From patchwork Wed Jul 26 17:30:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jisheng Zhang X-Patchwork-Id: 13328418 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AAFB6C0015E for ; Wed, 26 Jul 2023 17:42:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=u82Sb6kFtschOPYioNon/IqBEADJW+NUf5557pdeAG8=; b=qwvfaMQF5RK3ug n0/6ggIJR0Z1b3iF5TwVxiiSmDBQw5kx6MUv5ihMdqZIMiZMLo83vtcBi5SDeZycGbaoTL1MXXiW6 ANHNDOcKTUZg0NmY7tDXaodRJtxhaaA2lq8wfb581GOirYOUuqz8KZufn51VrjZf+gtDIA5ekZa71 QS+iM26SVpBmzpDTAn8aLVuyArbVr/uaD5SYUvP3JzPp8z+fiKlkFwCzaxN55vW5zyVOHPit+GZ4r 9gP27bruwmskDISxbRMPO2ZK6CfxusP81rMalOzDDQ2cfIFC/PAmvfiWiONJMEcVzL5TdInYgfjEF 7JivpJAnRvFbxpq/92/Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qOiWb-00BCUK-2I; Wed, 26 Jul 2023 17:42:13 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qOiWU-00BCQT-26 for linux-riscv@lists.infradead.org; Wed, 26 Jul 2023 17:42:07 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id CDBF861C0A; Wed, 26 Jul 2023 17:42:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E90F2C433C7; Wed, 26 Jul 2023 17:42:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690393325; bh=FoAwbwQLJJvL1URKvVipUOgohpgmWIsUn9uEVNXhbv4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Hwi9cpkOp5qyxCKXnFW+26Vq/LNWYfZRyi9CI0m8x6q9gKxP0xKNHmKHxiN3khZdO VQKVo3IQ0913QtAp52fnxpEKeegDd7NI2ubQ9fxgGDHIUfy94gjD0Z2IV8hGPgxpVb YQaY1vexRV7F9vL3/dCQMUvaSMPUXkX/uW6+7HXBep4yEXbNYkBcaOQc5DvM5MdOrV 3WJ00MF0BwFzViuZaXZPd6dDbHSZbSOCnTwivlK/bIE6ojgjAz3rET4r2/VKhdF0E3 S/uMori21qVJjlBqjHW6hAccFsvwY0+ASlLx50f9Qt9LE811HW23GU769K4alyTT2i 7MGwzfvVI3bbQ== From: Jisheng Zhang To: Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: Andrew Jones , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/3] riscv: vdso.lds.S: remove hardcoded 0x800 .text start addr Date: Thu, 27 Jul 2023 01:30:24 +0800 Message-Id: <20230726173024.3684-4-jszhang@kernel.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230726173024.3684-1-jszhang@kernel.org> References: <20230726173024.3684-1-jszhang@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230726_104206_731330_8E5631E0 X-CRM114-Status: GOOD ( 12.37 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org I believe the hardcoded 0x800 and related comments come from the long history VDSO_TEXT_OFFSET in x86 vdso code, but commit 5b9304933730 ("x86 vDSO: generate vdso-syms.lds") and commit f6b46ebf904f ("x86 vDSO: new layout") removes the comment and hard coding for x86. Similar as x86 and other arch, riscv doesn't need the rigid layout using VDSO_TEXT_OFFSET since it "no longer matters to the kernel". so we could remove the hard coding now, and removing it brings a small vdso.so and aligns with other architectures. Also, having enough separation between data and text is important for I-cache, so similar as x86, move .note, .eh_frame_hdr, and .eh_frame between .rodata and .text. Signed-off-by: Jisheng Zhang Reviewed-by: Andrew Jones --- arch/riscv/kernel/vdso/vdso.lds.S | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/arch/riscv/kernel/vdso/vdso.lds.S b/arch/riscv/kernel/vdso/vdso.lds.S index 671aa21769bc..cbe2a179331d 100644 --- a/arch/riscv/kernel/vdso/vdso.lds.S +++ b/arch/riscv/kernel/vdso/vdso.lds.S @@ -23,12 +23,8 @@ SECTIONS .gnu.version_d : { *(.gnu.version_d) } .gnu.version_r : { *(.gnu.version_r) } - .note : { *(.note.*) } :text :note .dynamic : { *(.dynamic) } :text :dynamic - .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr - .eh_frame : { KEEP (*(.eh_frame)) } :text - .rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) *(.got.plt) *(.got) @@ -37,13 +33,16 @@ SECTIONS *(.bss .bss.* .gnu.linkonce.b.*) } + .note : { *(.note.*) } :text :note + + .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr + .eh_frame : { KEEP (*(.eh_frame)) } :text + /* - * This linker script is used both with -r and with -shared. - * For the layouts to match, we need to skip more than enough - * space for the dynamic symbol table, etc. If this amount is - * insufficient, ld -shared will error; simply increase it here. + * Text is well-separated from actual data: there's plenty of + * stuff that isn't used at runtime in between. */ - . = 0x800; + . = ALIGN(16); .text : { *(.text .text.*) } :text . = ALIGN(4);