[PATCH] Documentation/Changes: update binutils version requirement for ARMv7 builds

On 11/18/2013 02:06:18 PM, Paul Walmsley wrote:

Hi Rob,

On 11/17/2013 10:50 AM, Rob Landley wrote:

quoted

On 10/30/2013 11:27:07 AM, Paul Walmsley wrote:

quoted

ARMv7 builds now make use of the pldw opcode and the  
".arch_extension
mp"
pragma.  These aren't supported in binutils prior to 2.21.  So,  
update
Documentation/Changes accordingly.

Annotating the global Documentation/Changes with every per-arch
requirement... not sure that's the right place for it.

It doesn't matter to me where it's documented in the kernel  
documentation, but we should document it.

Agreed, I'd just rather not add target-specific information to a file  
that currently has target-agnostic information.

A new file under Documentation/arm describing the build requirements  
for that platform would be nice. At some point I want to collate the  
target-specific directories under a Documentation/arch (so  
Documentation/arch/arm and Documentation/arch/m68k and so on, mirroring  
the source layout), but that's unrelated to this.

And we should expect folks who post patches with new toolchain  
constraints to also
send patches for that documentation...

Agreed.

quoted

Noting armv7 requirements in
an arm-specific file makes sense. Annotating the top level one raises
the question of why not to do that for arc, unicore, openrisc,  
tile...

Yes - it's the following x86-specific text in Documentation/Changes  
that inspired
the patch:

-----
Linux on IA-32 has recently switched from using as86 to using gas for
assembling the 16-bit boot code, removing the need for as86 to compile
your kernel.  This change does, however, mean that you need a recent
release of binutils.
-----

(Sigh, define "recent". Bisection search time, I suppose...)

But we can move that to Documentation/x86/ also.

Agreed. Also the mcelog stuff looks x86-specific (or at least is  
currently documented as such). Also, I posted patches to remove the  
perl requirement but didn't remove the mention of perl from  
Documentation/Changes. I should fix that.

Also, Documentation/Changes is a weird name for the file describing the  
build environment requirements, but it's sort of grandfathered in at  
this point. That sort of implies I should add a  
Documentation/x86/Changes with the moved material, and the new arm file  
should be Documentation/arm/Changes. I suppose if the 00-INDEX  
clarifies that this describes the build environment requirements...

Which is worse, renaming a top level file that's been there for  
decades, or propagating the inaccurate name into subdirectories? Sigh,  
damned if you do...

Rob