Hi Nick, On Wed, 30 Mar 2022 11:04:50 -0700 Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > On Mon, Mar 28, 2022 at 7:29 AM Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > > > > KNOWN ISSUE: > > > > According to the report from Padmanabha[3] and my analysis [4], the embedded > > bootconfig data may not be updated if you do incremental build the kernel > > with CONFIG_LTO_CLANG_THIN. > > > > [3] https://lore.kernel.org/all/20220321183500.GA4065@pswork/T/#u > > [4] https://lore.kernel.org/all/20220327115526.cc4b0ff55fc53c97683c3e4d@xxxxxxxxxx/ > > > > This seems like clang's LTO Thin mode issue. It may not detect the inline > > asm depends on external files. > > > > I think the possible workaround is to split the inline asm which includes > > '.incbin' directive into an asm file. But this should be done in another > > seires because there are other features which uses '.incbin'. (e.g. > > /proc/config.gz) > > Hi Masami, > I saw Padmanabha's report (thanks for the report); sorry for not > responding sooner, I've been traveling recently for a funeral. Oh, sorry about that. I think this is not so hurry. > > Any chance we can use > > CFLAGS_REMOVE_<file>.o := $(CC_FLAGS_LTO) > > a la > commit d2dcd3e37475 ("x86, cpu: disable LTO for cpu.c") Hm, this looks good to me. Let me confirm that works. (Does this mean the bootconfig.o will be compiled to elf binary?) > > with a comment linking to > https://github.com/ClangBuiltLinux/linux/issues/1618 Thanks for reporting! > > for the Translation Units using .incbin, until we have had more time > to triage+fix? Yes. For this series, I can update with above one, but it doesn't cover the other parts. And since this issue is independent from the bootconfig, I think we need a wider patch series to mitigate this issue on config.gz (and other .incbin users) too. Thank you, > > -- > Thanks, > ~Nick Desaulniers -- Masami Hiramatsu <mhiramat@xxxxxxxxxx>
