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

[Schmauss, Erik]

> -Original Message-
> From: Rafael J. Wysocki 
> Sent: Thursday, September 26, 2019 12:26 PM
> To: Nikolaus Voss 
> Cc: Schmauss, Erik ; Shevchenko, Andriy
> ; Rafael J. Wysocki ;
> Moore, Robert ; Len Brown ;
> Jacek Anaszewski ; Pavel Machek
> ; Dan Murphy ; linux-a...@vger.kernel.org;
> de...@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  wrote:
> >
> > On Thu, 26 Sep 2019, Schmauss, Erik wrote:
> > >> -Original Message-
> > >> From: linux-acpi-ow...@vger.kernel.org
> > >> 
> > >> On Behalf Of Shevchenko, Andriy
> > >> Sent: Thursday, September 26, 2019 9:35 AM
> > >> To: Schmauss, Erik 
> > >> Cc: Nikolaus Voss ; Rafael J.
> > >> Wysocki ; Moore, Robert
> > >> ; Len Brown ; Jacek
> > >> Anaszewski ; Pavel Machek
> > >> ; Dan Murphy ; linux-
> > >> a...@vger.kernel.org; de...@acpica.org;
> > >> linux-kernel@vger.kernel.org; n...@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 
> > >>>> Sent: Thursday, September 12, 2019 1:08 AM
> > >>>> To: Shevchenko, Andriy ; Schmauss,
> > >>>> Erik ; Rafael J. Wysocki
> > >>>> ; Moore, Robert 
> > >>>> Cc: Len Brown ; Jacek Anaszewski
> > >>>> ; Pavel Machek ; Dan
> > >>>> Murphy ; linux-a...@vger.kernel.org;
> > >>>> de...@acpica.org; linux- ker...@vger.kernel.org; n...@vosn.de;
> > >>>> Nikolaus Voss 
> > >>>> 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

[Rafael J. Wysocki]

On Thu, Sep 26, 2019 at 8:44 PM Nikolaus Voss  wrote:
>
> On Thu, 26 Sep 2019, Schmauss, Erik wrote:
> >> -Original Message-
> >> From: linux-acpi-ow...@vger.kernel.org 
> >> On Behalf Of Shevchenko, Andriy
> >> Sent: Thursday, September 26, 2019 9:35 AM
> >> To: Schmauss, Erik 
> >> Cc: Nikolaus Voss ; Rafael J. Wysocki
> >> ; Moore, Robert ; Len Brown
> >> ; Jacek Anaszewski ; Pavel
> >> Machek ; Dan Murphy ; linux-
> >> a...@vger.kernel.org; de...@acpica.org; linux-kernel@vger.kernel.org;
> >> n...@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 
> >>>> Sent: Thursday, September 12, 2019 1:08 AM
> >>>> To: Shevchenko, Andriy ; Schmauss, Erik
> >>>> ; Rafael J. Wysocki ;
> >>>> Moore, Robert 
> >>>> Cc: Len Brown ; Jacek Anaszewski
> >>>> ; Pavel Machek ; Dan
> >>>> Murphy ; linux-a...@vger.kernel.org;
> >>>> de...@acpica.org; linux- ker...@vger.kernel.org; n...@vosn.de;
> >>>> Nikolaus Voss 
> >>>> 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

[Nikolaus Voss]

On Thu, 26 Sep 2019, Schmauss, Erik wrote:

-Original Message-
From: linux-acpi-ow...@vger.kernel.org 
On Behalf Of Shevchenko, Andriy
Sent: Thursday, September 26, 2019 9:35 AM
To: Schmauss, Erik 
Cc: Nikolaus Voss ; Rafael J. Wysocki
; Moore, Robert ; Len Brown
; Jacek Anaszewski ; Pavel
Machek ; Dan Murphy ; linux-
a...@vger.kernel.org; de...@acpica.org; linux-kernel@vger.kernel.org;
n...@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 
Sent: Thursday, September 12, 2019 1:08 AM
To: Shevchenko, Andriy ; Schmauss, Erik
; Rafael J. Wysocki ;
Moore, Robert 
Cc: Len Brown ; Jacek Anaszewski
; Pavel Machek ; Dan
Murphy ; linux-a...@vger.kernel.org;
de...@acpica.org; linux- ker...@vger.kernel.org; n...@vosn.de;
Nikolaus Voss 
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

