From: Alexander Lobakin <alexandr.lobakin@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>,
linux-hardening@vger.kernel.org, x86@kernel.org,
Borislav Petkov <bp@alien8.de>,
Jesse Brandeburg <jesse.brandeburg@intel.com>,
Kristen Carlson Accardi <kristen@linux.intel.com>,
Kees Cook <keescook@chromium.org>,
Miklos Szeredi <miklos@szeredi.hu>,
Ard Biesheuvel <ardb@kernel.org>, Tony Luck <tony.luck@intel.com>,
Bruce Schlobohm <bruce.schlobohm@intel.com>,
Jessica Yu <jeyu@kernel.org>, kernel test robot <lkp@intel.com>,
Miroslav Benes <mbenes@suse.cz>,
Evgenii Shatokhin <eshatokhin@virtuozzo.com>,
Jonathan Corbet <corbet@lwn.net>,
Masahiro Yamada <masahiroy@kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
Nick Desaulniers <ndesaulniers@google.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Christoph Hellwig <hch@lst.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Nathan Chancellor <nathan@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Marios Pomonis <pomonis@google.com>,
Sami Tolvanen <samitolvanen@google.com>,
"H.J. Lu" <hjl.tools@gmail.com>, Nicolas Pitre <nico@fluxnic.net>,
linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org,
linux-arch@vger.kernel.org, live-patching@vger.kernel.org,
llvm@lists.linux.dev
Subject: Re: [PATCH v10 05/15] x86: support asm function sections
Date: Mon, 14 Feb 2022 12:49:27 +0100 [thread overview]
Message-ID: <20220214114927.6104-1-alexandr.lobakin@intel.com> (raw)
In-Reply-To: <20220211154524.GX23216@worktop.programming.kicks-ass.net>
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 11 Feb 2022 16:45:24 +0100
> On Wed, Feb 09, 2022 at 07:57:42PM +0100, Alexander Lobakin wrote:
> > Address places which need special care and enable
> > CONFIG_ARCH_SUPPORTS_ASM_FUNCTION_SECTIONS.
> >
> > Notably:
> > - propagate `--sectname-subst` to KBUILD_AFLAGS in
> > x86/boot/Makefile and x86/boot/compressed/Makefile as both
> > override them;
> > - symbols starting with a dot (like ".Lrelocated") should be
> > handled manually with SYM_*_START_SECT(.Lrelocated, relocated)
> > as "two dots" is a special (and CPP doesn't want to concatenate
> > two dots in general);
> > - some symbols explicitly need to reside in one section (like
> > kexec control code, hibernation page etc.);
> > - macros creating aliases for functions (like __memcpy() for
> > memcpy() etc.) should go after the main declaration (as
> > aliases should be declared in the same section and they
> > don't have SYM_PUSH_SECTION() inside);
> > - things like ".org", ".align" should be manually pushed to
> > the same section the next symbol goes to;
> > - expand indirect_thunk wildcards in vmlinux.lds.S to catch
> > symbols back into the "main" section;
> > - inline ASM functions like __raw_callee*() should be pushed
> > manually as well.
> >
> > With these changes and `-ffunction-sections` enabled, "plain"
> > ".text" section is empty which means that everything works
> > right as expected.
