[PATCH] squashfs: Fix compilation on big endian systems

[PATCH] squashfs: Fix compilation on big endian systems

[Pali Rohár]

Signed-off-by: Pali Rohár <pali@kernel.org>
---
 fs/squashfs/sqfs.c     | 3 +--
 fs/squashfs/sqfs_dir.c | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
index 5d9c52af80ba..41cb811c1b32 100644
--- a/fs/squashfs/sqfs.c
+++ b/fs/squashfs/sqfs.c
@@ -11,8 +11,7 @@
 #include <errno.h>
 #include <fs.h>
 #include <linux/types.h>
-#include <linux/byteorder/little_endian.h>
-#include <linux/byteorder/generic.h>
+#include <asm/byteorder.h>
 #include <memalign.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/fs/squashfs/sqfs_dir.c b/fs/squashfs/sqfs_dir.c
index a265b98fe685..ed83c90682ff 100644
--- a/fs/squashfs/sqfs_dir.c
+++ b/fs/squashfs/sqfs_dir.c
@@ -7,8 +7,7 @@
 
 #include <errno.h>
 #include <linux/types.h>
-#include <linux/byteorder/little_endian.h>
-#include <linux/byteorder/generic.h>
+#include <asm/byteorder.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
-- 
2.20.1

Re: [PATCH] squashfs: Fix compilation on big endian systems

[Miquel Raynal]

Hi Pali,

pali@kernel.org wrote on Wed,  6 Apr 2022 23:31:53 +0200:

Would you mind explaining a little bit how this change fixes it? It
does not look straightforward to me.

> Signed-off-by: Pali Rohár <pali@kernel.org>
> ---
>  fs/squashfs/sqfs.c     | 3 +--
>  fs/squashfs/sqfs_dir.c | 3 +--
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> index 5d9c52af80ba..41cb811c1b32 100644
> --- a/fs/squashfs/sqfs.c
> +++ b/fs/squashfs/sqfs.c
> @@ -11,8 +11,7 @@
>  #include <errno.h>
>  #include <fs.h>
>  #include <linux/types.h>
> -#include <linux/byteorder/little_endian.h>
> -#include <linux/byteorder/generic.h>
> +#include <asm/byteorder.h>
>  #include <memalign.h>
>  #include <stdlib.h>
>  #include <string.h>
> diff --git a/fs/squashfs/sqfs_dir.c b/fs/squashfs/sqfs_dir.c
> index a265b98fe685..ed83c90682ff 100644
> --- a/fs/squashfs/sqfs_dir.c
> +++ b/fs/squashfs/sqfs_dir.c
> @@ -7,8 +7,7 @@
>  
>  #include <errno.h>
>  #include <linux/types.h>
> -#include <linux/byteorder/little_endian.h>
> -#include <linux/byteorder/generic.h>
> +#include <asm/byteorder.h>
>  #include <stdint.h>
>  #include <stdio.h>
>  #include <stdlib.h>

Cheers,
Miquèl

Re: [PATCH] squashfs: Fix compilation on big endian systems

[Pali Rohár]

On Thursday 07 April 2022 09:54:21 Miquel Raynal wrote:
> Hi Pali,
> 
> pali@kernel.org wrote on Wed,  6 Apr 2022 23:31:53 +0200:
> 
> Would you mind explaining a little bit how this change fixes it? It
> does not look straightforward to me.

Yes! I though that it is straightforward this change...
byteorder/little_endian.h defines cpu_to_le* macros for Little Endian
systems and byteorder/big_endian.h for Big Endian systems.

File asm/byteorder.h is then ARCH-specific and implements macros for the
current architecture (by including the correct header file).

