From: Kees Cook <keescook@chromium.org>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>,
Steven Rostedt <rostedt@goodmis.org>,
Will Deacon <will@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
clang-built-linux@googlegroups.com,
kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH v6 16/25] init: lto: fix PREL32 relocations
Date: Wed, 14 Oct 2020 15:53:59 -0700 [thread overview]
Message-ID: <202010141552.9172003F6A@keescook> (raw)
In-Reply-To: <20201013003203.4168817-17-samitolvanen@google.com>
On Mon, Oct 12, 2020 at 05:31:54PM -0700, Sami Tolvanen wrote:
> With LTO, the compiler can rename static functions to avoid global
> naming collisions. As initcall functions are typically static,
> renaming can break references to them in inline assembly. This
> change adds a global stub with a stable name for each initcall to
> fix the issue when PREL32 relocations are used.
>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
This is another independent improvement... this could land before the
other portions of the series.
-Kees
> ---
> include/linux/init.h | 31 +++++++++++++++++++++++++++----
> 1 file changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/init.h b/include/linux/init.h
> index af638cd6dd52..cea63f7e7705 100644
> --- a/include/linux/init.h
> +++ b/include/linux/init.h
> @@ -209,26 +209,49 @@ extern bool initcall_debug;
> */
> #define __initcall_section(__sec, __iid) \
> #__sec ".init.." #__iid
> +
> +/*
> + * With LTO, the compiler can rename static functions to avoid
> + * global naming collisions. We use a global stub function for
> + * initcalls to create a stable symbol name whose address can be
> + * taken in inline assembly when PREL32 relocations are used.
> + */
> +#define __initcall_stub(fn, __iid, id) \
> + __initcall_name(initstub, __iid, id)
> +
> +#define __define_initcall_stub(__stub, fn) \
> + int __init __stub(void); \
> + int __init __stub(void) \
> + { \
> + return fn(); \
> + } \
> + __ADDRESSABLE(__stub)
> #else
> #define __initcall_section(__sec, __iid) \
> #__sec ".init"
> +
> +#define __initcall_stub(fn, __iid, id) fn
> +
> +#define __define_initcall_stub(__stub, fn) \
> + __ADDRESSABLE(fn)
> #endif
>
> #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
> -#define ____define_initcall(fn, __name, __sec) \
> - __ADDRESSABLE(fn) \
> +#define ____define_initcall(fn, __stub, __name, __sec) \
> + __define_initcall_stub(__stub, fn) \
> asm(".section \"" __sec "\", \"a\" \n" \
> __stringify(__name) ": \n" \
> - ".long " #fn " - . \n" \
> + ".long " __stringify(__stub) " - . \n" \
> ".previous \n");
> #else
> -#define ____define_initcall(fn, __name, __sec) \
> +#define ____define_initcall(fn, __unused, __name, __sec) \
> static initcall_t __name __used \
> __attribute__((__section__(__sec))) = fn;
> #endif
>
> #define __unique_initcall(fn, id, __sec, __iid) \
> ____define_initcall(fn, \
> + __initcall_stub(fn, __iid, id), \
> __initcall_name(initcall, __iid, id), \
> __initcall_section(__sec, __iid))
>
> --
> 2.28.0.1011.ga647a8990f-goog
>
--
Kees Cook
WARNING: multiple messages have this Message-ID (diff)
From: Kees Cook <keescook@chromium.org>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: linux-arch@vger.kernel.org, x86@kernel.org,
"Paul E. McKenney" <paulmck@kernel.org>,
kernel-hardening@lists.openwall.com,
Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kbuild@vger.kernel.org,
Nick Desaulniers <ndesaulniers@google.com>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
clang-built-linux@googlegroups.com,
Sami Tolvanen <samitolvanen@google.com>,
linux-pci@vger.kernel.org, Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v6 16/25] init: lto: fix PREL32 relocations
Date: Wed, 14 Oct 2020 15:53:59 -0700 [thread overview]
Message-ID: <202010141552.9172003F6A@keescook> (raw)
In-Reply-To: <20201013003203.4168817-17-samitolvanen@google.com>
On Mon, Oct 12, 2020 at 05:31:54PM -0700, Sami Tolvanen wrote:
> With LTO, the compiler can rename static functions to avoid global
> naming collisions. As initcall functions are typically static,
> renaming can break references to them in inline assembly. This
> change adds a global stub with a stable name for each initcall to
> fix the issue when PREL32 relocations are used.