[Nikolaus Voss]

Hi Erik,

On Thu, 26 Sep 2019, Schmauss, Erik wrote:

-Original Message-
From: Nikolaus Voss 
Sent: Thursday, September 12, 2019 1:08 AM
To: Shevchenko, Andriy ; Schmauss, Erik
; Rafael J. Wysocki ; Moore,
Robert 
Cc: Len Brown ; Jacek Anaszewski
; Pavel Machek ; Dan Murphy
; linux-a...@vger.kernel.org; de...@acpica.org; linux-
ker...@vger.kernel.org; n...@vosn.de; Nikolaus Voss

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 
Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table
loads")
Signed-off-by: Nikolaus Voss 
---
 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, >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, _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,
+  

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-ow...@vger.kernel.org 
> > On Behalf Of Shevchenko, Andriy
> > Sent: Thursday, September 26, 2019 9:35 AM
> > To: Schmauss, Erik 
> > Cc: Nikolaus Voss ; Rafael J. Wysocki
> > ; Moore, Robert ; Len Brown
> > ; Jacek Anaszewski ; Pavel
> > Machek ; Dan Murphy ; linux-
> > a...@vger.kernel.org; de...@acpica.org; linux-kernel@vger.kernel.org;
> > n...@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 
> > > > Sent: Thursday, September 12, 2019 1:08 AM
> > > > To: Shevchenko, Andriy ; Schmauss, Erik
> > > > ; Rafael J. Wysocki ;
> > > > Moore, Robert 
> > > > Cc: Len Brown ; Jacek Anaszewski
> > > > ; Pavel Machek ; Dan
> > > > Murphy ; linux-a...@vger.kernel.org;
> > > > de...@acpica.org; linux- ker...@vger.kernel.org; n...@vosn.de;
> > > > Nikolaus Voss 
> > > > 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.gt2...@smile.fi.intel.com/

-- 
With Best Regards,
Andy Shevchenko

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

[Schmauss, Erik]

> -Original Message-
> From: linux-acpi-ow...@vger.kernel.org 
> On Behalf Of Shevchenko, Andriy
> Sent: Thursday, September 26, 2019 9:35 AM
> To: Schmauss, Erik 
> Cc: Nikolaus Voss ; Rafael J. Wysocki
> ; Moore, Robert ; Len Brown
> ; Jacek Anaszewski ; Pavel
> Machek ; Dan Murphy ; linux-
> a...@vger.kernel.org; de...@acpica.org; linux-kernel@vger.kernel.org;
> n...@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 
> > > Sent: Thursday, September 12, 2019 1:08 AM
> > > To: Shevchenko, Andriy ; Schmauss, Erik
> > > ; Rafael J. Wysocki ;
> > > Moore, Robert 
> > > Cc: Len Brown ; Jacek Anaszewski
> > > ; Pavel Machek ; Dan
> > > Murphy ; linux-a...@vger.kernel.org;
> > > de...@acpica.org; linux- ker...@vger.kernel.org; n...@vosn.de;
> > > Nikolaus Voss 
> > > 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 07:09:05PM +0300, Schmauss, Erik wrote:
> > -Original Message-
> > From: Nikolaus Voss 
> > Sent: Thursday, September 12, 2019 1:08 AM
> > To: Shevchenko, Andriy ; Schmauss, Erik
> > ; Rafael J. Wysocki ; Moore,
> > Robert 
> > Cc: Len Brown ; Jacek Anaszewski
> > ; Pavel Machek ; Dan Murphy
> > ; linux-a...@vger.kernel.org; de...@acpica.org; linux-
> > ker...@vger.kernel.org; n...@vosn.de; Nikolaus Voss
> > 
> > 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: Nikolaus Voss 
> Sent: Thursday, September 12, 2019 1:08 AM
> To: Shevchenko, Andriy ; Schmauss, Erik
> ; Rafael J. Wysocki ; Moore,
> Robert 
> Cc: Len Brown ; Jacek Anaszewski
> ; Pavel Machek ; Dan Murphy
> ; linux-a...@vger.kernel.org; de...@acpica.org; linux-
> ker...@vger.kernel.org; n...@vosn.de; Nikolaus Voss
> 
> 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 
> Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table
> loads")
> Signed-off-by: Nikolaus Voss 
> ---
>  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, >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, _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))
> + 

