From patchwork Tue Jul 9 15:52:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Linus Torvalds X-Patchwork-Id: 13728275 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 5EA7FC3DA41 for ; Tue, 9 Jul 2024 16:00:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0iU5zmVbhgxT4dsRxaiKfwBHkM4BLg/GO4Fb9WoHbvk=; b=Nh6ZOG7FmjAs6ywJUMnufIzbYK +x1wbxjAIg+d39rcYr/1BIy0PARDpPls9kociFuKquZRtx3OlCxT7OiCnKe2Jg9CNvVAj7GOfx1X8 AXhb+KcaEUPe8tz3YE3mXSJ6z9TF2peDtyZniavnxyj+5Zq5gpgWIF+hzwNR599BhYvA27wDtSV+G GS3Mo9q5cRkMLTxpV5ZFr3A6Xns3OGMSierYNSiUcULCWjmQLIWsBjte4Xx2mejG7I2IFTE+lQ3Yh 6GEDwlRSFU/QKlWAsRuM9h9+REoZYSJ2S+7hCeA6KmazWefCBiA3BAxhtgcATJsQFr+sH6yQ4CtD+ brwSxKPw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sRDFx-00000007pfW-3Vms; Tue, 09 Jul 2024 15:59:53 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sRDFK-00000007pUo-3DGO for linux-arm-kernel@lists.infradead.org; Tue, 09 Jul 2024 15:59:16 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 1F56861495; Tue, 9 Jul 2024 15:59:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BDFF2C3277B; Tue, 9 Jul 2024 15:59:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1720540753; bh=qEWhUwOtY4dP2oKEOdCg3gFZW6ZZXNIFIaLC2/7lZ38=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tu9CxVdlLl71f35UGAw1yqfOHP/IzhWMHe5o9gjUGh2wriwEPwA9r0fprr1gHHJzq R1GbrQqe3Ijmancms62GDovv+I2sPhfrm+VgG8+RsHWIUPuHjbEtsnr6n0sax4d+Ab 5dTGwu/I0Qx0rczI1G5OM9GKMsLijqPVP8KsAP3w= From: Linus Torvalds To: Mark Rutland Cc: Linux ARM , Linus Torvalds Subject: [PATCH 3/4] runtime constants: add x86 architecture support Date: Tue, 9 Jul 2024 08:52:37 -0700 Message-ID: <20240709155850.1034904-4-torvalds@linux-foundation.org> X-Mailer: git-send-email 2.45.1.209.gc6f12300df In-Reply-To: <20240709155850.1034904-1-torvalds@linux-foundation.org> References: <20240709155850.1034904-1-torvalds@linux-foundation.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240709_085914_956832_12468A79 X-CRM114-Status: GOOD ( 15.72 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org This implements the runtime constant infrastructure for x86, allowing the dcache d_hash() function to be generated using as a constant for hash table address followed by shift by a constant of the hash index. Signed-off-by: Linus Torvalds --- arch/x86/include/asm/runtime-const.h | 61 ++++++++++++++++++++++++++++ arch/x86/kernel/vmlinux.lds.S | 3 ++ 2 files changed, 64 insertions(+) create mode 100644 arch/x86/include/asm/runtime-const.h diff --git a/arch/x86/include/asm/runtime-const.h b/arch/x86/include/asm/runtime-const.h new file mode 100644 index 000000000000..24e3a53ca255 --- /dev/null +++ b/arch/x86/include/asm/runtime-const.h @@ -0,0 +1,61 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_RUNTIME_CONST_H +#define _ASM_RUNTIME_CONST_H + +#define runtime_const_ptr(sym) ({ \ + typeof(sym) __ret; \ + asm_inline("mov %1,%0\n1:\n" \ + ".pushsection runtime_ptr_" #sym ",\"a\"\n\t" \ + ".long 1b - %c2 - .\n\t" \ + ".popsection" \ + :"=r" (__ret) \ + :"i" ((unsigned long)0x0123456789abcdefull), \ + "i" (sizeof(long))); \ + __ret; }) + +// The 'typeof' will create at _least_ a 32-bit type, but +// will happily also take a bigger type and the 'shrl' will +// clear the upper bits +#define runtime_const_shift_right_32(val, sym) ({ \ + typeof(0u+(val)) __ret = (val); \ + asm_inline("shrl $12,%k0\n1:\n" \ + ".pushsection runtime_shift_" #sym ",\"a\"\n\t" \ + ".long 1b - 1 - .\n\t" \ + ".popsection" \ + :"+r" (__ret)); \ + __ret; }) + +#define runtime_const_init(type, sym) do { \ + extern s32 __start_runtime_##type##_##sym[]; \ + extern s32 __stop_runtime_##type##_##sym[]; \ + runtime_const_fixup(__runtime_fixup_##type, \ + (unsigned long)(sym), \ + __start_runtime_##type##_##sym, \ + __stop_runtime_##type##_##sym); \ +} while (0) + +/* + * The text patching is trivial - you can only do this at init time, + * when the text section hasn't been marked RO, and before the text + * has ever been executed. + */ +static inline void __runtime_fixup_ptr(void *where, unsigned long val) +{ + *(unsigned long *)where = val; +} + +static inline void __runtime_fixup_shift(void *where, unsigned long val) +{ + *(unsigned char *)where = val; +} + +static inline void runtime_const_fixup(void (*fn)(void *, unsigned long), + unsigned long val, s32 *start, s32 *end) +{ + while (start < end) { + fn(*start + (void *)start, val); + start++; + } +} + +#endif diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 3509afc6a672..6e73403e874f 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -357,6 +357,9 @@ SECTIONS PERCPU_SECTION(INTERNODE_CACHE_BYTES) #endif + RUNTIME_CONST(shift, d_hash_shift) + RUNTIME_CONST(ptr, dentry_hashtable) + . = ALIGN(PAGE_SIZE); /* freed after init ends here */