

appeared in the kernel.

> I'm not sure that I want to change the interface
> to AcpiLoadTable just for something that is being deprecated. Already, we
> throw an ACPI_EXCEPTION if the Unload operator is encountered in the AML byte
> stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
> 
>     ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
>         "AML Unload operator is not supported"));

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Ferry Toth]

Hello all,

Sorry to have sent our message with cancelled e-mail address. I have 
correct this now.

Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
> On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
>> -----Original Message-----
>> From: Nikolaus Voss [mailto:nv@vosn.de]
>> Sent: Friday, September 13, 2019 12:44 AM
>> To: Moore, Robert <robert.moore@intel.com>
>> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth <ftoth@telfort.nl>; nikolaus.voss@loewensteinmedical.de
>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
>>
>> Bob,
>>
>> On Thu, 12 Sep 2019, Moore, Robert wrote:
>>> The ability to unload an ACPI table (especially AML tables such as
>>> SSDTs) is in the process of being deprecated in ACPICA -- since it is
>>> also deprecated in the current ACPI specification. This is being done
>>> because of the difficulty of deleting the namespace entries for the
>>> table.  FYI, Windows does not properly support this function either.
>>
>> ok, I see it can be a problem to unload an AML table with all it's consequences e.g. with respect to driver unregistering in setups with complex dependencies. It will only work properly under certain conditions
>> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
>>
>> AcpiTbUnloadTable is not exported, it is an internal interface only -- as
>> recognized by the "AcpiTb".
> 
> In Linux it became a part of ABI when the
> 
> commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
> Author: Jan Kiszka <jan.kiszka@siemens.com>
> Date:   Fri Jun 9 20:36:31 2017 +0200
> 
>      ACPI: configfs: Unload SSDT on configfs entry removal
> 
> appeared in the kernel.

And the commit message explains quite well why it is an important feature:

"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."

>> I'm not sure that I want to change the interface
>> to AcpiLoadTable just for something that is being deprecated. Already, we
>> throw an ACPI_EXCEPTION if the Unload operator is encountered in the AML byte
>> stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
>>
>>      ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
>>          "AML Unload operator is not supported"));
> 

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Ferry Toth]

Hello all,

Sorry to have sent our message with cancelled e-mail address. I have 
correct this now.

Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
> On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
>> -----Original Message-----
>> From: Nikolaus Voss [mailto:nv@vosn.de]
>> Sent: Friday, September 13, 2019 12:44 AM
>> To: Moore, Robert <robert.moore@intel.com>
>> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth <ftoth@telfort.nl>; nikolaus.voss@loewensteinmedical.de
>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
>>
>> Bob,
>>
>> On Thu, 12 Sep 2019, Moore, Robert wrote:
>>> The ability to unload an ACPI table (especially AML tables such as
>>> SSDTs) is in the process of being deprecated in ACPICA -- since it is
>>> also deprecated in the current ACPI specification. This is being done
>>> because of the difficulty of deleting the namespace entries for the
>>> table.  FYI, Windows does not properly support this function either.
>>
>> ok, I see it can be a problem to unload an AML table with all it's consequences e.g. with respect to driver unregistering in setups with complex dependencies. It will only work properly under certain conditions
>> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
>>
>> AcpiTbUnloadTable is not exported, it is an internal interface only -- as
>> recognized by the "AcpiTb".
> 
> In Linux it became a part of ABI when the
> 
> commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
> Author: Jan Kiszka <jan.kiszka@siemens.com>
> Date:   Fri Jun 9 20:36:31 2017 +0200
> 
>      ACPI: configfs: Unload SSDT on configfs entry removal
> 
> appeared in the kernel.

And the commit message explains quite well why it is an important feature:

"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."

>> I'm not sure that I want to change the interface
>> to AcpiLoadTable just for something that is being deprecated. Already, we
>> throw an ACPI_EXCEPTION if the Unload operator is encountered in the AML byte
>> stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
>>
>>      ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
>>          "AML Unload operator is not supported"));
> 

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Moore, Robert]

-----Original Message-----
From: Ferry Toth [mailto:fntoth@gmail.com] 
Sent: Friday, September 13, 2019 9:48 AM
To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Moore, Robert <robert.moore@intel.com>
Cc: Nikolaus Voss <nv@vosn.de>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; nikolaus.voss@loewensteinmedical.de; Jan Kiszka <jan.kiszka@siemens.com>
Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index

Hello all,

Sorry to have sent our message with cancelled e-mail address. I have correct this now.

Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
> On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
>> -----Original Message-----
>> From: Nikolaus Voss [mailto:nv@vosn.de]
>> Sent: Friday, September 13, 2019 12:44 AM
>> To: Moore, Robert <robert.moore@intel.com>
>> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik 
>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len 
>> Brown <lenb@kernel.org>; Jacek Anaszewski 
>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy 
>> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; 
>> linux-kernel@vger.kernel.org; Ferry Toth <ftoth@telfort.nl>; 
>> nikolaus.voss@loewensteinmedical.de
>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table 
>> index
>>
>> Bob,
>>
>> On Thu, 12 Sep 2019, Moore, Robert wrote:
>>> The ability to unload an ACPI table (especially AML tables such as
>>> SSDTs) is in the process of being deprecated in ACPICA -- since it 
>>> is also deprecated in the current ACPI specification. This is being 
>>> done because of the difficulty of deleting the namespace entries for 
>>> the table.  FYI, Windows does not properly support this function either.
>>
>> ok, I see it can be a problem to unload an AML table with all it's 
>> consequences e.g. with respect to driver unregistering in setups with 
>> complex dependencies. It will only work properly under certain 
>> conditions
>> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
>>
>> AcpiTbUnloadTable is not exported, it is an internal interface only 
>> -- as recognized by the "AcpiTb".
> 
> In Linux it became a part of ABI when the
> 
> commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
> Author: Jan Kiszka <jan.kiszka@siemens.com>
> Date:   Fri Jun 9 20:36:31 2017 +0200
> 
>      ACPI: configfs: Unload SSDT on configfs entry removal
> 
> appeared in the kernel.

And the commit message explains quite well why it is an important feature:

"This allows to change SSDTs without rebooting the system.
It also allows to destroy devices again that a dynamically loaded SSDT created.

The biggest problem AFAIK is that under linux, many drivers cannot be unloaded. Also, there are many race conditions as the namespace entries "owned" by an SSDT being unloaded are deleted (out from underneath a driver).

This is widely similar to the DT overlay behavior."

>> I'm not sure that I want to change the interface to AcpiLoadTable 
>> just for something that is being deprecated. Already, we throw an 
>> ACPI_EXCEPTION if the Unload operator is encountered in the AML byte 
>> stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
>>
>>      ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
>>          "AML Unload operator is not supported"));
> 

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Rafael J. Wysocki]

On Fri, Sep 13, 2019 at 7:41 PM Moore, Robert <robert.moore@intel.com> wrote:
>
>
>
> -----Original Message-----
> From: Ferry Toth [mailto:fntoth@gmail.com]
> Sent: Friday, September 13, 2019 9:48 AM
> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Moore, Robert <robert.moore@intel.com>
> Cc: Nikolaus Voss <nv@vosn.de>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; nikolaus.voss@loewensteinmedical.de; Jan Kiszka <jan.kiszka@siemens.com>
> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
>
> Hello all,
>
> Sorry to have sent our message with cancelled e-mail address. I have correct this now.
>
> Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
> > On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
> >> -----Original Message-----
> >> From: Nikolaus Voss [mailto:nv@vosn.de]
> >> Sent: Friday, September 13, 2019 12:44 AM
> >> To: Moore, Robert <robert.moore@intel.com>
> >> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik
> >> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len
> >> Brown <lenb@kernel.org>; Jacek Anaszewski
> >> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
> >> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org;
> >> linux-kernel@vger.kernel.org; Ferry Toth <ftoth@telfort.nl>;
> >> nikolaus.voss@loewensteinmedical.de
> >> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table
> >> index
> >>
> >> Bob,
> >>
> >> On Thu, 12 Sep 2019, Moore, Robert wrote:
> >>> The ability to unload an ACPI table (especially AML tables such as
> >>> SSDTs) is in the process of being deprecated in ACPICA -- since it
> >>> is also deprecated in the current ACPI specification. This is being
> >>> done because of the difficulty of deleting the namespace entries for
> >>> the table.  FYI, Windows does not properly support this function either.
> >>
> >> ok, I see it can be a problem to unload an AML table with all it's
> >> consequences e.g. with respect to driver unregistering in setups with
> >> complex dependencies. It will only work properly under certain
> >> conditions
> >> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
> >>
> >> AcpiTbUnloadTable is not exported, it is an internal interface only
> >> -- as recognized by the "AcpiTb".
> >
> > In Linux it became a part of ABI when the
> >
> > commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
> > Author: Jan Kiszka <jan.kiszka@siemens.com>
> > Date:   Fri Jun 9 20:36:31 2017 +0200
> >
> >      ACPI: configfs: Unload SSDT on configfs entry removal
> >
> > appeared in the kernel.
>
> And the commit message explains quite well why it is an important feature:
>
> "This allows to change SSDTs without rebooting the system.
> It also allows to destroy devices again that a dynamically loaded SSDT created.
>
> The biggest problem AFAIK is that under linux, many drivers cannot be unloaded.
> Also, there are many race conditions as the namespace entries "owned" by an SSDT
> being unloaded are deleted (out from underneath a driver).

While that is true in general, there are cases in which unloading does
work and they
still need to be supported.

You may argue that adding support for unloading SSDTs loaded via
configfs was a mistake,
but that was done and it cannot be undone.

We cannot break existing setups in which it is in use and works.

> This is widely similar to the DT overlay behavior."
>
> >> I'm not sure that I want to change the interface to AcpiLoadTable
> >> just for something that is being deprecated. Already, we throw an
> >> ACPI_EXCEPTION if the Unload operator is encountered in the AML byte
> >> stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
> >>
> >>      ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
> >>          "AML Unload operator is not supported"));
> >
>

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Nikolaus Voss]

On Fri, 13 Sep 2019, Moore, Robert wrote:
>
>
> -----Original Message-----
> From: Ferry Toth [mailto:fntoth@gmail.com]
> Sent: Friday, September 13, 2019 9:48 AM
> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Moore, Robert <robert.moore@intel.com>
> Cc: Nikolaus Voss <nv@vosn.de>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; nikolaus.voss@loewensteinmedical.de; Jan Kiszka <jan.kiszka@siemens.com>
> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
>
> Hello all,
>
> Sorry to have sent our message with cancelled e-mail address. I have correct this now.
>
> Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
>> On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
>>> -----Original Message-----
>>> From: Nikolaus Voss [mailto:nv@vosn.de]
>>> Sent: Friday, September 13, 2019 12:44 AM
>>> To: Moore, Robert <robert.moore@intel.com>
>>> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik
>>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len
>>> Brown <lenb@kernel.org>; Jacek Anaszewski
>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
>>> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org;
>>> linux-kernel@vger.kernel.org; Ferry Toth <ftoth@telfort.nl>;
>>> nikolaus.voss@loewensteinmedical.de
>>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table
>>> index
>>>
>>> Bob,
>>>
>>> On Thu, 12 Sep 2019, Moore, Robert wrote:
>>>> The ability to unload an ACPI table (especially AML tables such as
>>>> SSDTs) is in the process of being deprecated in ACPICA -- since it
>>>> is also deprecated in the current ACPI specification. This is being
>>>> done because of the difficulty of deleting the namespace entries for
>>>> the table.  FYI, Windows does not properly support this function either.
>>>
>>> ok, I see it can be a problem to unload an AML table with all it's
>>> consequences e.g. with respect to driver unregistering in setups with
>>> complex dependencies. It will only work properly under certain
>>> conditions
>>> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
>>>
>>> AcpiTbUnloadTable is not exported, it is an internal interface only
>>> -- as recognized by the "AcpiTb".
>>
>> In Linux it became a part of ABI when the
>>
>> commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
>> Author: Jan Kiszka <jan.kiszka@siemens.com>
>> Date:   Fri Jun 9 20:36:31 2017 +0200
>>
>>      ACPI: configfs: Unload SSDT on configfs entry removal
>>
>> appeared in the kernel.
>
> And the commit message explains quite well why it is an important feature:
>
> "This allows to change SSDTs without rebooting the system.
> It also allows to destroy devices again that a dynamically loaded SSDT created.
>
> The biggest problem AFAIK is that under linux, many drivers cannot be unloaded. Also, there are many race conditions as the namespace entries "owned" by an SSDT being unloaded are deleted (out from underneath a driver).
>
> This is widely similar to the DT overlay behavior."
>
>>> I'm not sure that I want to change the interface to AcpiLoadTable
>>> just for something that is being deprecated. Already, we throw an
>>> ACPI_EXCEPTION if the Unload operator is encountered in the AML byte
>>> stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
>>>
>>>      ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
>>>          "AML Unload operator is not supported"));

Bob, what is your suggestion to fix the regression then?