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 
> > Sent: Thursday, September 12, 2019 12:37 PM
> > To: Moore, Robert ; Nikolaus Voss
> > ; Shevchenko, Andriy
> > ; Schmauss, Erik ;
> > Rafael J. Wysocki 
> > Cc: Len Brown ; Jacek Anaszewski
> > ; Pavel Machek ; Dan Murphy
> > ; linux-a...@vger.kernel.org; de...@acpica.org; linux-
> > ker...@vger.kernel.org; n...@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

[Schmauss, Erik]

> -Original Message-
> From: Ferry Toth 
> Sent: Thursday, September 12, 2019 12:37 PM
> To: Moore, Robert ; Nikolaus Voss
> ; Shevchenko, Andriy
> ; Schmauss, Erik ;
> Rafael J. Wysocki 
> Cc: Len Brown ; Jacek Anaszewski
> ; Pavel Machek ; Dan Murphy
> ; linux-a...@vger.kernel.org; de...@acpica.org; linux-
> ker...@vger.kernel.org; n...@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.v...@loewensteinmedical.de]
> > Sent: Thursday, September 12, 2019 1:08 AM
> > To: Shevchenko, Andriy ; Schmauss, Erik
> > ; Rafael J. Wysocki ;
> > Moore, Robert 
> > Cc: Len Brown ; Jacek Anaszewski
> > ; Pavel Machek ; Dan Murphy
> > ; linux-a...@vger.kernel.org; de...@acpica.org;
> > linux-kernel@vger.kernel.org; n...@vosn.de; Nikolaus Voss
> > 
> > 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 
> > Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on
> > host-directed table loads")
> > Signed-off-by: Nikolaus Voss 
> > ---
> >   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, >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)
> >

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, );
> >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

[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, );
   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 
Sent: Monday, September 23, 2019 2:05 AM
To: Moore, Robert 
Cc: Ferry Toth ; Shevchenko, Andriy ; Schmauss, Erik 
; Rafael J. Wysocki ; Len Brown ; Jacek Anaszewski 
; Pavel Machek ; Dan Murphy ; linux-a...@vger.kernel.org; 
de...@acpica.org; linux-kernel@vger.kernel.org; Jan Kiszka 
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:n...@vosn.de]
Sent: Wednesday, September 18, 2019 7:32 AM
To: Moore, Robert 
Cc: Ferry Toth ; Shevchenko, Andriy
; Schmauss, Erik
; Rafael J. Wysocki ; Len
Brown ; Jacek Anaszewski
; Pavel Machek ; Dan Murphy
; linux-a...@vger.kernel.org; de...@acpica.org;
linux-kernel@vger.kernel.org; Jan Kiszka 
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:n...@vosn.de]
Sent: Monday, September 16, 2019 2:47 AM
To: Moore, Robert 
Cc: Ferry Toth ; Shevchenko, Andriy
; Schmauss, Erik
; Rafael J. Wysocki ; Len
Brown ; Jacek Anaszewski
; Pavel Machek ; Dan Murphy
; linux-a...@vger.kernel.org; de...@acpica.org;
linux-kernel@vger.kernel.org; Jan Kiszka 
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:fnt...@gmail.com]
Sent: Friday, September 13, 2019 9:48 AM
To: Shevchenko, Andriy ; Moore, Robert

Cc: Nikolaus Voss ; Schmauss, Erik
; Rafael J. Wysocki ;
Len Brown ; Jacek Anaszewski
; Pavel Machek ; Dan
Murphy ; linux-a...@vger.kernel.org;
de...@acpica.org; linux-kernel@vger.kernel.org;
nikolaus.v...@loewensteinmedical.de;
Jan Kiszka 
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:n...@vosn.de]
Sent: Friday, September 13, 2019 12:44 AM
To: Moore, Robert 
Cc: Shevchenko, Andriy ; Schmauss,
Erik ; Rafael J. Wysocki
; Len Brown ; Jacek Anaszewski
; Pavel Machek ; Dan
Murphy ; linux-a...@vger.kernel.org;
de...@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth
; nikolaus.v...@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_un