> >
> > Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
> > ---
> > arch/x86/Kconfig | 1 +
> > arch/x86/boot/Makefile | 1 +
> > arch/x86/boot/compressed/Makefile | 1 +
> > arch/x86/boot/compressed/head_32.S | 2 +-
> > arch/x86/boot/compressed/head_64.S | 32 ++++++++++++-------
> > arch/x86/boot/pmjump.S | 2 +-
> > arch/x86/crypto/aesni-intel_asm.S | 4 +--
> > arch/x86/crypto/poly1305-x86_64-cryptogams.pl | 4 +++
> > arch/x86/include/asm/paravirt.h | 2 ++
> > arch/x86/include/asm/qspinlock_paravirt.h | 2 ++
> > arch/x86/kernel/head_32.S | 4 +--
> > arch/x86/kernel/head_64.S | 4 +--
> > arch/x86/kernel/kprobes/core.c | 2 ++
> > arch/x86/kernel/kvm.c | 2 ++
> > arch/x86/kernel/relocate_kernel_32.S | 10 +++---
> > arch/x86/kernel/relocate_kernel_64.S | 12 ++++---
> > arch/x86/kernel/vmlinux.lds.S | 2 +-
> > arch/x86/kvm/emulate.c | 7 +++-
> > arch/x86/lib/copy_user_64.S | 2 +-
> > arch/x86/lib/error-inject.c | 2 ++
> > arch/x86/lib/getuser.S | 5 ++-
> > arch/x86/lib/memcpy_64.S | 4 +--
> > arch/x86/lib/memmove_64.S | 5 ++-
> > arch/x86/lib/memset_64.S | 5 +--
> > arch/x86/lib/putuser.S | 2 +-
> > arch/x86/power/hibernate_asm_32.S | 10 +++---
> > arch/x86/power/hibernate_asm_64.S | 10 +++---
> > 27 files changed, 89 insertions(+), 50 deletions(-)
>
> Urgh, how much of that can you avoid by (ab)using __DISABLE_EXPORTS
> like:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?h=x86/wip.ibt&id=ab74f54f2b1f6cfeaf2b3ba6999bde7cabada9ca
Oh, never thought on that, looks like at least 3 of 27 files and
35 of 139 lines, nice!
I'll redo this one in the meantime whilst waiting for more comments
here.
Thanks!
Al
next prev parent reply other threads:[~2022-02-14 11:51 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-09 18:57 [PATCH v10 00/15] Function Granular KASLR Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 01/15] modpost: fix removing numeric suffixes Alexander Lobakin
2022-05-03 0:57 ` Masahiro Yamada
2022-05-03 7:31 ` Petr Mladek
2022-05-23 18:04 ` Masahiro Yamada
2022-05-24 11:33 ` Alexander Lobakin
2022-05-24 13:40 ` Masahiro Yamada
2022-02-09 18:57 ` [PATCH v10 02/15] livepatch: avoid position-based search if `-z unique-symbol` is available Alexander Lobakin
2022-02-11 17:41 ` Josh Poimboeuf
2022-02-11 18:05 ` Fāng-ruì Sòng
2022-02-11 18:35 ` Josh Poimboeuf
2022-02-14 12:24 ` Alexander Lobakin
2022-02-14 18:10 ` Josh Poimboeuf
2022-02-16 20:32 ` Joe Lawrence
2022-02-16 22:13 ` Josh Poimboeuf
2022-02-16 15:15 ` Miroslav Benes
2022-02-16 20:01 ` Josh Poimboeuf
2022-02-18 16:31 ` Alexander Lobakin
2022-02-18 20:08 ` Josh Poimboeuf
2022-02-14 12:14 ` Alexander Lobakin
2022-02-14 18:57 ` Josh Poimboeuf
2022-02-16 15:06 ` Miroslav Benes
2022-02-16 19:57 ` Josh Poimboeuf
2022-02-17 7:45 ` Miroslav Benes
2022-02-09 18:57 ` [PATCH v10 03/15] kallsyms: randomize /proc/kallsyms output order Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 04/15] arch: introduce asm function sections Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 05/15] x86: support " Alexander Lobakin
2022-02-11 15:45 ` Peter Zijlstra
2022-02-14 11:49 ` Alexander Lobakin [this message]
2022-02-09 18:57 ` [PATCH v10 06/15] x86: decouple ORC table sorting into a separate file Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 07/15] Makefile: add config options and build scripts for FG-KASLR Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 08/15] x86/tools: Add relative relocs for randomized functions Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 09/15] x86: Add support for function granular KASLR Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 10/15] FG-KASLR: use a scripted approach to handle .text.* sections Alexander Lobakin
2022-02-11 15:37 ` Peter Zijlstra
2022-02-14 11:34 ` Alexander Lobakin
2022-02-14 11:59 ` Peter Zijlstra
2022-02-14 12:30 ` Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 11/15] x86/boot: allow FG-KASLR to be selected Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 12/15] module: add arch-indep FG-KASLR for randomizing function layout Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 13/15] module: use a scripted approach for FG-KASLR Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 14/15] Documentation: add documentation " Alexander Lobakin
2022-02-09 18:57 ` [PATCH v10 15/15] maintainers: add MAINTAINERS entry " Alexander Lobakin
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