On Thu, Nov 16, 2017 at 11:54:33AM +0000, Will Deacon wrote: > On Wed, Nov 15, 2017 at 01:34:21PM -0800, Sami Tolvanen wrote: > > From: Alex Matveev <alxmtvv@xxxxxxxxx> > > > > Use UNDEFINE_MRS_S and UNDEFINE_MSR_S to define corresponding macros > > in-place and workaround gcc and clang limitations on redefining macros > > across different assembler blocks. > > What limitations? Can you elaborate please? Is this a fix? Hi Will, Regarding GCC. When it joins preprocessed source files into single asm file, mrs_s/msr_s becomes either not declared or declared multiple times. ./ccuFb68h.s:33120: Error: Macro `mrs_s' was already defined ./ccuFb68h.s:33124: Error: Macro `msr_s' was already defined I'm not sure that GCC works correctly in this case, and I sent the email to Linaro toolchain group to clarify it. See below. Yury [...] Links: My unfinished branch: https://github.com/norov/linux/tree/lto Andi Kleen tree: https://github.com/andikleen/linux-misc/tree/lto-411-1 Sami Tolvanen's recent work for clang: https://lkml.org/lkml/2017/11/3/606 Question we have for now: There's mrs_s/msr_s macro that doesn't work with LTO - linker complains very loudly that macro is either not declared, or declared multiple times. (To reproduce - try to build my kernel branch w/o last patch). The same (?) problem is observed with clang, and people there considered it as feature, not a bug. https://bugs.llvm.org/show_bug.cgi?id=19749 We have the fix for both clang and gcc, but it looks hacky. Maybe it worth to fix mrs/msr issue on toolchain side? -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
