diff mbox series

[04/14] firmware_loader: add built-in firmware kconfig entry

Message ID 20210917182226.3532898-5-mcgrof@kernel.org (mailing list archive)
State Not Applicable
Delegated to: Johannes Berg
Headers show
Series firmware_loader: built-in API and make x86 use it | expand

Commit Message

Luis Chamberlain Sept. 17, 2021, 6:22 p.m. UTC
From: Luis Chamberlain <mcgrof@kernel.org>

The built-in firmware is always supported when a user enables
FW_LOADER=y today, that is, it is built-in to the kernel. When the
firmware loader is built as a module, support for built-in firmware
is skipped. This requirement is not really clear to users or even
developers.

Also, by default the EXTRA_FIRMWARE is always set to an empty string
and so by default we really have nothing built-in to that kernel's
sections for built-in firmware, so today a all FW_LOADER=y kernels
spins their wheels on an empty set of built-in firmware for each
firmware request with no true need for it.

Add a new kconfig entry to represent built-in firmware support more
clearly. This let's knock 3 birds with one stone:

 o Clarifies that support for built-in firmware requires the
   firmware loader to be built-in to the kernel

 o By default we now always skip built-in firmware even if a FW_LOADER=y

 o This also lets us make it clear that the EXTRA_FIRMWARE_DIR
   kconfig entry is only used for built-in firmware

Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 .../driver-api/firmware/built-in-fw.rst       |  2 ++
 Documentation/x86/microcode.rst               |  5 ++--
 drivers/base/firmware_loader/Kconfig          | 25 +++++++++++++------
 drivers/base/firmware_loader/Makefile         |  3 +--
 drivers/base/firmware_loader/main.c           |  4 +--
 5 files changed, 26 insertions(+), 13 deletions(-)

Comments

Greg Kroah-Hartman Oct. 5, 2021, 2:30 p.m. UTC | #1
On Fri, Sep 17, 2021 at 11:22:16AM -0700, Luis R. Rodriguez wrote:
> From: Luis Chamberlain <mcgrof@kernel.org>
> 
> The built-in firmware is always supported when a user enables
> FW_LOADER=y today, that is, it is built-in to the kernel. When the
> firmware loader is built as a module, support for built-in firmware
> is skipped. This requirement is not really clear to users or even
> developers.
> 
> Also, by default the EXTRA_FIRMWARE is always set to an empty string
> and so by default we really have nothing built-in to that kernel's
> sections for built-in firmware, so today a all FW_LOADER=y kernels
> spins their wheels on an empty set of built-in firmware for each
> firmware request with no true need for it.
> 
> Add a new kconfig entry to represent built-in firmware support more
> clearly. This let's knock 3 birds with one stone:
> 
>  o Clarifies that support for built-in firmware requires the
>    firmware loader to be built-in to the kernel
> 
>  o By default we now always skip built-in firmware even if a FW_LOADER=y
> 
>  o This also lets us make it clear that the EXTRA_FIRMWARE_DIR
>    kconfig entry is only used for built-in firmware
> 
> Reviewed-by: Borislav Petkov <bp@suse.de>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  .../driver-api/firmware/built-in-fw.rst       |  2 ++
>  Documentation/x86/microcode.rst               |  5 ++--
>  drivers/base/firmware_loader/Kconfig          | 25 +++++++++++++------
>  drivers/base/firmware_loader/Makefile         |  3 +--
>  drivers/base/firmware_loader/main.c           |  4 +--
>  5 files changed, 26 insertions(+), 13 deletions(-)
> 
> diff --git a/Documentation/driver-api/firmware/built-in-fw.rst b/Documentation/driver-api/firmware/built-in-fw.rst
> index bc1c961bace1..9dd2b1df44f0 100644
> --- a/Documentation/driver-api/firmware/built-in-fw.rst
> +++ b/Documentation/driver-api/firmware/built-in-fw.rst
> @@ -8,6 +8,7 @@ the filesystem. Instead, firmware can be looked for inside the kernel
>  directly. You can enable built-in firmware using the kernel configuration
>  options:
>  
> +  * CONFIG_FW_LOADER_BUILTIN
>    * CONFIG_EXTRA_FIRMWARE
>    * CONFIG_EXTRA_FIRMWARE_DIR
>  
> @@ -17,6 +18,7 @@ into the kernel with CONFIG_EXTRA_FIRMWARE:
>  * Speed
>  * Firmware is needed for accessing the boot device, and the user doesn't
>    want to stuff the firmware into the boot initramfs.
> +* Testing built-in firmware
>  
>  Even if you have these needs there are a few reasons why you may not be
>  able to make use of built-in firmware:
> diff --git a/Documentation/x86/microcode.rst b/Documentation/x86/microcode.rst
> index a320d37982ed..d199f0b98869 100644
> --- a/Documentation/x86/microcode.rst
> +++ b/Documentation/x86/microcode.rst
> @@ -114,11 +114,12 @@ Builtin microcode
>  =================
>  
>  The loader supports also loading of a builtin microcode supplied through
> -the regular builtin firmware method CONFIG_EXTRA_FIRMWARE. Only 64-bit is
> -currently supported.
> +the regular builtin firmware method using CONFIG_FW_LOADER_BUILTIN and
> +CONFIG_EXTRA_FIRMWARE. Only 64-bit is currently supported.
>  
>  Here's an example::
>  
> +  CONFIG_FW_LOADER_BUILTIN=y
>    CONFIG_EXTRA_FIRMWARE="intel-ucode/06-3a-09 amd-ucode/microcode_amd_fam15h.bin"
>    CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware"
>  
> diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
> index 5b24f3959255..de4fcd9d41f3 100644
> --- a/drivers/base/firmware_loader/Kconfig
> +++ b/drivers/base/firmware_loader/Kconfig
> @@ -29,8 +29,10 @@ if FW_LOADER
>  config FW_LOADER_PAGED_BUF
>  	bool
>  
> -config EXTRA_FIRMWARE
> -	string "Build named firmware blobs into the kernel binary"
> +config FW_LOADER_BUILTIN
> +	bool "Enable support for built-in firmware"
> +	default n

