From: Sami Tolvanen <samitolvanen@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Will Deacon <will@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Kees Cook <keescook@chromium.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,
Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH v9 06/16] kbuild: lto: add a default list of used symbols
Date: Fri, 11 Dec 2020 10:46:23 -0800 [thread overview]
Message-ID: <20201211184633.3213045-7-samitolvanen@google.com> (raw)
In-Reply-To: <20201211184633.3213045-1-samitolvanen@google.com>
With CONFIG_LTO_CLANG, LLVM bitcode has not yet been compiled into a
binary when the .mod files are generated, which means they don't yet
contain references to certain symbols that will be present in the final
binaries. This includes intrinsic functions, such as memcpy, memmove,
and memset [1], and stack protector symbols [2]. This change adds a
default symbol list to use with CONFIG_TRIM_UNUSED_KSYMS when Clang's
LTO is used.
[1] https://llvm.org/docs/LangRef.html#standard-c-c-library-intrinsics
[2] https://llvm.org/docs/LangRef.html#llvm-stackprotector-intrinsic
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
init/Kconfig | 1 +
scripts/lto-used-symbollist | 5 +++++
2 files changed, 6 insertions(+)
create mode 100644 scripts/lto-used-symbollist
diff --git a/init/Kconfig b/init/Kconfig
index 0872a5a2e759..e88c919c1bf1 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -2297,6 +2297,7 @@ config TRIM_UNUSED_KSYMS
config UNUSED_KSYMS_WHITELIST
string "Whitelist of symbols to keep in ksymtab"
depends on TRIM_UNUSED_KSYMS
+ default "scripts/lto-used-symbollist" if LTO_CLANG
help
By default, all unused exported symbols will be un-exported from the
build when TRIM_UNUSED_KSYMS is selected.
diff --git a/scripts/lto-used-symbollist b/scripts/lto-used-symbollist
new file mode 100644
index 000000000000..38e7bb9ebaae
--- /dev/null
+++ b/scripts/lto-used-symbollist
@@ -0,0 +1,5 @@
+memcpy
+memmove
+memset
+__stack_chk_fail
+__stack_chk_guard
--
2.29.2.576.ga3fc446d84-goog
next prev parent reply other threads:[~2020-12-11 20:29 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-11 18:46 [PATCH v9 00/16] Add support for Clang LTO Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 01/16] tracing: move function tracer options to Kconfig Sami Tolvanen
2021-02-24 20:17 ` [PATCH v9 01/16] tracing: move function tracer options to Kconfig (causing parisc build failures) Guenter Roeck
2021-02-24 20:38 ` Kees Cook
2021-02-24 20:54 ` Sami Tolvanen
2021-02-24 22:29 ` Guenter Roeck
2021-02-24 22:28 ` Guenter Roeck
2021-02-24 22:42 ` Kees Cook
2020-12-11 18:46 ` [PATCH v9 02/16] kbuild: add support for Clang LTO Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 03/16] kbuild: lto: fix module versioning Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 04/16] kbuild: lto: limit inlining Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 05/16] kbuild: lto: merge module sections Sami Tolvanen
2020-12-11 18:46 ` Sami Tolvanen [this message]
2020-12-11 19:32 ` [PATCH v9 06/16] kbuild: lto: add a default list of used symbols Kees Cook
2020-12-11 19:40 ` Sami Tolvanen
2020-12-11 19:45 ` Nick Desaulniers
2020-12-11 18:46 ` [PATCH v9 07/16] init: lto: ensure initcall ordering Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 08/16] init: lto: fix PREL32 relocations Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 09/16] PCI: Fix PREL32 relocations for LTO Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 10/16] modpost: lto: strip .lto from module names Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 11/16] scripts/mod: disable LTO for empty.c Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 12/16] efi/libstub: disable LTO Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 13/16] drivers/misc/lkdtm: disable LTO for rodata.o Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 14/16] arm64: vdso: disable LTO Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 15/16] arm64: disable recordmcount with DYNAMIC_FTRACE_WITH_REGS Sami Tolvanen
2020-12-11 18:46 ` [PATCH v9 16/16] arm64: allow LTO to be selected Sami Tolvanen
2020-12-11 19:38 ` [PATCH v9 00/16] Add support for Clang LTO Kees Cook
2021-01-09 0:27 ` Kees Cook
2021-01-09 14:54 ` Sedat Dilek
2021-01-09 15:36 ` Josh Poimboeuf
2021-01-09 15:46 ` Sedat Dilek
2021-01-09 16:07 ` Josh Poimboeuf
2021-01-09 16:21 ` Sedat Dilek
2021-01-09 16:32 ` Josh Poimboeuf
2021-01-09 16:45 ` Sedat Dilek
2021-01-09 17:03 ` Josh Poimboeuf
2021-01-09 17:05 ` Josh Poimboeuf
2021-01-09 17:33 ` Sedat Dilek
2021-01-09 23:44 ` Sedat Dilek
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