On Tue, Aug 18, 2020 at 05:44:03PM -0700, Linus Torvalds wrote: > On Tue, Aug 18, 2020 at 4:43 PM Arvind Sankar <nived...@alum.mit.edu> wrote: > > > > This by itself is insufficient for gcc if the optimization was > > explicitly enabled by CFLAGS, so also add a flag to explicitly disable > > it. > > Using -fno-tree-loop-distribute-patterns seems to really be a bit too > incestuous with internal compiler knowledge.
Fair enough -- you ok with just the -ffreestanding? That's what protects the memset in arch/x86/boot/compressed/string.c. I think this is worthwhile to be safe. > > That generic memcpy implementation is horrible anyway. It should never be > used. > > So I'd rather see this either removed entirely, ot possibly rewritten > to be a somewhat proper memcpy implementation, and in the process made > to not be recognizable by the compiler (possibly by adding a dummy > barrier() or something like that). > > Looking at the implementation of "strscpy()" in the same file, and > then comparing that to the ludicrously simplisting "memcpy()", I > really get the feeling that that memcpy() is not worth having. > > Linus I don't think anything actually uses the generic memcpy, and I think only c6x uses the generic memset. Might be worth optimizing strnlen etc with the word-at-a-time thing though.