n is always the default, no need to list it again.

> +	depends on FW_LOADER=y

I don't see what this gets us to add another config option.  Are you
making things easier later on?

Anyway, I took the first 3 patches here, please fix this up and rebase
and resend.

thanks,

greg k-h
Luis Chamberlain Oct. 11, 2021, 5:35 p.m. UTC | #2
On Tue, Oct 05, 2021 at 04:30:06PM +0200, Greg KH wrote:
> On Fri, Sep 17, 2021 at 11:22:16AM -0700, Luis R. Rodriguez wrote:
> > From: Luis Chamberlain <mcgrof@kernel.org>
> > 
> > The built-in firmware is always supported when a user enables
> > FW_LOADER=y today, that is, it is built-in to the kernel. When the
> > firmware loader is built as a module, support for built-in firmware
> > is skipped. This requirement is not really clear to users or even
> > developers.
> > 
> > Also, by default the EXTRA_FIRMWARE is always set to an empty string
> > and so by default we really have nothing built-in to that kernel's
> > sections for built-in firmware, so today a all FW_LOADER=y kernels
> > spins their wheels on an empty set of built-in firmware for each
> > firmware request with no true need for it.
> > 
> > Add a new kconfig entry to represent built-in firmware support more
> > clearly. This let's knock 3 birds with one stone:
> > 
> >  o Clarifies that support for built-in firmware requires the
> >    firmware loader to be built-in to the kernel
> > 
> >  o By default we now always skip built-in firmware even if a FW_LOADER=y
> > 
> >  o This also lets us make it clear that the EXTRA_FIRMWARE_DIR
> >    kconfig entry is only used for built-in firmware
> > 
> > Reviewed-by: Borislav Petkov <bp@suse.de>
> > Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> > ---
> >  .../driver-api/firmware/built-in-fw.rst       |  2 ++
> >  Documentation/x86/microcode.rst               |  5 ++--
> >  drivers/base/firmware_loader/Kconfig          | 25 +++++++++++++------
> >  drivers/base/firmware_loader/Makefile         |  3 +--
> >  drivers/base/firmware_loader/main.c           |  4 +--
> >  5 files changed, 26 insertions(+), 13 deletions(-)
> > 
> > diff --git a/Documentation/driver-api/firmware/built-in-fw.rst b/Documentation/driver-api/firmware/built-in-fw.rst
> > index bc1c961bace1..9dd2b1df44f0 100644
> > --- a/Documentation/driver-api/firmware/built-in-fw.rst
> > +++ b/Documentation/driver-api/firmware/built-in-fw.rst
> > @@ -8,6 +8,7 @@ the filesystem. Instead, firmware can be looked for inside the kernel
> >  directly. You can enable built-in firmware using the kernel configuration
> >  options:
> >  
> > +  * CONFIG_FW_LOADER_BUILTIN
> >    * CONFIG_EXTRA_FIRMWARE
> >    * CONFIG_EXTRA_FIRMWARE_DIR
> >  
> > @@ -17,6 +18,7 @@ into the kernel with CONFIG_EXTRA_FIRMWARE:
> >  * Speed
> >  * Firmware is needed for accessing the boot device, and the user doesn't
> >    want to stuff the firmware into the boot initramfs.
> > +* Testing built-in firmware
> >  
> >  Even if you have these needs there are a few reasons why you may not be
> >  able to make use of built-in firmware:
> > diff --git a/Documentation/x86/microcode.rst b/Documentation/x86/microcode.rst
> > index a320d37982ed..d199f0b98869 100644
> > --- a/Documentation/x86/microcode.rst
> > +++ b/Documentation/x86/microcode.rst
> > @@ -114,11 +114,12 @@ Builtin microcode
> >  =================
> >  
> >  The loader supports also loading of a builtin microcode supplied through
> > -the regular builtin firmware method CONFIG_EXTRA_FIRMWARE. Only 64-bit is
> > -currently supported.
> > +the regular builtin firmware method using CONFIG_FW_LOADER_BUILTIN and
> > +CONFIG_EXTRA_FIRMWARE. Only 64-bit is currently supported.
> >  
> >  Here's an example::
> >  
> > +  CONFIG_FW_LOADER_BUILTIN=y
> >    CONFIG_EXTRA_FIRMWARE="intel-ucode/06-3a-09 amd-ucode/microcode_amd_fam15h.bin"
> >    CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware"
> >  
> > diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
> > index 5b24f3959255..de4fcd9d41f3 100644
> > --- a/drivers/base/firmware_loader/Kconfig
> > +++ b/drivers/base/firmware_loader/Kconfig
> > @@ -29,8 +29,10 @@ if FW_LOADER
> >  config FW_LOADER_PAGED_BUF
> >  	bool
> >  
> > -config EXTRA_FIRMWARE
> > -	string "Build named firmware blobs into the kernel binary"
> > +config FW_LOADER_BUILTIN
> > +	bool "Enable support for built-in firmware"
> > +	default n
> 
> n is always the default, no need to list it again.

Oh, alrighty, I'll remove that line.

> > +	depends on FW_LOADER=y
> 
> I don't see what this gets us to add another config option.  Are you
> making things easier later on?

This makes a few things clearer for both developers and users.
The code in question is a *feature* *only* when FW_LOADER=y, by
adding a new kconfig to represent this and clearly makeing it
depend on FW_LOADER=y it let's us:

  o Clarify that support for built-in firmware requires
    the firmware loader to be built-in to the kernel
  o By default we now always skip built-in firmware even if a FW_LOADER=y
  o This also lets us make it clear that the EXTRA_FIRMWARE_DIR
    kconfig entry is only used for built-in firmware

The above is not easily obvious to developers (including myself when
I was reviewing this code) or users without this new kconfig entry.

Should I re-send by just removing the one line you asked for?

