On Mon, Jan 29, 2018 at 01:00:10PM -0500, Jeffrey Walton wrote: > On Mon, Jan 29, 2018 at 12:33 PM, Greg KH <greg@xxxxxxxxx> wrote: > > On Mon, Jan 29, 2018 at 12:16:19PM -0500, Jeffrey Walton wrote: > >> ... > >> It would be nice if they moved away from UB and implementation defined > >> behvior, but sometimes the political problems are heavier than the > >> technical solutions. > > > > What do you mean by this? What "UB" does the kernel rely on that > > prevents compilers from properly building it? We do have some pretty > > strict requirements in the kernel for a compiler, but anything "odd" is > > usually just a bug and we are always willing to take patches to fix > > them. > > https://groups.google.com/forum/#!topic/linux.kernel/-VzG6FWZiy8 and > https://www.spinics.net/lists/linux-crypto/msg19466.html . > > I found the first one from 2013 amusing: > > JW >> According to Section 5.8, "Shift Operators" of > JW >> http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2798.pdf: > JW >> "The operands shall be of integral or enumeration type ... > CL > The kernel doesn't try to be fully standard conformant. > > The second one from 2016 was disappointing. It suggested a standards > compliant rotate that was constant time for the linux-crypto folks. > That was rejected by some: > > PA >> So you are actually saying outright that we should sacrifice *actual* > PA >> portability in favor of *theoretical* portability? What kind of > PA >> twilight zone did we just step into?! Well, let's not get into the crazy crypto code in the kernel, it's not a good example of much these days :) > Its kind of like I said... the political problems are harder than the > technical solutions. Those should now all be gone, thanks to some persistent developers. clang builds the kernel just fine as I mentioned, and if you look close, people are working to get something other than 'ld' to link it as well :) thanks, greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