>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
This is another independent improvement... this could land before the
other portions of the series.
-Kees
> ---
> include/linux/init.h | 31 +++++++++++++++++++++++++++----
> 1 file changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/init.h b/include/linux/init.h
> index af638cd6dd52..cea63f7e7705 100644
> --- a/include/linux/init.h
> +++ b/include/linux/init.h
> @@ -209,26 +209,49 @@ extern bool initcall_debug;
> */
> #define __initcall_section(__sec, __iid) \
> #__sec ".init.." #__iid
> +
> +/*
> + * With LTO, the compiler can rename static functions to avoid
> + * global naming collisions. We use a global stub function for
> + * initcalls to create a stable symbol name whose address can be
> + * taken in inline assembly when PREL32 relocations are used.
> + */
> +#define __initcall_stub(fn, __iid, id) \
> + __initcall_name(initstub, __iid, id)
> +
> +#define __define_initcall_stub(__stub, fn) \
> + int __init __stub(void); \
> + int __init __stub(void) \
> + { \
> + return fn(); \
> + } \
> + __ADDRESSABLE(__stub)
> #else
> #define __initcall_section(__sec, __iid) \
> #__sec ".init"
> +
> +#define __initcall_stub(fn, __iid, id) fn
> +
> +#define __define_initcall_stub(__stub, fn) \
> + __ADDRESSABLE(fn)
> #endif
>
> #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
> -#define ____define_initcall(fn, __name, __sec) \
> - __ADDRESSABLE(fn) \
> +#define ____define_initcall(fn, __stub, __name, __sec) \
> + __define_initcall_stub(__stub, fn) \
> asm(".section \"" __sec "\", \"a\" \n" \
> __stringify(__name) ": \n" \
> - ".long " #fn " - . \n" \
> + ".long " __stringify(__stub) " - . \n" \
> ".previous \n");
> #else
> -#define ____define_initcall(fn, __name, __sec) \
> +#define ____define_initcall(fn, __unused, __name, __sec) \
> static initcall_t __name __used \
> __attribute__((__section__(__sec))) = fn;
> #endif
>
> #define __unique_initcall(fn, id, __sec, __iid) \
> ____define_initcall(fn, \
> + __initcall_stub(fn, __iid, id), \
> __initcall_name(initcall, __iid, id), \
> __initcall_section(__sec, __iid))
>
> --
> 2.28.0.1011.ga647a8990f-goog
>
--
Kees Cook
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-10-15 1:19 UTC|newest]
Thread overview: 188+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-13 0:31 [PATCH v6 00/25] Add support for Clang LTO Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 01/25] kbuild: preprocess module linker script Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 02/25] objtool: Add a pass for generating __mcount_loc Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-14 16:50 ` Ingo Molnar
2020-10-14 16:50 ` Ingo Molnar
2020-10-14 18:21 ` Peter Zijlstra
2020-10-14 18:21 ` Peter Zijlstra
2020-10-15 20:10 ` Josh Poimboeuf
2020-10-15 20:10 ` Josh Poimboeuf