So currently if you try to compile squashfs for big endian systems you
get compile error:

  In file included from ./arch/powerpc/include/asm/byteorder.h:82,
                   from include/linux/unaligned/access_ok.h:4,
                   from ./arch/powerpc/include/asm/unaligned.h:9,
                   from fs/squashfs/sqfs_filesystem.h:11,
                   from fs/squashfs/sqfs_dir.c:16:
  include/linux/byteorder/big_endian.h:34: warning: "__cpu_to_le32" redefined
   #define __cpu_to_le32(x) ((__force __le32)__swab32((x)))

  In file included from fs/squashfs/sqfs_dir.c:10:
  include/linux/byteorder/little_endian.h:34: note: this is the location of the previous definition
   #define __cpu_to_le32(x) ((__force __le32)(__u32)(x))

Or:

  In file included from fs/squashfs/sqfs.c:14:
  include/linux/byteorder/little_endian.h:89:21: error: redefinition of ‘__be16_to_cpup’
   static inline __u16 __be16_to_cpup(const __be16 *p)
                       ^~~~~~~~~~~~~~
  In file included from ./arch/powerpc/include/asm/byteorder.h:82,
                   from include/linux/unaligned/access_ok.h:4,
                   from ./arch/powerpc/include/asm/unaligned.h:9,
                   from fs/squashfs/sqfs.c:10:
  include/linux/byteorder/big_endian.h:89:21: note: previous definition of ‘__be16_to_cpup’ was here
   static inline __u16 __be16_to_cpup(const __be16 *p)
                       ^~~~~~~~~~~~~~

As some header files include correct asm/byteorder.h file and this
squashfs includes additional little_endian.h.

> > Signed-off-by: Pali Rohár <pali@kernel.org>
> > ---
> >  fs/squashfs/sqfs.c     | 3 +--
> >  fs/squashfs/sqfs_dir.c | 3 +--
> >  2 files changed, 2 insertions(+), 4 deletions(-)
> > 
> > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > index 5d9c52af80ba..41cb811c1b32 100644
> > --- a/fs/squashfs/sqfs.c
> > +++ b/fs/squashfs/sqfs.c
> > @@ -11,8 +11,7 @@
> >  #include <errno.h>
> >  #include <fs.h>
> >  #include <linux/types.h>
> > -#include <linux/byteorder/little_endian.h>
> > -#include <linux/byteorder/generic.h>
> > +#include <asm/byteorder.h>
> >  #include <memalign.h>
> >  #include <stdlib.h>
> >  #include <string.h>
> > diff --git a/fs/squashfs/sqfs_dir.c b/fs/squashfs/sqfs_dir.c
> > index a265b98fe685..ed83c90682ff 100644
> > --- a/fs/squashfs/sqfs_dir.c
> > +++ b/fs/squashfs/sqfs_dir.c
> > @@ -7,8 +7,7 @@
> >  
> >  #include <errno.h>
> >  #include <linux/types.h>
> > -#include <linux/byteorder/little_endian.h>
> > -#include <linux/byteorder/generic.h>
> > +#include <asm/byteorder.h>
> >  #include <stdint.h>
> >  #include <stdio.h>
> >  #include <stdlib.h>
> 
> Cheers,
> Miquèl

Re: [PATCH] squashfs: Fix compilation on big endian systems

[Miquel Raynal]

Hi Pali,

pali@kernel.org wrote on Thu, 7 Apr 2022 11:41:59 +0200:

