[PATCH] x86/fpu: allow kernel_fpu_{begin,end} to be used by non-GPL modules

[PATCH] x86/fpu: allow kernel_fpu_{begin,end} to be used by non-GPL modules

[Aleksa Sarai]

Prior to [1], all non-GPL modules were able to make use of SIMD on x86
by making use of the __kernel_fpu_* API. Given that __kernel_fpu_* were
both EXPORT_SYMBOL'd and kernel_fpu_* are such trivial wrappers around
the now-static __kernel_fpu_*, it seems to me that there is no reason to
have different licensing rules for them.

In the case of OpenZFS, the lack of SIMD on newer Linux kernels has
caused significant performance problems (since ZFS uses SIMD for
calculation of blkptr checksums as well as raidz calculations).

[1]: commit 12209993e98c ("x86/fpu: Don't export __kernel_fpu_{begin,end}()")

Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
 arch/x86/kernel/fpu/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 2e5003fef51a..8de5687a470d 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -127,14 +127,14 @@ void kernel_fpu_begin(void)
 	preempt_disable();
 	__kernel_fpu_begin();
 }
-EXPORT_SYMBOL_GPL(kernel_fpu_begin);
+EXPORT_SYMBOL(kernel_fpu_begin);
 
 void kernel_fpu_end(void)
 {
 	__kernel_fpu_end();
 	preempt_enable();
 }
-EXPORT_SYMBOL_GPL(kernel_fpu_end);
+EXPORT_SYMBOL(kernel_fpu_end);
 
 /*
  * Save the FPU state (mark it for reload if necessary):
-- 
2.21.0

Re: [PATCH] x86/fpu: allow kernel_fpu_{begin,end} to be used by non-GPL modules

[Greg KH]

On Wed, May 22, 2019 at 02:42:04PM +1000, Aleksa Sarai wrote:
> Prior to [1], all non-GPL modules were able to make use of SIMD on x86
> by making use of the __kernel_fpu_* API. Given that __kernel_fpu_* were
> both EXPORT_SYMBOL'd and kernel_fpu_* are such trivial wrappers around
> the now-static __kernel_fpu_*, it seems to me that there is no reason to
> have different licensing rules for them.
> 
> In the case of OpenZFS, the lack of SIMD on newer Linux kernels has
> caused significant performance problems (since ZFS uses SIMD for
> calculation of blkptr checksums as well as raidz calculations).
> 
> [1]: commit 12209993e98c ("x86/fpu: Don't export __kernel_fpu_{begin,end}()")
> 
> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
> Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
> ---
>  arch/x86/kernel/fpu/core.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
> index 2e5003fef51a..8de5687a470d 100644
> --- a/arch/x86/kernel/fpu/core.c
> +++ b/arch/x86/kernel/fpu/core.c
> @@ -127,14 +127,14 @@ void kernel_fpu_begin(void)
>  	preempt_disable();
>  	__kernel_fpu_begin();
>  }
> -EXPORT_SYMBOL_GPL(kernel_fpu_begin);
> +EXPORT_SYMBOL(kernel_fpu_begin);
>  
>  void kernel_fpu_end(void)
>  {
>  	__kernel_fpu_end();
>  	preempt_enable();
>  }
> -EXPORT_SYMBOL_GPL(kernel_fpu_end);
> +EXPORT_SYMBOL(kernel_fpu_end);

No, please, we have gone over this before, we do not care at all about
external kernel modules, ESPECIALLY ones that are not GPL compatible.

greg k-h

Re: [zfs-devel] Re: [PATCH] x86/fpu: allow kernel_fpu_{begin,end} to be used by non-GPL modules

[Mason Loring Bliss]

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On Wed, May 22, 2019 at 12:09:59PM +0200, Greg KH wrote:

> No, please, we have gone over this before, we do not care at all about
> external kernel modules, ESPECIALLY ones that are not GPL compatible.

The best option here is for you to start caring. Makes the world a better
place.

Free software people doing what they can to attack other free software based
on relatively trivial idealogical differences isn't a good look, and it's bad
for the users.

-- 
Mason Loring Bliss  ((   If I have not seen as far as others, it is because
 mason@blisses.org   ))   giants were standing on my shoulders. - Hal Abelson

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