  Luis
Greg Kroah-Hartman Oct. 11, 2021, 5:46 p.m. UTC | #3
On Mon, Oct 11, 2021 at 10:35:37AM -0700, Luis Chamberlain wrote:
> On Tue, Oct 05, 2021 at 04:30:06PM +0200, Greg KH wrote:
> > On Fri, Sep 17, 2021 at 11:22:16AM -0700, Luis R. Rodriguez wrote:
> > > From: Luis Chamberlain <mcgrof@kernel.org>
> > > 
> > > The built-in firmware is always supported when a user enables
> > > FW_LOADER=y today, that is, it is built-in to the kernel. When the
> > > firmware loader is built as a module, support for built-in firmware
> > > is skipped. This requirement is not really clear to users or even
> > > developers.
> > > 
> > > Also, by default the EXTRA_FIRMWARE is always set to an empty string
> > > and so by default we really have nothing built-in to that kernel's
> > > sections for built-in firmware, so today a all FW_LOADER=y kernels
> > > spins their wheels on an empty set of built-in firmware for each
> > > firmware request with no true need for it.
> > > 
> > > Add a new kconfig entry to represent built-in firmware support more
> > > clearly. This let's knock 3 birds with one stone:
> > > 
> > >  o Clarifies that support for built-in firmware requires the
> > >    firmware loader to be built-in to the kernel
> > > 
> > >  o By default we now always skip built-in firmware even if a FW_LOADER=y
> > > 
> > >  o This also lets us make it clear that the EXTRA_FIRMWARE_DIR
> > >    kconfig entry is only used for built-in firmware
> > > 
> > > Reviewed-by: Borislav Petkov <bp@suse.de>
> > > Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> > > ---
> > >  .../driver-api/firmware/built-in-fw.rst       |  2 ++
> > >  Documentation/x86/microcode.rst               |  5 ++--
> > >  drivers/base/firmware_loader/Kconfig          | 25 +++++++++++++------
> > >  drivers/base/firmware_loader/Makefile         |  3 +--
> > >  drivers/base/firmware_loader/main.c           |  4 +--
> > >  5 files changed, 26 insertions(+), 13 deletions(-)
> > > 
> > > diff --git a/Documentation/driver-api/firmware/built-in-fw.rst b/Documentation/driver-api/firmware/built-in-fw.rst
> > > index bc1c961bace1..9dd2b1df44f0 100644
> > > --- a/Documentation/driver-api/firmware/built-in-fw.rst
> > > +++ b/Documentation/driver-api/firmware/built-in-fw.rst
> > > @@ -8,6 +8,7 @@ the filesystem. Instead, firmware can be looked for inside the kernel
> > >  directly. You can enable built-in firmware using the kernel configuration
> > >  options:
> > >  
> > > +  * CONFIG_FW_LOADER_BUILTIN
> > >    * CONFIG_EXTRA_FIRMWARE
> > >    * CONFIG_EXTRA_FIRMWARE_DIR
> > >  
> > > @@ -17,6 +18,7 @@ into the kernel with CONFIG_EXTRA_FIRMWARE:
> > >  * Speed
> > >  * Firmware is needed for accessing the boot device, and the user doesn't
> > >    want to stuff the firmware into the boot initramfs.
> > > +* Testing built-in firmware
> > >  
> > >  Even if you have these needs there are a few reasons why you may not be
> > >  able to make use of built-in firmware:
> > > diff --git a/Documentation/x86/microcode.rst b/Documentation/x86/microcode.rst
> > > index a320d37982ed..d199f0b98869 100644
> > > --- a/Documentation/x86/microcode.rst
> > > +++ b/Documentation/x86/microcode.rst
> > > @@ -114,11 +114,12 @@ Builtin microcode
> > >  =================
> > >  
> > >  The loader supports also loading of a builtin microcode supplied through
> > > -the regular builtin firmware method CONFIG_EXTRA_FIRMWARE. Only 64-bit is
> > > -currently supported.
> > > +the regular builtin firmware method using CONFIG_FW_LOADER_BUILTIN and
> > > +CONFIG_EXTRA_FIRMWARE. Only 64-bit is currently supported.
> > >  
> > >  Here's an example::
> > >  
> > > +  CONFIG_FW_LOADER_BUILTIN=y
> > >    CONFIG_EXTRA_FIRMWARE="intel-ucode/06-3a-09 amd-ucode/microcode_amd_fam15h.bin"
> > >    CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware"
> > >  
> > > diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
> > > index 5b24f3959255..de4fcd9d41f3 100644
> > > --- a/drivers/base/firmware_loader/Kconfig
> > > +++ b/drivers/base/firmware_loader/Kconfig
> > > @@ -29,8 +29,10 @@ if FW_LOADER
> > >  config FW_LOADER_PAGED_BUF
> > >  	bool
> > >  
> > > -config EXTRA_FIRMWARE
> > > -	string "Build named firmware blobs into the kernel binary"
> > > +config FW_LOADER_BUILTIN
> > > +	bool "Enable support for built-in firmware"
> > > +	default n
> > 
> > n is always the default, no need to list it again.
> 
> Oh, alrighty, I'll remove that line.
> 
> > > +	depends on FW_LOADER=y
> > 
> > I don't see what this gets us to add another config option.  Are you
> > making things easier later on?
> 
> This makes a few things clearer for both developers and users.
> The code in question is a *feature* *only* when FW_LOADER=y, by
> adding a new kconfig to represent this and clearly makeing it
> depend on FW_LOADER=y it let's us:
> 
>   o Clarify that support for built-in firmware requires
>     the firmware loader to be built-in to the kernel

That is good.

