Re: Recent changes to sysctl.h breaks glibc

["H. Peter Anvin" <hpa@zytor.com>]

Chris Friesen wrote:
> Riley Williams wrote:
> 
>> First, is there anything in include/asm that is actually needed
>> outside the kernel itself? There shouldn't be, and if there is,
>> it needs to be moved to a header under include/linux that is
>> included in the relevant include/asm file.
> 
> It's handy for stuff like getting high res timestamps without having to 
> ifdef the case of building on different architechtures.  Also, there are 
> files under include/linux which end up including asm stuff in turn.
> 
>> The basic rule would be that external software can make free
>> use of headers under include/linux but should never make any
>> use whatsoever of headers under include/kernel or include/asm
>> for any reason.
> 
> 
> What if the include/linux files themselves make use of the asm files?
> 

No, not acceptable.

The thing is, trying to redefine the old namespaces is hopeless at this 
point.  Hence the proposed new namespace <linux/abi/*.h> ... 
<linux/abi/arch/*.h> would be my preference for an arch-specific 
subnamespace.

Thus the rule is:

a) <linux/abi/*> files MUST NOT include files outside <linux/abi/*>

b) <linux/*.h> and <asm/*.h> are legacy namespaces.  They should be 
considered to be completely different in kernel and userspace -- in 
effect, glibc will eventually ship with its own set of these headers.

c) <linux/abi/*> files should be clean for inclusion from either kernel 
or userspace.

	-hpa