I believe we do have the infrastructure in llvm to implement a working patch. The "asm goto" was introduced as a solution to a problem (optimizing tracepoints/ nop patching). When we started the discussion in llvm about adding this feature, questions arose if we can design a better solution for this problem than "asm goto".
You can find a more about the discussion in the llvm community here: http://lists.llvm.org/pipermail/llvm-dev/2017-April/111748.html * This is the middle of the thread, and there are more messages later on. Thanks, Marina -----Original Message----- From: Greg Kroah-Hartman [mailto:[email protected]] Sent: Wednesday, February 14, 2018 11:53 To: Chandler Carruth <[email protected]> Cc: Yatsina, Marina <[email protected]>; Kees Cook <[email protected]>; David Woodhouse <[email protected]>; Kreitzer, David L <[email protected]>; Grischenko, Andrei L <[email protected]>; [email protected]; LLVM Developers <[email protected]>; [email protected]; Tayree, Coby <[email protected]>; Matthias Braun <[email protected]>; Dean Michael Berris <[email protected]>; James Y Knight <[email protected]>; Guenter Roeck <[email protected]>; X86 ML <[email protected]>; LKML <[email protected]>; Alan Cox <[email protected]>; Rik van Riel <[email protected]>; Andi Kleen <[email protected]>; Josh Poimboeuf <[email protected]>; Tom Lendacky <[email protected]>; Peter Zijlstra <[email protected]>; Linus Torvalds <[email protected]>; Jiri Kosina <[email protected]>; Andy Lutomirski <[email protected]>; Hansen, Dave <[email protected]>; Tim Chen <[email protected]>; Paul Turner <[email protected]>; Stephen Hines <[email protected]>; Nick Desaulniers <[email protected]> Subject: Re: clang asm-goto support (Was Re: [PATCH v2] x86/retpoline: Add clang support) On Wed, Feb 14, 2018 at 08:41:43AM +0000, Chandler Carruth wrote: > Marina, Kees: > > I think the combination of LKML and the LLVM developer's list is > probably too large a set of folks to have a (somewhat) lengthy > exploration of options and how to go about this and find a good path forward. Why is there any need to discuss "options" here? What is preventing the implementation of "asm goto" in llvm? Is it the lack of a working patch, or something else? thanks, greg k-h --------------------------------------------------------------------- Intel Israel (74) Limited This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.