>   o By default we now always skip built-in firmware even if a FW_LOADER=y

I do not understand, why would we ever want to skip built-in firmware?

>   o This also lets us make it clear that the EXTRA_FIRMWARE_DIR
>     kconfig entry is only used for built-in firmware

How was it ever used for anything else?  :)

> The above is not easily obvious to developers (including myself when
> I was reviewing this code) or users without this new kconfig entry.
> 
> Should I re-send by just removing the one line you asked for?

I can not take this as-is, so yes :)

thanks,

greg k-h
Luis Chamberlain Oct. 11, 2021, 10:30 p.m. UTC | #4
On Mon, Oct 11, 2021 at 07:46:04PM +0200, Greg KH wrote:
> On Mon, Oct 11, 2021 at 10:35:37AM -0700, Luis Chamberlain wrote:
> > On Tue, Oct 05, 2021 at 04:30:06PM +0200, Greg KH wrote:
> > > On Fri, Sep 17, 2021 at 11:22:16AM -0700, Luis R. Rodriguez wrote:
> > > > From: Luis Chamberlain <mcgrof@kernel.org>
> > > > 
> > > > The built-in firmware is always supported when a user enables
> > > > FW_LOADER=y today, that is, it is built-in to the kernel. When the
> > > > firmware loader is built as a module, support for built-in firmware
> > > > is skipped. This requirement is not really clear to users or even
> > > > developers.
> > > > 
> > > > Also, by default the EXTRA_FIRMWARE is always set to an empty string
> > > > and so by default we really have nothing built-in to that kernel's
> > > > sections for built-in firmware, so today a all FW_LOADER=y kernels
> > > > spins their wheels on an empty set of built-in firmware for each
> > > > firmware request with no true need for it.
> > > > 
> > > > Add a new kconfig entry to represent built-in firmware support more
> > > > clearly. This let's knock 3 birds with one stone:
> > > > 
> > > >  o Clarifies that support for built-in firmware requires the
> > > >    firmware loader to be built-in to the kernel
> > > > 
> > > >  o By default we now always skip built-in firmware even if a FW_LOADER=y
> > > > 
> > > >  o This also lets us make it clear that the EXTRA_FIRMWARE_DIR
> > > >    kconfig entry is only used for built-in firmware
> > > > 
> > > > Reviewed-by: Borislav Petkov <bp@suse.de>
> > > > Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> > > > ---
> > > >  .../driver-api/firmware/built-in-fw.rst       |  2 ++
> > > >  Documentation/x86/microcode.rst               |  5 ++--
> > > >  drivers/base/firmware_loader/Kconfig          | 25 +++++++++++++------
> > > >  drivers/base/firmware_loader/Makefile         |  3 +--
> > > >  drivers/base/firmware_loader/main.c           |  4 +--
> > > >  5 files changed, 26 insertions(+), 13 deletions(-)
> > > > 
> > > > diff --git a/Documentation/driver-api/firmware/built-in-fw.rst b/Documentation/driver-api/firmware/built-in-fw.rst
> > > > index bc1c961bace1..9dd2b1df44f0 100644
> > > > --- a/Documentation/driver-api/firmware/built-in-fw.rst
> > > > +++ b/Documentation/driver-api/firmware/built-in-fw.rst
