From: Borislav Petkov Date: Wed, 5 Feb 2014 00:55:11 +0000 (+0100) Subject: x86: Disable generation of traditional x87 instructions X-Git-Tag: v3.15-rc1~177^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b399fe355b30d0102e7690c99e6f764ddfd32ec3;p=pandora-kernel.git x86: Disable generation of traditional x87 instructions We recently had the case where wrongly used floating-constant 'E' caused the generation of traditional x87 instructions in kernel code and wreaking all kinds of havoc. Disable the generation of those too. This will save people a lot of time when trying to debug such issues by erroring out of the build instead of let them manifest themselves in very spectacular and happy-crappy ways at runtime. We're using -mno-fp-ret-in-387 in addition to -mno-80387 (which is == -msoft-float) because, as the gcc manpage says: On machines where a function returns floating-point results in the 80387 register stack, some floating-point opcodes may be emitted even if -msoft-float is used. so we want to turn off *all* non-integer instructions involving any architectural FPU state, unless it is absolutely necessary (and those cases need special handling anyway). Cc: Jiri Kosina Cc: Michael Matz Cc: Michal Hocko Signed-off-by: Borislav Petkov Link: http://lkml.kernel.org/r/1391561711-3023-1-git-send-email-bp@alien8.de Signed-off-by: H. Peter Anvin --- Reading git-diff-tree failed