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Linux 5.0: _kernel_fpu{begin,end} no longer exported #8259

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tonyhutter opened this issue Jan 9, 2019 · 7 comments · Fixed by #8363
Closed

Linux 5.0: _kernel_fpu{begin,end} no longer exported #8259

tonyhutter opened this issue Jan 9, 2019 · 7 comments · Fixed by #8363
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@tonyhutter
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Status: Blocked Depends on another pending change Type: Building Indicates an issue related to building binaries

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@tonyhutter
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tonyhutter commented Jan 9, 2019 •
edited

System information

Type Version/Name
Distribution Name Fedora
Distribution Version 30 (rawhide)
Linux Kernel 5.0.0-0.rc1.git0.1.fc30.x86_64
Architecture x86-64
ZFS Version master
SPL Version master

Describe the problem you're observing

The 4.2 kernel refractored the FPU code: https://lwn.net/Articles/643235/ It seems the latest kernels removed the old compatibility headers.

We need to rename our #includes <asm/i387.h> -> <asm/fpu/api.h> and <asm/xcr.h> -> <asm/fpu/internal.h> on newer kernels.

Describe how to reproduce the problem

make on rawhide with ZFS master

Include any warning/errors/backtraces from the system logs

/home/hutter/current_kernel_time64/include/linux/simd_x86.h:98:10: fatal error: asm/i387.h: No such file or directory
 #include <asm/i387.h>
          ^~~~~~~~~~~~
compilation terminated.
@mdionne
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mdionne commented Jan 9, 2019

The underlying issue comes from kernel commit 12209993e98c5fa1855c467f22a24e3d5b8be205 ("x86/fpu: Don't export _kernel_fpu{begin,end}()"), which unexports __kernel_fpu_begin(), and causes the configure tests not to define HAVE_FPU_API_H. Changing the header locations will just lead to another failure later because kernel_fpu_begin/end() are exported GPL, and can't be used directly from the zfs module.

See the thread on LKML starting here: https://marc.info/?l=linux-kernel&m=154689892914091

Marc

@tonyhutter
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@mdionne thanks for bringing this to our attention. Hopefully they change their minds and EXPORT_SYMBOL(kernel_fpu_begin) so we can use that instead.

@tonyhutter tonyhutter self-assigned this Jan 10, 2019
@tonyhutter tonyhutter added Type: Building Indicates an issue related to building binaries Status: Blocked Depends on another pending change labels Jan 10, 2019
@ideologysec
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https://marc.info/?l=linux-kernel&m=154714516832389&w=2

Gotta love the replies. Greg K-H:

My tolerance for ZFS is pretty non-existant. Sun explicitly did not
want their code to work on Linux, so why would we do extra work to get
their code to work properly?

@sbuller

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@tonyhutter
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I think we need to operate under the assumption that they're not going to export the functions, and just disable the vectorized versions of the checksums if _kernel_fpu{begin,end} are not detected.