2020-10-13 0:31 ` [PATCH v6 03/25] objtool: Don't autodetect vmlinux.o Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 04/25] tracing: move function tracer options to Kconfig Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 05/25] tracing: add support for objtool mcount Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 06/25] x86, build: use " Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 07/25] treewide: remove DISABLE_LTO Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-14 22:43 ` Kees Cook
2020-10-14 22:43 ` Kees Cook
2020-10-17 1:46 ` Masahiro Yamada
2020-10-17 1:46 ` Masahiro Yamada
2020-10-13 0:31 ` [PATCH v6 08/25] kbuild: add support for Clang LTO Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 09/25] kbuild: lto: fix module versioning Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 10/25] objtool: Split noinstr validation from --vmlinux Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 11/25] kbuild: lto: postpone objtool Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 12/25] kbuild: lto: limit inlining Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 13/25] kbuild: lto: merge module sections Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-14 22:49 ` Kees Cook
2020-10-14 22:49 ` Kees Cook
2020-10-20 16:42 ` Sami Tolvanen
2020-10-20 16:42 ` Sami Tolvanen
2020-10-20 16:42 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 14/25] kbuild: lto: remove duplicate dependencies from .mod files Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-14 22:50 ` Kees Cook
2020-10-14 22:50 ` Kees Cook
2020-12-03 17:59 ` Masahiro Yamada
2020-12-03 17:59 ` Masahiro Yamada
2020-12-03 18:47 ` Sami Tolvanen
2020-12-03 18:47 ` Sami Tolvanen
2020-12-03 18:47 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 15/25] init: lto: ensure initcall ordering Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 16/25] init: lto: fix PREL32 relocations Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-14 22:53 ` Kees Cook [this message]
2020-10-14 22:53 ` Kees Cook
2020-10-15 0:12 ` Jann Horn
2020-10-15 0:12 ` Jann Horn
2020-10-15 0:12 ` Jann Horn
2020-10-13 0:31 ` [PATCH v6 17/25] PCI: Fix PREL32 relocations for LTO Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-14 22:58 ` Kees Cook
2020-10-14 22:58 ` Kees Cook
2020-10-13 0:31 ` [PATCH v6 18/25] modpost: lto: strip .lto from module names Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 19/25] scripts/mod: disable LTO for empty.c Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 20/25] efi/libstub: disable LTO Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` [PATCH v6 21/25] drivers/misc/lkdtm: disable LTO for rodata.o Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:31 ` Sami Tolvanen
2020-10-13 0:32 ` [PATCH v6 22/25] x86/asm: annotate indirect jumps Sami Tolvanen
2020-10-13 0:32 ` Sami Tolvanen
2020-10-13 0:32 ` Sami Tolvanen
2020-10-14 22:46 ` Kees Cook
2020-10-14 22:46 ` Kees Cook
2020-10-14 23:23 ` Jann Horn
2020-10-14 23:23 ` Jann Horn
2020-10-14 23:23 ` Jann Horn
2020-10-15 10:22 ` Peter Zijlstra
2020-10-15 10:22 ` Peter Zijlstra
2020-10-15 20:39 ` Josh Poimboeuf
