From: Will Deacon <will@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ard Biesheuvel <ardb@kernel.org>,
Peter Collingbourne <pcc@google.com>,
James Morse <james.morse@arm.com>, Borislav Petkov <bp@suse.de>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Russell King <linux@armlinux.org.uk>,
Masahiro Yamada <masahiroy@kernel.org>,
Arvind Sankar <nivedita@alum.mit.edu>,
Nick Desaulniers <ndesaulniers@google.com>,
Nathan Chancellor <natechancellor@gmail.com>,
Arnd Bergmann <arnd@arndb.de>,
x86@kernel.org, clang-built-linux@googlegroups.com,
linux-arch@vger.kernel.org, linux-efi@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 9/9] arm64/build: Warn on orphan section placement
Date: Wed, 24 Jun 2020 08:57:12 +0100 [thread overview]
Message-ID: <20200624075712.GB5853@willie-the-truck> (raw)
In-Reply-To: <20200624014940.1204448-10-keescook@chromium.org>
On Tue, Jun 23, 2020 at 06:49:40PM -0700, Kees Cook wrote:
> We don't want to depend on the linker's orphan section placement
> heuristics as these can vary between linkers, and may change between
> versions. All sections need to be explicitly named in the linker
> script.
>
> Avoid .eh_frame* by making sure both -fno-asychronous-unwind-tables and
> -fno-unwind-tables are present in both CFLAGS and AFLAGS. Remove one
> last instance of .eh_frame by removing the needless Call Frame Information
> annotations from arch/arm64/kernel/smccc-call.S.
>
> Add .plt, .data.rel.ro, .igot.*, and .iplt to discards as they are not
> actually used. While .got.plt is also not used, it must be included
> otherwise ld.bfd will fail to link with the error:
>
> aarch64-linux-gnu-ld: discarded output section: `.got.plt'
>
> However, as it'd be better to validate that it stays effectively empty,
> add an assert.
>
> Explicitly include debug sections when they're present.
>
> Fix a case of needless quotes in __section(), which Clang doesn't like.
>
> Finally, enable orphan section warnings.
>
> Thanks to Ard Biesheuvel for many hints on correct ways to handle
> mysterious sections. :)
Sorry to be a pain, but this patch is doing 3 or 4 independent things at
once. Please could you split it up a bit?
e.g.
- Removal of cfi directives from smccc macro
- Removal of quotes around section name for clang
- Avoid generating .eh_frame
- Ensure all sections are accounted for in linker script and warn on orphans
That way it's a bit easier to manage, we can revert/backport bits later if
necessary and you get more patches in the kernel ;)
You can also add my Ack on all the patches:
Acked-by: Will Deacon <will@kernel.org>
Will
next prev parent reply other threads:[~2020-06-24 7:57 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 1:49 [PATCH v3 0/9] Warn on orphan section placement Kees Cook
2020-06-24 1:49 ` [PATCH v3 1/9] vmlinux.lds.h: Add .gnu.version* to DISCARDS Kees Cook
2020-06-24 1:49 ` [PATCH v3 2/9] vmlinux.lds.h: Add .symtab, .strtab, and .shstrtab to STABS_DEBUG Kees Cook
2020-06-24 15:39 ` Arvind Sankar
2020-06-24 16:16 ` Fangrui Song
2020-06-24 17:11 ` Arvind Sankar
2020-06-24 17:26 ` Fangrui Song
2020-06-24 17:35 ` Arvind Sankar
2020-06-24 1:49 ` [PATCH v3 3/9] efi/libstub: Remove .note.gnu.property Kees Cook
2020-06-24 3:31 ` Fangrui Song
2020-06-24 4:44 ` Kees Cook
2020-06-24 10:43 ` Will Deacon
2020-06-24 10:46 ` Ard Biesheuvel
2020-06-24 11:26 ` Will Deacon
2020-06-24 13:48 ` Dave Martin
2020-06-24 15:26 ` Will Deacon
2020-06-24 16:26 ` Dave Martin
2020-06-24 15:21 ` Kees Cook
2020-06-24 15:31 ` Ard Biesheuvel
2020-06-24 15:45 ` Kees Cook
2020-06-24 15:48 ` Ard Biesheuvel
2020-06-24 16:29 ` Dave Martin
2020-06-24 16:40 ` Ard Biesheuvel
2020-06-24 17:16 ` Dave Martin
2020-06-24 18:23 ` Ard Biesheuvel
2020-06-24 18:57 ` Ard Biesheuvel
2020-06-24 1:49 ` [PATCH v3 4/9] x86/build: Warn on orphan section placement Kees Cook
[not found] ` <202006250240.J1VuMKoC%lkp@intel.com>
2020-06-27 15:44 ` Kees Cook
2020-06-29 14:54 ` Marco Elver
2020-06-29 15:26 ` Kees Cook
2020-06-24 1:49 ` [PATCH v3 5/9] x86/boot: " Kees Cook
2020-06-24 1:49 ` [PATCH v3 6/9] arm/build: " Kees Cook
2020-06-24 1:49 ` [PATCH v3 7/9] arm/boot: " Kees Cook
2020-06-24 1:49 ` [PATCH v3 8/9] arm64/build: Use common DISCARDS in linker script Kees Cook
2020-06-24 1:49 ` [PATCH v3 9/9] arm64/build: Warn on orphan section placement Kees Cook
2020-06-24 7:57 ` Will Deacon [this message]
2020-06-24 15:36 ` Kees Cook
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