We could revert acpi_configfs.c to use acpi_tb_install_and_load_table() 
instead of acpi_load_table(), leaving loaded APCI objects uninitalized, 
but at least, unloading will work again.

Do we have any other options?

Niko

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Moore, Robert]

-----Original Message-----
From: Nikolaus Voss [mailto:nv@vosn.de] 
Sent: Monday, September 16, 2019 2:47 AM
To: Moore, Robert <robert.moore@intel.com>
Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index

On Fri, 13 Sep 2019, Moore, Robert wrote:
>
>
> -----Original Message-----
> From: Ferry Toth [mailto:fntoth@gmail.com]
> Sent: Friday, September 13, 2019 9:48 AM
> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Moore, Robert 
> <robert.moore@intel.com>
> Cc: Nikolaus Voss <nv@vosn.de>; Schmauss, Erik 
> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len 
> Brown <lenb@kernel.org>; Jacek Anaszewski 
> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy 
> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; 
> linux-kernel@vger.kernel.org; nikolaus.voss@loewensteinmedical.de; Jan 
> Kiszka <jan.kiszka@siemens.com>
> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
>
> Hello all,
>
> Sorry to have sent our message with cancelled e-mail address. I have correct this now.
>
> Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
>> On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
>>> -----Original Message-----
>>> From: Nikolaus Voss [mailto:nv@vosn.de]
>>> Sent: Friday, September 13, 2019 12:44 AM
>>> To: Moore, Robert <robert.moore@intel.com>
>>> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik 
>>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; 
>>> Len Brown <lenb@kernel.org>; Jacek Anaszewski 
>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan 
>>> Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; 
>>> devel@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth 
>>> <ftoth@telfort.nl>; nikolaus.voss@loewensteinmedical.de
>>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table 
>>> index
>>>
>>> Bob,
>>>
>>> On Thu, 12 Sep 2019, Moore, Robert wrote:
>>>> The ability to unload an ACPI table (especially AML tables such as
>>>> SSDTs) is in the process of being deprecated in ACPICA -- since it 
>>>> is also deprecated in the current ACPI specification. This is being 
>>>> done because of the difficulty of deleting the namespace entries 
>>>> for the table.  FYI, Windows does not properly support this function either.
>>>
>>> ok, I see it can be a problem to unload an AML table with all it's 
>>> consequences e.g. with respect to driver unregistering in setups 
>>> with complex dependencies. It will only work properly under certain 
>>> conditions
>>> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
>>>
>>> AcpiTbUnloadTable is not exported, it is an internal interface only
>>> -- as recognized by the "AcpiTb".
>>
>> In Linux it became a part of ABI when the
>>
>> commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
>> Author: Jan Kiszka <jan.kiszka@siemens.com>
>> Date:   Fri Jun 9 20:36:31 2017 +0200
>>
>>      ACPI: configfs: Unload SSDT on configfs entry removal
>>
>> appeared in the kernel.
>
> And the commit message explains quite well why it is an important feature:
>
> "This allows to change SSDTs without rebooting the system.
> It also allows to destroy devices again that a dynamically loaded SSDT created.
>
> The biggest problem AFAIK is that under linux, many drivers cannot be unloaded. Also, there are many race conditions as the namespace entries "owned" by an SSDT being unloaded are deleted (out from underneath a driver).
>
> This is widely similar to the DT overlay behavior."
>
>>> I'm not sure that I want to change the interface to AcpiLoadTable 
>>> just for something that is being deprecated. Already, we throw an 
>>> ACPI_EXCEPTION if the Unload operator is encountered in the AML byte 
>>> stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
>>>
>>>      ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
>>>          "AML Unload operator is not supported"));

Bob, what is your suggestion to fix the regression then?

We could revert acpi_configfs.c to use acpi_tb_install_and_load_table() instead of acpi_load_table(), leaving loaded APCI objects uninitalized, but at least, unloading will work again.

I guess my next question is: why do you want to unload a table in the first place?


Do we have any other options?

Niko

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Nikolaus Voss]

On Wed, 18 Sep 2019, Moore, Robert wrote:
>
>
> -----Original Message-----
> From: Nikolaus Voss [mailto:nv@vosn.de]
> Sent: Monday, September 16, 2019 2:47 AM
> To: Moore, Robert <robert.moore@intel.com>
> Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
>
> On Fri, 13 Sep 2019, Moore, Robert wrote:
>>
>>
>> -----Original Message-----
>> From: Ferry Toth [mailto:fntoth@gmail.com]
>> Sent: Friday, September 13, 2019 9:48 AM
>> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Moore, Robert
>> <robert.moore@intel.com>
>> Cc: Nikolaus Voss <nv@vosn.de>; Schmauss, Erik
>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len
>> Brown <lenb@kernel.org>; Jacek Anaszewski
>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
>> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org;
>> linux-kernel@vger.kernel.org; nikolaus.voss@loewensteinmedical.de; Jan
>> Kiszka <jan.kiszka@siemens.com>
>> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
>>
>> Hello all,
>>
>> Sorry to have sent our message with cancelled e-mail address. I have correct this now.
>>
>> Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
>>> On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
>>>> -----Original Message-----
>>>> From: Nikolaus Voss [mailto:nv@vosn.de]
>>>> Sent: Friday, September 13, 2019 12:44 AM
>>>> To: Moore, Robert <robert.moore@intel.com>
>>>> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik
>>>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>;
>>>> Len Brown <lenb@kernel.org>; Jacek Anaszewski
>>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan
>>>> Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org;
>>>> devel@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth
>>>> <ftoth@telfort.nl>; nikolaus.voss@loewensteinmedical.de
>>>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table
>>>> index
>>>>
>>>> Bob,
>>>>
>>>> On Thu, 12 Sep 2019, Moore, Robert wrote:
>>>>> The ability to unload an ACPI table (especially AML tables such as
>>>>> SSDTs) is in the process of being deprecated in ACPICA -- since it
>>>>> is also deprecated in the current ACPI specification. This is being
>>>>> done because of the difficulty of deleting the namespace entries
>>>>> for the table.  FYI, Windows does not properly support this function either.
>>>>
>>>> ok, I see it can be a problem to unload an AML table with all it's
>>>> consequences e.g. with respect to driver unregistering in setups
>>>> with complex dependencies. It will only work properly under certain
>>>> conditions
>>>> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
>>>>
>>>> AcpiTbUnloadTable is not exported, it is an internal interface only
>>>> -- as recognized by the "AcpiTb".
>>>
>>> In Linux it became a part of ABI when the
>>>
>>> commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
>>> Author: Jan Kiszka <jan.kiszka@siemens.com>
>>> Date:   Fri Jun 9 20:36:31 2017 +0200
>>>
>>>      ACPI: configfs: Unload SSDT on configfs entry removal
>>>
>>> appeared in the kernel.
>>
>> And the commit message explains quite well why it is an important feature:
>>
>> "This allows to change SSDTs without rebooting the system.
>> It also allows to destroy devices again that a dynamically loaded SSDT created.
>>
>> The biggest problem AFAIK is that under linux, many drivers cannot be unloaded. Also, there are many race conditions as the namespace entries "owned" by an SSDT being unloaded are deleted (out from underneath a driver).
>>
>> This is widely similar to the DT overlay behavior."
>>
>>>> I'm not sure that I want to change the interface to AcpiLoadTable
>>>> just for something that is being deprecated. Already, we throw an
>>>> ACPI_EXCEPTION if the Unload operator is encountered in the AML byte
>>>> stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
>>>>
>>>>      ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
>>>>          "AML Unload operator is not supported"));
>
> Bob, what is your suggestion to fix the regression then?
>
> We could revert acpi_configfs.c to use acpi_tb_install_and_load_table() 
> instead of acpi_load_table(), leaving loaded APCI objects uninitalized, 
> but at least, unloading will work again.
>
> I guess my next question is: why do you want to unload a table in the 
> first place?

Because it worked before and there are people who rely on it. If it's 
deprecated there should be a user notification and a reasonable 
end-of-life timeline to give these users a chance to develop an 
alternative solution.

Niko

>
>
> Do we have any other options?
>
> Niko
>

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Moore, Robert]

-----Original Message-----
From: Nikolaus Voss [mailto:nv@vosn.de] 
Sent: Wednesday, September 18, 2019 7:32 AM
To: Moore, Robert <robert.moore@intel.com>
Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index

On Wed, 18 Sep 2019, Moore, Robert wrote:
>
>
> -----Original Message-----
> From: Nikolaus Voss [mailto:nv@vosn.de]
> Sent: Monday, September 16, 2019 2:47 AM
> To: Moore, Robert <robert.moore@intel.com>
> Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy 
> <andriy.shevchenko@intel.com>; Schmauss, Erik 
> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len 
> Brown <lenb@kernel.org>; Jacek Anaszewski 
> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy 
> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; 
> linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
>
> On Fri, 13 Sep 2019, Moore, Robert wrote:
>>
>>
>> -----Original Message-----
>> From: Ferry Toth [mailto:fntoth@gmail.com]
>> Sent: Friday, September 13, 2019 9:48 AM
>> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Moore, Robert 
>> <robert.moore@intel.com>
>> Cc: Nikolaus Voss <nv@vosn.de>; Schmauss, Erik 
>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len 
>> Brown <lenb@kernel.org>; Jacek Anaszewski 
>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy 
>> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; 
>> linux-kernel@vger.kernel.org; nikolaus.voss@loewensteinmedical.de; 
>> Jan Kiszka <jan.kiszka@siemens.com>
>> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table 
>> index
>>
>> Hello all,
>>
>> Sorry to have sent our message with cancelled e-mail address. I have correct this now.
>>
>> Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
>>> On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
>>>> -----Original Message-----
>>>> From: Nikolaus Voss [mailto:nv@vosn.de]
>>>> Sent: Friday, September 13, 2019 12:44 AM
>>>> To: Moore, Robert <robert.moore@intel.com>
>>>> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, 
>>>> Erik <erik.schmauss@intel.com>; Rafael J. Wysocki 
>>>> <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski 
>>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan 
>>>> Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; 
>>>> devel@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth 
>>>> <ftoth@telfort.nl>; nikolaus.voss@loewensteinmedical.de
>>>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table 
>>>> index
>>>>
>>>> Bob,
>>>>
>>>> On Thu, 12 Sep 2019, Moore, Robert wrote:
>>>>> The ability to unload an ACPI table (especially AML tables such as
>>>>> SSDTs) is in the process of being deprecated in ACPICA -- since it 
>>>>> is also deprecated in the current ACPI specification. This is 
>>>>> being done because of the difficulty of deleting the namespace 
>>>>> entries for the table.  FYI, Windows does not properly support this function either.
>>>>
>>>> ok, I see it can be a problem to unload an AML table with all it's 
>>>> consequences e.g. with respect to driver unregistering in setups 
>>>> with complex dependencies. It will only work properly under certain 
>>>> conditions
>>>> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
>>>>
>>>> AcpiTbUnloadTable is not exported, it is an internal interface only
>>>> -- as recognized by the "AcpiTb".
>>>
>>> In Linux it became a part of ABI when the
>>>
>>> commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
>>> Author: Jan Kiszka <jan.kiszka@siemens.com>
>>> Date:   Fri Jun 9 20:36:31 2017 +0200
>>>
>>>      ACPI: configfs: Unload SSDT on configfs entry removal
>>>
>>> appeared in the kernel.
>>
>> And the commit message explains quite well why it is an important feature:
>>
>> "This allows to change SSDTs without rebooting the system.
>> It also allows to destroy devices again that a dynamically loaded SSDT created.
>>
>> The biggest problem AFAIK is that under linux, many drivers cannot be unloaded. Also, there are many race conditions as the namespace entries "owned" by an SSDT being unloaded are deleted (out from underneath a driver).
>>
>> This is widely similar to the DT overlay behavior."
>>
>>>> I'm not sure that I want to change the interface to AcpiLoadTable 
>>>> just for something that is being deprecated. Already, we throw an 
>>>> ACPI_EXCEPTION if the Unload operator is encountered in the AML 
>>>> byte stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
>>>>
>>>>      ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
>>>>          "AML Unload operator is not supported"));
>
> Bob, what is your suggestion to fix the regression then?
>
> We could revert acpi_configfs.c to use 
> acpi_tb_install_and_load_table() instead of acpi_load_table(), leaving 
> loaded APCI objects uninitalized, but at least, unloading will work again.
>
> I guess my next question is: why do you want to unload a table in the 
> first place?