> On Thursday 07 April 2022 09:54:21 Miquel Raynal wrote:
> > Hi Pali,
> > 
> > pali@kernel.org wrote on Wed,  6 Apr 2022 23:31:53 +0200:
> > 
> > Would you mind explaining a little bit how this change fixes it? It
> > does not look straightforward to me.  
> 
> Yes! I though that it is straightforward this change...
> byteorder/little_endian.h defines cpu_to_le* macros for Little Endian
> systems and byteorder/big_endian.h for Big Endian systems.
> 
> File asm/byteorder.h is then ARCH-specific and implements macros for the
> current architecture (by including the correct header file).
> 
> So currently if you try to compile squashfs for big endian systems you
> get compile error:
> 
>   In file included from ./arch/powerpc/include/asm/byteorder.h:82,
>                    from include/linux/unaligned/access_ok.h:4,
>                    from ./arch/powerpc/include/asm/unaligned.h:9,
>                    from fs/squashfs/sqfs_filesystem.h:11,
>                    from fs/squashfs/sqfs_dir.c:16:
>   include/linux/byteorder/big_endian.h:34: warning: "__cpu_to_le32" redefined
>    #define __cpu_to_le32(x) ((__force __le32)__swab32((x)))
> 
>   In file included from fs/squashfs/sqfs_dir.c:10:
>   include/linux/byteorder/little_endian.h:34: note: this is the location of the previous definition
>    #define __cpu_to_le32(x) ((__force __le32)(__u32)(x))
> 
> Or:
> 
>   In file included from fs/squashfs/sqfs.c:14:
>   include/linux/byteorder/little_endian.h:89:21: error: redefinition of ‘__be16_to_cpup’
>    static inline __u16 __be16_to_cpup(const __be16 *p)
>                        ^~~~~~~~~~~~~~
>   In file included from ./arch/powerpc/include/asm/byteorder.h:82,
>                    from include/linux/unaligned/access_ok.h:4,
>                    from ./arch/powerpc/include/asm/unaligned.h:9,
>                    from fs/squashfs/sqfs.c:10:
>   include/linux/byteorder/big_endian.h:89:21: note: previous definition of ‘__be16_to_cpup’ was here
>    static inline __u16 __be16_to_cpup(const __be16 *p)
>                        ^~~~~~~~~~~~~~
> 
> As some header files include correct asm/byteorder.h file and this
> squashfs includes additional little_endian.h.

Great, thanks for the thorough explanation. Based on what you said,
wouldn't it be cleaner to just get rid of the little_endian.h include
rather than also use the ARCH specific byteorder.h header?

> 
> > > Signed-off-by: Pali Rohár <pali@kernel.org>
> > > ---
> > >  fs/squashfs/sqfs.c     | 3 +--
> > >  fs/squashfs/sqfs_dir.c | 3 +--
> > >  2 files changed, 2 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > > index 5d9c52af80ba..41cb811c1b32 100644
> > > --- a/fs/squashfs/sqfs.c
> > > +++ b/fs/squashfs/sqfs.c
> > > @@ -11,8 +11,7 @@
> > >  #include <errno.h>
> > >  #include <fs.h>
> > >  #include <linux/types.h>
> > > -#include <linux/byteorder/little_endian.h>
> > > -#include <linux/byteorder/generic.h>
> > > +#include <asm/byteorder.h>
> > >  #include <memalign.h>
> > >  #include <stdlib.h>
> > >  #include <string.h>
> > > diff --git a/fs/squashfs/sqfs_dir.c b/fs/squashfs/sqfs_dir.c
> > > index a265b98fe685..ed83c90682ff 100644
> > > --- a/fs/squashfs/sqfs_dir.c
> > > +++ b/fs/squashfs/sqfs_dir.c
> > > @@ -7,8 +7,7 @@
> > >  
> > >  #include <errno.h>
> > >  #include <linux/types.h>
> > > -#include <linux/byteorder/little_endian.h>
> > > -#include <linux/byteorder/generic.h>
> > > +#include <asm/byteorder.h>
> > >  #include <stdint.h>
> > >  #include <stdio.h>
> > >  #include <stdlib.h>  
> > 
> > Cheers,
> > Miquèl  


Thanks,
Miquèl

Re: [PATCH] squashfs: Fix compilation on big endian systems

[Pali Rohár]