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, );
if (ACPI_SUCCESS (Status))
{
/* Complete the initialization/resolution of new objects */

AcpiNsInitializeObjects ();
}


-Original Message-
From: Nikolaus Voss  
Sent: Monday, September 23, 2019 2:05 AM
To: Moore, Robert 
Cc: Ferry Toth ; Shevchenko, Andriy 
; Schmauss, Erik ; Rafael 
J. Wysocki ; Len Brown ; Jacek Anaszewski 
; Pavel Machek ; Dan Murphy 
; linux-a...@vger.kernel.org; de...@acpica.org; 
linux-kernel@vger.kernel.org; Jan Kiszka 
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:n...@vosn.de]
> Sent: Wednesday, September 18, 2019 7:32 AM
> To: Moore, Robert 
> Cc: Ferry Toth ; Shevchenko, Andriy 
> ; Schmauss, Erik 
> ; Rafael J. Wysocki ; Len 
> Brown ; Jacek Anaszewski 
> ; Pavel Machek ; Dan Murphy 
> ; linux-a...@vger.kernel.org; de...@acpica.org; 
> linux-kernel@vger.kernel.org; Jan Kiszka 
> 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:n...@vosn.de]
>> Sent: Monday, September 16, 2019 2:47 AM
>> To: Moore, Robert 
>> Cc: Ferry Toth ; Shevchenko, Andriy 
>> ; Schmauss, Erik 
>> ; Rafael J. Wysocki ; Len 
>> Brown ; Jacek Anaszewski 
>> ; Pavel Machek ; Dan Murphy 
>> ; linux-a...@vger.kernel.org; de...@acpica.org; 
>> linux-kernel@vger.kernel.org; Jan Kiszka 
>> 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:fnt...@gmail.com]
>>> Sent: Friday, September 13, 2019 9:48 AM
>>> To: Shevchenko, Andriy ; Moore, Robert 
>>> 
>>> Cc: Nikolaus Voss ; Schmauss, Erik 
>>> ; Rafael J. Wysocki ; 
>>> Len Brown ; Jacek Anaszewski 
>>> ; Pavel Machek ; Dan 
>>> Murphy ; linux-a...@vger.kernel.org; 
>>> de...@acpica.org; linux-kernel@vger.kernel.org; 
>>> nikolaus.v...@loewensteinmedical.de;
>>> Jan Kiszka 
>>> 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:n...@vosn.de]
>>>>> Sent: Friday, September 13, 2019 12:44 AM
>>>>> To: Moore, Robert 
>>>>> Cc: Shevchenko, Andriy ; Schmauss, 
>>>>> Erik ; Rafael J. Wysocki 
>>>>> ; Len Brown ; Jacek Anaszewski 
>>>>> ; Pavel Machek ; Dan 
>>>>> Murphy ; linux-a...@vger.kernel.org; 
>>>>> de...@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth 
>>>>> ; nikolaus.v...@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 wor

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 
Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table 
loads")
Signed-off-by: Nikolaus Voss 


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, >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, _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))

 

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:n...@vosn.de]
Sent: Wednesday, September 18, 2019 7:32 AM
To: Moore, Robert 
Cc: Ferry Toth ; Shevchenko, Andriy ; Schmauss, Erik 
; Rafael J. Wysocki ; Len Brown ; Jacek Anaszewski 
; Pavel Machek ; Dan Murphy ; linux-a...@vger.kernel.org; 
de...@acpica.org; linux-kernel@vger.kernel.org; Jan Kiszka 
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:n...@vosn.de]
Sent: Monday, September 16, 2019 2:47 AM
To: Moore, Robert 
Cc: Ferry Toth ; Shevchenko, Andriy
; Schmauss, Erik
; Rafael J. Wysocki ; Len
Brown ; Jacek Anaszewski
; Pavel Machek ; Dan Murphy
; linux-a...@vger.kernel.org; de...@acpica.org;
linux-kernel@vger.kernel.org; Jan Kiszka 
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:fnt...@gmail.com]
Sent: Friday, September 13, 2019 9:48 AM
To: Shevchenko, Andriy ; Moore, Robert