Because it worked before and there are people who rely on it. If it's deprecated there should be a user notification and a reasonable end-of-life timeline to give these users a chance to develop an alternative solution.

So, I still don't understand why this no longer works. We did not make any purposeful changes in this area - AFAIK.
Bob

Niko

>
>
> Do we have any other options?
>
> Niko
>

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Nikolaus Voss]

On Thu, 19 Sep 2019, Moore, Robert wrote:
>
>
> -----Original Message-----
> From: Nikolaus Voss [mailto:nv@vosn.de]
> Sent: Wednesday, September 18, 2019 7:32 AM
> To: Moore, Robert <robert.moore@intel.com>
> Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
>
> On Wed, 18 Sep 2019, Moore, Robert wrote:
>>
>>
>> -----Original Message-----
>> From: Nikolaus Voss [mailto:nv@vosn.de]
>> Sent: Monday, September 16, 2019 2:47 AM
>> To: Moore, Robert <robert.moore@intel.com>
>> Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy
>> <andriy.shevchenko@intel.com>; Schmauss, Erik
>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len
>> Brown <lenb@kernel.org>; Jacek Anaszewski
>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
>> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org;
>> linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
>>
>> On Fri, 13 Sep 2019, Moore, Robert wrote:
>>>
>>>
>>> -----Original Message-----
>>> From: Ferry Toth [mailto:fntoth@gmail.com]
>>> Sent: Friday, September 13, 2019 9:48 AM
>>> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Moore, Robert
>>> <robert.moore@intel.com>
>>> Cc: Nikolaus Voss <nv@vosn.de>; Schmauss, Erik
>>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len
>>> Brown <lenb@kernel.org>; Jacek Anaszewski
>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
>>> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org;
>>> linux-kernel@vger.kernel.org; nikolaus.voss@loewensteinmedical.de;
>>> Jan Kiszka <jan.kiszka@siemens.com>
>>> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table
>>> index
>>>
>>> Hello all,
>>>
>>> Sorry to have sent our message with cancelled e-mail address. I have correct this now.
>>>
>>> Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
>>>> On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
>>>>> -----Original Message-----
>>>>> From: Nikolaus Voss [mailto:nv@vosn.de]
>>>>> Sent: Friday, September 13, 2019 12:44 AM
>>>>> To: Moore, Robert <robert.moore@intel.com>
>>>>> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss,
>>>>> Erik <erik.schmauss@intel.com>; Rafael J. Wysocki
>>>>> <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski
>>>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan
>>>>> Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org;
>>>>> devel@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth
>>>>> <ftoth@telfort.nl>; nikolaus.voss@loewensteinmedical.de
>>>>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table
>>>>> index
>>>>>
>>>>> Bob,
>>>>>
>>>>> On Thu, 12 Sep 2019, Moore, Robert wrote:
>>>>>> The ability to unload an ACPI table (especially AML tables such as
>>>>>> SSDTs) is in the process of being deprecated in ACPICA -- since it
>>>>>> is also deprecated in the current ACPI specification. This is
>>>>>> being done because of the difficulty of deleting the namespace
>>>>>> entries for the table.  FYI, Windows does not properly support this function either.
>>>>>
>>>>> ok, I see it can be a problem to unload an AML table with all it's
>>>>> consequences e.g. with respect to driver unregistering in setups
>>>>> with complex dependencies. It will only work properly under certain
>>>>> conditions
>>>>> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
>>>>>
>>>>> AcpiTbUnloadTable is not exported, it is an internal interface only
>>>>> -- as recognized by the "AcpiTb".
>>>>
>>>> In Linux it became a part of ABI when the
>>>>
>>>> commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
>>>> Author: Jan Kiszka <jan.kiszka@siemens.com>
>>>> Date:   Fri Jun 9 20:36:31 2017 +0200
>>>>
>>>>      ACPI: configfs: Unload SSDT on configfs entry removal
>>>>
>>>> appeared in the kernel.
>>>
>>> And the commit message explains quite well why it is an important feature:
>>>
>>> "This allows to change SSDTs without rebooting the system.
>>> It also allows to destroy devices again that a dynamically loaded SSDT created.
>>>
>>> The biggest problem AFAIK is that under linux, many drivers cannot be unloaded. Also, there are many race conditions as the namespace entries "owned" by an SSDT being unloaded are deleted (out from underneath a driver).
>>>
>>> This is widely similar to the DT overlay behavior."
>>>
>>>>> I'm not sure that I want to change the interface to AcpiLoadTable
>>>>> just for something that is being deprecated. Already, we throw an
>>>>> ACPI_EXCEPTION if the Unload operator is encountered in the AML
>>>>> byte stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
>>>>>
>>>>>      ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
>>>>>          "AML Unload operator is not supported"));
>>
>> Bob, what is your suggestion to fix the regression then?
>>
>> We could revert acpi_configfs.c to use
>> acpi_tb_install_and_load_table() instead of acpi_load_table(), leaving
>> loaded APCI objects uninitalized, but at least, unloading will work again.
>>
>> I guess my next question is: why do you want to unload a table in the
>> first place?
>
> Because it worked before and there are people who rely on it. If it's 
> deprecated there should be a user notification and a reasonable 
> end-of-life timeline to give these users a chance to develop an 
> alternative solution.
>
> So, I still don't understand why this no longer works. We did not make 
> any purposeful changes in this area - AFAIK. Bob

It's because the acpi_configfs driver formerly used 
acpi_tb_install_and_load_table() which returns the table index, but 
doesn't resolve the references. It now uses acpi_load_table() which 
resolves the references, but doesn't return the table index, so unloading 
doesn't work any more.

>
> Niko
>
>>
>>
>> Do we have any other options?
>>
>> Niko
>>
>

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Moore, Robert]

How about this:
Go back to using acpi_tb_install_and_load_table(), but then call acpi_ns_initialize_objects afterwards This is what acpi_load_table does.


    ACPI_INFO (("Host-directed Dynamic ACPI Table Load:"));
    Status = AcpiTbInstallAndLoadTable (ACPI_PTR_TO_PHYSADDR (Table),
        ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL, FALSE, &TableIndex);
    if (ACPI_SUCCESS (Status))
    {
        /* Complete the initialization/resolution of new objects */

        AcpiNsInitializeObjects ();
    }


-----Original Message-----
From: Nikolaus Voss <nv@vosn.de> 
Sent: Monday, September 23, 2019 2:05 AM
To: Moore, Robert <robert.moore@intel.com>
Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index

On Thu, 19 Sep 2019, Moore, Robert wrote:
>
>
> -----Original Message-----
> From: Nikolaus Voss [mailto:nv@vosn.de]
> Sent: Wednesday, September 18, 2019 7:32 AM
> To: Moore, Robert <robert.moore@intel.com>
> Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy 
> <andriy.shevchenko@intel.com>; Schmauss, Erik 
> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len 
> Brown <lenb@kernel.org>; Jacek Anaszewski 
> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy 
> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; 
> linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
>
> On Wed, 18 Sep 2019, Moore, Robert wrote:
>>
>>
>> -----Original Message-----
>> From: Nikolaus Voss [mailto:nv@vosn.de]
>> Sent: Monday, September 16, 2019 2:47 AM
>> To: Moore, Robert <robert.moore@intel.com>
>> Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy 
>> <andriy.shevchenko@intel.com>; Schmauss, Erik 
>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len 
>> Brown <lenb@kernel.org>; Jacek Anaszewski 
>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy 
>> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; 
>> linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table 
>> index
>>
>> On Fri, 13 Sep 2019, Moore, Robert wrote:
>>>
>>>
>>> -----Original Message-----
>>> From: Ferry Toth [mailto:fntoth@gmail.com]
>>> Sent: Friday, September 13, 2019 9:48 AM
>>> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Moore, Robert 
>>> <robert.moore@intel.com>
>>> Cc: Nikolaus Voss <nv@vosn.de>; Schmauss, Erik 
>>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; 
>>> Len Brown <lenb@kernel.org>; Jacek Anaszewski 
>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan 
>>> Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; 
>>> devel@acpica.org; linux-kernel@vger.kernel.org; 
>>> nikolaus.voss@loewensteinmedical.de;
>>> Jan Kiszka <jan.kiszka@siemens.com>
>>> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table 
>>> index
>>>
>>> Hello all,
>>>
>>> Sorry to have sent our message with cancelled e-mail address. I have correct this now.
>>>
>>> Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
>>>> On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
>>>>> -----Original Message-----
>>>>> From: Nikolaus Voss [mailto:nv@vosn.de]
>>>>> Sent: Friday, September 13, 2019 12:44 AM
>>>>> To: Moore, Robert <robert.moore@intel.com>
>>>>> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, 
>>>>> Erik <erik.schmauss@intel.com>; Rafael J. Wysocki 
>>>>> <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski 
>>>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan 
>>>>> Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; 
>>>>> devel@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth 
>>>>> <ftoth@telfort.nl>; nikolaus.voss@loewensteinmedical.de
>>>>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table 
>>>>> index
>>>>>
>>>>> Bob,
>>>>>
>>>>> On Thu, 12 Sep 2019, Moore, Robert wrote:
>>>>>> The ability to unload an ACPI table (especially AML tables such 
>>>>>> as
>>>>>> SSDTs) is in the process of being deprecated in ACPICA -- since 
>>>>>> it is also deprecated in the current ACPI specification. This is 
>>>>>> being done because of the difficulty of deleting the namespace 
>>>>>> entries for the table.  FYI, Windows does not properly support this function either.
>>>>>
>>>>> ok, I see it can be a problem to unload an AML table with all it's 
>>>>> consequences e.g. with respect to driver unregistering in setups 
>>>>> with complex dependencies. It will only work properly under 
>>>>> certain conditions
>>>>> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
>>>>>
>>>>> AcpiTbUnloadTable is not exported, it is an internal interface 
>>>>> only
>>>>> -- as recognized by the "AcpiTb".
>>>>
>>>> In Linux it became a part of ABI when the
>>>>
>>>> commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
>>>> Author: Jan Kiszka <jan.kiszka@siemens.com>
>>>> Date:   Fri Jun 9 20:36:31 2017 +0200
>>>>
>>>>      ACPI: configfs: Unload SSDT on configfs entry removal
>>>>
>>>> appeared in the kernel.
>>>
>>> And the commit message explains quite well why it is an important feature:
>>>
>>> "This allows to change SSDTs without rebooting the system.
>>> It also allows to destroy devices again that a dynamically loaded SSDT created.
>>>
>>> The biggest problem AFAIK is that under linux, many drivers cannot be unloaded. Also, there are many race conditions as the namespace entries "owned" by an SSDT being unloaded are deleted (out from underneath a driver).
>>>
>>> This is widely similar to the DT overlay behavior."
>>>
>>>>> I'm not sure that I want to change the interface to AcpiLoadTable 
>>>>> just for something that is being deprecated. Already, we throw an 
>>>>> ACPI_EXCEPTION if the Unload operator is encountered in the AML 
>>>>> byte stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
>>>>>
>>>>>      ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
>>>>>          "AML Unload operator is not supported"));
>>
>> Bob, what is your suggestion to fix the regression then?
>>
>> We could revert acpi_configfs.c to use
>> acpi_tb_install_and_load_table() instead of acpi_load_table(), 
>> leaving loaded APCI objects uninitalized, but at least, unloading will work again.
>>
>> I guess my next question is: why do you want to unload a table in the 
>> first place?
>
> Because it worked before and there are people who rely on it. If it's 
> deprecated there should be a user notification and a reasonable 
> end-of-life timeline to give these users a chance to develop an 
> alternative solution.
>
> So, I still don't understand why this no longer works. We did not make 
> any purposeful changes in this area - AFAIK. Bob

It's because the acpi_configfs driver formerly used
acpi_tb_install_and_load_table() which returns the table index, but doesn't resolve the references. It now uses acpi_load_table() which resolves the references, but doesn't return the table index, so unloading doesn't work any more.

