linux-kernel - Re: linux-next: manual merge of the tip tree with the kbuild tree

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAK7LNARc_Ku2=TkuFNspzW434f2kjYEjs_GDzOCdBF-3feVstg@mail.gmail.com>
Date:   Fri, 27 May 2022 21:18:37 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     Josh Poimboeuf <jpoimboe@...nel.org>
Cc:     Stephen Rothwell <sfr@...b.auug.org.au>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Next Mailing List <linux-next@...r.kernel.org>
Subject: Re: linux-next: manual merge of the tip tree with the kbuild tree

On Fri, May 27, 2022 at 3:04 PM Masahiro Yamada <masahiroy@...nel.org> wrote:
>
> On Fri, May 27, 2022 at 1:47 PM Josh Poimboeuf <jpoimboe@...nel.org> wrote:
> >
> > On Fri, May 27, 2022 at 11:19:02AM +0900, Masahiro Yamada wrote:
> > > [1] original behavior in Josh's commit
> > >
> > > $ git checkout 753da4179d08b625d8df72e97724e22749969fd3
> > > $ make defconfig
> > > $ make -j8 kernel/
> > > $ head -n 1   kernel/.fork.o.cmd
> > >
> > >
> > > I do not see the "--linked" parameter in the objtool command.
> > >
> > >
> > >
> > >
> > > [2] behavior in linux-next
> > >
> > >
> > > $ git checkout next-20220523
> > > $ make defconfig
> > > $ make -j8 kernel/
> > > $ head -n 1   kernel/.fork.o.cmd
> > >
> > > I see the "--linked" parameter in the objtool command.
> > >
> > > kernel/fork.o  is a direct output from GCC,
> > > not from linker.
> >
> > Yes, good catch.  That flag should only be used for linked objects like
> > vmlinux.o or some_module.o.
> >
> > Objtool only runs on such objects when CONFIG_LTO_CLANG,
> > CONFIG_X86_KERNEL_IBT, or CONFIG_NOINSTR_VALIDATION (vmlinux.o-only) is
> > enabled.
> >
> > --
> > Josh
>
>
> When CONFIG_LTO_CLANG=y or CONFIG_X86_KERNEL_IBT=y
> is "--linked" necessary for single-object modules?
>
>
> "single-object module" means a module that consists of only one object.
>
> See this figure:
> https://patchwork.kernel.org/project/linux-kbuild/patch/20220513113930.10488-6-masahiroy@kernel.org/
>
>
>
>
> In your commit, --linked is passed to all *.prelink.o
> whether it consists of a single object or links
> multiple objects.




Anyway, please let me clean up this part in the kbuild tree:

https://patchwork.kernel.org/project/linux-kbuild/patch/20220527100155.1996314-2-masahiroy@kernel.org/





-- 
Best Regards
Masahiro Yamada