Cc: Nikolaus Voss ; Schmauss, Erik
; Rafael J. Wysocki ; Len
Brown ; Jacek Anaszewski
; Pavel Machek ; Dan Murphy
; linux-a...@vger.kernel.org; de...@acpica.org;
linux-kernel@vger.kernel.org; nikolaus.v...@loewensteinmedical.de;
Jan Kiszka 
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:n...@vosn.de]
Sent: Friday, September 13, 2019 12:44 AM
To: Moore, Robert 
Cc: Shevchenko, Andriy ; Schmauss,
Erik ; Rafael J. Wysocki
; Len Brown ; Jacek Anaszewski
; Pavel Machek ; Dan
Murphy ; linux-a...@vger.kernel.org;
de...@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth
; nikolaus.v...@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 
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 does

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

[Moore, Robert]

-Original Message-
From: Nikolaus Voss [mailto:n...@vosn.de] 
Sent: Wednesday, September 18, 2019 7:32 AM
To: Moore, Robert 
Cc: Ferry Toth ; Shevchenko, Andriy 
; Schmauss, Erik ; Rafael 
J. Wysocki ; Len Brown ; Jacek Anaszewski 
; Pavel Machek ; Dan Murphy 
; linux-a...@vger.kernel.org; de...@acpica.org; 
linux-kernel@vger.kernel.org; Jan Kiszka 
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:n...@vosn.de]
> Sent: Monday, September 16, 2019 2:47 AM
> To: Moore, Robert 
> Cc: Ferry Toth ; Shevchenko, Andriy 
> ; Schmauss, Erik 
> ; Rafael J. Wysocki ; Len 
> Brown ; Jacek Anaszewski 
> ; Pavel Machek ; Dan Murphy 
> ; linux-a...@vger.kernel.org; de...@acpica.org; 
> linux-kernel@vger.kernel.org; Jan Kiszka 
> 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:fnt...@gmail.com]
>> Sent: Friday, September 13, 2019 9:48 AM
>> To: Shevchenko, Andriy ; Moore, Robert 
>> 
>> Cc: Nikolaus Voss ; Schmauss, Erik 
>> ; Rafael J. Wysocki ; Len 
>> Brown ; Jacek Anaszewski 
>> ; Pavel Machek ; Dan Murphy 
>> ; linux-a...@vger.kernel.org; de...@acpica.org; 
>> linux-kernel@vger.kernel.org; nikolaus.v...@loewensteinmedical.de; 
>> Jan Kiszka 
>> 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:n...@vosn.de]
>>>> Sent: Friday, September 13, 2019 12:44 AM
>>>> To: Moore, Robert 
>>>> Cc: Shevchenko, Andriy ; Schmauss, 
>>>> Erik ; Rafael J. Wysocki 
>>>> ; Len Brown ; Jacek Anaszewski 
>>>> ; Pavel Machek ; Dan 
>>>> Murphy ; linux-a...@vger.kernel.org; 
>>>> de...@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth 
>>>> ; nikolaus.v...@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 
>>> 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 

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 
> Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table 
> loads")
> Signed-off-by: Nikolaus Voss 

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, >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, _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
> 

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:n...@vosn.de]
Sent: Monday, September 16, 2019 2:47 AM
To: Moore, Robert 
Cc: Ferry Toth ; Shevchenko, Andriy ; Schmauss, Erik 
; Rafael J. Wysocki ; Len Brown ; Jacek Anaszewski 
; Pavel Machek ; Dan Murphy ; linux-a...@vger.kernel.org; 
de...@acpica.org; linux-kernel@vger.kernel.org; Jan Kiszka 
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:fnt...@gmail.com]
Sent: Friday, September 13, 2019 9:48 AM
To: Shevchenko, Andriy ; Moore, Robert