>
> Niko
>
>>
>>
>> Do we have any other options?
>>
>> Niko
>>
>

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Nikolaus Voss]

On Tue, 24 Sep 2019, Moore, Robert wrote:
> How about this:
> Go back to using acpi_tb_install_and_load_table(), but then call acpi_ns_initialize_objects afterwards This is what acpi_load_table does.
>
>
>    ACPI_INFO (("Host-directed Dynamic ACPI Table Load:"));
>    Status = AcpiTbInstallAndLoadTable (ACPI_PTR_TO_PHYSADDR (Table),
>        ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL, FALSE, &TableIndex);
>    if (ACPI_SUCCESS (Status))
>    {
>        /* Complete the initialization/resolution of new objects */
>
>        AcpiNsInitializeObjects ();
>    }

The idea was to have all drivers use the same interface for dynamically 
loading ACPI tables, i.e. efivar_ssdt_load() (which already used 
acpi_load_table()) and the acpi_configfs driver. The efivar driver doesn't 
provide a possibility to unload the table, so acpi_load_table() is okay 
for this purpose. According to Bob, acpi_tb_install_and_load_table() is 
not part of the external ACPICA API declared under include/acpi (though it 
is exported).

The counterpart of acpi_load_table() - inline comment "Note1: Mainly 
intended to support hotplug addition of SSDTs" - seems to be 
acpi_unload_parent_table() - inline comment "Note: Mainly intended to 
support hotplug removal of SSDTs" - but it doesn't expect a table index 
but an acpi_handle as argument, and it is only used within ACPICA, so IMO 
the API can't be properly used in our case and should be improved even 
though unloading tables is deprecated.

If changing the API is not an option, we can choose between Rafael's way 
(extending the API instead of changing it) or Bob's proposal (doing the 
same thing - hotplug-loading a SSDT - in different ways, in case of 
acpi_configfs using ACPICA internal API). I don't have a clear favorite, 
but I'm tending to Rafael's solution my favorite being the API change.

Niko

>
>
> -----Original Message-----
> From: Nikolaus Voss <nv@vosn.de>
> Sent: Monday, September 23, 2019 2:05 AM
> To: Moore, Robert <robert.moore@intel.com>
> Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
>
> On Thu, 19 Sep 2019, Moore, Robert wrote:
>>
>>
>> -----Original Message-----
>> From: Nikolaus Voss [mailto:nv@vosn.de]
>> Sent: Wednesday, September 18, 2019 7:32 AM
>> To: Moore, Robert <robert.moore@intel.com>
>> Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy
>> <andriy.shevchenko@intel.com>; Schmauss, Erik
>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len
>> Brown <lenb@kernel.org>; Jacek Anaszewski
>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
>> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org;
>> linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
>>
>> On Wed, 18 Sep 2019, Moore, Robert wrote:
>>>
>>>
>>> -----Original Message-----
>>> From: Nikolaus Voss [mailto:nv@vosn.de]
>>> Sent: Monday, September 16, 2019 2:47 AM
>>> To: Moore, Robert <robert.moore@intel.com>
>>> Cc: Ferry Toth <fntoth@gmail.com>; Shevchenko, Andriy
>>> <andriy.shevchenko@intel.com>; Schmauss, Erik
>>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Len
>>> Brown <lenb@kernel.org>; Jacek Anaszewski
>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
>>> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org;
>>> linux-kernel@vger.kernel.org; Jan Kiszka <jan.kiszka@siemens.com>
>>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table
>>> index
>>>
>>> On Fri, 13 Sep 2019, Moore, Robert wrote:
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Ferry Toth [mailto:fntoth@gmail.com]
>>>> Sent: Friday, September 13, 2019 9:48 AM
>>>> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Moore, Robert
>>>> <robert.moore@intel.com>
>>>> Cc: Nikolaus Voss <nv@vosn.de>; Schmauss, Erik
>>>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>;
>>>> Len Brown <lenb@kernel.org>; Jacek Anaszewski
>>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan
>>>> Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org;
>>>> devel@acpica.org; linux-kernel@vger.kernel.org;
>>>> nikolaus.voss@loewensteinmedical.de;
>>>> Jan Kiszka <jan.kiszka@siemens.com>
>>>> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table
>>>> index
>>>>
>>>> Hello all,
>>>>
>>>> Sorry to have sent our message with cancelled e-mail address. I have correct this now.
>>>>
>>>> Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
>>>>> On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
>>>>>> -----Original Message-----
>>>>>> From: Nikolaus Voss [mailto:nv@vosn.de]
>>>>>> Sent: Friday, September 13, 2019 12:44 AM
>>>>>> To: Moore, Robert <robert.moore@intel.com>
>>>>>> Cc: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss,
>>>>>> Erik <erik.schmauss@intel.com>; Rafael J. Wysocki
>>>>>> <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Jacek Anaszewski
>>>>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan
>>>>>> Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org;
>>>>>> devel@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth
>>>>>> <ftoth@telfort.nl>; nikolaus.voss@loewensteinmedical.de
>>>>>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table
>>>>>> index
>>>>>>
>>>>>> Bob,
>>>>>>
>>>>>> On Thu, 12 Sep 2019, Moore, Robert wrote:
>>>>>>> The ability to unload an ACPI table (especially AML tables such
>>>>>>> as
>>>>>>> SSDTs) is in the process of being deprecated in ACPICA -- since
>>>>>>> it is also deprecated in the current ACPI specification. This is
>>>>>>> being done because of the difficulty of deleting the namespace
>>>>>>> entries for the table.  FYI, Windows does not properly support this function either.
>>>>>>
>>>>>> ok, I see it can be a problem to unload an AML table with all it's
>>>>>> consequences e.g. with respect to driver unregistering in setups
>>>>>> with complex dependencies. It will only work properly under
>>>>>> certain conditions
>>>>>> - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before.
>>>>>>
>>>>>> AcpiTbUnloadTable is not exported, it is an internal interface
>>>>>> only
>>>>>> -- as recognized by the "AcpiTb".
>>>>>
>>>>> In Linux it became a part of ABI when the
>>>>>
>>>>> commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
>>>>> Author: Jan Kiszka <jan.kiszka@siemens.com>
>>>>> Date:   Fri Jun 9 20:36:31 2017 +0200
>>>>>
>>>>>      ACPI: configfs: Unload SSDT on configfs entry removal
>>>>>
>>>>> appeared in the kernel.
>>>>
>>>> And the commit message explains quite well why it is an important feature:
>>>>
>>>> "This allows to change SSDTs without rebooting the system.
>>>> It also allows to destroy devices again that a dynamically loaded SSDT created.
>>>>
>>>> The biggest problem AFAIK is that under linux, many drivers cannot be unloaded. Also, there are many race conditions as the namespace entries "owned" by an SSDT being unloaded are deleted (out from underneath a driver).
>>>>
>>>> This is widely similar to the DT overlay behavior."
>>>>
>>>>>> I'm not sure that I want to change the interface to AcpiLoadTable
>>>>>> just for something that is being deprecated. Already, we throw an
>>>>>> ACPI_EXCEPTION if the Unload operator is encountered in the AML
>>>>>> byte stream. The same thing with AcpiUnloadParentTable - it is being deprecated.
>>>>>>
>>>>>>      ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED,
>>>>>>          "AML Unload operator is not supported"));
>>>
>>> Bob, what is your suggestion to fix the regression then?
>>>
>>> We could revert acpi_configfs.c to use
>>> acpi_tb_install_and_load_table() instead of acpi_load_table(),
>>> leaving loaded APCI objects uninitalized, but at least, unloading will work again.
>>>
>>> I guess my next question is: why do you want to unload a table in the
>>> first place?
>>
>> Because it worked before and there are people who rely on it. If it's
>> deprecated there should be a user notification and a reasonable
>> end-of-life timeline to give these users a chance to develop an
>> alternative solution.
>>
>> So, I still don't understand why this no longer works. We did not make
>> any purposeful changes in this area - AFAIK. Bob
>
> It's because the acpi_configfs driver formerly used
> acpi_tb_install_and_load_table() which returns the table index, but doesn't resolve the references. It now uses acpi_load_table() which resolves the references, but doesn't return the table index, so unloading doesn't work any more.
>
>>
>> Niko
>>
>>>
>>>
>>> Do we have any other options?
>>>
>>> Niko
>>>
>>

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Shevchenko, Andriy]

On Wed, Sep 25, 2019 at 12:18:11PM +0200, Nikolaus Voss wrote:
> On Tue, 24 Sep 2019, Moore, Robert wrote:
> > How about this:
> > Go back to using acpi_tb_install_and_load_table(), but then call acpi_ns_initialize_objects afterwards This is what acpi_load_table does.
> > 
> > 
> >    ACPI_INFO (("Host-directed Dynamic ACPI Table Load:"));
> >    Status = AcpiTbInstallAndLoadTable (ACPI_PTR_TO_PHYSADDR (Table),
> >        ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL, FALSE, &TableIndex);
> >    if (ACPI_SUCCESS (Status))
> >    {
> >        /* Complete the initialization/resolution of new objects */
> > 
> >        AcpiNsInitializeObjects ();
> >    }
> 
> The idea was to have all drivers use the same interface for dynamically
> loading ACPI tables, i.e. efivar_ssdt_load() (which already used
> acpi_load_table()) and the acpi_configfs driver. The efivar driver doesn't
> provide a possibility to unload the table, so acpi_load_table() is okay for
> this purpose. 

> According to Bob, acpi_tb_install_and_load_table() is not part
> of the external ACPICA API declared under include/acpi (though it is
> exported).

You are answering to Bob himself :-)

So, above is another proposal and we can create a common symmetric APIs in ACPI
glue layer for all users even if some of them don't care about unloading.

> The counterpart of acpi_load_table() - inline comment "Note1: Mainly
> intended to support hotplug addition of SSDTs" - seems to be
> acpi_unload_parent_table() - inline comment "Note: Mainly intended to
> support hotplug removal of SSDTs" - but it doesn't expect a table index but
> an acpi_handle as argument, and it is only used within ACPICA, so IMO the
> API can't be properly used in our case and should be improved even though
> unloading tables is deprecated.
> 
> If changing the API is not an option, we can choose between Rafael's way
> (extending the API instead of changing it) or Bob's proposal (doing the same
> thing - hotplug-loading a SSDT - in different ways, in case of acpi_configfs
> using ACPICA internal API). I don't have a clear favorite, but I'm tending
> to Rafael's solution my favorite being the API change.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Rafael J. Wysocki]

On Thursday, September 12, 2019 10:07:42 AM CEST Nikolaus Voss wrote:
> For unloading an ACPI table, it is necessary to provide the
> index of the table. The method intended for dynamically
> loading or hotplug addition of tables, acpi_load_table(),
> should provide this information via an optional pointer
> to the loaded table index.
> 
> This patch fixes the table unload function of acpi_configfs.
> 
> Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table loads")
> Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>

Overall, I think that something similar to this patch will be needed, but
please don't change the acpi_load_table() signature.  Instead, define it as
a wrapper around a new function called, say, acpi_load_table_with_index()
that will take two arguments, like acpi_load_table() in your patch.

Then, you'd only need to call acpi_load_table_with_index() directly from
acpi_table_aml_write().

In that case, IMO, it will be easier to handle the divergence between the
upstream ACPICA and the kernel in the future in case the upstream doesn't
decide to incorporate your change.

