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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=qzws6VAVgyA/bHAW4bIM+1/PEs3H7Fw9+snejeFUOZY=; b=oTt0/daYg6OwIflIOWjHfS9YSkn5Lz7DLFSDiWrco0A7yAG0ZjpK4KLUY2jCBBNN2j eIWGiypc+B/h5ZF3qJgk5OMxEXVm2AeV1dGXWQAB0mkvUkujWoSQ/JcCfGHWwjeDR6uN NWeCGBFD4GD0micYcTZOr3dFIVMtiAmIA4zE4IbtV5OkupHqaQmA09Y2BGiekA9LB8AP DkDOrorCyGGg+fBicwxo3A3L/UYUtqgrr6Lw4N5NdBRI4w0i7s/XQtUqEH18j41lC4GO LCshgOj6i4RVwq9MN5ErmyuRnSR6UikB0uyuiJIbK3azuj3XZllfSsvWcZhbTIVX3muj H1cw== X-Gm-Message-State: AOAM533Ql9tgiJFhq3I5wsX39xejfIRKtELIQPuQqI7zZYXz67QZtNUM WNTGUBY+gVwcsA69pq6AC+oSis8kNfOmNgrGB5Y= X-Google-Smtp-Source: ABdhPJyqBKHj8evcoo3MhmAmuS+y/1ePCLsQz2DyXY+1GspPP4nM4pP9zEhExeD4dZEE75tM/6sOY94GicyknkeuYRM= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:f693:9fff:fef4:1b6d]) (user=samitolvanen job=sendgmr) by 2002:a17:90a:3948:: with SMTP id n8mr5186825pjf.156.1599165081221; Thu, 03 Sep 2020 13:31:21 -0700 (PDT) Date: Thu, 3 Sep 2020 13:30:38 -0700 In-Reply-To: <20200903203053.3411268-1-samitolvanen@google.com> Message-Id: <20200903203053.3411268-14-samitolvanen@google.com> Mime-Version: 1.0 References: <20200624203200.78870-1-samitolvanen@google.com> <20200903203053.3411268-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.526.ge36021eeef-goog Subject: [PATCH v2 13/28] kbuild: lto: merge module sections From: Sami Tolvanen To: Masahiro Yamada , Will Deacon X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200903_163126_148511_0975C82B X-CRM114-Status: GOOD ( 16.35 ) X-Spam-Score: -8.2 (--------) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-8.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [2607:f8b0:4864:20:0:0:0:549 listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -7.5 USER_IN_DEF_DKIM_WL From: address is in the default DKIM white-list 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.5 DKIMWL_WL_MED DKIMwl.org - Medium sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, x86@kernel.org, Kees Cook , "Paul E. McKenney" , kernel-hardening@lists.openwall.com, Peter Zijlstra , Greg Kroah-Hartman , linux-kbuild@vger.kernel.org, Nick Desaulniers , linux-kernel@vger.kernel.org, Steven Rostedt , clang-built-linux@googlegroups.com, Sami Tolvanen , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org LLD always splits sections with LTO, which increases module sizes. This change adds a linker script that merges the split sections in the final module. Suggested-by: Nick Desaulniers Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- Makefile | 2 ++ scripts/module-lto.lds | 26 ++++++++++++++++++++++++++ 2 files changed, 28 insertions(+) create mode 100644 scripts/module-lto.lds diff --git a/Makefile b/Makefile index c69e07bd506a..bb82a4323f1d 100644 --- a/Makefile +++ b/Makefile @@ -921,6 +921,8 @@ CC_FLAGS_LTO_CLANG += -fvisibility=default # Limit inlining across translation units to reduce binary size LD_FLAGS_LTO_CLANG := -mllvm -import-instr-limit=5 KBUILD_LDFLAGS += $(LD_FLAGS_LTO_CLANG) + +KBUILD_LDS_MODULE += $(srctree)/scripts/module-lto.lds endif ifdef CONFIG_LTO diff --git a/scripts/module-lto.lds b/scripts/module-lto.lds new file mode 100644 index 000000000000..cbb11dc3639a --- /dev/null +++ b/scripts/module-lto.lds @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * With CONFIG_LTO_CLANG, LLD always enables -fdata-sections and + * -ffunction-sections, which increases the size of the final module. + * Merge the split sections in the final binary. + */ +SECTIONS { + __patchable_function_entries : { *(__patchable_function_entries) } + + .bss : { + *(.bss .bss.[0-9a-zA-Z_]*) + *(.bss..L*) + } + + .data : { + *(.data .data.[0-9a-zA-Z_]*) + *(.data..L*) + } + + .rodata : { + *(.rodata .rodata.[0-9a-zA-Z_]*) + *(.rodata..L*) + } + + .text : { *(.text .text.[0-9a-zA-Z_]*) } +}