Cc: Nikolaus Voss ; Schmauss, Erik
; Rafael J. Wysocki ; Len
Brown ; Jacek Anaszewski
; Pavel Machek ; Dan Murphy
; linux-a...@vger.kernel.org; de...@acpica.org;
linux-kernel@vger.kernel.org; nikolaus.v...@loewensteinmedical.de; Jan
Kiszka 
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:n...@vosn.de]
Sent: Friday, September 13, 2019 12:44 AM
To: Moore, Robert 
Cc: Shevchenko, Andriy ; Schmauss, Erik
; Rafael J. Wysocki ;
Len Brown ; Jacek Anaszewski
; Pavel Machek ; Dan
Murphy ; linux-a...@vger.kernel.org;
de...@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth
; nikolaus.v...@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 
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:n...@vosn.de] 
Sent: Monday, September 16, 2019 2:47 AM
To: Moore, Robert 
Cc: Ferry Toth ; Shevchenko, Andriy 
; Schmauss, Erik ; Rafael 
J. Wysocki ; Len Brown ; Jacek Anaszewski 
; Pavel Machek ; Dan Murphy 
; linux-a...@vger.kernel.org; de...@acpica.org; 
linux-kernel@vger.kernel.org; Jan Kiszka 
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:fnt...@gmail.com]
> Sent: Friday, September 13, 2019 9:48 AM
> To: Shevchenko, Andriy ; Moore, Robert 
> 
> Cc: Nikolaus Voss ; Schmauss, Erik 
> ; Rafael J. Wysocki ; Len 
> Brown ; Jacek Anaszewski 
> ; Pavel Machek ; Dan Murphy 
> ; linux-a...@vger.kernel.org; de...@acpica.org; 
> linux-kernel@vger.kernel.org; nikolaus.v...@loewensteinmedical.de; Jan 
> Kiszka 
> 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:n...@vosn.de]
>>> Sent: Friday, September 13, 2019 12:44 AM
>>> To: Moore, Robert 
>>> Cc: Shevchenko, Andriy ; Schmauss, Erik 
>>> ; Rafael J. Wysocki ; 
>>> Len Brown ; Jacek Anaszewski 
>>> ; Pavel Machek ; Dan 
>>> Murphy ; linux-a...@vger.kernel.org; 
>>> de...@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth 
>>> ; nikolaus.v...@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 
>> 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 Fri, 13 Sep 2019, Moore, Robert wrote:



-Original Message-
From: Ferry Toth [mailto:fnt...@gmail.com]
Sent: Friday, September 13, 2019 9:48 AM
To: Shevchenko, Andriy ; Moore, Robert 

Cc: Nikolaus Voss ; Schmauss, Erik ; Rafael J. Wysocki 
; Len Brown ; Jacek Anaszewski ; Pavel 
Machek ; Dan Murphy ; linux-a...@vger.kernel.org; de...@acpica.org; 
linux-kernel@vger.kernel.org; nikolaus.v...@loewensteinmedical.de; Jan Kiszka 
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:n...@vosn.de]
Sent: Friday, September 13, 2019 12:44 AM
To: Moore, Robert 
Cc: Shevchenko, Andriy ; Schmauss, Erik
; Rafael J. Wysocki ; Len
Brown ; Jacek Anaszewski
; Pavel Machek ; Dan Murphy
; linux-a...@vger.kernel.org; de...@acpica.org;
linux-kernel@vger.kernel.org; Ferry Toth ;
nikolaus.v...@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 
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

[Rafael J. Wysocki]

On Fri, Sep 13, 2019 at 7:41 PM Moore, Robert  wrote:
>
>
>
> -Original Message-
> From: Ferry Toth [mailto:fnt...@gmail.com]
> Sent: Friday, September 13, 2019 9:48 AM
> To: Shevchenko, Andriy ; Moore, Robert 
> 
> Cc: Nikolaus Voss ; Schmauss, Erik ; 
> Rafael J. Wysocki ; Len Brown ; Jacek 
> Anaszewski ; Pavel Machek ; Dan 
> Murphy ; linux-a...@vger.kernel.org; de...@acpica.org; 
> linux-kernel@vger.kernel.org; nikolaus.v...@loewensteinmedical.de; Jan Kiszka 
> 
> 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:n...@vosn.de]
> >> Sent: Friday, September 13, 2019 12:44 AM
> >> To: Moore, Robert 
> >> Cc: Shevchenko, Andriy ; Schmauss, Erik
> >> ; Rafael J. Wysocki ; Len
> >> Brown ; Jacek Anaszewski
> >> ; Pavel Machek ; Dan Murphy
> >> ; linux-a...@vger.kernel.org; de...@acpica.org;
> >> linux-kernel@vger.kernel.org; Ferry Toth ;
> >> nikolaus.v...@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 
> > 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