> ---
>  drivers/acpi/acpi_configfs.c   | 2 +-
>  drivers/acpi/acpica/dbfileio.c | 2 +-
>  drivers/acpi/acpica/tbxfload.c | 8 ++++++--
>  drivers/firmware/efi/efi.c     | 2 +-
>  include/acpi/acpixf.h          | 3 ++-
>  5 files changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
> index 57d9d574d4dde..77f81242a28e6 100644
> --- a/drivers/acpi/acpi_configfs.c
> +++ b/drivers/acpi/acpi_configfs.c
> @@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
>  	if (!table->header)
>  		return -ENOMEM;
>  
> -	ret = acpi_load_table(table->header);
> +	ret = acpi_load_table(table->header, &table->index);
>  	if (ret) {
>  		kfree(table->header);
>  		table->header = NULL;
> diff --git a/drivers/acpi/acpica/dbfileio.c b/drivers/acpi/acpica/dbfileio.c
> index c6e25734dc5cd..e1b6e54a96ac1 100644
> --- a/drivers/acpi/acpica/dbfileio.c
> +++ b/drivers/acpi/acpica/dbfileio.c
> @@ -93,7 +93,7 @@ acpi_status acpi_db_load_tables(struct acpi_new_table_desc *list_head)
>  	while (table_list_head) {
>  		table = table_list_head->table;
>  
> -		status = acpi_load_table(table);
> +		status = acpi_load_table(table, NULL);
>  		if (ACPI_FAILURE(status)) {
>  			if (status == AE_ALREADY_EXISTS) {
>  				acpi_os_printf
> diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c
> index 86f1693f6d29a..d08cd8ffcbdb6 100644
> --- a/drivers/acpi/acpica/tbxfload.c
> +++ b/drivers/acpi/acpica/tbxfload.c
> @@ -268,7 +268,8 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
>   *
>   * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
>   *                                    table to be loaded.
> - *
> + *              table_idx           - Pointer to a u32 for storing the table
> + *                                    index, might be NULL
>   * RETURN:      Status
>   *
>   * DESCRIPTION: Dynamically load an ACPI table from the caller's buffer. Must
> @@ -278,7 +279,7 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
>   *              to ensure that the table is not deleted or unmapped.
>   *
>   ******************************************************************************/
> -acpi_status acpi_load_table(struct acpi_table_header *table)
> +acpi_status acpi_load_table(struct acpi_table_header *table, u32 *table_idx)
>  {
>  	acpi_status status;
>  	u32 table_index;
> @@ -297,6 +298,9 @@ acpi_status acpi_load_table(struct acpi_table_header *table)
>  	status = acpi_tb_install_and_load_table(ACPI_PTR_TO_PHYSADDR(table),
>  						ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
>  						FALSE, &table_index);
> +	if (table_idx)
> +		*table_idx = table_index;
> +
>  	if (ACPI_SUCCESS(status)) {
>  
>  		/* Complete the initialization/resolution of new objects */
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index ad3b1f4866b35..9773e4212baef 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -308,7 +308,7 @@ static __init int efivar_ssdt_load(void)
>  			goto free_data;
>  		}
>  
> -		ret = acpi_load_table(data);
> +		ret = acpi_load_table(data, NULL);
>  		if (ret) {
>  			pr_err("failed to load table: %d\n", ret);
>  			goto free_data;
> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
> index 3845c8fcc94e5..c90bbdc4146a6 100644
> --- a/include/acpi/acpixf.h
> +++ b/include/acpi/acpixf.h
> @@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
>  					       u8 physical))
>  
>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> -			    acpi_load_table(struct acpi_table_header *table))
> +			    acpi_load_table(struct acpi_table_header *table,
> +					    u32 *table_idx))
>  
>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>  			    acpi_unload_parent_table(acpi_handle object))
> 

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Nikolaus Voss]

On Thu, 19 Sep 2019, Rafael J. Wysocki wrote:
> On Thursday, September 12, 2019 10:07:42 AM CEST Nikolaus Voss wrote:
>> For unloading an ACPI table, it is necessary to provide the
>> index of the table. The method intended for dynamically
>> loading or hotplug addition of tables, acpi_load_table(),
>> should provide this information via an optional pointer
>> to the loaded table index.
>>
>> This patch fixes the table unload function of acpi_configfs.
>>
>> Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>> Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table loads")
>> Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
>
> Overall, I think that something similar to this patch will be needed, but
> please don't change the acpi_load_table() signature.  Instead, define it as
> a wrapper around a new function called, say, acpi_load_table_with_index()
> that will take two arguments, like acpi_load_table() in your patch.
>
> Then, you'd only need to call acpi_load_table_with_index() directly from
> acpi_table_aml_write().
>
> In that case, IMO, it will be easier to handle the divergence between the
> upstream ACPICA and the kernel in the future in case the upstream doesn't
> decide to incorporate your change.

Ok, I'll prepare a patch.

>
>> ---
>>  drivers/acpi/acpi_configfs.c   | 2 +-
>>  drivers/acpi/acpica/dbfileio.c | 2 +-
>>  drivers/acpi/acpica/tbxfload.c | 8 ++++++--
>>  drivers/firmware/efi/efi.c     | 2 +-
>>  include/acpi/acpixf.h          | 3 ++-
>>  5 files changed, 11 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
>> index 57d9d574d4dde..77f81242a28e6 100644
>> --- a/drivers/acpi/acpi_configfs.c
>> +++ b/drivers/acpi/acpi_configfs.c
>> @@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
>>  	if (!table->header)
>>  		return -ENOMEM;
>>
>> -	ret = acpi_load_table(table->header);
>> +	ret = acpi_load_table(table->header, &table->index);
>>  	if (ret) {
>>  		kfree(table->header);
>>  		table->header = NULL;
>> diff --git a/drivers/acpi/acpica/dbfileio.c b/drivers/acpi/acpica/dbfileio.c
>> index c6e25734dc5cd..e1b6e54a96ac1 100644
>> --- a/drivers/acpi/acpica/dbfileio.c
>> +++ b/drivers/acpi/acpica/dbfileio.c
>> @@ -93,7 +93,7 @@ acpi_status acpi_db_load_tables(struct acpi_new_table_desc *list_head)
>>  	while (table_list_head) {
>>  		table = table_list_head->table;
>>
>> -		status = acpi_load_table(table);
>> +		status = acpi_load_table(table, NULL);
>>  		if (ACPI_FAILURE(status)) {
>>  			if (status == AE_ALREADY_EXISTS) {
>>  				acpi_os_printf
>> diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c
>> index 86f1693f6d29a..d08cd8ffcbdb6 100644
>> --- a/drivers/acpi/acpica/tbxfload.c
>> +++ b/drivers/acpi/acpica/tbxfload.c
>> @@ -268,7 +268,8 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
>>   *
>>   * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
>>   *                                    table to be loaded.
>> - *
>> + *              table_idx           - Pointer to a u32 for storing the table
>> + *                                    index, might be NULL
>>   * RETURN:      Status
>>   *
>>   * DESCRIPTION: Dynamically load an ACPI table from the caller's buffer. Must
>> @@ -278,7 +279,7 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
>>   *              to ensure that the table is not deleted or unmapped.
>>   *
>>   ******************************************************************************/
>> -acpi_status acpi_load_table(struct acpi_table_header *table)
>> +acpi_status acpi_load_table(struct acpi_table_header *table, u32 *table_idx)
>>  {
>>  	acpi_status status;
>>  	u32 table_index;
>> @@ -297,6 +298,9 @@ acpi_status acpi_load_table(struct acpi_table_header *table)
>>  	status = acpi_tb_install_and_load_table(ACPI_PTR_TO_PHYSADDR(table),
>>  						ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
>>  						FALSE, &table_index);
>> +	if (table_idx)
>> +		*table_idx = table_index;
>> +
>>  	if (ACPI_SUCCESS(status)) {
>>
>>  		/* Complete the initialization/resolution of new objects */
>> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
>> index ad3b1f4866b35..9773e4212baef 100644
>> --- a/drivers/firmware/efi/efi.c
>> +++ b/drivers/firmware/efi/efi.c
>> @@ -308,7 +308,7 @@ static __init int efivar_ssdt_load(void)
>>  			goto free_data;
>>  		}
>>
>> -		ret = acpi_load_table(data);
>> +		ret = acpi_load_table(data, NULL);
>>  		if (ret) {
>>  			pr_err("failed to load table: %d\n", ret);
>>  			goto free_data;
>> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
>> index 3845c8fcc94e5..c90bbdc4146a6 100644
>> --- a/include/acpi/acpixf.h
>> +++ b/include/acpi/acpixf.h
>> @@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
>>  					       u8 physical))
>>
>>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>> -			    acpi_load_table(struct acpi_table_header *table))
>> +			    acpi_load_table(struct acpi_table_header *table,
>> +					    u32 *table_idx))
>>
>>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>>  			    acpi_unload_parent_table(acpi_handle object))
>>
>
>
>
>

[PATCH] ACPICA: Introduce acpi_load_table_with_index()

[Nikolaus Voss]

For unloading an ACPI table, it is necessary to provide the
index of the table. The method intended for dynamically
loading or hotplug addition of tables, acpi_load_table(),
does not provide this information, so a new function
acpi_load_table_with_index() with the same functionality,
but an optional pointer to the loaded table index is introduced.

The new function is used in the acpi_configfs driver to save the
index of the newly loaded table in order to unload it later.

Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table loads")
Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
---
 drivers/acpi/acpi_configfs.c   |  2 +-
 drivers/acpi/acpica/tbxfload.c | 43 ++++++++++++++++++++++++++++++++++
 include/acpi/acpixf.h          |  6 +++++
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
index 57d9d574d4dd..9e77d5a266c0 100644
--- a/drivers/acpi/acpi_configfs.c
+++ b/drivers/acpi/acpi_configfs.c
@@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
 	if (!table->header)
 		return -ENOMEM;
 
-	ret = acpi_load_table(table->header);
+	ret = acpi_load_table_with_index(table->header, &table->index);
 	if (ret) {
 		kfree(table->header);
 		table->header = NULL;
diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c
index 86f1693f6d29..7ea4fc879cb6 100644
--- a/drivers/acpi/acpica/tbxfload.c
+++ b/drivers/acpi/acpica/tbxfload.c
@@ -309,6 +309,49 @@ acpi_status acpi_load_table(struct acpi_table_header *table)
 
 ACPI_EXPORT_SYMBOL(acpi_load_table)
 
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_load_table_with_index
+ *
+ * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
+ *                                    table to be loaded.
+ *              table_idx           - Pointer to a u32 for storing the table
+ *                                    index, might be NULL
+ * RETURN:      Status
+ *
+ * DESCRIPTION: see acpi_load_table() above. Additionally returns the index
+ *              of the newly created table in table_idx.
+ *
+ ******************************************************************************/
+acpi_status acpi_load_table_with_index(struct acpi_table_header *table,
+				       u32 *table_idx)
+{
+	acpi_status status;
+	u32 table_index;
+
+	ACPI_FUNCTION_TRACE(acpi_load_table_with_index);
+
+	/* Parameter validation */
+	if (!table)
+		return_ACPI_STATUS(AE_BAD_PARAMETER);
+
+	/* Install the table and load it into the namespace */
+	ACPI_INFO(("Host-directed Dynamic ACPI Table Load:"));
+	status = acpi_tb_install_and_load_table(
+		ACPI_PTR_TO_PHYSADDR(table), ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
+		FALSE, &table_index);
+	if (table_idx)
+		*table_idx = table_index;
+
+	if (ACPI_SUCCESS(status)) {
+		/* Complete the initialization/resolution of new objects */
+		acpi_ns_initialize_objects();
+	}
+
+	return_ACPI_STATUS(status);
+}
+ACPI_EXPORT_SYMBOL(acpi_load_table_with_index)
+
 /*******************************************************************************
  *
  * FUNCTION:    acpi_unload_parent_table
diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
index e5e041413581..af375ab318de 100644
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -460,6 +460,12 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			    acpi_load_table(struct acpi_table_header *table))
 
+
+ACPI_EXTERNAL_RETURN_STATUS(acpi_status
+			    acpi_load_table_with_index(
+				    struct acpi_table_header *table,
+				    u32 *table_idx))
+
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			    acpi_unload_parent_table(acpi_handle object))
 
-- 
2.17.1

Re: [PATCH] ACPICA: Introduce acpi_load_table_with_index()

[Shevchenko, Andriy]

On Mon, Sep 23, 2019 at 11:47:01AM +0200, Nikolaus Voss wrote:
> For unloading an ACPI table, it is necessary to provide the
> index of the table. The method intended for dynamically
> loading or hotplug addition of tables, acpi_load_table(),
> does not provide this information, so a new function
> acpi_load_table_with_index() with the same functionality,
> but an optional pointer to the loaded table index is introduced.
> 
> The new function is used in the acpi_configfs driver to save the
> index of the newly loaded table in order to unload it later.