On Thursday 07 April 2022 11:54:55 Miquel Raynal wrote:
> Hi Pali,
> 
> pali@kernel.org wrote on Thu, 7 Apr 2022 11:41:59 +0200:
> 
> > On Thursday 07 April 2022 09:54:21 Miquel Raynal wrote:
> > > Hi Pali,
> > > 
> > > pali@kernel.org wrote on Wed,  6 Apr 2022 23:31:53 +0200:
> > > 
> > > Would you mind explaining a little bit how this change fixes it? It
> > > does not look straightforward to me.  
> > 
> > Yes! I though that it is straightforward this change...
> > byteorder/little_endian.h defines cpu_to_le* macros for Little Endian
> > systems and byteorder/big_endian.h for Big Endian systems.
> > 
> > File asm/byteorder.h is then ARCH-specific and implements macros for the
> > current architecture (by including the correct header file).
> > 
> > So currently if you try to compile squashfs for big endian systems you
> > get compile error:
> > 
> >   In file included from ./arch/powerpc/include/asm/byteorder.h:82,
> >                    from include/linux/unaligned/access_ok.h:4,
> >                    from ./arch/powerpc/include/asm/unaligned.h:9,
> >                    from fs/squashfs/sqfs_filesystem.h:11,
> >                    from fs/squashfs/sqfs_dir.c:16:
> >   include/linux/byteorder/big_endian.h:34: warning: "__cpu_to_le32" redefined
> >    #define __cpu_to_le32(x) ((__force __le32)__swab32((x)))
> > 
> >   In file included from fs/squashfs/sqfs_dir.c:10:
> >   include/linux/byteorder/little_endian.h:34: note: this is the location of the previous definition
> >    #define __cpu_to_le32(x) ((__force __le32)(__u32)(x))
> > 
> > Or:
> > 
> >   In file included from fs/squashfs/sqfs.c:14:
> >   include/linux/byteorder/little_endian.h:89:21: error: redefinition of ‘__be16_to_cpup’
> >    static inline __u16 __be16_to_cpup(const __be16 *p)
> >                        ^~~~~~~~~~~~~~
> >   In file included from ./arch/powerpc/include/asm/byteorder.h:82,
> >                    from include/linux/unaligned/access_ok.h:4,
> >                    from ./arch/powerpc/include/asm/unaligned.h:9,
> >                    from fs/squashfs/sqfs.c:10:
> >   include/linux/byteorder/big_endian.h:89:21: note: previous definition of ‘__be16_to_cpup’ was here
> >    static inline __u16 __be16_to_cpup(const __be16 *p)
> >                        ^~~~~~~~~~~~~~
> > 
> > As some header files include correct asm/byteorder.h file and this
> > squashfs includes additional little_endian.h.
> 
> Great, thanks for the thorough explanation. Based on what you said,
> wouldn't it be cleaner to just get rid of the little_endian.h include
> rather than also use the ARCH specific byteorder.h header?

I think that this is not possible. squashfs code uses le16_to_cpu()
macro and its correct definition is provided only by arch specific
asm/byteorder.h.

> > 
> > > > Signed-off-by: Pali Rohár <pali@kernel.org>
> > > > ---
> > > >  fs/squashfs/sqfs.c     | 3 +--
> > > >  fs/squashfs/sqfs_dir.c | 3 +--
> > > >  2 files changed, 2 insertions(+), 4 deletions(-)
> > > > 
> > > > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > > > index 5d9c52af80ba..41cb811c1b32 100644
> > > > --- a/fs/squashfs/sqfs.c
> > > > +++ b/fs/squashfs/sqfs.c
> > > > @@ -11,8 +11,7 @@
> > > >  #include <errno.h>
> > > >  #include <fs.h>
> > > >  #include <linux/types.h>
> > > > -#include <linux/byteorder/little_endian.h>
> > > > -#include <linux/byteorder/generic.h>
> > > > +#include <asm/byteorder.h>
> > > >  #include <memalign.h>
> > > >  #include <stdlib.h>
> > > >  #include <string.h>
> > > > diff --git a/fs/squashfs/sqfs_dir.c b/fs/squashfs/sqfs_dir.c
> > > > index a265b98fe685..ed83c90682ff 100644
> > > > --- a/fs/squashfs/sqfs_dir.c
> > > > +++ b/fs/squashfs/sqfs_dir.c
> > > > @@ -7,8 +7,7 @@
> > > >  
> > > >  #include <errno.h>
> > > >  #include <linux/types.h>
> > > > -#include <linux/byteorder/little_endian.h>
> > > > -#include <linux/byteorder/generic.h>
> > > > +#include <asm/byteorder.h>
> > > >  #include <stdint.h>
> > > >  #include <stdio.h>
> > > >  #include <stdlib.h>  
> > > 
> > > Cheers,
> > > Miquèl  
> 
> 
> Thanks,
> Miquèl