> > > > @@ -8,6 +8,7 @@ the filesystem. Instead, firmware can be looked for inside the kernel
> > > >  directly. You can enable built-in firmware using the kernel configuration
> > > >  options:
> > > >  
> > > > +  * CONFIG_FW_LOADER_BUILTIN
> > > >    * CONFIG_EXTRA_FIRMWARE
> > > >    * CONFIG_EXTRA_FIRMWARE_DIR
> > > >  
> > > > @@ -17,6 +18,7 @@ into the kernel with CONFIG_EXTRA_FIRMWARE:
> > > >  * Speed
> > > >  * Firmware is needed for accessing the boot device, and the user doesn't
> > > >    want to stuff the firmware into the boot initramfs.
> > > > +* Testing built-in firmware
> > > >  
> > > >  Even if you have these needs there are a few reasons why you may not be
> > > >  able to make use of built-in firmware:
> > > > diff --git a/Documentation/x86/microcode.rst b/Documentation/x86/microcode.rst
> > > > index a320d37982ed..d199f0b98869 100644
> > > > --- a/Documentation/x86/microcode.rst
> > > > +++ b/Documentation/x86/microcode.rst
> > > > @@ -114,11 +114,12 @@ Builtin microcode
> > > >  =================
> > > >  
> > > >  The loader supports also loading of a builtin microcode supplied through
> > > > -the regular builtin firmware method CONFIG_EXTRA_FIRMWARE. Only 64-bit is
> > > > -currently supported.
> > > > +the regular builtin firmware method using CONFIG_FW_LOADER_BUILTIN and
> > > > +CONFIG_EXTRA_FIRMWARE. Only 64-bit is currently supported.
> > > >  
> > > >  Here's an example::
> > > >  
> > > > +  CONFIG_FW_LOADER_BUILTIN=y
> > > >    CONFIG_EXTRA_FIRMWARE="intel-ucode/06-3a-09 amd-ucode/microcode_amd_fam15h.bin"
> > > >    CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware"
> > > >  
> > > > diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
> > > > index 5b24f3959255..de4fcd9d41f3 100644
> > > > --- a/drivers/base/firmware_loader/Kconfig
> > > > +++ b/drivers/base/firmware_loader/Kconfig
> > > > @@ -29,8 +29,10 @@ if FW_LOADER
> > > >  config FW_LOADER_PAGED_BUF
> > > >  	bool
> > > >  
> > > > -config EXTRA_FIRMWARE
> > > > -	string "Build named firmware blobs into the kernel binary"
> > > > +config FW_LOADER_BUILTIN
> > > > +	bool "Enable support for built-in firmware"
> > > > +	default n
> > > 
> > > n is always the default, no need to list it again.
> > 
> > Oh, alrighty, I'll remove that line.
> > 
> > > > +	depends on FW_LOADER=y
> > > 
> > > I don't see what this gets us to add another config option.  Are you
> > > making things easier later on?
> > 
> > This makes a few things clearer for both developers and users.
> > The code in question is a *feature* *only* when FW_LOADER=y, by
> > adding a new kconfig to represent this and clearly makeing it
> > depend on FW_LOADER=y it let's us:
> > 
> >   o Clarify that support for built-in firmware requires
> >     the firmware loader to be built-in to the kernel
> 
> That is good.
> 
> >   o By default we now always skip built-in firmware even if a FW_LOADER=y
> 
> I do not understand, why would we ever want to skip built-in firmware?

