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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=IM6BeG4IsHqc2HlM1gNMjcO8xaf7Yq/XvaXPBJbuDVo=; b=oLjSYYRSWiPjObfaunaiYitFZFsiaRIRw6C/2L3t1fjVo8OeCTUe+4bXyKrK3V3lPI YFdc9usX/GIt2ecMe5ojmxK6P3vkEwuuevEi8XcFN65CEVc07XKulGg07X53T5/NN+Bn CPFKhL9lztnRtQhtFBu1F2LDEe6fy3lXY0vmu0TBcNpXz8r2V5CIWzTUMb3OXDJs0RKa GIjAgp0Y4J3hyFkbWmtat8sFM4pH0ZV5pgJ5iMF84C/1QsqzZn06Vsr5OKwl3fDzGLdc g01p37mgx7M2Nv3e3c9/ccHGIme6IT2B8fNycaLR/a3mdf3ulCdC9OcJKJpnQCRSvaDr d3wA== X-Gm-Message-State: AOAM530khCZTeoli5nIc9Ks0n5ozv+pVR2eMpeOurOWlhd+eAphXGgcC Ly3qSMOKdCrcQiKEH4ZsxeUJpYKQhulAF5IcWBU= X-Google-Smtp-Source: ABdhPJwNKfL9Sa5Ulz2e3Crqy4KfEW60CIVw40VTunkPV2+OV55f90wO4GzRLD40XF/w621iqWtNnOlUAz7CC7ffa0E= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:f693:9fff:fef4:1b6d]) (user=samitolvanen job=sendgmr) by 2002:ad4:5565:: with SMTP id w5mr6385766qvy.24.1601416026659; Tue, 29 Sep 2020 14:47:06 -0700 (PDT) Date: Tue, 29 Sep 2020 14:46:17 -0700 In-Reply-To: <20200929214631.3516445-1-samitolvanen@google.com> Message-Id: <20200929214631.3516445-16-samitolvanen@google.com> Mime-Version: 1.0 References: <20200929214631.3516445-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.709.gb0816b6eb0-goog Subject: [PATCH v4 15/29] kbuild: lto: merge module sections From: Sami Tolvanen To: Masahiro Yamada , Will Deacon , Steven Rostedt X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200929_174711_147804_EADA2E25 X-CRM114-Status: GOOD ( 12.76 ) 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:f8b0:4864:20:0:0:0:84a 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_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's 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 trust 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, 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 linker script rules to merge the split sections in the final module. Suggested-by: Nick Desaulniers Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- scripts/module.lds.S | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 69b9b71a6a47..037120173a22 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -25,5 +25,33 @@ SECTIONS { __jump_table 0 : ALIGN(8) { KEEP(*(__jump_table)) } } +#ifdef CONFIG_LTO_CLANG +/* + * 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_]*) } +} +#endif + /* bring in arch-specific sections */ #include