Re: [PATCH] squashfs: Fix compilation on big endian systems

[Pali Rohár]

On Wednesday 06 April 2022 23:31:53 Pali Rohár wrote:
> Signed-off-by: Pali Rohár <pali@kernel.org>
> ---
>  fs/squashfs/sqfs.c     | 3 +--
>  fs/squashfs/sqfs_dir.c | 3 +--
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> index 5d9c52af80ba..41cb811c1b32 100644
> --- a/fs/squashfs/sqfs.c
> +++ b/fs/squashfs/sqfs.c
> @@ -11,8 +11,7 @@
>  #include <errno.h>
>  #include <fs.h>
>  #include <linux/types.h>
> -#include <linux/byteorder/little_endian.h>
> -#include <linux/byteorder/generic.h>
> +#include <asm/byteorder.h>
>  #include <memalign.h>
>  #include <stdlib.h>
>  #include <string.h>
> diff --git a/fs/squashfs/sqfs_dir.c b/fs/squashfs/sqfs_dir.c
> index a265b98fe685..ed83c90682ff 100644
> --- a/fs/squashfs/sqfs_dir.c
> +++ b/fs/squashfs/sqfs_dir.c
> @@ -7,8 +7,7 @@
>  
>  #include <errno.h>
>  #include <linux/types.h>
> -#include <linux/byteorder/little_endian.h>
> -#include <linux/byteorder/generic.h>
> +#include <asm/byteorder.h>
>  #include <stdint.h>
>  #include <stdio.h>
>  #include <stdlib.h>
> -- 
> 2.20.1
> 

PING?

Re: [PATCH] squashfs: Fix compilation on big endian systems

[Pali Rohár]

On Tuesday 10 May 2022 16:33:56 Pali Rohár wrote:
> On Wednesday 06 April 2022 23:31:53 Pali Rohár wrote:
> > Signed-off-by: Pali Rohár <pali@kernel.org>
> > ---
> >  fs/squashfs/sqfs.c     | 3 +--
> >  fs/squashfs/sqfs_dir.c | 3 +--
> >  2 files changed, 2 insertions(+), 4 deletions(-)
> > 
> > diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
> > index 5d9c52af80ba..41cb811c1b32 100644
> > --- a/fs/squashfs/sqfs.c
> > +++ b/fs/squashfs/sqfs.c
> > @@ -11,8 +11,7 @@
> >  #include <errno.h>
> >  #include <fs.h>
> >  #include <linux/types.h>
> > -#include <linux/byteorder/little_endian.h>
> > -#include <linux/byteorder/generic.h>
> > +#include <asm/byteorder.h>
> >  #include <memalign.h>
> >  #include <stdlib.h>
> >  #include <string.h>
> > diff --git a/fs/squashfs/sqfs_dir.c b/fs/squashfs/sqfs_dir.c
> > index a265b98fe685..ed83c90682ff 100644
> > --- a/fs/squashfs/sqfs_dir.c
> > +++ b/fs/squashfs/sqfs_dir.c
> > @@ -7,8 +7,7 @@
> >  
> >  #include <errno.h>
> >  #include <linux/types.h>
> > -#include <linux/byteorder/little_endian.h>
> > -#include <linux/byteorder/generic.h>
> > +#include <asm/byteorder.h>
> >  #include <stdint.h>
> >  #include <stdio.h>
> >  #include <stdlib.h>
> > -- 
> > 2.20.1
> > 
> 
> PING?

