From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
sfr@canb.auug.org.au, mbenes@suse.cz
Subject: Re: [PATCH] objtool: Teach get_alt_entry() about more relocation types
Date: Thu, 30 Sep 2021 10:41:37 -0700 [thread overview]
Message-ID: <20210930174137.atf6tuzgd2iivx3c@treble> (raw)
In-Reply-To: <YVWUvknIEVNkPvnP@hirez.programming.kicks-ass.net>
On Thu, Sep 30, 2021 at 12:43:10PM +0200, Peter Zijlstra wrote:
>
> Occasionally objtool encounters symbol (as opposed to section)
> relocations in .altinstructions. Typically they are the alternatives
> written by elf_add_alternative() as encountered on a noinstr
> validation run on vmlinux after having already ran objtool on the
> individual .o files.
>
> Basically this is the counterpart of commit 44f6a7c0755d ("objtool:
> Fix seg fault with Clang non-section symbols"), because when these new
> assemblers (binutils now also does this) strip the section symbols,
> elf_add_reloc_to_insn() is forced to emit symbol based relocations.
>
> As such, teach get_alt_entry() about different relocation types.
>
> Fixes: 9bc0bb50727c ("objtool/x86: Rewrite retpoline thunk calls")
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Reported-by: Borislav Petkov <bp@alien8.de>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> tools/objtool/special.c | 32 +++++++++++++++++++++++++-------
> 1 file changed, 25 insertions(+), 7 deletions(-)
>
> --- a/tools/objtool/special.c
> +++ b/tools/objtool/special.c
> @@ -58,6 +58,24 @@ void __weak arch_handle_alternative(unsi
> {
> }
>
> +static bool reloc2sec_off(struct reloc *reloc, struct section **sec, unsigned long *off)
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Though I'd prefer U change it 2 a function name which doesn't look like
a Prince song title.
--
Josh
next prev parent reply other threads:[~2021-09-30 17:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-30 10:43 [PATCH] objtool: Teach get_alt_entry() about more relocation types Peter Zijlstra
2021-09-30 17:32 ` Nathan Chancellor
2021-09-30 17:41 ` Josh Poimboeuf [this message]
2021-10-01 12:10 ` [tip: objtool/urgent] " tip-bot2 for Peter Zijlstra
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