[Moore, Robert]

-Original Message-
From: Ferry Toth [mailto:fnt...@gmail.com] 
Sent: Friday, September 13, 2019 9:48 AM
To: Shevchenko, Andriy ; Moore, Robert 

Cc: Nikolaus Voss ; Schmauss, Erik ; 
Rafael J. Wysocki ; Len Brown ; Jacek 
Anaszewski ; Pavel Machek ; Dan 
Murphy ; linux-a...@vger.kernel.org; de...@acpica.org; 
linux-kernel@vger.kernel.org; nikolaus.v...@loewensteinmedical.de; Jan Kiszka 

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:n...@vosn.de]
>> Sent: Friday, September 13, 2019 12:44 AM
>> To: Moore, Robert 
>> Cc: Shevchenko, Andriy ; Schmauss, Erik 
>> ; Rafael J. Wysocki ; Len 
>> Brown ; Jacek Anaszewski 
>> ; Pavel Machek ; Dan Murphy 
>> ; linux-a...@vger.kernel.org; de...@acpica.org; 
>> linux-kernel@vger.kernel.org; Ferry Toth ; 
>> nikolaus.v...@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 
> 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

[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:n...@vosn.de]
Sent: Friday, September 13, 2019 12:44 AM
To: Moore, Robert 
Cc: Shevchenko, Andriy ; Schmauss, Erik ; Rafael J. Wysocki 
; Len Brown ; Jacek Anaszewski ; Pavel 
Machek ; Dan Murphy ; linux-a...@vger.kernel.org; de...@acpica.org; 
linux-kernel@vger.kernel.org; Ferry Toth ; nikolaus.v...@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 
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

[Shevchenko, Andriy]

On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
> -Original Message-
> From: Nikolaus Voss [mailto:n...@vosn.de] 
> Sent: Friday, September 13, 2019 12:44 AM
> To: Moore, Robert 
> Cc: Shevchenko, Andriy ; Schmauss, Erik 
> ; Rafael J. Wysocki ; Len Brown 
> ; Jacek Anaszewski ; Pavel 
> Machek ; Dan Murphy ; 
> linux-a...@vger.kernel.org; de...@acpica.org; linux-kernel@vger.kernel.org; 
> Ferry Toth ; nikolaus.v...@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 
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

[Moore, Robert]

-Original Message-
From: Nikolaus Voss [mailto:n...@vosn.de] 
Sent: Friday, September 13, 2019 12:44 AM
To: Moore, Robert 
Cc: Shevchenko, Andriy ; Schmauss, Erik 
; Rafael J. Wysocki ; Len Brown 
; Jacek Anaszewski ; Pavel Machek 
; Dan Murphy ; linux-a...@vger.kernel.org; 
de...@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth ; 
nikolaus.v...@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

[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

[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.v...@loewensteinmedical.de]
Sent: Thursday, September 12, 2019 1:08 AM
To: Shevchenko, Andriy ; Schmauss, Erik 
; Rafael J. Wysocki ; Moore, Robert 

Cc: Len Brown ; Jacek Anaszewski ; Pavel Machek 
; Dan Murphy ; linux-a...@vger.kernel.org; de...@acpica.org; 
linux-kernel@vger.kernel.org; n...@vosn.de; Nikolaus Voss 
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 
Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table 
loads")
Signed-off-by: Nikolaus Voss 
---
  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, >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, _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 

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.v...@loewensteinmedical.de] 
Sent: Thursday, September 12, 2019 1:08 AM
To: Shevchenko, Andriy ; Schmauss, Erik 
; Rafael J. Wysocki ; Moore, 
Robert 
Cc: Len Brown ; Jacek Anaszewski ; 
Pavel Machek ; Dan Murphy ; 
linux-a...@vger.kernel.org; de...@acpica.org; linux-kernel@vger.kernel.org; 
n...@vosn.de; Nikolaus Voss 
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 
Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table 
loads")
Signed-off-by: Nikolaus Voss 
---
 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, >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, _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