PING?

Re: [PATCH] squashfs: Fix compilation on big endian systems

[Tom Rini]

[-- Attachment #1: Type: text/plain, Size: 3081 bytes --]

On Thu, Apr 07, 2022 at 11:58:55AM +0200, Pali Rohár wrote:
> On Thursday 07 April 2022 11:54:55 Miquel Raynal wrote:
> > Hi Pali,
> > 
> > pali@kernel.org wrote on Thu, 7 Apr 2022 11:41:59 +0200:
> > 
> > > On Thursday 07 April 2022 09:54:21 Miquel Raynal wrote:
> > > > Hi Pali,
> > > > 
> > > > pali@kernel.org wrote on Wed,  6 Apr 2022 23:31:53 +0200:
> > > > 
> > > > Would you mind explaining a little bit how this change fixes it? It
> > > > does not look straightforward to me.  
> > > 
> > > Yes! I though that it is straightforward this change...
> > > byteorder/little_endian.h defines cpu_to_le* macros for Little Endian
> > > systems and byteorder/big_endian.h for Big Endian systems.
> > > 
> > > File asm/byteorder.h is then ARCH-specific and implements macros for the
> > > current architecture (by including the correct header file).
> > > 
> > > So currently if you try to compile squashfs for big endian systems you
> > > get compile error:
> > > 
> > >   In file included from ./arch/powerpc/include/asm/byteorder.h:82,
> > >                    from include/linux/unaligned/access_ok.h:4,
> > >                    from ./arch/powerpc/include/asm/unaligned.h:9,
> > >                    from fs/squashfs/sqfs_filesystem.h:11,
> > >                    from fs/squashfs/sqfs_dir.c:16:
> > >   include/linux/byteorder/big_endian.h:34: warning: "__cpu_to_le32" redefined
> > >    #define __cpu_to_le32(x) ((__force __le32)__swab32((x)))
> > > 
> > >   In file included from fs/squashfs/sqfs_dir.c:10:
> > >   include/linux/byteorder/little_endian.h:34: note: this is the location of the previous definition
> > >    #define __cpu_to_le32(x) ((__force __le32)(__u32)(x))
> > > 
> > > Or:
> > > 
> > >   In file included from fs/squashfs/sqfs.c:14:
> > >   include/linux/byteorder/little_endian.h:89:21: error: redefinition of ‘__be16_to_cpup’
> > >    static inline __u16 __be16_to_cpup(const __be16 *p)
> > >                        ^~~~~~~~~~~~~~
> > >   In file included from ./arch/powerpc/include/asm/byteorder.h:82,
> > >                    from include/linux/unaligned/access_ok.h:4,
> > >                    from ./arch/powerpc/include/asm/unaligned.h:9,
> > >                    from fs/squashfs/sqfs.c:10:
> > >   include/linux/byteorder/big_endian.h:89:21: note: previous definition of ‘__be16_to_cpup’ was here
> > >    static inline __u16 __be16_to_cpup(const __be16 *p)
> > >                        ^~~~~~~~~~~~~~
> > > 
> > > As some header files include correct asm/byteorder.h file and this
> > > squashfs includes additional little_endian.h.
> > 
> > Great, thanks for the thorough explanation. Based on what you said,
> > wouldn't it be cleaner to just get rid of the little_endian.h include
> > rather than also use the ARCH specific byteorder.h header?
> 
> I think that this is not possible. squashfs code uses le16_to_cpu()
> macro and its correct definition is provided only by arch specific
> asm/byteorder.h.

Miquel, is this sufficient explanation?  Thanks.