I'll test it later, though couple of remarks:
- would it make sense to provide a counter part helper for unloading? Now it
  looks a bit inconsistent in configfs when we use acpi_load_*() vs.
  acpi_tb_*() in remove.
- please, include Ferry into Cc (as done in this mail)

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] ACPICA: Introduce acpi_load_table_with_index()

[Shevchenko, Andriy]

On Tue, Sep 24, 2019 at 03:07:34PM +0300, Shevchenko, Andriy wrote:
> On Mon, Sep 23, 2019 at 11:47:01AM +0200, Nikolaus Voss wrote:
> > For unloading an ACPI table, it is necessary to provide the
> > index of the table. The method intended for dynamically
> > loading or hotplug addition of tables, acpi_load_table(),
> > does not provide this information, so a new function
> > acpi_load_table_with_index() with the same functionality,
> > but an optional pointer to the loaded table index is introduced.
> > 
> > The new function is used in the acpi_configfs driver to save the
> > index of the newly loaded table in order to unload it later.
> 
> I'll test it later, though couple of remarks:
> - would it make sense to provide a counter part helper for unloading? Now it
>   looks a bit inconsistent in configfs when we use acpi_load_*() vs.
>   acpi_tb_*() in remove.

...and I think we may unexport acpi_tb_* in this case as Bob suggested for it
to be internal API.

> - please, include Ferry into Cc (as done in this mail)


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] ACPICA: Introduce acpi_load_table_with_index()

[Nikolaus Voss]

On Tue, 24 Sep 2019, Shevchenko, Andriy wrote:
> On Tue, Sep 24, 2019 at 03:07:34PM +0300, Shevchenko, Andriy wrote:
>> On Mon, Sep 23, 2019 at 11:47:01AM +0200, Nikolaus Voss wrote:
>>> For unloading an ACPI table, it is necessary to provide the
>>> index of the table. The method intended for dynamically
>>> loading or hotplug addition of tables, acpi_load_table(),
>>> does not provide this information, so a new function
>>> acpi_load_table_with_index() with the same functionality,
>>> but an optional pointer to the loaded table index is introduced.
>>>
>>> The new function is used in the acpi_configfs driver to save the
>>> index of the newly loaded table in order to unload it later.
>>
>> I'll test it later, though couple of remarks:
>> - would it make sense to provide a counter part helper for unloading? Now it
>>   looks a bit inconsistent in configfs when we use acpi_load_*() vs.
>>   acpi_tb_*() in remove.

Yes, IMO it would make sense, but it is an ACPICA API change. Bob, what's 
your opinion?

>
> ...and I think we may unexport acpi_tb_* in this case as Bob suggested for it
> to be internal API.

see above.

>
>> - please, include Ferry into Cc (as done in this mail)
>

Re: [PATCH] ACPICA: Introduce acpi_load_table_with_index()

[Andy Shevchenko]

On Mon, Sep 23, 2019 at 11:47:01AM +0200, Nikolaus Voss wrote:
> For unloading an ACPI table, it is necessary to provide the
> index of the table. The method intended for dynamically
> loading or hotplug addition of tables, acpi_load_table(),
> does not provide this information, so a new function
> acpi_load_table_with_index() with the same functionality,
> but an optional pointer to the loaded table index is introduced.
> 
> The new function is used in the acpi_configfs driver to save the
> index of the newly loaded table in order to unload it later.
> 

Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

But consider addressing my comments in one of previous mails.

> Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table loads")
> Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> ---
>  drivers/acpi/acpi_configfs.c   |  2 +-
>  drivers/acpi/acpica/tbxfload.c | 43 ++++++++++++++++++++++++++++++++++
>  include/acpi/acpixf.h          |  6 +++++
>  3 files changed, 50 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
> index 57d9d574d4dd..9e77d5a266c0 100644
> --- a/drivers/acpi/acpi_configfs.c
> +++ b/drivers/acpi/acpi_configfs.c
> @@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
>  	if (!table->header)
>  		return -ENOMEM;
>  
> -	ret = acpi_load_table(table->header);
> +	ret = acpi_load_table_with_index(table->header, &table->index);
>  	if (ret) {
>  		kfree(table->header);
>  		table->header = NULL;
> diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c
> index 86f1693f6d29..7ea4fc879cb6 100644
> --- a/drivers/acpi/acpica/tbxfload.c
> +++ b/drivers/acpi/acpica/tbxfload.c
> @@ -309,6 +309,49 @@ acpi_status acpi_load_table(struct acpi_table_header *table)
>  
>  ACPI_EXPORT_SYMBOL(acpi_load_table)
>  
> +/*******************************************************************************
> + *
> + * FUNCTION:    acpi_load_table_with_index
> + *
> + * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
> + *                                    table to be loaded.
> + *              table_idx           - Pointer to a u32 for storing the table
> + *                                    index, might be NULL
> + * RETURN:      Status
> + *
> + * DESCRIPTION: see acpi_load_table() above. Additionally returns the index
> + *              of the newly created table in table_idx.
> + *
> + ******************************************************************************/
> +acpi_status acpi_load_table_with_index(struct acpi_table_header *table,
> +				       u32 *table_idx)
> +{
> +	acpi_status status;
> +	u32 table_index;
> +
> +	ACPI_FUNCTION_TRACE(acpi_load_table_with_index);
> +
> +	/* Parameter validation */
> +	if (!table)
> +		return_ACPI_STATUS(AE_BAD_PARAMETER);
> +
> +	/* Install the table and load it into the namespace */
> +	ACPI_INFO(("Host-directed Dynamic ACPI Table Load:"));
> +	status = acpi_tb_install_and_load_table(
> +		ACPI_PTR_TO_PHYSADDR(table), ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
> +		FALSE, &table_index);
> +	if (table_idx)
> +		*table_idx = table_index;
> +
> +	if (ACPI_SUCCESS(status)) {
> +		/* Complete the initialization/resolution of new objects */
> +		acpi_ns_initialize_objects();
> +	}
> +
> +	return_ACPI_STATUS(status);
> +}
> +ACPI_EXPORT_SYMBOL(acpi_load_table_with_index)
> +
>  /*******************************************************************************
>   *
>   * FUNCTION:    acpi_unload_parent_table
> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
> index e5e041413581..af375ab318de 100644
> --- a/include/acpi/acpixf.h
> +++ b/include/acpi/acpixf.h
> @@ -460,6 +460,12 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>  			    acpi_load_table(struct acpi_table_header *table))
>  
> +
> +ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> +			    acpi_load_table_with_index(
> +				    struct acpi_table_header *table,
> +				    u32 *table_idx))
> +
>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>  			    acpi_unload_parent_table(acpi_handle object))
>  
> -- 
> 2.17.1
> 

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] ACPICA: Introduce acpi_load_table_with_index()

[Nikolaus Voss]

On Tue, 24 Sep 2019, Andy Shevchenko wrote:
> On Mon, Sep 23, 2019 at 11:47:01AM +0200, Nikolaus Voss wrote:
>> For unloading an ACPI table, it is necessary to provide the
>> index of the table. The method intended for dynamically
>> loading or hotplug addition of tables, acpi_load_table(),
>> does not provide this information, so a new function
>> acpi_load_table_with_index() with the same functionality,
>> but an optional pointer to the loaded table index is introduced.
>>
>> The new function is used in the acpi_configfs driver to save the
>> index of the newly loaded table in order to unload it later.
>>
>
> Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Thanks!

>
> But consider addressing my comments in one of previous mails.
>
>> Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>> Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table loads")
>> Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
>> ---
>>  drivers/acpi/acpi_configfs.c   |  2 +-
>>  drivers/acpi/acpica/tbxfload.c | 43 ++++++++++++++++++++++++++++++++++
>>  include/acpi/acpixf.h          |  6 +++++
>>  3 files changed, 50 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
>> index 57d9d574d4dd..9e77d5a266c0 100644
>> --- a/drivers/acpi/acpi_configfs.c
>> +++ b/drivers/acpi/acpi_configfs.c
>> @@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
>>  	if (!table->header)
>>  		return -ENOMEM;
>>
>> -	ret = acpi_load_table(table->header);
>> +	ret = acpi_load_table_with_index(table->header, &table->index);
>>  	if (ret) {
>>  		kfree(table->header);
>>  		table->header = NULL;
>> diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c
>> index 86f1693f6d29..7ea4fc879cb6 100644
>> --- a/drivers/acpi/acpica/tbxfload.c
>> +++ b/drivers/acpi/acpica/tbxfload.c
>> @@ -309,6 +309,49 @@ acpi_status acpi_load_table(struct acpi_table_header *table)
>>
>>  ACPI_EXPORT_SYMBOL(acpi_load_table)
>>
>> +/*******************************************************************************
>> + *
>> + * FUNCTION:    acpi_load_table_with_index
>> + *
>> + * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
>> + *                                    table to be loaded.
>> + *              table_idx           - Pointer to a u32 for storing the table
>> + *                                    index, might be NULL
>> + * RETURN:      Status
>> + *
>> + * DESCRIPTION: see acpi_load_table() above. Additionally returns the index
>> + *              of the newly created table in table_idx.
>> + *
>> + ******************************************************************************/
>> +acpi_status acpi_load_table_with_index(struct acpi_table_header *table,
>> +				       u32 *table_idx)
>> +{
>> +	acpi_status status;
>> +	u32 table_index;
>> +
>> +	ACPI_FUNCTION_TRACE(acpi_load_table_with_index);
>> +
>> +	/* Parameter validation */
>> +	if (!table)
>> +		return_ACPI_STATUS(AE_BAD_PARAMETER);
>> +
>> +	/* Install the table and load it into the namespace */
>> +	ACPI_INFO(("Host-directed Dynamic ACPI Table Load:"));
>> +	status = acpi_tb_install_and_load_table(
>> +		ACPI_PTR_TO_PHYSADDR(table), ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
>> +		FALSE, &table_index);
>> +	if (table_idx)
>> +		*table_idx = table_index;
>> +
>> +	if (ACPI_SUCCESS(status)) {
>> +		/* Complete the initialization/resolution of new objects */
>> +		acpi_ns_initialize_objects();
>> +	}
>> +
>> +	return_ACPI_STATUS(status);
>> +}
>> +ACPI_EXPORT_SYMBOL(acpi_load_table_with_index)
>> +
>>  /*******************************************************************************
>>   *
>>   * FUNCTION:    acpi_unload_parent_table
>> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
>> index e5e041413581..af375ab318de 100644
>> --- a/include/acpi/acpixf.h
>> +++ b/include/acpi/acpixf.h
>> @@ -460,6 +460,12 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
>>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>>  			    acpi_load_table(struct acpi_table_header *table))
>>
>> +
>> +ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>> +			    acpi_load_table_with_index(
>> +				    struct acpi_table_header *table,
>> +				    u32 *table_idx))
>> +
>>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>>  			    acpi_unload_parent_table(acpi_handle object))
>>
>> --
>> 2.17.1
>>
>

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Schmauss, Erik]

> -----Original Message-----
> From: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> Sent: Thursday, September 12, 2019 1:08 AM
> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik
> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Moore,
> Robert <robert.moore@intel.com>
> Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-
> kernel@vger.kernel.org; nv@vosn.de; Nikolaus Voss
> <nikolaus.voss@loewensteinmedical.de>
> Subject: [PATCH] ACPICA: make acpi_load_table() return table index
> 
Hi Nikolaus,

> For unloading an ACPI table, it is necessary to provide the index of the table.
> The method intended for dynamically loading or hotplug addition of tables,
> acpi_load_table(), should provide this information via an optional pointer to
> the loaded table index.

