Fix compile failures due to arm64 includes in stable kernels

Fix compile failures due to arm64 includes in stable kernels

[Sebastian Kemper]

Hello all,

Some older stable kernels provide some arm64 headers like opcodes.h,
that include their non-64bit equivalents. For example:

arch/arm64/include/asm/opcodes.h

tries to include

<../../arm/include/asm/opcodes.h>

It's obvious that there is one hierarchy level missing. This causes
build failures:

    CC [M]  /build/lede-snapshots/aarch64_cortex-a53/build/sdk/build_dir/target-aarch64_cortex-a53_musl/linux-brcm2708_bcm2710/dahdi-linux-2.11.1-20180111/drivers/dahdi/dahdi-base.o
  In file included from ./arch/arm64/include/asm/sysreg.h:25:0,
                   from ./arch/arm64/include/asm/cputype.h:94,
                   from ./arch/arm64/include/asm/cachetype.h:19,
                   from ./arch/arm64/include/asm/cache.h:19,
                   from ./include/linux/cache.h:5,
                   from ./include/linux/printk.h:8,
                   from ./include/linux/kernel.h:13,
                   from /build/lede-snapshots/aarch64_cortex-a53/build/sdk/build_dir/target-aarch64_cortex-a53_musl/linux-brcm2708_bcm2710/dahdi-linux-2.11.1-20180111/drivers/dahdi/dahdi-base.c:38:
  ./arch/arm64/include/asm/opcodes.h:5:10: fatal error: ../../arm/include/asm/opcodes.h: No such file or directory
   #include <../../arm/include/asm/opcodes.h>
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  compilation terminated.

Some example packages that fail to build are dahdi-linux and
cryptodev-linux.

linux-3.16.56:
  - does not have opcodes.h, but the xen headers

      hypercall.h
      interface.h
      hypervisor.h
      page.h
      
    have the wrong include lines.
    
linux-4.1.50:
  - affected (needs a small change in the patch for opcodes.h due to slightly different layout)
  
linux-4.4.123:
  - affected
  
linux-4.9.89:
  - affected

The attached patch fixes the includes.

I understand that to get a patch accepted into the stable series one
needs to provide a commit to master. But in this case that doesn't seem
possible as these headers do not exist anymore in newer kernels.

What do you think? Does the above make sense to you to backport to the
stable kernels?

Thanks!
Sebastian
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Fix compile failures due to arm64 includes in stable kernels

[Stefano Stabellini]

On Sun, 25 Mar 2018, Sebastian Kemper wrote:
> Hello all,
> 
> Some older stable kernels provide some arm64 headers like opcodes.h,
> that include their non-64bit equivalents. For example:
> 
> arch/arm64/include/asm/opcodes.h
> 
> tries to include
> 
> <../../arm/include/asm/opcodes.h>
> 
> It's obvious that there is one hierarchy level missing. This causes
> build failures:
> 
>     CC [M]  /build/lede-snapshots/aarch64_cortex-a53/build/sdk/build_dir/target-aarch64_cortex-a53_musl/linux-brcm2708_bcm2710/dahdi-linux-2.11.1-20180111/drivers/dahdi/dahdi-base.o
>   In file included from ./arch/arm64/include/asm/sysreg.h:25:0,
>                    from ./arch/arm64/include/asm/cputype.h:94,
>                    from ./arch/arm64/include/asm/cachetype.h:19,
>                    from ./arch/arm64/include/asm/cache.h:19,
>                    from ./include/linux/cache.h:5,
>                    from ./include/linux/printk.h:8,
>                    from ./include/linux/kernel.h:13,
>                    from /build/lede-snapshots/aarch64_cortex-a53/build/sdk/build_dir/target-aarch64_cortex-a53_musl/linux-brcm2708_bcm2710/dahdi-linux-2.11.1-20180111/drivers/dahdi/dahdi-base.c:38:
>   ./arch/arm64/include/asm/opcodes.h:5:10: fatal error: ../../arm/include/asm/opcodes.h: No such file or directory
>    #include <../../arm/include/asm/opcodes.h>
>             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   compilation terminated.
> 
> Some example packages that fail to build are dahdi-linux and
> cryptodev-linux.
> 
> linux-3.16.56:
>   - does not have opcodes.h, but the xen headers
> 
>       hypercall.h
>       interface.h
>       hypervisor.h
>       page.h
>       
>     have the wrong include lines.
>     
> linux-4.1.50:
>   - affected (needs a small change in the patch for opcodes.h due to slightly different layout)
>   
> linux-4.4.123:
>   - affected
>   
> linux-4.9.89:
>   - affected
> 
> The attached patch fixes the includes.
> 
> I understand that to get a patch accepted into the stable series one
> needs to provide a commit to master. But in this case that doesn't seem
> possible as these headers do not exist anymore in newer kernels.
> 
> What do you think? Does the above make sense to you to backport to the
> stable kernels?

It is not actually a bug: the path was correct given the way the
Makefiles were written -- if you build a regular arm64 kernel with the
default config and CONFIG_XEN enabled, it will work fine.