Because it is done this way today only implicitly because
EXTRA_FIRMWARE is empty. Using a kconfig entry makes this
more obvious.

> >   o This also lets us make it clear that the EXTRA_FIRMWARE_DIR
> >     kconfig entry is only used for built-in firmware
> 
> How was it ever used for anything else?  :)

Well later this patch set also renames this to something more
sensible, and so that change is clearer through this patch.

> I can not take this as-is, so yes :)

Well please let me know again once you read the above explanations.

I think the new kconfig is very well justified given the above.

  Luis
Luis Chamberlain Oct. 18, 2021, 9 p.m. UTC | #5
On Mon, Oct 11, 2021 at 03:30:24PM -0700, Luis Chamberlain wrote:
> On Mon, Oct 11, 2021 at 07:46:04PM +0200, Greg KH wrote:
> > >   o By default we now always skip built-in firmware even if a FW_LOADER=y
> > 
> > I do not understand, why would we ever want to skip built-in firmware?
> 
> Because it is done this way today only implicitly because
> EXTRA_FIRMWARE is empty. Using a kconfig entry makes this
> more obvious.

Greg,

The fact that it was not obvious to you we were effectively disabling
the built-in firmware functionality by default using side kconfig
symbols is a good reason to clarify this situation with its own kconfig
symbol.

And consider what I started below as well.

Please let me know why on the other hand we should *not* add this new
kconfig symbol?