We'll take this patch for ACPICA upstream

Thanks,
Erik
> 
> This patch fixes the table unload function of acpi_configfs.
> 
> Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table
> loads")
> Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> ---
>  drivers/acpi/acpi_configfs.c   | 2 +-
>  drivers/acpi/acpica/dbfileio.c | 2 +-
>  drivers/acpi/acpica/tbxfload.c | 8 ++++++--
>  drivers/firmware/efi/efi.c     | 2 +-
>  include/acpi/acpixf.h          | 3 ++-
>  5 files changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c index
> 57d9d574d4dde..77f81242a28e6 100644
> --- a/drivers/acpi/acpi_configfs.c
> +++ b/drivers/acpi/acpi_configfs.c
> @@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item
> *cfg,
>  	if (!table->header)
>  		return -ENOMEM;
> 
> -	ret = acpi_load_table(table->header);
> +	ret = acpi_load_table(table->header, &table->index);
>  	if (ret) {
>  		kfree(table->header);
>  		table->header = NULL;
> diff --git a/drivers/acpi/acpica/dbfileio.c b/drivers/acpi/acpica/dbfileio.c index
> c6e25734dc5cd..e1b6e54a96ac1 100644
> --- a/drivers/acpi/acpica/dbfileio.c
> +++ b/drivers/acpi/acpica/dbfileio.c
> @@ -93,7 +93,7 @@ acpi_status acpi_db_load_tables(struct
> acpi_new_table_desc *list_head)
>  	while (table_list_head) {
>  		table = table_list_head->table;
> 
> -		status = acpi_load_table(table);
> +		status = acpi_load_table(table, NULL);
>  		if (ACPI_FAILURE(status)) {
>  			if (status == AE_ALREADY_EXISTS) {
>  				acpi_os_printf
> diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c index
> 86f1693f6d29a..d08cd8ffcbdb6 100644
> --- a/drivers/acpi/acpica/tbxfload.c
> +++ b/drivers/acpi/acpica/tbxfload.c
> @@ -268,7 +268,8 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
>   *
>   * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
>   *                                    table to be loaded.
> - *
> + *              table_idx           - Pointer to a u32 for storing the table
> + *                                    index, might be NULL
>   * RETURN:      Status
>   *
>   * DESCRIPTION: Dynamically load an ACPI table from the caller's buffer. Must
> @@ -278,7 +279,7 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
>   *              to ensure that the table is not deleted or unmapped.
>   *
> 
> *******************************************************************
> ***********/
> -acpi_status acpi_load_table(struct acpi_table_header *table)
> +acpi_status acpi_load_table(struct acpi_table_header *table, u32
> +*table_idx)
>  {
>  	acpi_status status;
>  	u32 table_index;
> @@ -297,6 +298,9 @@ acpi_status acpi_load_table(struct acpi_table_header
> *table)
>  	status =
> acpi_tb_install_and_load_table(ACPI_PTR_TO_PHYSADDR(table),
> 
> 	ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
>  						FALSE, &table_index);
> +	if (table_idx)
> +		*table_idx = table_index;
> +
>  	if (ACPI_SUCCESS(status)) {
> 
>  		/* Complete the initialization/resolution of new objects */ diff
> --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index
> ad3b1f4866b35..9773e4212baef 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -308,7 +308,7 @@ static __init int efivar_ssdt_load(void)
>  			goto free_data;
>  		}
> 
> -		ret = acpi_load_table(data);
> +		ret = acpi_load_table(data, NULL);
>  		if (ret) {
>  			pr_err("failed to load table: %d\n", ret);
>  			goto free_data;
> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h index
> 3845c8fcc94e5..c90bbdc4146a6 100644
> --- a/include/acpi/acpixf.h
> +++ b/include/acpi/acpixf.h
> @@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> ACPI_INIT_FUNCTION
>  					       u8 physical))
> 
>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> -			    acpi_load_table(struct acpi_table_header *table))
> +			    acpi_load_table(struct acpi_table_header *table,
> +					    u32 *table_idx))
> 
>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>  			    acpi_unload_parent_table(acpi_handle object))
> --
> 2.17.1

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Shevchenko, Andriy]

On Thu, Sep 26, 2019 at 07:09:05PM +0300, Schmauss, Erik wrote:
> > -----Original Message-----
> > From: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> > Sent: Thursday, September 12, 2019 1:08 AM
> > To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik
> > <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Moore,
> > Robert <robert.moore@intel.com>
> > Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
> > <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
> > <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-
> > kernel@vger.kernel.org; nv@vosn.de; Nikolaus Voss
> > <nikolaus.voss@loewensteinmedical.de>
> > Subject: [PATCH] ACPICA: make acpi_load_table() return table index
> > 
> Hi Nikolaus,
> 
> > For unloading an ACPI table, it is necessary to provide the index of the table.
> > The method intended for dynamically loading or hotplug addition of tables,
> > acpi_load_table(), should provide this information via an optional pointer to
> > the loaded table index.
> 
> We'll take this patch for ACPICA upstream

Erik,

how about to have also counterpart to acpi_load_table() which will do
what it's done now in acpi_configfs.c via acpi_tb_*() API?

Because it's kinda strange to call acpi_load_table*() and acpi_tb_*()
in the same module.

-- 
With Best Regards,
Andy Shevchenko

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Schmauss, Erik]

> -----Original Message-----
> From: linux-acpi-owner@vger.kernel.org <linux-acpi-owner@vger.kernel.org>
> On Behalf Of Shevchenko, Andriy
> Sent: Thursday, September 26, 2019 9:35 AM
> To: Schmauss, Erik <erik.schmauss@intel.com>
> Cc: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>; Rafael J. Wysocki
> <rjw@rjwysocki.net>; Moore, Robert <robert.moore@intel.com>; Len Brown
> <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel
> Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-
> acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org;
> nv@vosn.de
> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
> 
> On Thu, Sep 26, 2019 at 07:09:05PM +0300, Schmauss, Erik wrote:
> > > -----Original Message-----
> > > From: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> > > Sent: Thursday, September 12, 2019 1:08 AM
> > > To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik
> > > <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>;
> > > Moore, Robert <robert.moore@intel.com>
> > > Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
> > > <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan
> > > Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org;
> > > devel@acpica.org; linux- kernel@vger.kernel.org; nv@vosn.de;
> > > Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> > > Subject: [PATCH] ACPICA: make acpi_load_table() return table index
> > >
> > Hi Nikolaus,
> >
> > > For unloading an ACPI table, it is necessary to provide the index of the table.
> > > The method intended for dynamically loading or hotplug addition of
> > > tables, acpi_load_table(), should provide this information via an
> > > optional pointer to the loaded table index.
> >
> > We'll take this patch for ACPICA upstream
> 
> Erik,
> 
Hi Andy,

> how about to have also counterpart to acpi_load_table() which will do what it's
> done now in acpi_configfs.c via acpi_tb_*() API?

I should have given more details. We decided to add this extra parameter in AcpiLoadTable and
we're going to create an AcpiUnloadTable function that will take table index to unload the table (basically the acpi_tb_unload..).
Once we do this, you can use table indices with AcpiUnloadTable and AcpiLoadTable.

Erik
> 
> Because it's kinda strange to call acpi_load_table*() and acpi_tb_*() in the
> same module.
> 
> --
> With Best Regards,
> Andy Shevchenko
> 

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Shevchenko, Andriy]

On Thu, Sep 26, 2019 at 07:51:00PM +0300, Schmauss, Erik wrote:
> > -----Original Message-----
> > From: linux-acpi-owner@vger.kernel.org <linux-acpi-owner@vger.kernel.org>
> > On Behalf Of Shevchenko, Andriy
> > Sent: Thursday, September 26, 2019 9:35 AM
> > To: Schmauss, Erik <erik.schmauss@intel.com>
> > Cc: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>; Rafael J. Wysocki
> > <rjw@rjwysocki.net>; Moore, Robert <robert.moore@intel.com>; Len Brown
> > <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel
> > Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-
> > acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org;
> > nv@vosn.de
> > Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
> > 
> > On Thu, Sep 26, 2019 at 07:09:05PM +0300, Schmauss, Erik wrote:
> > > > -----Original Message-----
> > > > From: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> > > > Sent: Thursday, September 12, 2019 1:08 AM
> > > > To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik
> > > > <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>;
> > > > Moore, Robert <robert.moore@intel.com>
> > > > Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
> > > > <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan
> > > > Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org;
> > > > devel@acpica.org; linux- kernel@vger.kernel.org; nv@vosn.de;
> > > > Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> > > > Subject: [PATCH] ACPICA: make acpi_load_table() return table index
> > > >
> > > Hi Nikolaus,
> > >
> > > > For unloading an ACPI table, it is necessary to provide the index of the table.
> > > > The method intended for dynamically loading or hotplug addition of
> > > > tables, acpi_load_table(), should provide this information via an
> > > > optional pointer to the loaded table index.
> > >
> > > We'll take this patch for ACPICA upstream
> > 
> > Erik,
> > 
> Hi Andy,
> 
> > how about to have also counterpart to acpi_load_table() which will do what it's
> > done now in acpi_configfs.c via acpi_tb_*() API?
> 
> I should have given more details. We decided to add this extra parameter in AcpiLoadTable and
> we're going to create an AcpiUnloadTable function that will take table index to unload the table (basically the acpi_tb_unload..).
> Once we do this, you can use table indices with AcpiUnloadTable and AcpiLoadTable.

Sounds like what we discussed with Nikolaus earlier [1].
Thanks!

[1]: https://lore.kernel.org/linux-acpi/20190924120734.GT2680@smile.fi.intel.com/

-- 
With Best Regards,
Andy Shevchenko

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Nikolaus Voss]

On Thu, 26 Sep 2019, Schmauss, Erik wrote:
>> -----Original Message-----
>> From: linux-acpi-owner@vger.kernel.org <linux-acpi-owner@vger.kernel.org>
>> On Behalf Of Shevchenko, Andriy
>> Sent: Thursday, September 26, 2019 9:35 AM
>> To: Schmauss, Erik <erik.schmauss@intel.com>
>> Cc: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>; Rafael J. Wysocki
>> <rjw@rjwysocki.net>; Moore, Robert <robert.moore@intel.com>; Len Brown
>> <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel
>> Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-
>> acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org;
>> nv@vosn.de
>> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
>>
>> On Thu, Sep 26, 2019 at 07:09:05PM +0300, Schmauss, Erik wrote:
>>>> -----Original Message-----
>>>> From: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
>>>> Sent: Thursday, September 12, 2019 1:08 AM
>>>> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik
>>>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>;
>>>> Moore, Robert <robert.moore@intel.com>
>>>> Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
>>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan
>>>> Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org;
>>>> devel@acpica.org; linux- kernel@vger.kernel.org; nv@vosn.de;
>>>> Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
>>>> Subject: [PATCH] ACPICA: make acpi_load_table() return table index
>>>>
>>> Hi Nikolaus,
>>>
>>>> For unloading an ACPI table, it is necessary to provide the index of the table.
>>>> The method intended for dynamically loading or hotplug addition of
>>>> tables, acpi_load_table(), should provide this information via an
>>>> optional pointer to the loaded table index.
>>>
>>> We'll take this patch for ACPICA upstream
>>
>> Erik,
>>
> Hi Andy,
>
>> how about to have also counterpart to acpi_load_table() which will do what it's
>> done now in acpi_configfs.c via acpi_tb_*() API?
>
> I should have given more details. We decided to add this extra parameter 
> in AcpiLoadTable and we're going to create an AcpiUnloadTable function 
> that will take table index to unload the table (basically the 
> acpi_tb_unload..). Once we do this, you can use table indices with 
> AcpiUnloadTable and AcpiLoadTable.

that's even better news.

Rafael, shall I prepare anything?