@tonyhutter tonyhutter changed the title Linux 5.0: asm/i387.h: No such file or directory Linux 5.0: _kernel_fpu{begin,end} no longer exported Jan 14, 2019
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 17, 2019
@tonyhutter
Linux 5.0: Disable vector instructions on 5.0+ kernels
c5c9ced 
The 5.0 kernel no longer exports the functions we need to vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Fixes: openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 17, 2019
@tonyhutter
Linux 5.0: Disable vector instructions on 5.0+ kernels
2c1fba5 
The 5.0 kernel no longer exports the functions we need to vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Fixes: openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 17, 2019
@tonyhutter
Linux 5.0: Disable vector instructions on 5.0+ kernels
b01ef60 
The 5.0 kernel no longer exports the functions we need to do vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Fixes: openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 17, 2019
@tonyhutter
Linux 5.0: Disable vector instructions on 5.0+ kernels
c781eff 
The 5.0 kernel no longer exports the functions we need to do vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Fixes: openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 22, 2019
@tonyhutter
Linux 5.0: Disable vector instructions on 5.0+ kernels
44de5ab 
The 5.0 kernel no longer exports the functions we need to do vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Fixes: openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 22, 2019
@tonyhutter
Linux 5.0: Disable vector instructions on 5.0+ kernels
9cc8182 
The 5.0 kernel no longer exports the functions we need to do vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Fixes: openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 22, 2019
@tonyhutter
Linux 5.0: Disable vector instructions on 5.0+ kernels
29d25be 
The 5.0 kernel no longer exports the functions we need to do vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Fixes: openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 23, 2019
@tonyhutter
Linux 5.0: Disable vector instructions on 5.0+ kernels
f51fb11 
The 5.0 kernel no longer exports the functions we need to do vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Fixes: openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 25, 2019
@tonyhutter
Linux 5.0: Disable vector instructions on 5.0+ kernels
f314268 
The 5.0 kernel no longer exports the functions we need to do vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Fixes: openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Jan 30, 2019
@tonyhutter
Linux 5.0 compat: Disable vector instructions on 5.0+ kernels
99d4985 
The 5.0 kernel no longer exports the functions we need to do vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Feb 1, 2019
@tonyhutter
kernel_fpu cleanups
11cd406 
This patch fixes a few issues when detecting which kernel_fpu functions
are available.

- Use kernel_fpu_begin() if it's exported on newer kernels.

- Use ZFS_LINUX_TRY_COMPILE_SYMBOL() to choose the right kernel_fpu
  function when using --enable-linux-builtin.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes: openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Feb 1, 2019
@tonyhutter
kernel_fpu fixes
3a953fb 
This patch fixes a few issues when detecting which kernel_fpu functions
are available.

- Use kernel_fpu_begin() if it's exported on newer kernels.

- Use ZFS_LINUX_TRY_COMPILE_SYMBOL() to choose the right kernel_fpu
  function when using --enable-linux-builtin.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes: openzfs#8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Feb 12, 2019
@tonyhutter
Linux 5.0 compat: Disable vector instructions on 5.0+ kernels
263ec2e 
The 5.0 kernel no longer exports the functions we need to do vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes openzfs#8259
tonyhutter added a commit that referenced this issue Mar 4, 2019
@tonyhutter
Linux 5.0 compat: Disable vector instructions on 5.0+ kernels
e22bfd8 
The 5.0 kernel no longer exports the functions we need to do vector
(SSE/SSE2/SSE3/AVX...) instructions.  Disable vector-based checksum
algorithms when building against those kernels.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #8259
tonyhutter added a commit to tonyhutter/zfs that referenced this issue Mar 5, 2019
@tonyhutter
kernel_fpu fixes
3385e4b 
This patch fixes a few issues when detecting which kernel_fpu functions
are available.

- Use kernel_fpu_begin() if it's exported on newer kernels.

- Use ZFS_LINUX_TRY_COMPILE_SYMBOL() to choose the right kernel_fpu
  function when using --enable-linux-builtin.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes: openzfs#8259
behlendorf pushed a commit that referenced this issue Mar 7, 2019
@tonyhutter @behlendorf
kernel_fpu fixes
becdcec 
This patch fixes a few issues when detecting which kernel_fpu functions
are available.

- Use kernel_fpu_begin() if it's exported on newer kernels.

- Use ZFS_LINUX_TRY_COMPILE_SYMBOL() to choose the right kernel_fpu
  function when using --enable-linux-builtin.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #8259
Closes #8363
@tonyhutter
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Looks like the kernel people may have backported their patch to older kernels:

For the record, it appears the FPU export was removed in 4.19.38 (released 2019-05-02) via d4ff57d0320bf441ad5a3084b3adbba4da1d79f8 and 4.14.120 (released 2019-05-16) via a725c5201f0807a9f843db525f5f98f6c7a4c25b.

#8793 (comment)

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kernel_fpu fixes tonyhutter/zfs
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