2020-10-15 20:39 ` Josh Poimboeuf
2020-10-20 16:45 ` Sami Tolvanen
2020-10-20 16:45 ` Sami Tolvanen
2020-10-20 16:45 ` Sami Tolvanen
2020-10-20 18:52 ` Josh Poimboeuf
2020-10-20 18:52 ` Josh Poimboeuf
2020-10-20 19:24 ` Sami Tolvanen
2020-10-20 19:24 ` Sami Tolvanen
2020-10-20 19:24 ` Sami Tolvanen
2020-10-21 8:56 ` Peter Zijlstra
2020-10-21 8:56 ` Peter Zijlstra
2020-10-21 9:08 ` Peter Zijlstra
2020-10-21 9:08 ` Peter Zijlstra
2020-10-21 9:32 ` Peter Zijlstra
2020-10-21 9:32 ` Peter Zijlstra
2020-10-21 21:27 ` Josh Poimboeuf
2020-10-21 21:27 ` Josh Poimboeuf
2020-10-22 7:25 ` Peter Zijlstra
2020-10-22 7:25 ` Peter Zijlstra
2020-10-23 17:48 ` Sami Tolvanen
2020-10-23 17:48 ` Sami Tolvanen
2020-10-23 18:04 ` Nick Desaulniers
2020-10-23 18:04 ` Nick Desaulniers
2020-10-23 18:04 ` Nick Desaulniers
2020-10-21 15:01 ` Sami Tolvanen
2020-10-21 15:01 ` Sami Tolvanen
2020-10-21 15:01 ` Sami Tolvanen
2020-10-22 0:22 ` Sami Tolvanen
2020-10-22 0:22 ` Sami Tolvanen
2020-10-22 0:22 ` Sami Tolvanen
2020-10-23 17:36 ` Sami Tolvanen
2020-10-23 17:36 ` Sami Tolvanen
2020-11-09 23:11 ` Sami Tolvanen
2020-11-09 23:11 ` Sami Tolvanen
2020-11-09 23:11 ` Sami Tolvanen
2020-11-10 2:29 ` Josh Poimboeuf
2020-11-10 2:29 ` Josh Poimboeuf
2020-11-10 3:18 ` Nick Desaulniers
2020-11-10 3:18 ` Nick Desaulniers
2020-11-10 3:18 ` Nick Desaulniers
2020-11-10 4:48 ` Sami Tolvanen
2020-11-10 4:48 ` Sami Tolvanen
2020-11-10 4:48 ` Sami Tolvanen
2020-11-10 16:11 ` Josh Poimboeuf
2020-11-10 16:11 ` Josh Poimboeuf
2020-11-10 17:46 ` Josh Poimboeuf
2020-11-10 17:46 ` Josh Poimboeuf
2020-11-10 18:59 ` Sami Tolvanen
2020-11-10 18:59 ` Sami Tolvanen
2020-11-10 18:59 ` Sami Tolvanen
2020-11-13 19:54 ` Josh Poimboeuf
2020-11-13 19:54 ` Josh Poimboeuf
2020-11-13 20:24 ` Sami Tolvanen
2020-11-13 20:24 ` Sami Tolvanen
2020-11-13 20:24 ` Sami Tolvanen
2020-11-13 20:52 ` Josh Poimboeuf
2020-11-13 20:52 ` Josh Poimboeuf
2020-11-13 22:34 ` Josh Poimboeuf
2020-11-13 22:34 ` Josh Poimboeuf
2020-11-13 22:54 ` Sami Tolvanen
2020-11-13 22:54 ` Sami Tolvanen
2020-11-13 22:54 ` Sami Tolvanen
2020-11-13 22:56 ` Josh Poimboeuf
2020-11-13 22:56 ` Josh Poimboeuf
2020-11-13 23:31 ` Sami Tolvanen
2020-11-13 23:31 ` Sami Tolvanen
2020-11-13 23:31 ` Sami Tolvanen
2020-11-14 0:49 ` Josh Poimboeuf
2020-11-14 0:49 ` Josh Poimboeuf
2020-10-21 9:51 ` Peter Zijlstra
2020-10-21 9:51 ` Peter Zijlstra
2020-10-21 18:30 ` Josh Poimboeuf
2020-10-21 18:30 ` Josh Poimboeuf
2020-10-13 0:32 ` [PATCH v6 23/25] x86, vdso: disable LTO only for vDSO Sami Tolvanen
2020-10-13 0:32 ` Sami Tolvanen
2020-10-13 0:32 ` Sami Tolvanen
2020-10-13 0:32 ` [PATCH v6 24/25] x86, cpu: disable LTO for cpu.c Sami Tolvanen
2020-10-13 0:32 ` Sami Tolvanen
2020-10-13 0:32 ` Sami Tolvanen
2020-10-13 0:32 ` [PATCH v6 25/25] x86, build: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen
2020-10-13 0:32 ` Sami Tolvanen
2020-10-13 0:32 ` Sami Tolvanen
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