From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3716BC43331 for ; Tue, 24 Mar 2020 14:25:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0A7EB2080C for ; Tue, 24 Mar 2020 14:25:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="2yf+DNRc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728764AbgCXOZd (ORCPT ); Tue, 24 Mar 2020 10:25:33 -0400 Received: from merlin.infradead.org ([205.233.59.134]:53626 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728414AbgCXOYw (ORCPT ); Tue, 24 Mar 2020 10:24:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-Id:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=3t6eU71lRjUzrJDVhnXtMZVERuAG0gMD+7bjUByhvLs=; b=2yf+DNRcDJmrd2cHCiHGWbJTpe 3NONZ8IUGCOtgAuKtV8RIMIFP/PjwwiksrWV58SP17dzTKLm5lZ20Kch/OtE9mPgr0zG2v+L2zIzm /Q8GkLwj5ZD8vqCBhW7KeKfzBUJJV5CEqU1eX930lSZC4KbDZLZFB3fEGbogTiYDS/fsliae2pdAr l1vce9wXj9d7H2ODoirZSgdNkn33HaAIK5uju+ogUOk1JlrRUJxX1zyTmGlp3z2fu8aUKJca83Gh1 wwF8tDkTmC5FSXp/6r+49b1UXp1GEQfVSGkPFflnoYEFT+bJ1Dlq7PDY3CQ15R9rpSFNjwNk39F+B XDL+09DQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jGkTv-0003om-3S; Tue, 24 Mar 2020 14:24:39 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 7A6B030794D; Tue, 24 Mar 2020 15:24:35 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 14498286C13B6; Tue, 24 Mar 2020 15:24:35 +0100 (CET) Message-Id: <20200324142245.819003994@infradead.org> User-Agent: quilt/0.65 Date: Tue, 24 Mar 2020 14:56:12 +0100 From: Peter Zijlstra To: x86@kernel.org Cc: peterz@infradead.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com, torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, namit@vmware.com, hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com Subject: [RESEND][PATCH v3 09/17] x86/static_call: Add out-of-line static call implementation References: <20200324135603.483964896@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add the x86 out-of-line static call implementation. For each key, a permanent trampoline is created which is the destination for all static calls for the given key. The trampoline has a direct jump which gets patched by static_call_update() when the destination function changes. Signed-off-by: Josh Poimboeuf [peterz: fixed trampoline, rewrote patching code] Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/Kconfig | 1 + arch/x86/include/asm/static_call.h | 22 ++++++++++++++++++++++ arch/x86/kernel/Makefile | 1 + arch/x86/kernel/static_call.c | 31 +++++++++++++++++++++++++++++++ 4 files changed, 55 insertions(+) create mode 100644 arch/x86/include/asm/static_call.h create mode 100644 arch/x86/kernel/static_call.c --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -205,6 +205,7 @@ config X86 select HAVE_FUNCTION_ARG_ACCESS_API select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR select HAVE_STACK_VALIDATION if X86_64 + select HAVE_STATIC_CALL select HAVE_RSEQ select HAVE_SYSCALL_TRACEPOINTS select HAVE_UNSTABLE_SCHED_CLOCK --- /dev/null +++ b/arch/x86/include/asm/static_call.h @@ -0,0 +1,22 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_STATIC_CALL_H +#define _ASM_STATIC_CALL_H + +#include + +/* + * For CONFIG_HAVE_STATIC_CALL, this is a permanent trampoline which + * does a direct jump to the function. The direct jump gets patched by + * static_call_update(). + */ +#define ARCH_DEFINE_STATIC_CALL_TRAMP(name, func) \ + asm(".pushsection .text, \"ax\" \n" \ + ".align 4 \n" \ + ".globl " STATIC_CALL_TRAMP_STR(name) " \n" \ + STATIC_CALL_TRAMP_STR(name) ": \n" \ + " jmp.d32 " #func " \n" \ + ".type " STATIC_CALL_TRAMP_STR(name) ", @function \n" \ + ".size " STATIC_CALL_TRAMP_STR(name) ", . - " STATIC_CALL_TRAMP_STR(name) " \n" \ + ".popsection \n") + +#endif /* _ASM_STATIC_CALL_H */ --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -63,6 +63,7 @@ obj-y += tsc.o tsc_msr.o io_delay.o rt obj-y += pci-iommu_table.o obj-y += resource.o obj-y += irqflags.o +obj-y += static_call.o obj-y += process.o obj-y += fpu/ --- /dev/null +++ b/arch/x86/kernel/static_call.c @@ -0,0 +1,31 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include + +static void __static_call_transform(void *insn, u8 opcode, void *func) +{ + const void *code = text_gen_insn(opcode, (long)insn, (long)func); + + if (WARN_ONCE(*(u8 *)insn != opcode, + "unexpected static call insn opcode 0x%x at %pS\n", + opcode, insn)) + return; + + if (memcmp(insn, code, CALL_INSN_SIZE) == 0) + return; + + text_poke_bp(insn, code, CALL_INSN_SIZE, NULL); +} + +void arch_static_call_transform(void *site, void *tramp, void *func) +{ + mutex_lock(&text_mutex); + + if (tramp) + __static_call_transform(tramp, JMP32_INSN_OPCODE, func); + + mutex_unlock(&text_mutex); +} +EXPORT_SYMBOL_GPL(arch_static_call_transform);