Niko

>
> Erik
>>
>> Because it's kinda strange to call acpi_load_table*() and acpi_tb_*() in the
>> same module.
>>
>> --
>> With Best Regards,
>> Andy Shevchenko
>>
>

-- 
Nikolaus Voss - Aastwiete 4 - 22880 Wedel

Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Rafael J. Wysocki]

On Thu, Sep 26, 2019 at 8:44 PM Nikolaus Voss <nv@vosn.de> wrote:
>
> On Thu, 26 Sep 2019, Schmauss, Erik wrote:
> >> -----Original Message-----
> >> From: linux-acpi-owner@vger.kernel.org <linux-acpi-owner@vger.kernel.org>
> >> On Behalf Of Shevchenko, Andriy
> >> Sent: Thursday, September 26, 2019 9:35 AM
> >> To: Schmauss, Erik <erik.schmauss@intel.com>
> >> Cc: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>; Rafael J. Wysocki
> >> <rjw@rjwysocki.net>; Moore, Robert <robert.moore@intel.com>; Len Brown
> >> <lenb@kernel.org>; Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel
> >> Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-
> >> acpi@vger.kernel.org; devel@acpica.org; linux-kernel@vger.kernel.org;
> >> nv@vosn.de
> >> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
> >>
> >> On Thu, Sep 26, 2019 at 07:09:05PM +0300, Schmauss, Erik wrote:
> >>>> -----Original Message-----
> >>>> From: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> >>>> Sent: Thursday, September 12, 2019 1:08 AM
> >>>> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik
> >>>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>;
> >>>> Moore, Robert <robert.moore@intel.com>
> >>>> Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
> >>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan
> >>>> Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org;
> >>>> devel@acpica.org; linux- kernel@vger.kernel.org; nv@vosn.de;
> >>>> Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> >>>> Subject: [PATCH] ACPICA: make acpi_load_table() return table index
> >>>>
> >>> Hi Nikolaus,
> >>>
> >>>> For unloading an ACPI table, it is necessary to provide the index of the table.
> >>>> The method intended for dynamically loading or hotplug addition of
> >>>> tables, acpi_load_table(), should provide this information via an
> >>>> optional pointer to the loaded table index.
> >>>
> >>> We'll take this patch for ACPICA upstream
> >>
> >> Erik,
> >>
> > Hi Andy,
> >
> >> how about to have also counterpart to acpi_load_table() which will do what it's
> >> done now in acpi_configfs.c via acpi_tb_*() API?
> >
> > I should have given more details. We decided to add this extra parameter
> > in AcpiLoadTable and we're going to create an AcpiUnloadTable function
> > that will take table index to unload the table (basically the
> > acpi_tb_unload..). Once we do this, you can use table indices with
> > AcpiUnloadTable and AcpiLoadTable.
>
> that's even better news.
>
> Rafael, shall I prepare anything?

I don't think so.  I'm expecting to get a proper fix from the upstream
through the normal process.

Thanks,
Rafael

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Schmauss, Erik]

> -----Original Message-----
> From: Rafael J. Wysocki <rafael@kernel.org>
> Sent: Thursday, September 26, 2019 12:26 PM
> To: Nikolaus Voss <nv@vosn.de>
> Cc: Schmauss, Erik <erik.schmauss@intel.com>; Shevchenko, Andriy
> <andriy.shevchenko@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>;
> Moore, Robert <robert.moore@intel.com>; Len Brown <lenb@kernel.org>;
> Jacek Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek
> <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org;
> devel@acpica.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
> 
> On Thu, Sep 26, 2019 at 8:44 PM Nikolaus Voss <nv@vosn.de> wrote:
> >
> > On Thu, 26 Sep 2019, Schmauss, Erik wrote:
> > >> -----Original Message-----
> > >> From: linux-acpi-owner@vger.kernel.org
> > >> <linux-acpi-owner@vger.kernel.org>
> > >> On Behalf Of Shevchenko, Andriy
> > >> Sent: Thursday, September 26, 2019 9:35 AM
> > >> To: Schmauss, Erik <erik.schmauss@intel.com>
> > >> Cc: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>; Rafael J.
> > >> Wysocki <rjw@rjwysocki.net>; Moore, Robert
> > >> <robert.moore@intel.com>; Len Brown <lenb@kernel.org>; Jacek
> > >> Anaszewski <jacek.anaszewski@gmail.com>; Pavel Machek
> > >> <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; linux-
> > >> acpi@vger.kernel.org; devel@acpica.org;
> > >> linux-kernel@vger.kernel.org; nv@vosn.de
> > >> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table
> > >> index
> > >>
> > >> On Thu, Sep 26, 2019 at 07:09:05PM +0300, Schmauss, Erik wrote:
> > >>>> -----Original Message-----
> > >>>> From: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> > >>>> Sent: Thursday, September 12, 2019 1:08 AM
> > >>>> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss,
> > >>>> Erik <erik.schmauss@intel.com>; Rafael J. Wysocki
> > >>>> <rjw@rjwysocki.net>; Moore, Robert <robert.moore@intel.com>
> > >>>> Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
> > >>>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan
> > >>>> Murphy <dmurphy@ti.com>; linux-acpi@vger.kernel.org;
> > >>>> devel@acpica.org; linux- kernel@vger.kernel.org; nv@vosn.de;
> > >>>> Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> > >>>> Subject: [PATCH] ACPICA: make acpi_load_table() return table
> > >>>> index
> > >>>>
> > >>> Hi Nikolaus,
> > >>>
> > >>>> For unloading an ACPI table, it is necessary to provide the index of the
> table.
> > >>>> The method intended for dynamically loading or hotplug addition
> > >>>> of tables, acpi_load_table(), should provide this information via
> > >>>> an optional pointer to the loaded table index.
> > >>>
> > >>> We'll take this patch for ACPICA upstream
> > >>
> > >> Erik,
> > >>
> > > Hi Andy,
> > >
> > >> how about to have also counterpart to acpi_load_table() which will
> > >> do what it's done now in acpi_configfs.c via acpi_tb_*() API?
> > >
> > > I should have given more details. We decided to add this extra
> > > parameter in AcpiLoadTable and we're going to create an
> > > AcpiUnloadTable function that will take table index to unload the
> > > table (basically the acpi_tb_unload..). Once we do this, you can use
> > > table indices with AcpiUnloadTable and AcpiLoadTable.
> >
> > that's even better news.
> >
> > Rafael, shall I prepare anything?
Hi everyone,

> I don't think so.  I'm expecting to get a proper fix from the upstream through
> the normal process.
Just so that we are on the same page:

I've backported Nikolaus's patch for upstream here https://github.com/acpica/acpica/pull/506
and Bob has implemented the new API here: https://github.com/acpica/acpica/commit/c69369cd9cf0134e1aac516e97d612947daa8dc2

Once we do a release, I will send Bob's change to the linux ACPI mailing list.
Feel free to use this new API where you see fit.

Thanks,
Erik

> 
> Thanks,
> Rafael

RE: [PATCH] ACPICA: make acpi_load_table() return table index

[Nikolaus Voss]

Hi Erik,

On Thu, 26 Sep 2019, Schmauss, Erik wrote:
>> -----Original Message-----
>> From: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
>> Sent: Thursday, September 12, 2019 1:08 AM
>> To: Shevchenko, Andriy <andriy.shevchenko@intel.com>; Schmauss, Erik
>> <erik.schmauss@intel.com>; Rafael J. Wysocki <rjw@rjwysocki.net>; Moore,
>> Robert <robert.moore@intel.com>
>> Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
>> <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
>> <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-
>> kernel@vger.kernel.org; nv@vosn.de; Nikolaus Voss
>> <nikolaus.voss@loewensteinmedical.de>
>> Subject: [PATCH] ACPICA: make acpi_load_table() return table index
>>
> Hi Nikolaus,
>
>> For unloading an ACPI table, it is necessary to provide the index of the table.
>> The method intended for dynamically loading or hotplug addition of tables,
>> acpi_load_table(), should provide this information via an optional pointer to
>> the loaded table index.
>
> We'll take this patch for ACPICA upstream

that's good news, thanks!
Niko

>
> Thanks,
> Erik
>>
>> This patch fixes the table unload function of acpi_configfs.
>>
>> Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>> Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table
>> loads")
>> Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
>> ---
>>  drivers/acpi/acpi_configfs.c   | 2 +-
>>  drivers/acpi/acpica/dbfileio.c | 2 +-
>>  drivers/acpi/acpica/tbxfload.c | 8 ++++++--
>>  drivers/firmware/efi/efi.c     | 2 +-
>>  include/acpi/acpixf.h          | 3 ++-
>>  5 files changed, 11 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c index
>> 57d9d574d4dde..77f81242a28e6 100644
>> --- a/drivers/acpi/acpi_configfs.c
>> +++ b/drivers/acpi/acpi_configfs.c
>> @@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item
>> *cfg,
>>  	if (!table->header)
>>  		return -ENOMEM;
>>
>> -	ret = acpi_load_table(table->header);
>> +	ret = acpi_load_table(table->header, &table->index);
>>  	if (ret) {
>>  		kfree(table->header);
>>  		table->header = NULL;
>> diff --git a/drivers/acpi/acpica/dbfileio.c b/drivers/acpi/acpica/dbfileio.c index
>> c6e25734dc5cd..e1b6e54a96ac1 100644
>> --- a/drivers/acpi/acpica/dbfileio.c
>> +++ b/drivers/acpi/acpica/dbfileio.c
>> @@ -93,7 +93,7 @@ acpi_status acpi_db_load_tables(struct
>> acpi_new_table_desc *list_head)
>>  	while (table_list_head) {
>>  		table = table_list_head->table;
>>
>> -		status = acpi_load_table(table);
>> +		status = acpi_load_table(table, NULL);
>>  		if (ACPI_FAILURE(status)) {
>>  			if (status == AE_ALREADY_EXISTS) {
>>  				acpi_os_printf
>> diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c index
>> 86f1693f6d29a..d08cd8ffcbdb6 100644
>> --- a/drivers/acpi/acpica/tbxfload.c
>> +++ b/drivers/acpi/acpica/tbxfload.c
>> @@ -268,7 +268,8 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
>>   *
>>   * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
>>   *                                    table to be loaded.
>> - *
>> + *              table_idx           - Pointer to a u32 for storing the table
>> + *                                    index, might be NULL
>>   * RETURN:      Status
>>   *
>>   * DESCRIPTION: Dynamically load an ACPI table from the caller's buffer. Must
>> @@ -278,7 +279,7 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
>>   *              to ensure that the table is not deleted or unmapped.
>>   *
>>
>> *******************************************************************
>> ***********/
>> -acpi_status acpi_load_table(struct acpi_table_header *table)
>> +acpi_status acpi_load_table(struct acpi_table_header *table, u32
>> +*table_idx)
>>  {
>>  	acpi_status status;
>>  	u32 table_index;
>> @@ -297,6 +298,9 @@ acpi_status acpi_load_table(struct acpi_table_header
>> *table)
>>  	status =
>> acpi_tb_install_and_load_table(ACPI_PTR_TO_PHYSADDR(table),
>>
>> 	ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
>>  						FALSE, &table_index);
>> +	if (table_idx)
>> +		*table_idx = table_index;
>> +
>>  	if (ACPI_SUCCESS(status)) {
>>
>>  		/* Complete the initialization/resolution of new objects */ diff
>> --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index
>> ad3b1f4866b35..9773e4212baef 100644
>> --- a/drivers/firmware/efi/efi.c
>> +++ b/drivers/firmware/efi/efi.c
>> @@ -308,7 +308,7 @@ static __init int efivar_ssdt_load(void)
>>  			goto free_data;
>>  		}
>>
>> -		ret = acpi_load_table(data);
>> +		ret = acpi_load_table(data, NULL);
>>  		if (ret) {
>>  			pr_err("failed to load table: %d\n", ret);
>>  			goto free_data;
>> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h index
>> 3845c8fcc94e5..c90bbdc4146a6 100644
>> --- a/include/acpi/acpixf.h
>> +++ b/include/acpi/acpixf.h
>> @@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>> ACPI_INIT_FUNCTION
>>  					       u8 physical))
>>
>>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>> -			    acpi_load_table(struct acpi_table_header *table))
>> +			    acpi_load_table(struct acpi_table_header *table,
>> +					    u32 *table_idx))
>>
>>  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
>>  			    acpi_unload_parent_table(acpi_handle object))
>> --
>> 2.17.1
>