> > >   o This also lets us make it clear that the EXTRA_FIRMWARE_DIR
> > >     kconfig entry is only used for built-in firmware
> > 
> > How was it ever used for anything else?  :)
> 
> Well later this patch set also renames this to something more
> sensible, and so that change is clearer through this patch.
> 
> > I can not take this as-is, so yes :)
> 
> Well please let me know again once you read the above explanations.
> 
> I think the new kconfig is very well justified given the above.
> 
>   Luis
Greg Kroah-Hartman Oct. 19, 2021, 6:16 a.m. UTC | #6
On Mon, Oct 18, 2021 at 02:00:25PM -0700, Luis Chamberlain wrote:
> On Mon, Oct 11, 2021 at 03:30:24PM -0700, Luis Chamberlain wrote:
> > On Mon, Oct 11, 2021 at 07:46:04PM +0200, Greg KH wrote:
> > > >   o By default we now always skip built-in firmware even if a FW_LOADER=y
> > > 
> > > I do not understand, why would we ever want to skip built-in firmware?
> > 
> > Because it is done this way today only implicitly because
> > EXTRA_FIRMWARE is empty. Using a kconfig entry makes this
> > more obvious.
> 
> Greg,
> 
> The fact that it was not obvious to you we were effectively disabling
> the built-in firmware functionality by default using side kconfig
> symbols is a good reason to clarify this situation with its own kconfig
> symbol.
> 
> And consider what I started below as well.
> 
> Please let me know why on the other hand we should *not* add this new
> kconfig symbol?

Because added complexity for no real good reason?  You need to justify
why we need yet-another firmware kconfig option here.  We should be
working to remove them, not add more, if at all possible.

thanks,

greg k-h
Luis Chamberlain Oct. 19, 2021, 3:52 p.m. UTC | #7
On Tue, Oct 19, 2021 at 08:16:14AM +0200, Greg KH wrote:
> On Mon, Oct 18, 2021 at 02:00:25PM -0700, Luis Chamberlain wrote:
> > On Mon, Oct 11, 2021 at 03:30:24PM -0700, Luis Chamberlain wrote:
> > > On Mon, Oct 11, 2021 at 07:46:04PM +0200, Greg KH wrote:
> > > > >   o By default we now always skip built-in firmware even if a FW_LOADER=y
> > > > 
> > > > I do not understand, why would we ever want to skip built-in firmware?
> > > 
> > > Because it is done this way today only implicitly because
> > > EXTRA_FIRMWARE is empty. Using a kconfig entry makes this
> > > more obvious.
> > 
> > Greg,
> > 
> > The fact that it was not obvious to you we were effectively disabling
> > the built-in firmware functionality by default using side kconfig
> > symbols is a good reason to clarify this situation with its own kconfig
> > symbol.
> > 
> > And consider what I started below as well.
> > 
> > Please let me know why on the other hand we should *not* add this new
> > kconfig symbol?
> 
> Because added complexity for no real good reason?  You need to justify
> why we need yet-another firmware kconfig option here.  We should be
> working to remove them, not add more, if at all possible.

I did, it actually simplifies things more and makes the fact that we
disable the functionality of the built-in firmware by default clearer.

So no, this is not adding complexity.

 Luis
diff mbox series

Patch

diff --git a/Documentation/driver-api/firmware/built-in-fw.rst b/Documentation/driver-api/firmware/built-in-fw.rst
index bc1c961bace1..9dd2b1df44f0 100644
--- a/Documentation/driver-api/firmware/built-in-fw.rst
+++ b/Documentation/driver-api/firmware/built-in-fw.rst
@@ -8,6 +8,7 @@  the filesystem. Instead, firmware can be looked for inside the kernel
 directly. You can enable built-in firmware using the kernel configuration
 options:
 
+  * CONFIG_FW_LOADER_BUILTIN
   * CONFIG_EXTRA_FIRMWARE
   * CONFIG_EXTRA_FIRMWARE_DIR
 
@@ -17,6 +18,7 @@  into the kernel with CONFIG_EXTRA_FIRMWARE:
 * Speed
 * Firmware is needed for accessing the boot device, and the user doesn't
   want to stuff the firmware into the boot initramfs.
+* Testing built-in firmware
 
 Even if you have these needs there are a few reasons why you may not be
 able to make use of built-in firmware:
diff --git a/Documentation/x86/microcode.rst b/Documentation/x86/microcode.rst
index a320d37982ed..d199f0b98869 100644
--- a/Documentation/x86/microcode.rst
+++ b/Documentation/x86/microcode.rst
@@ -114,11 +114,12 @@  Builtin microcode
 =================
 
 The loader supports also loading of a builtin microcode supplied through
-the regular builtin firmware method CONFIG_EXTRA_FIRMWARE. Only 64-bit is
-currently supported.
+the regular builtin firmware method using CONFIG_FW_LOADER_BUILTIN and
+CONFIG_EXTRA_FIRMWARE. Only 64-bit is currently supported.
 
