From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Date: Thu, 17 Feb 2011 10:06:40 -0800
David, why are you saying that regular "just mark the structure alignment correctly" doesn't work?
Because it's been proven to not work: http://marc.info/?l=linux-kernel&m=129674396021733&w=2 http://marc.info/?l=linux-kernel&m=129674399621795&w=2 http://marc.info/?l=linux-kernel&m=129674396121739&w=2 http://marc.info/?l=linux-kernel&m=129674396021735&w=2 GCC is very clever with "static" objects these days. It thinks that, because you mark something "static", it can align it any way it wants because it controls the domain in which the object exists. It "knows" that the object can't be part of an array, and therefore no external entity can be concerned about the true "size" of the object (specifically wrt. side effects of the alignment of the object). In these cases it takes the explicit alignment attribute as a minimum, not as an absolute requirement. But we lie to the compiler, we mark things static then put them into a special a special section, then try to iterate over those objects globally as an array and expect the compiler to lay them all out with identical alignments and sizes everywhere. And this doesn't work. -- To unsubscribe from this list: send the line "unsubscribe linux-m68k" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
