Date: Thu, 25 Jun 2020 20:33:51 +0200 From: Peter Zijlstra <peterz@...radead.org> To: Sami Tolvanen <samitolvanen@...gle.com> Cc: Masahiro Yamada <masahiroy@...nel.org>, Will Deacon <will@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, "Paul E. McKenney" <paulmck@...nel.org>, Kees Cook <keescook@...omium.org>, Nick Desaulniers <ndesaulniers@...gle.com>, clang-built-linux@...glegroups.com, kernel-hardening@...ts.openwall.com, linux-arch@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org, x86@...nel.org Subject: Re: [PATCH 05/22] kbuild: lto: postpone objtool On Thu, Jun 25, 2020 at 09:22:26AM -0700, Sami Tolvanen wrote: > On Thu, Jun 25, 2020 at 09:47:16AM +0200, Peter Zijlstra wrote: > > Right, then we need to make --no-vmlinux work properly when > > !DEBUG_ENTRY, which I think might be buggered due to us overriding the > > argument when the objname ends with "vmlinux.o". > > Right. Can we just remove that and pass --vmlinux to objtool in > link-vmlinux.sh, or is the override necessary somewhere else? Think we can remove it; it was just convenient when running manually. > > > > > +ifdef CONFIG_STACK_VALIDATION > > > > > +ifneq ($(SKIP_STACK_VALIDATION),1) > > > > > +cmd_ld_ko_o += \ > > > > > + $(objtree)/tools/objtool/objtool \ > > > > > + $(if $(CONFIG_UNWINDER_ORC),orc generate,check) \ > > > > > + --module \ > > > > > + $(if $(CONFIG_FRAME_POINTER),,--no-fp) \ > > > > > + $(if $(CONFIG_GCOV_KERNEL),--no-unreachable,) \ > > > > > + $(if $(CONFIG_RETPOLINE),--retpoline,) \ > > > > > + $(if $(CONFIG_X86_SMAP),--uaccess,) \ > > > > > + $(@:.ko=$(prelink-ext).o); > > > > > + > > > > > +endif # SKIP_STACK_VALIDATION > > > > > +endif # CONFIG_STACK_VALIDATION > > > > > > > > What about the objtool invocation from link-vmlinux.sh ? > > > > > > What about it? The existing objtool_link invocation in link-vmlinux.sh > > > works fine for our purposes as well. > > > > Well, I was wondering why you're adding yet another objtool invocation > > while we already have one. > > Because we can't run objtool until we have compiled bitcode to native > code, so for modules, we're need another invocation after everything has > been compiled. Well, that I understand, my question was why we need one in scripts/link-vmlinux.sh and an additional one. I think we're just talking past one another and agree we only need one.
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