I am guessing you see these issues with out-of-tree modules, right?

Fortunately, on newer kernels the whole thing has been reworked, and
should solve the problem for you. The commit you are looking for is
2fbadc3002c5f172d20aa2e7e48920c5f14ed11f:

commit 7465c84a9380779235af42146dae6798b89b1d12
Author: Marc Zyngier <marc.zyngier@arm.com>
Date:   Fri Dec 2 14:19:35 2016 +0000

    arm/arm64: xen: Move shared architecture headers to include/xen/arm
    
    ARM and arm64 Xen ports share a number of headers, leading to
    packaging issues when these headers needs to be exported, as it
    breaks the reasonable requirement that an architecture port
    has self-contained headers.
    
    Fix the issue by moving the 5 header files to include/xen/arm,
    and keep local placeholders to include the relevant files.
    
    Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
    Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

I am CC'ing the original author.

Fix compile failures due to arm64 includes in stable kernels

[Sebastian Kemper]

On Tue, Mar 27, 2018 at 05:23:47PM -0700, Stefano Stabellini wrote:
> On Sun, 25 Mar 2018, Sebastian Kemper wrote:
> > Hello all,
> > 
> > Some older stable kernels provide some arm64 headers like opcodes.h,
> > that include their non-64bit equivalents. For example:
> > 
> > arch/arm64/include/asm/opcodes.h
> > 
> > tries to include
> > 
> > <../../arm/include/asm/opcodes.h>
> > 
> > It's obvious that there is one hierarchy level missing. This causes
> > build failures:
> > 
> >     CC [M]  /build/lede-snapshots/aarch64_cortex-a53/build/sdk/build_dir/target-aarch64_cortex-a53_musl/linux-brcm2708_bcm2710/dahdi-linux-2.11.1-20180111/drivers/dahdi/dahdi-base.o
> >   In file included from ./arch/arm64/include/asm/sysreg.h:25:0,
> >                    from ./arch/arm64/include/asm/cputype.h:94,
> >                    from ./arch/arm64/include/asm/cachetype.h:19,
> >                    from ./arch/arm64/include/asm/cache.h:19,
> >                    from ./include/linux/cache.h:5,
> >                    from ./include/linux/printk.h:8,
> >                    from ./include/linux/kernel.h:13,
> >                    from /build/lede-snapshots/aarch64_cortex-a53/build/sdk/build_dir/target-aarch64_cortex-a53_musl/linux-brcm2708_bcm2710/dahdi-linux-2.11.1-20180111/drivers/dahdi/dahdi-base.c:38:
> >   ./arch/arm64/include/asm/opcodes.h:5:10: fatal error: ../../arm/include/asm/opcodes.h: No such file or directory
> >    #include <../../arm/include/asm/opcodes.h>
> >             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >   compilation terminated.
> > 
> > Some example packages that fail to build are dahdi-linux and
> > cryptodev-linux.
> > 
> > linux-3.16.56:
> >   - does not have opcodes.h, but the xen headers
> > 
> >       hypercall.h
> >       interface.h
> >       hypervisor.h
> >       page.h
> >       
> >     have the wrong include lines.
> >     
> > linux-4.1.50:
> >   - affected (needs a small change in the patch for opcodes.h due to slightly different layout)
> >   
> > linux-4.4.123:
> >   - affected
> >   
> > linux-4.9.89:
> >   - affected
> > 
> > The attached patch fixes the includes.
> > 
> > I understand that to get a patch accepted into the stable series one
> > needs to provide a commit to master. But in this case that doesn't seem
> > possible as these headers do not exist anymore in newer kernels.
> > 
> > What do you think? Does the above make sense to you to backport to the
> > stable kernels?
> 
> It is not actually a bug: the path was correct given the way the
> Makefiles were written -- if you build a regular arm64 kernel with the
> default config and CONFIG_XEN enabled, it will work fine.
> 
> I am guessing you see these issues with out-of-tree modules, right?

Hi Stefano,

Correct. They're out-of-tree modules.

As this seems to imply that my suggested patch could result in in-tree
modules not compiling anymore, I'll just drop it.

Thanks for your feedback!

Kind regards,
Sebastian

> Fortunately, on newer kernels the whole thing has been reworked, and
> should solve the problem for you. The commit you are looking for is
> 2fbadc3002c5f172d20aa2e7e48920c5f14ed11f:
> 
> commit 7465c84a9380779235af42146dae6798b89b1d12
> Author: Marc Zyngier <marc.zyngier@arm.com>
> Date:   Fri Dec 2 14:19:35 2016 +0000
> 
>     arm/arm64: xen: Move shared architecture headers to include/xen/arm
>     
>     ARM and arm64 Xen ports share a number of headers, leading to
>     packaging issues when these headers needs to be exported, as it
>     breaks the reasonable requirement that an architecture port
>     has self-contained headers.
>     
>     Fix the issue by moving the 5 header files to include/xen/arm,
>     and keep local placeholders to include the relevant files.
>     
>     Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>     Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
> 
> I am CC'ing the original author.