-- 
Tom

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Re: [PATCH] squashfs: Fix compilation on big endian systems

[Miquel Raynal]

Hi Tom,

trini@konsulko.com wrote on Wed, 1 Jun 2022 10:08:20 -0400:

> On Thu, Apr 07, 2022 at 11:58:55AM +0200, Pali Rohár wrote:
> > On Thursday 07 April 2022 11:54:55 Miquel Raynal wrote:  
> > > Hi Pali,
> > > 
> > > pali@kernel.org wrote on Thu, 7 Apr 2022 11:41:59 +0200:
> > >   
> > > > On Thursday 07 April 2022 09:54:21 Miquel Raynal wrote:  
> > > > > Hi Pali,
> > > > > 
> > > > > pali@kernel.org wrote on Wed,  6 Apr 2022 23:31:53 +0200:
> > > > > 
> > > > > Would you mind explaining a little bit how this change fixes it? It
> > > > > does not look straightforward to me.    
> > > > 
> > > > Yes! I though that it is straightforward this change...
> > > > byteorder/little_endian.h defines cpu_to_le* macros for Little Endian
> > > > systems and byteorder/big_endian.h for Big Endian systems.
> > > > 
> > > > File asm/byteorder.h is then ARCH-specific and implements macros for the
> > > > current architecture (by including the correct header file).
> > > > 
> > > > So currently if you try to compile squashfs for big endian systems you
> > > > get compile error:
> > > > 
> > > >   In file included from ./arch/powerpc/include/asm/byteorder.h:82,
> > > >                    from include/linux/unaligned/access_ok.h:4,
> > > >                    from ./arch/powerpc/include/asm/unaligned.h:9,
> > > >                    from fs/squashfs/sqfs_filesystem.h:11,
> > > >                    from fs/squashfs/sqfs_dir.c:16:
> > > >   include/linux/byteorder/big_endian.h:34: warning: "__cpu_to_le32" redefined
> > > >    #define __cpu_to_le32(x) ((__force __le32)__swab32((x)))
> > > > 
> > > >   In file included from fs/squashfs/sqfs_dir.c:10:
> > > >   include/linux/byteorder/little_endian.h:34: note: this is the location of the previous definition
> > > >    #define __cpu_to_le32(x) ((__force __le32)(__u32)(x))
> > > > 
> > > > Or:
> > > > 
> > > >   In file included from fs/squashfs/sqfs.c:14:
> > > >   include/linux/byteorder/little_endian.h:89:21: error: redefinition of ‘__be16_to_cpup’
> > > >    static inline __u16 __be16_to_cpup(const __be16 *p)
> > > >                        ^~~~~~~~~~~~~~
> > > >   In file included from ./arch/powerpc/include/asm/byteorder.h:82,
> > > >                    from include/linux/unaligned/access_ok.h:4,
> > > >                    from ./arch/powerpc/include/asm/unaligned.h:9,
> > > >                    from fs/squashfs/sqfs.c:10:
> > > >   include/linux/byteorder/big_endian.h:89:21: note: previous definition of ‘__be16_to_cpup’ was here
> > > >    static inline __u16 __be16_to_cpup(const __be16 *p)
> > > >                        ^~~~~~~~~~~~~~
> > > > 
> > > > As some header files include correct asm/byteorder.h file and this
> > > > squashfs includes additional little_endian.h.  
> > > 
> > > Great, thanks for the thorough explanation. Based on what you said,
> > > wouldn't it be cleaner to just get rid of the little_endian.h include
> > > rather than also use the ARCH specific byteorder.h header?  
> > 
> > I think that this is not possible. squashfs code uses le16_to_cpu()
> > macro and its correct definition is provided only by arch specific
> > asm/byteorder.h.  
> 
> Miquel, is this sufficient explanation?  Thanks.

Yes, sorry, it seems like in U-Boot including the asm header is the way
to go, so:

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks,
Miquèl

Re: [PATCH] squashfs: Fix compilation on big endian systems

[Tom Rini]

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On Wed, Apr 06, 2022 at 11:31:53PM +0200, Pali Rohár wrote:

> Signed-off-by: Pali Rohár <pali@kernel.org>
> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

Applied to u-boot/master, thanks!

-- 
Tom

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