 Here's an example::
 
+  CONFIG_FW_LOADER_BUILTIN=y
   CONFIG_EXTRA_FIRMWARE="intel-ucode/06-3a-09 amd-ucode/microcode_amd_fam15h.bin"
   CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware"
 
diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
index 5b24f3959255..de4fcd9d41f3 100644
--- a/drivers/base/firmware_loader/Kconfig
+++ b/drivers/base/firmware_loader/Kconfig
@@ -29,8 +29,10 @@  if FW_LOADER
 config FW_LOADER_PAGED_BUF
 	bool
 
-config EXTRA_FIRMWARE
-	string "Build named firmware blobs into the kernel binary"
+config FW_LOADER_BUILTIN
+	bool "Enable support for built-in firmware"
+	default n
+	depends on FW_LOADER=y
 	help
 	  Device drivers which require firmware can typically deal with
 	  having the kernel load firmware from the various supported
@@ -43,7 +45,14 @@  config EXTRA_FIRMWARE
 	  in boot and cannot rely on the firmware being placed in an initrd or
 	  initramfs.
 
-	  This option is a string and takes the (space-separated) names of the
+	  Support for built-in firmware is not supported if you are using
+	  the firmware loader as a module.
+
+config EXTRA_FIRMWARE
+	string "Build named firmware blobs into the kernel binary"
+	depends on FW_LOADER_BUILTIN
+	help
+	  This option is a string and takes the space-separated names of the
 	  firmware files -- the same names that appear in MODULE_FIRMWARE()
 	  and request_firmware() in the source. These files should exist under
 	  the directory specified by the EXTRA_FIRMWARE_DIR option, which is
@@ -61,12 +70,14 @@  config EXTRA_FIRMWARE
 	  consult a lawyer of your own before distributing such an image.
 
 config EXTRA_FIRMWARE_DIR
-	string "Firmware blobs root directory"
-	depends on EXTRA_FIRMWARE != ""
+	string "Directory with firmware to be built-in to the kernel"
+	depends on FW_LOADER_BUILTIN
 	default "/lib/firmware"
 	help
-	  This option controls the directory in which the kernel build system
-	  looks for the firmware files listed in the EXTRA_FIRMWARE option.
+	  This option specifies the directory which the kernel build system
+	  will use to look for the firmware files which are going to be
+	  built into the kernel using the space-separated EXTRA_FIRMWARE
+	  entries.
 
 config FW_LOADER_USER_HELPER
 	bool "Enable the firmware sysfs fallback mechanism"
diff --git a/drivers/base/firmware_loader/Makefile b/drivers/base/firmware_loader/Makefile
index e87843408fe6..a2dbfa19201c 100644
--- a/drivers/base/firmware_loader/Makefile
+++ b/drivers/base/firmware_loader/Makefile
@@ -1,10 +1,9 @@ 
 # SPDX-License-Identifier: GPL-2.0
 # Makefile for the Linux firmware loader
 
+obj-$(CONFIG_FW_LOADER_BUILTIN) += builtin/
 obj-$(CONFIG_FW_LOADER_USER_HELPER) += fallback_table.o
 obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
 firmware_class-objs := main.o
 firmware_class-$(CONFIG_FW_LOADER_USER_HELPER) += fallback.o
 firmware_class-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += fallback_platform.o
-
-obj-y += builtin/
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index d95b5fe5f700..45075c7f9290 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -95,7 +95,7 @@  static struct firmware_cache fw_cache;
 
 /* Builtin firmware support */
 
-#ifdef CONFIG_FW_LOADER
+#ifdef CONFIG_FW_LOADER_BUILTIN
 
 extern struct builtin_fw __start_builtin_fw[];
 extern struct builtin_fw __end_builtin_fw[];
@@ -148,7 +148,7 @@  static bool fw_is_builtin_firmware(const struct firmware *fw)
 	return false;
 }
 
-#else /* Module case - no builtin firmware support */
+#else
 
 static inline bool firmware_request_builtin(struct firmware *fw,
 					    const char *name)